XU Xue-xia
,
BAI Bing-zhe
钢铁研究学报(英文版)
Modified CCT diagram of carbide free bainite-martensite（CFB/M）high strength steel was established applying small sample control cooling. In addition, the influence of thermomechanical treatment temperature on its structure and properties was discussed. The experimental results show that when deformed at 860oC and below, ferrite transformation occurred due to strain, and with the decrease of ausforming temperature, the quantity of ferrite increased and strength and toughness deteriorate. Therefore, certain information were provided for drawing technical parameter of ausforming process; firstly, the thermomechanical treatment temperature shouldn’t be above 860oC to avoid ferrite formation induced by deformation; secondly, cooling rate shouldn’t be too slow to avoid ferrite precipitating during cooling process after ausforming process.
关键词:
thermomechanical treatment;carbide free bainite/martensite(CFB/M);high strength steel
ZHANG Han
,
BAI Bing-zhe
,
et al
钢铁研究学报(英文版)
A new Mn series oil quenching super strong bainitic steel was developed on the basis of the alloy system of the original Mn series air cooling bainitic steel. The mechanical properties of the new steel are well combined while precious alloy elements and complicated technologies are not needed for its production. Experimental results show that: bainite/martensite(B/M) dual phase microstructure can be obtained within a very wide cooling rate range and bainite microstructure exists even when the cooling rate reaches as fast as 60oC/s; the hardenability of the steel is better than that of 40CrNiMo and 42CrMo; the round bar made of the steel with the diameter of 250mm, which goes through tempering at 350oC after oil quenching, exhibits its central mechanical properties as follows: σb=1550MPa, σ0.2=1270MPa, δ5=15%, aku=95J/cm2 (at room temperature).
关键词:
bainite;oil quenching;hardenability;mechanical property;martensite
