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(11) | EP 1 431 410 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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Free cutting alloy Automatenlegierung Alliage de décolletage |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
Background Art
[0002] Alloy has widespread applications because of a variety of characteristics thereof. A free cutting alloy excellent in machinability is, in a case, selected for improvement of productivity. In order to improve machinability, for example, free cutting alloy containing an element improving machinability such as S, Pb, Se or Bi (hereinafter referred to as machinability-improving element) is widely used. Especially in a case where machinability is particularly required because of precise finishing in machining or for other reasons, not only is a content of such a machinability improving element increased in an alloy, but the elements are also added to an alloy in combination.
[0003] While S, which has widely been used for improvement of machinability, is in many cases added in the form of MnS, addition thereof in an alloy in a large content causes for degrading corrosion resistivity, hot workability and cold workability of the alloy. Moreover, when the alloy is exposed to the air, a sulfur component included in the alloy is released into the air in the form of a sulfur containing gas, which causes sulfur contamination in peripheral areas of parts with ease. Therefore, there arises a necessity of suppressing release of sulfur containing gas (hereinafter referred to as improvement on out-gas resistivity). Elements such as S, Se and Te, however, deteriorate magnetic properties to a great extent in an electromagnetic stainless steel and the like.
[0004] Therefore, various proposals have been made: a Mn content is limited, a Cr content in sulfide is increased or in a case where S is contained, Ti is added in combination with S in order to disperse sulfide in the shape of a sphere (for example, see JP-A-98-46292 or JP-A-81-16653). To increase a Cr content in sulfide, however, tends to greatly decrease, in machinability and hot workability and therefore, such a alloy has been restricted on its application in many cases.
[0005] R. Kiessling et al. "Non metallic inclusions in steel". 1978 relates to sulphide inclusions in steel.
[0006] GB 1 519 313 relates to a stainless steel alloy and to a ferritic free-machining steel having an excellent machinability and a high corrosion resistance.
[0007] Free cutting stainless steels are mentioned in JP-A-10-130794, JP-A-11-140597 (US-A-6033625), JP-A-63-093843 or in US-A-4705581 wherein sulphides or selenides and or telurides are used.
[0008] It is accordingly an object of the present invention is to provide free cutting alloy excellent in machinability, showing outstanding characteristics as an alloy such as corrosion resistivity, hot workability and cold workability or specific magnetic characteristics, which are comparable to those of conventional alloys.
Summary of the Invention
[0009] In order to achieve the above described object, a free cutting alloy of the present invention is characterized by the free cutting alloy of claims 1 to 4. "(Ti,Zr)" means one or two of Ti and Zr.
[0010] Machinability of an alloy can be improved by forming the above described (Ti, Zr) based compound in a matrix metal phase of the alloy. Furthermore, by forming this compound in the alloy, formation of compounds such as MnS and (Mn,Cr)S, easy to reduce corrosion resistivity and hot workability of the alloy, can be prevented or suppressed, thereby enabling corrosion resistivity, hot workability and cold workability to be retained at good levels. That is, according to the present invention, a free cutting alloy excellent in machinability can be realized without any degradation in useful characteristics as an alloy such as hardness, corrosion resistivity, hot workability, cold workability and specific magnetic characteristics.
[0011] Further, a (Ti,Zr) based compound formed in a free cutting alloy of the present invention is dispersed in the alloy structure. Machinability of an alloy can be further increased especially by dispersing the compound in an alloy structure. In order to increase the effect, a particle size of the (Ti,Zr) based compound as observed in the structure of a polished section of the alloy is preferably, for example, approximately in the range of 0.1 to 30 µm on the average and further, an area ratio of the compound in the structure is preferably in the range of 1 to 20 %, wherein the particle size is defined by the maximum distance between two parallel lines circumscribing a particle in observation when parallel lines are drawn intersecting on a region including the particle in observation while changing a direction of the parallel lines.
[0012] The above described (Ti,Zr) based alloy can include at least a compound expressed in a composition formula (Ti,Zr)4(S,Se,Te)2C2 (hereinafter also referred to as carbo-sulfide/selenide), wherein one or more of Ti and Zr may be included in the compound and one or more of S, Se and Te may be included in the compound. By forming a compound in the form of the above described composition formula, not only can machinability of an alloy be improved, but corrosion resistivity is also improved.
[0013] It should be appreciated that identification of a (Ti,Zr) based compound in an alloy can be performed by X-ray diffraction (for example, a diffractometer method), an electron probe microanalysis method (EPMA) and the like technique. For example, the presence or absence of the compound of (Ti,Zr)4(S,Se,Te)2C2 can be confirmed according to whether or not a peak corresponding to the compound appear in a diffraction chart measured by an X-ray diffractometer. Further, a region in the alloy structure in which the compound is formed can also be specified by comparison between two-dimensional mapping results on characteristic X-ray intensities of Ti, Zr, S, Se or C obtained from a surface analysis by EPMA conducted on a section structure of the alloy.
Brief Description of the Drawings
[0014]
Fig. 1 is a graph showing compositional regions in combination of a content of one or more of Ti and Zr, a content of C and a content of one or more of S, Se and Te in a free cutting alloy of the present invention constituted as electromagnetic stainless alloy;
Fig. 2 is a graph showing an example of Schaeffler diagram;
Fig. 3 is a graph showing a relation between B1 or Hc and α in Example 1
Fig. 4 is a graph showing a relation between a boring time or a cracking threshold working ratio and α in Example 1.
Fig. 5 is a graph showing a relation between a pitting potential (Vc) and α in Example 1;
Fig. 6 is a graph showing dependencies of solubility products on temperature of components of TiO, TiN, Ti4C2S2, TiC, TiS and CrS in γ-Fe;
Preferred Embodiments of the Invention
[0015] The present invention, to be concrete, can be preferably applied on an alloy constituted as stainless steel. In this case, in order to form a (Ti,Zr) based compound without any degradation in characteristics as stainless steel, such an alloy preferably contains one or more of Ti and Zr such that WTi + 0.52 WZr = 0.05 to 0.5 mass %, wherein WTi and Wzr denote respective contents in mass % of Ti and Zr; and one or more of S, Se and Te. Reference is made to Formulae 1 and 2 in claim 1.
