(19)
(11) EP 0 445 519 A1

(12) EUROPEAN PATENT APPLICATION

(43) Date of publication:
11.09.1991 Bulletin 1991/37

(21) Application number: 91101082.5

(22) Date of filing: 28.01.1991
(51) International Patent Classification (IPC)5C22C 38/02, C22C 38/04
(84) Designated Contracting States:
DE GB SE

(30) Priority: 20.02.1990 JP 37431/90

(71) Applicant: NKK CORPORATION
Tokyo 100 (JP)

(72) Inventors:
  • Shikanai, Nobuo, c/o NKK Corp.
    Tokyo (JP)
  • Sanpei, Tetsuya, c/o NKK Corp.
    Tokyo (JP)
  • Yako, Kazunori, c/o NKK Corp.
    Tokyo (JP)
  • Kunisada, Yasunobu, c/o NKK Corp.
    Tokyo (JP)
  • Hirabe, Kenji, c/o NKK Corp.
    Tokyo (JP)

(74) Representative: Henkel, Feiler, Hänzel & Partner 
Möhlstrasse 37
81675 München
81675 München (DE)


(56) References cited: : 
   
       


    (54) Wear-resistant steel for intermediate and room temperature service


    (57) A wear-resistant steel for the intermediate and room temperature service consisting essentially of:
    carbon
    : from 0.08 to 0.40 wt.%,
    silicon
    : from 0.8 to 2.5 wt.%,
    manganese
    : from 0.1 to 2.0 wt.%,

    and
    the balance being iron and incidental impurities.
    The above-mentioned wear-resistant steel has a Brinell hardness at a room-temperature of at least 250, a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness.


    Description

    REFERENCE TO PATENTS, APPLICATIONS AND PUBLICATIONS PERTINENT TO THE INVENTION



    [0001] As far as we know, there are available the following prior art documents pertinent to the present invention:

    (1) Japanese Patent Provisional Publication No. 62-142,726 dated June 26, 1987;

    (2) Japanese Patent Provisional Publication No. 63-169,359 dated July 13, 1988; and

    (3) Japanese Patent Provisional Publication No. 1-142,023 dated June 2, 1989.



    [0002] The contents of the prior art disclosed in the above-mentioned prior art documents will be discussed hereafter under the heading of the "BACKGROUND OF THE INVENTION."

    FIELD OF THE INVENTION



    [0003] The present invention relates to a wear-resistant steel having a high hardness in an intermediate temperature region and a room-temperature region.

    BACKGROUND OF THE INVENTION



    [0004] 

    [0005] A wear-resistant steel is used as a material for portions exposed to serious wear in an industrial machine and a transportation machine such as a power shovel, a bulldozer, a hopper or a bucket and parts thereof. Wear resistance of steel can be improved by increasing hardness of the steel. A steel having a high hardness which contains carbon, silicon and manganese in prescribed amounts and is additionally added with elements to increase hardness, is therefore used as the wear-resistant steel mentioned above.

    [0006] The following wear-resistant steels have so far been proposed as steels excellent in wear resistance and satisfactory in weldability, toughness and workability:

    (1) A wear-resistant steel sheet having an excellent weldability, disclosed in Japanese Patent Provisional Publication No. 62-142,726 dated June 26, 1987, which consists essentially of:

    carbon
    : from 0.10 to 0.19 wt.%,
    silicon
    : from 0.05 to 0.55 wt.%,
    manganese
    : from 0.90 to 1.60 wt.%,
    and
    the balance being iron and incidental impurities;
    where, a carbon equivalent (C + 1/24 Si + 1/6 Nn + 1/40 Ni + 1/5 Cr + 1/4 Mo + 1/14 V) being within a range of from 0.35 to 0.44 wt.%
    (hereinafter referred to as the "prior art 1").
    The above-mentioned wear-resistant steel sheet of the prior art 1 may additionally contain at least one of vanadium and niobium in an amount of up to 0.10 wt.%.

