EP 3155134 A1 20170419 - METHOD OF HEAT TREATMENT OF BEARING STEEL
Title (en)
METHOD OF HEAT TREATMENT OF BEARING STEEL
Title (de)
VERFAHREN ZUR WÄRMEBEHANDLUNG VON LAGERSTAHL
Title (fr)
PROCÉDÉ DE TRAITEMENT THERMIQUE D'ACIER POUR ROULEMENTS
Publication
Application
Priority
- CZ 2014405 A 20140612
- CZ 2015000060 W 20150611
Abstract (en)
[origin: WO2015188796A1] This heat treatment of bearing steel comprises annealing and hardening. Hardening is carried out after annealing and after the manufacture of structural parts from this steel. The first part of the annealing process is heating of the steel at a rate of more than 1 °C/s to a temperature in the range between 750 °C and 900 °C. It is followed by holding at the temperature achieved for at least 400 seconds. This is followed by cooling at a rate higher than 0.02 °C/s to a temperature, at which austenite begins to transform to ferrite and carbides. In the next step, there is cooling to such temperature and at such rate that complete transformation of austenite to ferrite and carbides takes place at least in the desired location of the steel. The cycle of heating, holding and cooling is carried out at least once. Then the steel is cooled to the ambient temperature. In the preferred embodiment, the quenching temperature during subsequent hardening is lower than the quenching temperature of the conventionally annealed steel in question. The steel may be heated by induction.
IPC 8 full level
C21D 1/78 (2006.01); C21D 1/32 (2006.01); C21D 9/32 (2006.01); C21D 9/40 (2006.01); C22C 38/02 (2006.01); C22C 38/18 (2006.01); F16C 33/62 (2006.01)
CPC (source: EP)
C21D 1/32 (2013.01); C21D 1/785 (2013.01); C21D 9/32 (2013.01); C21D 9/40 (2013.01); C22C 38/02 (2013.01); C22C 38/18 (2013.01); F16C 33/62 (2013.01); C21D 2211/004 (2013.01); C21D 2211/005 (2013.01); F16C 2202/04 (2013.01); F16C 2204/66 (2013.01); F16C 2223/18 (2013.01)
Citation (examination)
GARG A ET AL: "Estimation of martensite carbon content in as-quenched AISI 52100 steel by X-ray diffraction", MATERIALS LETTERS, ELSEVIER, AMSTERDAM, NL, vol. 4, no. 4, 1 June 1986 (1986-06-01), pages 214 - 218, XP024150418, ISSN: 0167-577X, [retrieved on 19860601], DOI: 10.1016/0167-577X(86)90100-X
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated extension state (EPC)
BA ME
DOCDB simple family (publication)
WO 2015188796 A1 20151217; WO 2015188796 A4 20170302; CZ 2014405 A3 20151223; CZ 305587 B6 20151223; EP 3155134 A1 20170419
DOCDB simple family (application)
CZ 2015000060 W 20150611; CZ 2014405 A 20140612; EP 15741719 A 20150611