Cooling process and mechanical properties design of high carbon hot rolled high strength (HRHS) steels

✍ Scribed by Cheng Liu; Yunxu Liu; Changtao Ji; Qihui Zhu; Jikui Zhang

• Publisher: Elsevier Science
• Year: 1998
• Weight: 59 KB
• Volume: 19
• Category: Article
• ISSN: 0261-3069
• DOI: 10.1016/s0261-3069(98)00017-x

✦ Synopsis

The HRHS steel has been used at its very best in automobile parts. Compared with hardened and tempered steels, it can save Ž . on a vast amount of heat energy omitting the hardening and tempering from the process , lower the noise in operation, ensure Ž . safety in production greatly avoiding microcrack of parts in quenching . At present, on the basis of the residual heating after Ž . Ž . forging and the controlled cooling, the medium carbon ; 0.4 wt.% Mn᎐V or Ti, Nb, Zr HRHS alloy steels with pearlite and ferrite microstructure have been mainly used in automobile factories all over the world. However, because the ability to control cooling is not too much in continuous cooling for parts, thus there are a lot of problems in industrial production including only one kind of steel grade corresponding to one kind of part, the strict requirement of controlling hardenability band, only in parts Ž . with relatively low strength and toughness HB 229 ; 269 and high cost. Mechanical properties and microstructure after Ž . continuous cooling and isothermal treatment of the high carbon ; 0.7 wt.% HRHS steel are investigated in this paper. Experimental results show that the investigated steel has extremely flaked pearlite after isothermal treatment and mechanical Ž . properties which can attain a standard of high strength and toughness HB 269 ; 306 of medium carbon hardened and tempered steels with tempered sorbite. Moreover, it can not only maintain the good points of medium carbon HRHS steel in industry, but also overcome its deficiency.