XING Shu-qing
,
CHEN Zheng-zong
,
MA Yong-lin
,
LI Hui-qin
钢铁研究学报(英文版)
The effect of refined precipitations and dispersed phases on the toughness of SS400 steel was investigated by rapid tempering with thermomechanical simulation tester, and the electromagnetic induction rapid tempering process was simulated. The conventional tempering and rapid tempering process were proceeded respectively, and both samples were quenched in 10% of agitated iced brine. The tempering temperatures were designed as 560, 620 and 680 ℃, respectively. Rapid tempering specimens were heated at a heating rate of 20 ℃/s, and all samples of these three tempering temperatures were maintained 30, 40 and 50 s with the Gleeble1500-D tester, respectively. The impact test at -40 ℃ were carried out on a Charpy impact machine (CBD-300) with a maximum measurement range of 300 J and the microstructures were analyzed in detail using optical microscope (OM) and scanning electron microscope (SEM). The experiment results show that the upper bainite, martensite and small amount of austenite were obtained in the rapidly quenched samples. In comparison to the conventional process, the matrix microstructure was changed from the larger size and bulk ferrite to the refined banding structure, and the cementites were obviously refined and precipitated inside the grains and along the grain boundaries. The cryogenic impact test implies that the maximum values of impact toughness with holding time of 30 or 50 s are achieved at tempering temperature of 620 ℃. Furthermore, a favorite value of impact toughness with holding time of 40 s is available.
关键词:
SS400 steel
,
rapid tempering process
,
thermomechanical simulation tester
,
precipitation
,
cryogenic impact toughness
陈书浩，王新华
,
何肖飞
,
曾建华
,
王万军
钢铁
研究了攀钢新钢钒公司生产帘线钢72A过程中钢中氮含量变化对钢中TiN夹杂析出的影响。研究发现，随着钢中氮含量的升高，钢中析出的TiN夹杂数量变多，尺寸变大。热力学研究表明，在帘线钢中TiN一般只能在固相区形成，考虑元素偏析对凝固前沿元素富集的影响，凝固过程中TiN能在固液两相区析出。在帘线钢生产过程中，为了控制钢中TiN的析出，除了控制钛含量，控制钢中氮含量及氮偏析更加重要。理论计算结果表明，当钢中钛的质量分数控制在0.0003%~0.0005%区间时，将钢中氮的质量分数控制在0.0017%~0.0029%区间内能显著降低乃至杜绝帘线钢中TiN的析出。攀钢将帘线钢中钛、氮的质量分数分别控制在0.0005%以下和0.002%以下，显著减少了钢中TiN的析出，个别炉次中没有发现尺寸大于2μm的TiN夹杂。
关键词:
帘线钢
,
TiN
,
precipitation
,
solidification
,
segregation
王康
,
，杨卯生，樊刚，俞峰，鲍俭
,
，闫文凯
钢铁
对16Cr14Co12Mo5耐热耐蚀轴承钢在1050℃高温淬火后，在490～540℃两次回火后的组织性能以及强韧化机制进行研究。结果表明：随着回火温度的升高，抗拉强度Rm逐渐增加，最大时超过了1900MPa，屈服强度Rp0.2在500℃回火后达到1400MPa，随后逐渐减小；断面收缩率和伸长率略有减小，而硬度略有增长。材料强韧化主要源于高位错板条马氏体以及其中残余奥氏体薄膜和沉淀析出的碳化物和金属间化合物。采取适宜淬回火工艺制度所导致弥散析出的碳化物和金属间化合物是试样的强度和韧性达到最佳配合的关键。
关键词:
轴承钢
,
precipitation
,
carbide
,
intermetallic compound