[0016] Ti and Zr are indispensable elements for forming a (Ti,Zr) based compound playing a central role in exerting the effect of improving machinability of a free cutting alloy of the present invention. The above effect exerted when Ti and Zr are added into an alloy is determined by the sum of the numbers of atoms (or the sum of the numbers of values in mol), regardless of kinds of metals, Ti or Zr. Since a ratio between atomic weights is almost 1 : 0.52, Ti of a smaller atomic weight exerts a larger effect with a smaller mass. Thus, a value of WTi + 0.52 Wzr is said to be compositional parameter reflects the sum of the numbers of atoms of Zr and Ti included in an alloy.
[0017] While the composition as stainless steel of the present invention is described above, machinability as an alloy is required also in an electromagnetic alloy used as a functional material. Although electromagnetic alloys are in many cases poor machinability, not only corrosion resistivity and cold workability but also electromagnetic characteristics were in cases deteriorated when machinability-improving elements such as S and Pb were added for improvement on machinability. Moreover, since characteristics of the alloy are largely changed by subtle shifts in balances between constituting elements, it has been difficult that machinability is improved while retaining excellent electromagnetic characteristics. According to the present invention, an effect of improving machinability can be achieved while the characteristics in the electromagnetic alloy is maintained.
[0018] To be concrete, the present invention can be preferably used as an electromagnetic alloy (hereinafter referred to as a fourth selection invention). The present inventors have acquired the following findings and completed the fourth selection invention based thereon: When in ferritic electromagnetic alloy, one or more of Ti and Zr, C, and one or more of S, Se and Te are added in combination, the components are in combinations of the specific contents: a content of one or more of Ti and Zr is in the range of 0.05 to 0.5 mass % in terms of Ti %+ 0.52 Zr % (which is indicated by X); a content of C is in the ranges of 0.02X to 0.06 X mass %, 0.19 X to 0.26 X mass % or 0.02 X to 0.26 X; and a content of one or more of S, Se and Te is in the ranges of (Z - 0.07)X to (Z + 0.07)X mass %, (Z + 0.07)X to (Z + 0.45)X mass %, or (Z + 0.45) X to (Z + 0.70)X mass %, wherein S% + 0.41 Se % + 0.25 Te % is indicated by Y, and thereby machinability can be improved while soft magnetic characteristics, cold workability and corrosion resistivity are controlled in good states. In description of the fourth selection invention, expression of a element symbol with % following such as Ti %, Zr %, S %, Se %, Te % or C % means a content in mass % of a corresponding component indicated by the element symbol C/X and C %/X in the following description are the same in meaning.
[0019] That is, the fourth selection invention of the present invention constituted as the electromagnetic stainless steel contains: 0.01 to 3 mass % Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % Al; one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of X of the following formula 1; C in the range of 0.02 X to 0.06 X mass % (C/X = 0.02 to 0.06) or 0.19 X to 0.26 X mass % (C/X = 0.19 to 0.26), wherein X is expressed by the following formula 1; one or more of S, Se and Te in the range of (Z - 0.07)X to (Z + 0.07)X mass %, wherein X; Z and Y are values of the respective following formulae 1, 3 and 2, furthermore, according to a necessity contains one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V and still further according to a necessity contains one or more of Pb, B and REM in the respective contents of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM; and the balance being Fe and inevitable impurities:
and
[0020] A free cutting alloy relating to the fourth selection invention contains: 0.01 to 3 mass %, Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % Al; one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of X of the following formula 1; C in the range of 0.02 X to 0.26 X mass % (C/X = 0.02 to 0.26) wherein X is expressed by the following formula 1; one or more of S, Se and Te in the range of (Z + 0.07)X to (Z + 0.45)X mass %, wherein X, Z and Y are values of the respective following formulae 1, 3 and 2, further according to a necessity contains one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V and still further according to a necessity contains one or more of Pb, B and REM in respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM; and the balance being Fe and inevitable impurities.
[0021] A free cutting alloy relating to the fourth selection invention contains: 0.01 to 3 mass % Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % At one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of X of the following formula 1; C in the range of 0.02 X to 0.26 X mass % when X is expressed by the following formula 1; one or more of S, Se and Te in the range of (Z + 0.45)X to (Z + 0.70)X mass % when X, Z and Y are indicated by the respective following formulae 1, 3 and 2, and further according to a necessity contains one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in contents of 2 mass % or lower Ni; 2 mass % or lower Cu; 2 mass % or lower Mo; 1 mass % or lower Nb; 1 mass % or lower V; and the balance being Fe and inevitable impurities.
[0022] Further detailed description will be given of the free cutting alloy relating to the fourth selection invention as follows: The composition is specified, by a combination of a content of one or more of Ti and Zr, a content of C and a content of one or more of S, Se and Te, which are mainly included in the ferritic stainless steel; in addition to one or more of Ti and Zr, C and one or more of S, Se and Te, contains: 0.01 to 3 mass % Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % Al, further according to a necessity contains one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V and still further according to a necessity contains one or more of Pb, B and REM in the respective contents of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM; and the balance being Fe and inevitable impurities.
[0023] Combinations of a content of one or more of Ti and Zr, a content of C, and a content of one or more of S, Se and Te are combination of one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of Ti % + 0.52 Zr % (which is indicated by X); C in the range of 0.02 X to 0.06 X mass % (C/X = 0.02 to 0.06), 0.19 X to 0.26 X mass % (C/X = 0.19 to 0.26) or 0.02 X to 0.26 X mass % (C/X = 0.02 to 0.26); and one or more of S, Se and Te in the range of (Z - 0.07)X to (Z + 0.07)X mass % ((Z - 0.07) ≤ Y/X ≤ (Z + 0.07)), (Z + 0.07)X to (Z + 0.45)X mass % ( (Z + 0.07) < Y/X ≤ (Z + 0.45)), or (Z + 0.45)X to (Z + 0.70)X mass % ((Z + 0.45) < Y/X ≤ (Z + 0.70)).