    (2) A wear-resistant steel sheet having a high toughness, disclosed in Japanese Patent Provisional Publication No. 63-169,359 dated July 13, 1988, which consists essentially of:

    carbon
    : from 0.10 to 0.20 wt.%,
    silicon
    : from 0.03 to 0.75 wt.%,
    manganese
    : from 0.4 to 1.8 wt.%,
    phosphorus
    : up to 0.015 wt.%,
    sulfur
    : up to 0.002 wt.%,
    nitrogen
    : up to 0.0025 wt.%,
    sol. Al
    : from 0.001 to 0.080 wt.%,
    oxygen
    : up to 0.0020 wt.%,
    and
    the balance being iron and incidental impurities
    (hereinafter referred to as the "prior art").
    The above-mentioned wear-resistant steel sheet of the prior art 2 may additionally contain at least one element selected from the group consisting of:
    copper
    : from 0.05 to 0.75 wt.%,
    nickel
    : from 0.05 to 1.50 wt.%,
    chromium
    : from 0.05 to 1.50 wt.%,
    molybdenum
    : from 0.01 to 0.75 wt.%,
    and
    boron
    : from 0.0001 to 0.0025 wt.%.

    (3) A wear-resistant steel sheet having an excellent bending workability, disclosed in Japanese Patent Provisional Publication No. 1-142,023 dated June 2, 1989, which consists essentially of:

    carbon
    : from 0.07 to 0.17 wt.%,
    silicon
    : from 0.05 to 0.55 wt.%,
    manganese
    : from 0.70 to 1.80 wt.%,
    vanadium
    : from 0.02 to 0.10 wt.%,
    boron
    : from 0.0003 to 0.0050 wt.%,
    aluminum
    : from 0.01 to 0.10 wt.%,
    and
    the balance being iron and incidental impurities
    (hereinafter referred to as the "prior art 3").
    The above-mentioned wear-resistant steel sheet of the prior art 3 may additionally contain at least one element selected from the group consisting of:
    copper
    : from 0.05 to 0.30 wt.%,
    nickel
    : from 0.05 to 0.45 wt.%,
    chromium
    : from 0.05 to 0.20 wt.%,
    and
    molybdenum
    : from 0.03 to 0.20 wt.%.



    [0007] According to the above-mentioned prior arts 1 to 3, a wear-resistant steel having a high room-temperature hardness is available in all cases. However, the prior arts 1 to 3 have the following problems: A wear-resistant steel is used also as a material for a machine and parts thereof for treating slag at a temperature within an intermediate temperature region of from about 300 to about 400°C in a slag yard. A wear-resistant steel used as such a material should preferably have a Brinell hardness(HB) at a room-temperature of at least 250, a Brinell hardness at a temperature of about 300°C of at least 90% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of about 400°C of at least 70% of its room-temperature Brinell hardness.

    [0008] However, according to the wear-resistant steels of the prior arts 1 to 3, while it is possible to improve wear resistance at a temperature within a room temperature region, it is impossible to improve wear resistance at a temperature within an intermediate temperature region of from about 300 to about 400°C. The wear-resistant steels of the prior arts 1 to 3 are not satisfactory in terms of wear resistance when used as a material for a machine and parts thereof employed at a temperature within an intermediate temperature region.

    [0009] With a view to improving wear resistance at a temperature within an intermediate temperature region, a conceivable measure is to largely increase a room-temperature hardness of steel, taking account of the decrease in hardness at a temperature within an intermediate temperature region. When a room-temperature hardness of steel is increased excessively, however, ductility, toughness, workability and weldability of the steel are deteriorated.

    [0010] Under such circumstances, there is a strong demand for the development of a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, and has a Brinell hardness at a temperature of about 300°C of at least 90% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of about 400°C of at least 70% of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely increasing its room-temperature Brinell hardness, but such a wear-resistant steel for the intermediate and room temperature service has not as yet been proposed.

    SUMMARY OF THE INVENTION



    [0011] 

    [0012] An object of the present invention is therefore to provide a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, and has a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely increasing its room-temperature Brinell hardness.

    [0013] In accordance with one of the features of the present invention, there is provided a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness, characterized by consisting essentially of:
    carbon
    : from 0.08 to 0.40 wt.%,
    silicon
    : from 0.8 to 2.5 wt.%,
    manganese
    : from 0.1 to 2.0 wt.%,

    and
    the balance being iron and incidental impurities.

