Process for manufacturing a carburized or carbonitrided steel component, and steel for the manufacture of this component

US6090225A · kind A · utility

Assignee

• Ascometal · FR

Inventor

• Claude Pichard · Moyeuvre-Grande, FR

Key dates

• Filing date: Jul 9, 1998
• Grant date: Jul 18, 2000
• Expiry date: Jul 9, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C38/00
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Process for manufacturing a mechanical component made of steel, in which a blank of the steel component is manufactured and a high-temperature carburizing or carbonitriding treatment of at least part of the surface of the blank of the component is carried out, the chemical composition of the steel of which the component is composed comprises, by weight: 0.15%.ltoreq.C.ltoreq.0.35%; 0%.ltoreq.Si.ltoreq.0.6%; 0%.ltoreq.Mn+Cr+Ni+Mo.ltoreq.5%; 0%.ltoreq.Al.ltoreq.0.1%; 0%.ltoreq.Cu.ltoreq.0.5%; 0%.ltoreq.Ti.ltoreq.0.05%; 0.004%.ltoreq.N.ltoreq.0.02%; 0%.ltoreq.S.ltoreq.0.15%; P.ltoreq.0.03%; optionally, up to 0.02% tellurium, up to 0.04% selenium, up to 0.07% lead, up to 0.005% calcium, the balance being iron and impurities resulting from the smelting; the chemical composition being adjusted so that the Jominy curve of the steel is such that: 45 HRC.ltoreq.J.sub.3 .ltoreq.50 HRC; 39 HRC.ltoreq.J.sub.11 .ltoreq.47 HRC; 31 HRC.ltoreq.J.sub.25 .ltoreq.40 HRC; the average values J.sub.3m, J.sub.11m and J.sub.25m of five Jominy tests are such that: .vertline.J.sub.11m -J.sub.3m .times.14/22-J.sub.25m .times.8/22.vertline..ltoreq.2.5 HRC and J.sub.3m -J.sub.15m .ltoreq.9 HRC. Carburizing or …