[0024] Next, the combinations of the ranges in content are described with reference to a graph shown in Fig. 1, where the abscissa is used for plotting C/X and the ordinate is used for plotting Y/X. A first combination of a content of one or more of Ti and Zr; a content of C and a content of one or more of S, Se and Te is a region enclosed by a straight line perpendicular to the abscissa passing through a position of C/X = 0.02, a straight line perpendicular to the abscissa passing through a position of C/X = 0.06, and curves of Y/X = 32 (C/X - 0.125)2 - 0.07 and Y/X = 32 (C/X - 0.125)2 + 0.07, wherein the formulae of Y/X = 32 (C/X - 0.125)2 - 0.07 and Y/X = 32 (C/X- 0.125)2 + 0.07 are obtained by substituting Z = 32(C/X- 0.125)2 into the above described (Z - 0.07)≤ Y/X ≤ (Z + 0.07), that is Y/X = (Z - 0.07) to (Z + 0.07). Further, a broken line in Fig. 1, Y/X = 32(C/X - 0.125)2 is a curve circumscribed by the C/X axis (a value on the Y/X axis = 0) and a in Fig. 1 is defined by a formula Y/X - 32(C/X - 0.125)2 = α. Further, a mark O with a number in Fig. 1-indicates a specimen No. of fourth selection inventive steel of the present invention of Example 1 and a mark ▲ indicates a specimen No. of an inventive steel of Example 1.
[0025] A second combination of a content of one or more of Ti and Zr; a content of C and one or more of S, Se and Te is a region enclosed by a straight line perpendicular to the abscissa passing through a position of C/X = 0.19, a straight line perpendicular to the abscissa passing through a position of C/X = 0.26, and curves of Y/X = 32 (C/X - 0.125)2 0.07 and Y/X = 32 (C/X- 0.125)2 + 0.07 in Fig. 1. A third combination of a content of one or more of Ti and Zr; a content of C and one or more of S, Se and Te is a region enclosed by a straight line perpendicular to the abscissa passing through a position of C/X = 0.02, a straight line perpendicular to the abscissa passing through a position of C/X = 0.26, and curves of Y/X = 32 (C/X - 0.125)2 + 0.07 and Y/X = 32 (C/X - 0.125)2 + 0.45 in Fig. 1.
[0026] A fourth combination of a content of one or more of Ti and Zr; a content of C and one or more of S, Se and Te is a region enclosed by a straight line perpendicular to the abscissa passing through a position of CB = 0.02, a straight line perpendicular to the abscissa passing through a position of C/X = 6.26, and curves of Y/X = 32 (C/X - 0.125)2 + 0.45 and Y/X = 32 (C/X - 0.125)2 + 0.70 in Fig. 1. Next, description will be given of the reason why the elements and contents thereof are selected of a free cutting alloy relating to the fourth selection invention as follows:
(1) 0.01 to 3 mass % Si
[0027] Si is useful not only as a deoxidizing agent, but also for contributing to increase in the maximum magnetic permeability and reduction in coercive force among soft magnetic characteristics as an electromagnetic stainless steel and furthermore, useful for increase in electric resistivity and improvement on responsibility in a high-frequency band, and therefore, Si is added for the purposes. While a Si content is necessary to be 0.01 % or higher in order to attain the effect, since when the content is excessive high, hardness increases and cold workability is degraded, the content is reduced when cold workability is regarded as a more important characteristic and intended increases in the soft magnetic characteristics and a high-frequency responsibility are compensated mainly by addition of Al, described later, corresponding to decrease in Si content. However, when machinability is regarded as an important characteristics, the upper limit of the Si content is set to 3 mass %.
(2) 2 mass % or lower Mn
[0028] Mn is an element useful as a deoxidizing agent, but since when a Mn content exceeds 2 mass %, soft magnetic characteristics are degraded, the Mn content is set to 2 mass % or lower.
(3) 5 to 25 mass % Cr
[0029] Cr is useful for improvement on corrosion resistivity and electric resistivity of steel, but for improvement on machinability by forming Cr(S,Se,Te) with S, Se and Te, which will be described later. Therefore, Cr is added for the improvements. Although it is necessary for Cr to be included in the range of 5 mass % or higher, the Cr content in excess of 25 mass % reduces cold workability and accordingly, the Cr content is set to 5 to 25 mass %.
(4) 0.01. to 5 mass % Al
[0030] A1 is useful not only as a deoxidizing agent, but for contributing increase in the maximum magnetic permeability and reduction in coercive force and furthermore, useful for increase in electric resistivity and improvement on responsibility in a high-frequency band, similar to Si. Therefore, Al is included for the improvements. Although it is necessary for Al to be included exceeding 0.01 mass % in order to exert the effects, not only a specific refining method is required but cold workability is also degraded when an Al content exceeds 5 mass % and accordingly, the Al content is set to from 0.01 to 5 mass %.
(5) One or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of Ti % + 0.52 Zr%=X
[0031] Ti and Zr forms (Ti,Zr)4C2(S,Se,Te)2 and/or (Ti,Zr)(S,Se,Te) in co-existence with C, S, Se and Te to contribute to increase in machinability and since among the two, (Ti,Zr)4C2(S,Se,Te)2 especially deteriorates neither soft magnetic characteristics nor corrosion resistivity and contributes to improvement on machinability without any loss of cold workability, due to fine dispersion thereof, the elements are therefore added for the improvements. Although the content of the elements singly or in combination is required to be 0.05 mass % of higher in terms of X in order to exert the effects, the soft magnetic characteristics are degraded when the content in terms of X exceeds 0.5 mass % and accordingly, the content is set to the range of 0.05 to 0.5 mass % in terms of X.