    [0014] The wear-resistant steel for the intermediate and room temperature service of the present invention may additionally contain at least one element selected from the group (A) consisting of:

    (A)

    copper
    : from 0.1 to 2.0 wt.%,
    nickel
    : from 0.1 to 10.0 wt.%,
    chromium
    : from 0.1 to 3.0 wt.%,
    molybdenu
    m : from 0.1 to 3.0 wt.%,
    and
    boron
    : from 0.0003 to 0.0100 wt.%.

    The wear-resistant steel for the intermediate and room temperature service of the present invention may additionally contain at least one element selected from the group (B) consisting of:

    (B)

    niobium
    : from 0.005 to 0.100 wt.%,
    vanadium
    : from 0.01 to 0.10 wt.%,
    and
    titanium
    : from 0.005 to 0.100 wt.%.



    [0015] Furthermore, the wear-resistant steel for the intermediate and room temperature service of the present invention may additionally contain at least one element selected from the above-mentioned group (A) and at least one element selected from the above-mentioned group (B).

    BRIEF DESCRIPTION OF THE DRAWING



    [0016] Fig. 1 is a graph illustrating the relationship between a silicon content and a Brinell hardness (HB) in a wear-resistant steel.

    DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS



    [0017] From the above-mentioned point of view, extensive studies were carried out to develop a wear-resistant steel for the intermediate and room temperature service having an excellent wear resistance in an intermediate temperature region without largely increasing its room-temperature hardness. As a result, findings were obtained that silicon contained in steel had a function of increasing, for a certain range of the content thereof, hardness of steel in an intermediate temperature region without increasing a room-temperature hardness thereof.

    [0018] The present invention was made on the basis of the above-mentioned findings, and the wear-resistant steel for the intermediate and room temperature service of the present invention consists essentially of:
    carbon
    : from 0.08 to 0.40 wt.%,
    silicon
    : from 0.8 to 2.5 wt.%,
    manganese
    : from 0.1 to 2.0 wt.%,

    and
    the balance being iron and incidental impurities.

    [0019] The wear-resistant steel for the intermediate and room temperature service of the present invention may additionally contain at least one element selected from the group (A) consisting of:

    (A)

    copper
    : from 0.1 to 2.0 wt.%,
    nickel
    : from 0.1 to 10.0 wt.%,
    chromium
    : from 0.1 to 3.0 wt.%,
    molybdenum
    : from 0.1 to 3.0 wt.%,
    and boron
    : from 0.0003 to 0.0100 wt.%.

    The wear-resistant steel for the intermediate and room temperature service of the present invention may additionally contain at least one element selected from the group (B) consisting of:

    (B)

    niobium
    : from 0.005 to 0.100 wt.%,
    vanadium
    : from 0.01 to 0.10 wt.%,
    and
    titanium
    : from 0.005 to 0.100 wt.%.



    [0020] Furthermore, the wear-resistant steel for the intermediate and room temperature service of the present invention may additionally contain at least one element selected from the above-mentioned group (A) and at least one element selected from the above-mentioned group (B).

    [0021] The chemical composition of the wear-resistant steel for the intermediate and room temperature service of the present invention is limited within a range as described above for the following reasons.

    (1) Carbon:



    [0022] Carbon is an element which exerts an important effect on hardness of steel. However, with a carbon content of under 0.08 wt.%, a Brinell hardness (HB) at a room-temperature of at least 250 is not available. With a carbon content of over 0.40 wt.%, on the other hand, a room-temperature Brinell hardness becomes excessively high to result in deterioration of ductility, toughness, workability and weldability of steel. The carbon content should therefore be limited within a range of from 0.08 to 0.40 wt.%.

    (2) Silicon:



    [0023] Silicon has a function of increasing hardness of steel in an intermediate temperature region without increasing its room-temperature hardness. However, with a silicon content of under 0.8 wt.%, a desired effect as mentioned above is not available.

