铁基粉末冶金零件热处理

热处理是一种成熟的,经常使用的工艺性技术。这篇文章评述了人们不大注意的铁基粉末冶金零件整体淬火时,孔隙度与合金含量对其淬透性的影响。     

化学成分回归分析预测20CrMnTiH钢的淬透性和机械性能

利用逐步回归分析的方法得出了化学成分对20CrMnTiH齿轮钢淬透性(J9,J15)和机械性能(σb、σS、ak)影响的回归方程,以便控制钢冶炼时的化学成分。     

SA350 LF2CL1管板锻件工艺优化

针对ASMESA3 5 0LF2CL1管板锻件AKV( -45 .6℃ )不合格问题进行分析 ,通过采用细化晶粒、提高材料淬透性的工艺方法彻底解决了这一问题     

Heat Treatment Properties of 42CrMo Steel for Bearing Ring of Varisized Shield Tunneling Machine

The heat treatment properties of 42 CrMo steel for bearing ring of varisized shield tunneling machine were investigated by optical microscope(OM), scanning electron microscope(SEM), transmission electron microscope(TEM),and impact tests. The addition of 0.03 wt% C into 42 CrMo steel can increase the hardness. But it reduces the impact energy by 46 J because of the appearance of coarser carbides in the matrix and the carbides along the austenite grain boundary.The addition of 0.40 wt% Mn into 42 CrMo steel can improve hardenability. However, the toughness of steel is also reduced by 26 J mainly because of the coarsening of carbides and the strengthening of matrix. Both hardenability and toughness of 42 CrMo steel can be improved by adding 1.49 wt% Ni and reducing 0.32 wt% Cr. The depth of hardening layer can be raised to 45 mm, and the impact energy at-20 °C is 120 J. Thus, it is concluded that a good combination of hardness, hardenability, and toughness of 42 CrMo steel can be achieved by alloying with adding some content of C and Ni.Detailed content of C and Ni should be on the requirements of heat treatment properties of steel for bearing ring of varisized shield tunneling machine.     

40 t EAF-LF-VD-3.7 t铸锭工艺高品质齿轮钢20MnCr5H-1的研制

采用40 t电弧炉-LF-VD-3.7 t锭模铸-轧制工艺开发了20MnCr5H-1高品质齿轮钢(/%:0.17~0.22C,≤0.12Si,1.0~1.5Mn,≤0.035P,0.015~0.035S,0.8~1.3Cr,≤0.0020O,0.015~0.045A1)-Φ80 mm材。通过控制EAF终点[P]≤0.015%,LF精炼渣碱度≥2.5,并调整钢中元素含量,VD处理、喂硫线等工艺措施,试制的5炉20MnCr5H-1钢的成分为(/%):0.16~0.20C,0.05~0.12Si,1.20~1.30Mn,0.009~0.025P,0.020~0.035S,1.00~1.10Cr,0.0008~0.0015O,0.015~0.040Al,淬透性带宽△HRC为4,各项指标均满足要求。     

新型高合金齿轮渗碳钢渗层淬透性研究

本文利用端淬试验法和剥层试验法研究了新型高合金钢17CrN iMo6的渗层淬透性,旨在找出参考含碳量的影响因素,绘制出了17CrN iMo6钢的渗碳层的淬透性曲线和参考含碳量曲线,以及不同J距离处的硬度延层深的变化曲线,结果表明,渗碳齿轮淬火后从表面到有效硬化层深度界限硬度550HV相对应的含碳量不是一个固定值,随着合金成分、淬火冷却状况及工件尺寸大小而变化。     

限制淬透性GCr4轴承钢的组织和性能

试验研究了成分为:1.00%C、0.40%Cr、0.03%Mo、0.034%Al、10×10^-6[O]的GCr4轴承钢经感应穿透加热-表面淬火(840±10)℃+回火150～160℃后的组织和性能。结果表明,热处理后GCr4钢表面层由孪晶马氏体和位错马氏体组成,心部组织为屈氏体+索氏体。GCr4钢的淬透性(J60,3.0 mm)明显低于GCr15钢(1.01%C、1.52%Cr、11×10^-6[O])的淬透性(J60,4.5 mm);其感应加热淬火+回火的冲击韧性和断裂韧性KIC分别比(840±10)℃淬火+(150～160)℃回火的GCr15钢提高66%～104%和67%。GCr4钢接触疲劳寿命较GCr15钢提高12%～26%。     

20CrMnTiH(FQ)淬透性工艺研究

淬透性是20CrMnTiH(FQ)的重要性能指标,20CrMnTiH(FQ)要求的淬透性带宽6-8HRC,属于窄带,在开发时曾发生大比例由于淬透性不合而由协议标准改用国标的情况,经过课题组的攻关,目前已完全解决淬透性问题,合格率由最初的50%～60%提高到98%。     

Characterization of the austemperability of partially austenitized ductile iron

This study focuses on the characterization of the hardenability and the austemperability of partially austenitized ductile iron melts alloyed with small amounts of Cu, Ni and Mn.     

履带钢硬度偏低原因分析和改进

针对目前莱钢生产的履带钢表面硬度值偏低问题,通过提高钢中合金元素Cr和Ti的含量与改进热处理工艺等措施的综合实施,获得了比较良好稳定的表面硬度,满足了特殊环境下履带钢具有耐磨性的使用要求。