(6) C in the range of 0.02 X to 0.06 X mass %, 0.19 X to 0.26 X mass % or 0.02 X to 0.26 X mass %
[0032] The reason why a C content is set to 0.02 X to 0.06 X mass % (0.02 ≤ C/X ≤ 0.06) or 0.19 X to 0.26 X mass % (0.19 ≤ C/X ≤ 0.26), wherein |α| ≤ 0.07, |α| being the absolute value of α and this applying hereinafter, and α =Y/X- 32(C/X- 0.125)2 (see Fig. 1), is that with such compositions adopted, in an electromagnetic stainless steel, soft magnetic characteristics and cold workability are especially excellent, machinability is also good due to dispersion in a fine particle state of (Ti,Zr)4C2(S,Se,Te)2 and (Ti,Zr)(S,Se,Te), the latter of which is formed in a small amount, and further, corrosion resistivity is also good, wherein (Ti,Zr)4C2(S,Se,Te)2 has a little effect to degrade the soft magnetic characteristics. Excellence in the soft magnetic characteristics in the region of this α is because of extremely low level of the presence of (Ti,Zr)C, (Ti,Zr)(S,Se,Te) and Mn(S,Se,Te).
[0033] In the content range of C of C/X < 0.02 (C < 0.02X mass %) and 0.06 < C/X < 0.19 (a C content exceeds 0.06 X mass % and less than 0.19 X mass %), formation of (Ti,Zr)4C2(S,Se,Te)2 is excessively small in amount, which exerts the effect at a poor level but in the content range of C of C/X > 0.26 (C > 0.26X mass.%), (Ti,Zr)C increases and thereby, the soft magnetic characteristics, cold workability and corrosion resistivity are degraded on the contrary, and accordingly, the C content is limited to the ranges of 0.02 ≤ C/X ≤ 0.06 (0.02 X to 0.06 X mass %) or 0.19 ≤ C/X ≤ 0.26 (0.19 X to 0.26 X mass %).
[0034] Moreover, the reason why the C content is set to the compositional range of 0.02 X to 0.26 X mass % (0.02 ≤ C/X ≤ 0.26), wherein 0.07 < α ≤ 0.45, is that electromagnetic stainless steel with good machinability, good soft magnetic characteristics and good cold workability can be attained by formation of (Ti,Zr)4C2(S,Se,Te)2 and (Ti,Zr)(S,Se,Te) excellent in corrosion resistivity, in a slightly increased amount. However, in the range of C < 0.02 X mass % (C/X < 0.02), the soft magnetic characteristics are degraded due to decrease in formation of (Ti,Zr)4C2(S,Se,Te)2 and increase in (Ti,Zr)(S,Se,Te) and in the range of C > 0.26 X (C/X > 0.26), the soft magnetic characteristics, cold workability and corrosion resistivity are deteriorated due to increase in (Ti,Zr)C. Accordingly, the C content range is limited to C = 0.02 X to 0.26 X mass % (0.02 ≤ C/X ≤ 0.26).
[0035] Further, the reason why the ranges of a C content are set to compositional range of 0.02 X to 0.26 X mass % (0.02 ≤ C/X ≤ 0.26), wherein 0.45 ≤ α ≤ 0.70, is that because of increase in (Ti,Zr)S, Cr(S,Se,Te) and Mn(S,Se,Te), electromagnetic stainless steel can be obtained with machinability especially excellent, corrosion resistivity and soft magnetic characteristics are at practical levels, though cold workability with a high working ratio is hard to be attained. However, in the compositional range of α > 0.70 and C < 0.02 X mass % (C/X < 0.02), the soft magnetic characteristics and corrosion resistivity are largely degraded due to increase in (Ti,Zr)S, Cr(S,Se,Te) and Mn(S,Se,Te), further in the compositional range of C > 0.26X mass % (C/X > 0.26), decreases in the soft magnetic characteristics and in corrosion resistivity are large due to increase in (Ti,Zr) C and accordingly, the C content is limited to C = 0.02 X to 0.26X mass % (0.02 ≤ C/X ≤ 0.26), wherein 0.45 ≤ α ≤ 0.70.
[0036] One or more of S, Se and Te is in the ranges of (Z - 0.07)X to (Z + 0.07)X mass %, (Z + 0.07)X to (Z + 0.45)X mass %, or (Z + 0.45) X to (Z + 0.70)X mass %, wherein Y = S% + 0.41 Se % + 0.25 Te % is indicated by Y and Z = 32(C/X - 0.125)2.
In a case where Y is in the range of (Z - 0.07)X to (Z+ 0.0.7)X mass %
The reason why Y is set to (Z - 0.07)X to (Z + 0.07)X mass % (- 0.07 ≤ α ≤ 0.07) and C is set to 0.02 X to 0.06 X mass % (0.02 ≤ C/X ≤ 0.06) or 0.19 X to 026 X mass % (0.19 ≤ C/X ≤ 0.26) is that in electromagnetic stainless steel of the composition, the soft magnetic characteristics and cold workability are especially excellent, machinability is good due to dispersion in a fine state of (Ti,Zr)4C2(S,Se,Te)2 and (Ti,Zr)(S,Se,Te), the latter of which is formed at a small amount, and moreover, corrosion resistivity is good as well. However, when Y is lower than (Z - 0.07)X %, that is when Y/X is lower than 32(C/X - 0.125)2 - 0.07, formation of (Ti,Zr)4C2(S,Se,Te)2 is excessively small in amount and thereby the effect thereof is poor, while Y is higher than (Z + 0.07)X mass %, that is when Y/X is higher than 32(C/X - 0.125)2 + 0.07, the soft magnetic characteristics, cold workability and corrosion resistivity are degraded on the contrary and therefore, Y is set in the range (Z - 0.07)X to (Z + 0.07)X mass %.