    [0024] The relationship between a silicon content and a Brinell hardness (HB) in a wear-resistant steel was investigated. More particularly, for test pieces of a hardened wear-resistant steel having a thickness of 20 mm, which contained 0.3 wt.% carbon, 0.7 wt.% manganese, 0.9 wt.% chromium and silicon in a certain amount, a Brinell hardness (HB) was measured for each test piece at a room-temperature, 300°C, 400°C and 500°C with the silicon content varying within a range of from about 0.4 to about 2.0 wt.%. The results are shown in Fig. 1.

    [0025] In Fig. 1, the mark "o" represents a Brinell hardness at a room-temperature of the test piece; the mark "·" represents a Brinell hardness at a temperature of 300°C of the test piece; the mark "Δ" represents a Brinell hardness at a temperature of 400°C of the test piece; and the mark "▲" represents a Brinell hardness at a temperature of 500°C of the test piece. As shown in Fig. 1, the test pieces showed a Brinell hardness at a room-temperature of about 500 almost constantly irrespective of the increase in the silicon content. The test pieces showed a Brinell hardness at a temperature of 300°C of at least 450, i.e., about 90% of its room-temperature Brinell hardness by increasing the silicon content to at least 0.8 wt.%. The test pieces showed a Brinell hardness at a temperature of 400°C of at least 350, i.e., about 70% of its room-temperature Brinell hardness by increasing the silicon content to at least 0.8 wt.%. The test pieces showed a Brinell hardness at a temperature of 500°C also increased, though on a relatively low level, by increasing the silicon content to at least 0.8 wt.%.

    [0026] With a silicon content of over 2.5 wt.%, on the other hand, δ -ferrite is produced in the steel structure, and this may cause degradation of a room-temperature hardness of steel, and the manufacturing cost of steel becomes higher. The silicon content should therefore be limited within a range of from 0.8 to 2.5 wt.%.

    (3) Manganese:



    [0027] Manganese has a function of improving hardenability of steel. However, with a manganese content of under 0.1 wt.%, a desired effect as mentioned above is not available. With a manganese content of over 2.0 wt.%, on the other hand, weldability of steel is degraded, and the manufacturing cost of steel becomes higher. The manganese content should therefore be limited within a range of from 0.1 to 2.0 wt.%.

    (4) Copper:



    [0028] Copper has a function of improving hardenability of steel. In the wear-resistant steel of the present invention, therefore, copper is additionally added as required. However, with a copper content of under 0.1 wt.%, a desired effect as mentioned above is not available. With a copper content of over 2.0 wt.%, on the other hand, hot workability of steel is degraded. The copper content should therefore be limited within a range of from 0.1 to 2.0 wt.%.

    (5) Nickel:



    [0029] Nickel has a function of improving hardenability and low-temperature toughness of steel. In the wear-resistant steel of the present invention, therefore, nickel is additionally added as required. However, with a nickel content of under 0.1 wt.%, a desired effect as mentioned above is not available. With a nickel content of over 10.0 wt.%, on the other hand, the manufacturing cost of steel becomes higher. The nickel content should therefore be limited within a range of from 0.1 to 10.0 wt.%.

    (6) Chromium:



    [0030] Chromium has a function of improving hardenability of steel. In the wear-resistant steel of the present invention, therefore, chromium is additionally added as required. However, with a chromium content of under 0.1 wt.%, a desired effect as mentioned above is not available. With a chromium content of over 3.0 wt.%, on the other hand, weldability of steel is degraded, and the manufacturing cost of steel becomes higher. The chromium content should therefore be limited within a range of from 0.1 to 3.0 wt.%.

    (7) Molybdenum:



    [0031] Similarly to chromium, molybdenum has a function of improving hardenability of steel. In the wear-resistant steel of the present invention, therefore, molybdenum is additionally added as required. However, with a molybdenum content of under 0.1 wt.%, a desired effect as mentioned above is not available. With a molybdenum content of over 3.0 wt.%, on the other hand, weldability of steel is degraded and the manufacturing cost of steel becomes higher. The molybdenum content should therefore be limited within a range of from 0.1 to 3.0 wt.%.

