EP 0473561 B1 19960207 - A method of heat treatment of a steel product
Title (en)
A method of heat treatment of a steel product
Title (de)
Verfahren zur Wärmebehandlung eines Stahlprodukts
Title (fr)
Procédé de traitement thermique d'un produit en acier
Publication
Application
Priority
BE 9000787 A 19900814
Abstract (en)
[origin: EP0473561A1] Method of heat treatment of a steel product leaving the rolling mill in which, during a first stage, the product is subjected to cooling with water to a surface temperature which is equal to or lower than the temperature of the onset of the martensite transformation (Ms point) of the steel, with a rate of cooling which is at least equal to the critical rate for quenching the steel; during a second stage the product is first of all subjected, by virtue of the heat released by the unquenched part of the product, to a reheating of the quenched surface layer to a surface temperature, known as the self-annealing temperature, of between 550 DEG C and 650 DEG C, and then to a secondary cooling to a surface temperature of less than 450 DEG C; the final cooling of the product to a temperature of less than 120 DEG C is then performed, for example with the aid of highly agitated water. During the stage which follows the self-annealing, the product may first of all advantageously be allowed to stay in air up to a temperature of approximately 550 DEG C, and then be cooled at high speed to a temperature substantially below 400 DEG C, and be reheated to a temperature of between 400 DEG C and 420 DEG C before being allowed to cool in air. <IMAGE>
IPC 1-7
IPC 8 full level
C21D 1/18 (2006.01); C21D 1/02 (2006.01); C21D 1/19 (2006.01); C21D 6/00 (2006.01)
CPC (source: EP)
Designated contracting state (EPC)
AT BE DE ES FR GB IT LU NL SE
DOCDB simple family (publication)
EP 0473561 A1 19920304; EP 0473561 B1 19960207; AT E133996 T1 19960215; BE 1004526 A6 19921208; DE 69116958 D1 19960321; JP H04232206 A 19920820
DOCDB simple family (application)
EP 91870119 A 19910806; AT 91870119 T 19910806; BE 9000787 A 19900814; DE 69116958 T 19910806; JP 20444391 A 19910814