Y in the range of (Z + 0.07)X to (Z + 0.45)X mass %
[0037] The reason why Y is set in the range of (Z + 0.07)X to (Z + 0.45)X mass % (0.07 α ≤ 0.45) and C is set in the range of 0.02X to 0.26X mass % (0.02 ≤ C/X ≤ 0.26) is that in electromagnetic stainless steel with the composition, there are realized excellent corrosion resistivity and machinability better than when Y is in the range of (Z - 0.07)X to (Z + 0.07)X mass % and in addition, good soft magnetic characteristics and good cold workability due to formation of (Ti,Zr)4C2(S,Se,Te)2 and (Ti,Zr)(S,Se,Te), slightly increased in amount. However, when Y is higher than (Z + 0.45)X mass %, that is when Y/X is higher than 32(C/X - 0.125)2 + 0.45, machinability is more excellent due to increase in (Ti,Zr)S, Cr(S,Se,Te) and Mn(S,Se,Te) while cold workability, corrosion resistivity and soft magnetic characteristics are degraded and therefore, Y is set in the range of (Z + 0.07)X to (Z + 0.45)X mass %.
Y in the range of (Z + 0.45)X to (Z + 0.70)X mass %
[0038] The reason why Y is set in the compositional range of (Z + 0.45)X to (Z + 0.70)X mass % . (0.45 . α ≤ 0.70) and C is set in the range of 0.02X to 0.26X mass % (0.02 ≤ C/X ≤ 0.26) is that in electromagnetic stainless steel with the composition, electromagnetic stainless steel can be obtained with especially excellent machinability, corrosion resistivity and soft magnetic characteristics thereof are at practical levels due to increase in (Ti,Zr)S, Cr(S,Se,Te) and Mn(S,Se,Te), though cold workability with a high working ratio is hard to be attained. However, when Y is set higher than(Z + 0.70)X mass %, that is when Y/X is set higher than 32(C/X - 0.125)2 + 0.70, machinability is further excellent due to increase in (Ti,Zr)S, Cr(S,Se,Te) and Mn(S,Se,Te), while since cold workability, corrosion resistivity and soft magnetic characteristics decrease lower than a level of practicability, Y is set in the range of (Z + 0.45)X to (Z + 0.70)X mass %.
2 mass % or lower Ni, 2 mass % or lower Cu, 2 mass % or lower Mo, 1mass % or lower Nb and 1 mass % or lower V
[0039] Ni: Cu, Mo, Nb and V are all useful for more of improvement on corrosion resistivity in a free cutting alloy relating to the fourth selection invention and therefore, the elements are included in the electromagnetic stainless steeL However, when the elements are added in excess of the respective upper limits, soft magnetic characteristics and cold workability are deteriorated. Accordingly, the contents are set as described above.
0.15 mass % or lower Pb; 0.01 mass % or lower B; and 0.1 mass % or lower REM
[0040] Pb is an element included for more of improvement on machinability and since the effect of improving machinability more than in a conventional case can be exerted with a Pb content a half that in the conventional case, the Pb content is set to 0.15 mass % or lower.
[0041] Since B and REM are elements useful for improving cold workability more in a steel of a free cutting alloy relating to the fourth selection invention, the elements are added in the steel However, when the contents exceed the respective above described upper limits, hot and cold workabilities decrease and accordingly, the contents are set as described above. As for REM, since low radioactivity elements are easy to be handled when being mainly used and from this viewpoint, it is useful to use one or more selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. It is desirable to use light rare earth elements, especially La or Ce from the viewpoint of conspicuous exertion of the effect and price. However, there arises no trouble in mixing in of a trace of radioactive rare earth elements such as Th and U inevitably remaining in a process to separate rare earth elements. Further, from the viewpoint of reduction in raw material cost, there can be used not-separated rare earth elements such as mish metal and didymium.
[0042] Description will be given of a production method for free cutting alloy relating to the fourth selection invention constituted as electromagnetic stainless steel as follows: Free cutting alloy relating to the fourth selection invention has a composition with a content of one or more of Ti and Zr, a content of C and a content of one or more of S, Se and Te, the elements being included in conventional electromagnetic stainless steel, wherein the contents are individually specified and the elements in combinations of the contents are included in the alloy and therefore, electromagnetic stainless steel of the fourth selection invention can be produced by a production method similar to a conventional production method for electromagnetic stainless steel.
Examples
[0043] The following experiments were performed in order to confirm the effects of the present invention. It should be appreciated that in the following description, test alloy relating to the present invention is referred to as inventive steel or inventive alloy, or as a selection inventive steel or a selection inventive alloy.
Example 1 Electromagnetic stainless steel
[0044] The following experiment was performed on a free cutting alloy relating to the fourth selection inventive steel of the present invention constituted as electromagnetic stainless steel. First, 7 kg blocks of inventive steels of the present invention and comparative steels provided for tests, whose compositions in mass % shown in Tables 1 and 2, were molten in a induction furnace in an Ar stream to obtain ingots of 80 mm in diameter. Then, the ingots were processed in hot forging at a temperature in the range of 1000 to 1050°C to be formed into rods of a circular section of 22 mm in diameter and thereafter, the rods were each machined into a diameter of 21 mm followed by cold rolling into a diameter of 18 mm The rods thus rolled were subjected to tests. In Tables 1 and 2, specimens Nos. 1 to 38 are test rods of fourth selection inventive steels and specimens Nos. 39 to 47 are test rods of inventive steels. The test rods were measured on magnetic characteristics, electric resistivity, machinability, cold workability and corrosion resistivity by measuring methods described below, which will be described below:
Tablet 1
Tablet 2
Measuring methods
1) Magnetic characteristics
[0045] A test piece in the shape of a ring, of 10 mm in outer diameter, 5 mm in inner diameter and 5 mm in thickness was prepared for measurement of magnetic characteristics. The test piece received magnetic annealing at 950°C and thereafter, direct current magnetic characteristics including a magnetic flux density and a direct current coercive force were measured by a B-H loop tracer: a magnetic flux density B1 (KG) under a magnetic field of 1 Oe and a magnetic flux density B10 (KG) under a magnetic field of 10 Oe and a direct current coercive force Hc (A/cm). Relations between a magnetic flux density B1 or a coercive force Nc and α are shown in Fig. 3.