    (8) Boron:



    [0032] Boron has a function of improving hardenability of steel with a slight content. In the wear-resistant steel of the present invention, therefore, boron is additionally added as required. However, with a boron content of under 0.0003 wt.%, a desired effect as mentioned above is not available. With a boron content of over 0.0100 wt.%, on the other hand, weldability and hardenability of steel are degraded. The boron content should therefore be limited within a range of from 0.0003 to 0.0100 wt.%.

    (9) Niobium:



    [0033] Niobium has a function of improving hardness of steel through precipitation hardening. In the wear-resistant steel of the present invention, therefore, niobium is additionally added as required. However, with a niobium content of under 0.005 wt.%, a desired effect as mentioned above is not available. With a niobium content of over 0.100 wt.%, on the other hand, weldability of steel is degraded. The niobium content should therefore be limited within a range of from 0.005 to 0.100 wt.%.

    (10) Vanadium



    [0034] Similarly to niobium, vanadium has a function of improving hardness of steel through precipitation hardening. In the wear-resistant steel of the present invention, therefore, vanadium is additionally added as required. However, with a vanadium content of under 0.01 wt.%, a desired effect as mentioned above is not available. With a vanadium content of over 0.10 wt.%, on the other hand, weldability of steel is degraded. The vanadium content should therefore be limited within a range of from 0.01 to 0.10 wt.%.

    (11) Titanium:



    [0035] Similarly to niobium, titanium has a function of improving hardness of steel through precipitation hardening. In the wear-resistant steel of the present invention, therefore, titanium is additionally added as required. However, with a titanium content of under 0.005 wt.%, a desired effect as mentioned above is not available. With a titanium content of over 0.100 wt.%, weldability of steel is degraded. The titanium content should therefore be limited within a range of from 0.005 to 0.100 wt.%.

    [0036] In the present invention, for example, a slab of a wear-resistant steel having the above-mentioned chemical composition may be hot-rolled to prepare a steel sheet, and the thus prepared steel sheet may be subjected to heat treatments including a hardening treatment, a tempering treatment, an ageing treatment and a stress relieving treatment. Hardness and toughness of the steel sheet can further be improved by the application of these heat treatments thereto.

    [0037] Now, the wear-resistant steel of the present invention is described more in detail by means of examples while comparing with a wear-resistant steel for comparison outside the scope of the present invention.

    EXAMPLES



    [0038] Ingots of the wear-resistant steel of the present invention having the chemical compositions within the scope of the present invention as shown in Table 1, and ingots of a wear-resistant steel for comparison having the chemical compositions outside the scope of the present invention as shown also in Table 1, were melted in a melting furnace, and then cast into slabs. The resultant slabs were then hot-rolled to prepare samples of the wear-resistant steel of the present invention (hereinafter referred to as the "samples of the invention") Nos. 1 to 13 having a thickness of 15 mm, and samples of the wear-resistant steel for comparison outside the scope of the present invention (hereinafter referred to as the "samples for comparison") Nos. 1 to 4 also having a thickness of 15 mm.

    [0039] The samples of the invention Nos. 1 to 4 and 6 to 13, and the samples for comparison Nos. 1 to 3 were subjected to any one of the following heat treatments as shown in the column of "heat treatment" in Table 1. The sample of the invention No. 5 and the sample for comparison No. 4 were maintained in the as-rolled state without being subjected to any heat treatment.

    (1) A sample is hardened by heating the sample to a temperature of 900°C and then water-quenching the heated sample from the above-mentioned temperature (hereinafter, this heat treatment being referred to as the "RQ");

    (2) A sample is subjected to the above-mentioned RQ, and then tempered at a temperature as shown in the parentheses in the column of "heat treatment" in Table 1 (hereinafter, this heat treatment being referred to as the "RQT");

    (3) A sample is directly hardened by immediately water-quenching the sample from the hot-rolling finishing temperature (hereinafter, this heat treatment being referred to as the "DQ"); and

    (4) A sample is subjected to the above-mentioned DQ, and then tempered at a temperature as shown in the parentheses in the column of "heat treatment" in Table 1 (hereinafter, this heat treatment being referred to as the "DQT").



    [0040] Then, for each of the samples of the invention Nos. 1 to 13 and the samples for comparison Nos. 1 to 4, a Brinell hardness (HB) at a room-temperature, a Brinell hardness at a temperature of 300°C and a Brinell hardness at a temperature of 400°C were investigated. The results are shown in Table 2. In the column of "Brinell hardness (HB)" in Table 2, the values of Brinell hardness shown in the subcolumns of "at 300°C" and "at 400°C" were obtained by converting the values measured in the tensile test, although the values of Brinell hardness shown in the subcolumn of "at room-temperature" were obtained by means of the Brinell test. Each value of percentages shown in the parentheses in the subcolumns of "at 300°C" and "at 400°C" presents a ratio of each value of Brinell hardnesses at temperatures of 300°C and 400°C to a value of its Brinell hardness at a room-temperature.





    [0041] As is clear from Tables 1 and 2, each of the samples for comparison Nos. 1 to 3, which have a low silicon content outside the scope of the present invention, has a Brinell hardness at a temperature of 300°C within a range of from 83 to 85% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400°C within a range of from 65 to 68% of its room-temperature Brinell hardness, both of which are lower than the target values in the present invention. The sample for comparison No. 4, which has a low carbon content outside the scope of the present invention, has a room-temperature Brinell hardness of 150, which is far lower than the target value in the present invention.

    [0042] Each of the samples of the invention Nos. 1 to 13 has, in contrast, a Brinell hardness at a room-temperature within a range of from 304 to 522, which is higher than the target value in the present invention, and has a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness, which is the target value in the present invention, and has a Brinell hardness at a temperature 400°C of at least 70% of its room-temperature Brinell hardness, which is the target value in the present invention. Thus, each of the samples of the invention Nos. 1 to 13 has an excellent wear resistance in the intermediate temperature region without largely increasing its room-temperature hardness.

    [0043] According to the present invention, as described above in detail, it is possible to obtain a wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, and has a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness, the last two Brinell hardnesses being available without largely increasing its room-temperature Brinell hardness, thus providing industrially useful effects.


    Claims

    1. A wear-resistant steel for the intermediate and room temperature service, which has a Brinell hardness at a room-temperature of at least 250, a Brinell hardness at a temperature of 300°C of at least 90% of its room-temperature Brinell hardness, and a Brinell hardness at a temperature of 400°C of at least 70% of its room-temperature Brinell hardness, characterized by consisting essentially of:

    carbon   : from 0.08 to 0.40 wt.%,

    silicon   : from 0.8 to 2.5 wt.%,

    manganese   : from 0.1 to 2.0 wt.%,

    and
    the balance being iron and incidental impurities.
     
    2. A wear-resistant steel for the intermediate and room temperature service as claimed in Claim 1, wherein:
       said wear-resistant steel additionally contains at least one element selected from the group consisting of:

    copper   : from 0.1 to 2.0 wt.%,

    nickel   : from 0.1 to 10.0 wt.%,

    chromium   : from 0.1 to 3.0 wt.%,

    molybdenum   : from 0.1 to 3.0 wt.%,

    and

    boron   : from 0.0003 to 0.0100 wt.%.


     
    3. A wear-resistant steel for the intermediate and room temperature service as claimed in Claim 1, wherein:
       said wear-resistant steel additionally contains at least one element selected from the group consisting of:

    niobium   : from 0.005 to 0.100 wt.%,

    vanadium   : from 0.01 to 0.10 wt.%,

    and

    titanium   : from 0.005 to 0.100 wt.%.


     
    4. A wear-resistant steel for the intermediate and room temperature service as claimed in Claim 3, wherein:
       said wear-resistant steel additionally contains at least one element selected from the group consisting of:

    copper   : from 0.1 to 2.0 wt.%,

    nickel   : from 0.1 to 10.0 wt.%,

    chromium   : from 0.1 to 3.0 wt.%,

    molybdenum   : from 0.1 to 3.0 wt.%,

    and

    boron   : from 0.0003 to 0.0100 wt.%.


     




    Drawing







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