2) Electric resistivity
[0046] Electric resistivity was measured on test pieces, which were each prepared by subjecting a test rod to cold wire drawing to obtain a wire of 1 mm in diameter, and then performing vacuum annealing at 950°C thereon.
3) Machinability
[0047] Machinability was evaluated as follows: a SKH 51 drill of 5 mm in diameter was used on a test piece of steel for machining at a number of revolution of 915 rpm under a load of 415 N on a cutting edge thereof and a time in sec consumed for boring a hole of 10 mm in depth was measured. Machinability was evaluated by a length of the time in sec.
4) Cold workability
[0048] Cold workability was evaluated by a cracking threshold working ratio and a procedure was as follows: a test piece was prepared in the shape of a cylinder, 20 mm in diameter and 30 mm in height. The test piece was annealed at 720°C and thereafter a compression test was performed on the test piece under a hydraulic pressure of 400 t to evaluate a cracking threshold working ratio. Relations of a boring time or a cracking threshold working ratio and α are shown in Fig. 4.
5) Pitting potential
[0049] A test piece was prepared in the shape of a disc whose size is 18 mm in diameter and 2 mm in thickness. The test piece was polished with sand papers up to No. 800 and subjected to magnetic annealing at 950° for 2 hr in a vacuum. Thereafter, a pitting potential Vc in mV was measured on the test piece in a 3.5 % NaCl aqueous solution at 30°C. Fig. 5 shows a relation between a pitting potential and α. The measuring results are shown in Tables 3 and 4.
Table 3
Table 4
[0050] As can be found from Tables 3 and 4, and Fig. 3, very excellent magnetic characteristics are shown: at I |α| ≤ 0.07, Hc < 1.0 A/cm and B1 > 2.5 KG. The magnetic characteristics changes rapidly in the vicinity of α = 0.07 and gradually in the range of 0.07 < α ≤ 0.45. The magnetic characteristics in relatively good ranges of 1.0 < Hc < 1.5 A/cm and 1.0 < B1 < 2.0 KG are retained in the range of 0.07 < α ≤ 0.45. While the magnetic characteristics again starts growing larger from a point in the vicinity of α = 0.45, the magnetic characteristics show 1.4 < Hc < 2.5 A/cm and 0.4 < B1 < 1.0 KG in the range of 0.45 < α ≤ 0.70, which falls in the ranges usable practically as electromagnetic stainless steel.
[0051] Moreover, as can be clear from Tables 3 and 4, and Fig. 4, while machinability does not show a correlation with α as clear as magnetic characteristics have, a relatively good machinability was obtained in the range of |α| ≤ 0.70 showing a boring time in the range of 14 to 17 sec, and excellent cold workability in the same range of |α| ≤ 0.70 was obtained showing a cracking threshold working ratio in the range of 80 to 86 %. The machinability and cracking threshold working ratio each show a large fluctuation between α values adjacent to each other, which occurs probably due to a difference in content of Si, Mn and Cr as one of causes. In the range of 0.07 < α ≤ 0.45, relatively good machinability was obtained showing a boring time in the range of 13 to 17 sec, and relative good cold workability was obtained showing a cracking threshold working ratio in the range of 75 to 85 %. On the other hand, in the range of 0.45 < α ≤ 0.70, while cold workability at a high working ratio is hard showing a cracking threshold working ratio being 76 % or less, excellent machinability was obtained showing a boring time in the range of 10 to 16 sec.
[0052] Specimens Nos. 8, 10, 19, 21, 30 and 32 including Pb as a component each have a short boring time compared with specimens of inventive steel of the present invention with respective α values close to those of the specimens including Pb. Further, specimens Nos. 8, 9 to 11, 19 to 22 and 30 to 33 including B and/or REM as a component each have a large cracking threshold working ratio compared with specimens of inventive steel of the present invention with respective α values close to those of the specimens including B and/or REM.
[0053] As can be clear from Tables 3 and 4 and Fig. 5 (where high Cr stainless steel with an extremely high Vc and low Cr stainless steel with a very low Vc are excluded), in the range of |α| ≤ 0.07, Vc is in the range of - 80 < Vc < 0 in mV and good corrosion resistivity is shown. In the range of 0.07 < α ≤ 0.45, Vc is in the range of - 50 < Vc < 70 in mV and better corrosion resistivity is shown. While Vc decreases further in the range of 0.45 < α ≤ 0.70, Vc is considered to be practically useful as far as Vc > - 150 mV.
[0054] Specimens Nos. 6, 7, 10, 11, 17, 18, 21, 22, 28, 29, 32 and 33 including Ni, Cu, Mo, Nb and V, which improve corrosion resistivity, have high Vc compared with specimens of inventive steel of the present invention with respective α values close to the specimens including Ni, Cu, Mo, Nb and V. Further, specimens Nos. 27 and 38 including an element which improves corrosion resistivity keep Vc of the same order as those of specimens of inventive steel of the present invention with respective α values smaller than the specimens including the corrosion resistivity improving element.
[0055] Specimens Nos. 39 to 47 of reference steel are outside the scope of the fourth selection inventive steel, as shown in Fig. 1. When comparing the reference steel with the fourth selection inventive steel, it is found that all the specimens of the reference steel each show a cracking threshold working ratio of 72 % or less and therefore, the fourth selection inventive steel is superior in cold workability. Further, when specimens of both kinds with respective α values close to each other are compared with each other, it is found that the fourth selection inventive steel is more excellent than the reference steel in magnetic characteristics and corrosion resistivity. Further, when comparing specimens Nos. 39 to 42 of the reference steel with specimens of the fourth selection inventive steel, it is found that the fourth selection inventive steel is better than the reference steel in machinability. When comparing reference steels of specimens Nos. 43 and 44 and fourth selection inventive steels, it is found that while both kinds of steel show almost the same level of machinability, the fourth selection inventive steels are better than the reference steels in the other characteristics and when comparing reference steels of specimens Nos. 45 to 47 with fourth selection inventive steels, it is found that the fourth selection inventive steels have better magnetic characteristics and better corrosion resistivity.
[0056] Fig. 6 shows dependencies of solubility products on temperature of compounds of TiO, TiN, Ti4C2S2, TiC, TiS and CrS in γ-Fe (an austenitic phase). Since Zr has a chemical property analogous to Ti, and Se and Te have a chemical property analogous to S, it is considered that compounds are formed in the descending order of priority of (Ti,Zr)0 > (Ti, Zr)N > (Ti,Zr)4C2(S,Se,Te) > (Ti,Zr)C > (Ti,Zr)(S,Se,Te) > Cr(S,Se,Te). Further, it was confirmed that the above described compounds were present in steel by X-ray analysis.
0.01 to 3 mass % Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % Al;
one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of X of the following formula 1;
C in the range of 0.02 X to 0.06 X mass %, wherein X is expressed by the following formula 1;
one or more of S, Se and Te so that the value Y is in the range of (Z -0.07)X to (Z
+ 0.07)X mass %, wherein X, Z and Y are values of the respective following formulae
1, 3 and 2; and the balance being Fe and inevitable impurities:
and
one or more selected from the group consisting ofNi, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V;
one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM;
one or more selected from the group consisting ofNi, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V; and further containing one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM.
0.01 to 3 mass % Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % Al;
one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of X of the following formula 1;
C in the range of 0.19 X to 0.26 X mass %, wherein X is expressed by the following formula 1;
one or more of S, Se and Te so that the value Y is in the range of (Z - 0.07)X to
(Z + 0.07)X mass %, wherein X, Z and Y are values of the respective following formulae
1, 3 and 2 and the balance being Fe and inevitable impurities:
and
and
one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V;
one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM;
one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V; and further containing one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM.
0.01 to 3 mass % Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % Al;
one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of X of the following formula 1;
C in the range of 0.02 X to 0.26 X mass %, wherein X is expressed by the following formula 1;
one or more of S, Se and Te so that the value Y is in the range of (Z + 0.07)X to
(Z + 0.45)X, the lower limit not included, mass %, wherein X, Z and Y are values of
the respective following formulae 1, 3 and 2; and the balance being Fe and inevitable
impurities:
and
and
one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V;
one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM;
one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in
the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V; and further containing one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM.
0.01 to 3 mass % Si; 2 mass % or lower Mn; 5 to 25 mass % Cr; 0.01 to 5 mass % Al;
one or more of Ti and Zr in the range of 0.05 to 0.5 mass % in terms of X of the following formula 1;
C in the range of 0.02 X to 0.26 X mass %, wherein X is expressed by the following formula 1;
one or more of S, Se and Te so that the value Y is in the range of (Z + 0.45)X to
(Z + 0.70) X, the lower limit not included, mass %, wherein X, Z and Y are values
of the respective following formulae 1, 3 and 2; and the balance being Fe and inevitable
impurities:
and
one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V;
one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM;
one or more selected from the group consisting of Ni, Cu, Mo, Nb and V in the respective ranges of 2 mass % or lower for Ni; 2 mass % or lower for Cu; 2 mass % or lower for Mo; 1 mass % or lower for Nb and 1 mass % or lower for V; and further containing one or more of Pb, B and REM in the respective ranges of 0.15 mass % or lower for Pb; 0.01 mass % or lower for B; and 0.1 mass % or lower for REM.
0,01 bis 3 Massen-% Si; 2 Massen-% oder weniger Mn; 5 bis 25 Massen-% Cr; 0,01 bis 5 Massen-% Al;
ein oder mehrere aus Ti und Zr in dem Bereich von 0,05 bis 0,5 Massen-% hinsichtlich X der folgenden Formel 1;
C in dem Bereich von 0,02 X bis 0,06 X Massen-%, worin X durch die folgende Formel 1 ausgedrückt ist;
ein oder mehrere aus S, Se und Te, sodass der Wert Y in dem Bereich von (Z - 0,07)X
bis (Z + 0,07)X Massen-% liegt, worin X, Z und Y Werte der jeweiligen folgenden Formeln
1, 3 und 2 sind; und wobei der Rest Fe und unvermeidbare Verunreinigungen darstellt:
und
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu; 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V;
ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM;
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu; 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V; und weiterhin enthaltend ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM.
0,01 bis 3 Massen-% Si; 2 Massen-% oder weniger Mn; 5 bis 25 Massen-% Cr; 0,01 bis 5 Massen-% Al;
ein oder mehrere aus Ti und Zr in dem Bereich von 0,05 bis 0,5 Massen-% hinsichtlich X in der folgenden Formel 1;
C in dem Bereich von 0,19 X bis 0,26 X Massen-%, worin X durch die folgende Formel ausgedrückt ist;
ein oder mehrere aus S, Se und Te, sodass der Wert Y in dem Bereich von (Z - 0,07)X
bis (Z + 0,07)X Massen-% liegt, worin X, Z und Y Werte der jeweiligen folgenden Formeln
1, 3 und 2 darstellen, und wobei der Rest Fe und unvermeidbare Verunreinigungen darstellt:
und
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu: 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V;
ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM;
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu; 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V; und weiterhin enthaltend ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM.
0,01 bis 3 Massen-% Si; 2 Massen-% oder weniger Mn; 5 bis 25 Massen-% Cr; 0,01 bis 5 Massen-% Al;
ein oder mehrere aus Ti und Zr in dem Bereich von 0,05 bis 0,5 Massen-% hinsichtlich X der folgenden Formel 1;
C in dem Bereich von 0,02 X bis 0,26 X Massen-%, worin X durch die folgende Formel 1 ausgedrückt ist;
ein oder mehrere aus S, Se und Te, sodass der Wert Y in dem Bereich von (Z + 0,07)X
bis (Z + 0,45)X, die untere Grenze nicht eingeschlossen, Massen-% liegt, worin X,
Z und Y Werte der jeweiligen folgenden Formeln 1, 3 und 2 sind; und wobei der Rest
Fe und unvermeidbare Verunreinigungen darstellt:
und
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu; 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V;
ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM;
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu; 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V; und weiterhin enthaltend ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM.
0,01 bis 3 Massen-% Si; 2 Massen-% oder weniger Mn; 5 bis 25 Massen-% Cr; 0,01 bis 5 Massen-% Al;
ein oder mehrere aus Ti und Zr in dem Bereich von 0,05 bis 0,5 Massen-% hinsichtlich X der folgenden Formel 1;
C in dem Bereich von 0,02 X bis 0,26 X Massen-%, worin X durch die folgende Formel 1 ausgedrückt ist;
ein oder mehrere aus S, Se und Te, sodass der Wert Y in dem Bereich von (Z + 0,45)X
bis (Z + 0,70)X, die untere Grenze nicht eingeschlossen, Massen-% liegt, worin X,
Z und Y Werte der jeweiligen folgenden Formeln 1, 3 und 2 sind; und wobei der Rest
Fe und unvermeidbare Verunreinigungen darstellt:
und
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu; 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V;
ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM;
ein oder mehrere, ausgewählt aus der Gruppe, bestehend aus Ni, Cu, Mo, Nb und V in den jeweiligen Bereichen von 2 Massen-% oder weniger für Ni; 2 Massen-% oder weniger für Cu; 2 Massen-% oder weniger für Mo; 1 Massen-% oder weniger für Nb und 1 Massen-% oder weniger für V; und weiterhin enthaltend ein oder mehrere aus Pb, B und REM in den jeweiligen Bereichen von 0,15 Massen-% oder weniger für Pb; 0,01 Massen-% oder weniger für B; und 0,1 Massen-% oder weniger für REM.
de 0,01 à 3 % en masse de Si ; 2 % en masse ou moins de Mn ; de 5 à 25 % en masse de Cr ; de 0,01 à 5 % en masse de Al ;
un ou plusieurs éléments choisis parmi Ti et Zr dans la plage de 0,05 à 0,5 % en masse en termes de X selon la formule 1 suivante ;
C dans la plage de 0,02X à 0,06X % en masse, X étant exprimé par la formule 1 suivante ;
un ou plusieurs éléments choisis parmi S, Se et Te, de sorte que la valeur Y est dans
la plage de (Z-0,07)X à (Z+0,07)X % en masse, X, Z et Y étant des valeurs correspondant
aux formules respectives 1, 3 et 2 suivantes ; et le reste étant du Fe et des impuretés
inévitables :
et
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2 % en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ;
un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM ;
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2 % en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ; et contenant en outre un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM.
de 0,01 à 3 % en masse de Si ; 2 % en masse ou moins de Mn ; de 5 à 25 % en masse de Cr ; de 0,01 à 5 % en masse de Al ;
un ou plusieurs éléments choisis parmi Ti et Zr dans la plage de 0,05 à 0,5 % en masse en termes de X selon la formule 1 suivante ;
C dans la plage de 0,19X à 0,26X % en masse, X étant exprimé par la formule 1 suivante ;
un ou plusieurs éléments choisis parmi S, Se et Te, de sorte que la valeur Y est dans
la plage de (Z-0,07)X à (Z+0,07)X % en masse, X, Z et Y étant des valeurs correspondant
aux formules respectives 1, 3 et 2 suivantes ; et le reste étant du Fe et des impuretés
inévitables :
et
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2 % en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ;
un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM ;
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2 % en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ; et contenant en outre un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM.
de 0,01 à 3 % en masse de Si ; 2 % en masse ou moins de Mn ; de 5 à 25 % en masse de Cr ; de 0,01 à 5 % en masse de A1 ;
un ou plusieurs éléments choisis parmi Ti et Zr dans la plage de 0,05 à 0,5 % en masse en termes de X selon la formule 1 suivante ;
C dans la plage de 0,02X à 0,26X % en masse, X étant exprimé par la formule 1 suivante ;
un ou plusieurs éléments choisis parmi S, Se et Te, de sorte que la valeur Y est dans
la plage de (Z+0,07)X à (Z+0,45)X % en masse, la limite inférieure n'étant pas incluse,
X, Z et Y étant des valeurs correspondant aux formules respectives 1, 3 et 2 suivantes
; et le reste de consistant en Fe et en impuretés inévitables :
et
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2 % en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ;
un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM ;
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2% en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ; et contenant en outre un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM.
de 0,01 à 3 % en masse de Si ; 2 % en masse ou moins de Mn ; de 5 à 25 % en masse de Cr ; de 0,01 à 5 % en masse de Al;
un ou plusieurs éléments choisis parmi Ti et Zr dans la plage de 0,05 à 0,5 % en masse en termes de X selon la formule 1 suivante ;
C dans la plage de 0,02X à 0,26X % en masse, X étant exprimé par la formule 1 suivante ;
un ou plusieurs éléments choisis parmi S, Se et Te, de sorte que la valeur Y est dans
la plage de (Z+0,45)X à (Z+0,70)X % en masse, la limite inférieure n'étant pas incluse,
X, Z et Y étant des valeurs correspondant aux formules respectives 1, 3 et 2 suivantes
; et le reste étant du Fe et des impuretés inévitables :
et
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2 % en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ;
un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM ;
un ou plusieurs éléments choisis parmi le groupe consistant en Ni, Cu, Mo, Nb et V dans les plages respectives de 2 % en masse ou moins pour Ni ; 2 % en masse ou moins pour Cu ; 2 % en masse ou moins pour Mo ; 1 % en masse ou moins pour Nb et 1 % en masse ou moins pour V ; et contenant en outre un ou plusieurs éléments choisis parmi Pb, B et les éléments de métal de terre rare (REM) dans les plages respectives de 0,15 % en masse ou moins pour Pb ; 0,01 % en masse ou moins pour B ; et 0,1 % en masse ou moins pour les éléments REM.