开卷机棱锥轴断裂的失效分析

通过扫描电镜断口、成分分析、金相分析和硬度测试等方法,对热轧平整线开卷机棱锥轴的失效原因进行了分析。结果显示该开卷机棱锥轴的断裂为准解理断裂。尽管轴的硬度能够达到设计要求,但在淬透性和强韧性方面,代用钢42CrMo比设计要求选用的40CrNiMo差。裂纹启裂是由应力集中、表面不平整和材料强韧性不够等综合因素引起,心部未淬透组织加速了裂纹的扩展速度。     

基于非线性方程法的齿轮钢淬透性计算模型

采用非线性回归方程计算方法,结合实际生产的齿轮钢淬透性数据对数学模型进行修正。在此基础上,开发了齿轮钢淬透性的计算预报平台,实现根据成分和预设的晶粒度级别预报任意端淬距离的淬透性值。模型预测精度高于传统的多元线性回归方法。     

窄淬透性齿轮钢20CrMnTiH5工艺研究

针对齿轮钢20CrMnTiH5窄淬透性带及低氧含量、高纯净度等生产质量难点,通过优化内控化学成分,采用四位一体短流程生产工艺,冶炼加强控制脱氧和夹杂物上浮工艺、轧制采用控轧控冷工艺、表面采用红外线探伤和修磨相结合方式,产品实物质量达到了低氧、晶粒细小、组织均匀、窄淬透性带、表面无缺陷的高质量水平。     

16MND5锻件的制造

通过控制冶炼时配料的化学成分,减少气体和夹杂物的含量。采用合适的锻造和热处理工艺,使锻件的超声波探伤检验、金相检验、力学性能检验结果全部合格,FATT50为-35℃,RTNDT≤-12℃。     

ALLOYING BEHAVIOUR OF Ca IN STEEL 58CrV

Effect of Ca on hardenability and CCT diagram of steel 58CrV has been investigated bymeans of end-quenching and thermal expansion.An addition of 0.006 wt-%Ca to the steelmay improve the hardenability,reduce the critical cooling rate of transformation of pearlite orbainite under continuous cooling and increase the M_s.AES analysis showed that Ca segre-gates markedly along austenitie grain boundaries,and accelecrates the segregation of C,Crand Si.It is believed that besides towards deoxidizing and desulphurizing as well as improvingsulphide morphology,a trace of Ca in steel 58CrV behaves towards microalloying.     

提高氮化钢38CrMoAlA综合性能的可行性研究

针对传统氮化钢38CrMoAlA存在的质量缺陷,重点研究了化学元素含量对材料性能的影响,并对优化前后材料的各项性能指标作了大量对比试验。结果表明:化学元素含量增加的材料淬透性好,强度高,组织均匀,综合力学性能好,品种优点更为突出,各项性能指标均优于传统的氮化钢38CrMoAlA。     

Comparison of hardenability and over-aging precipitation behaviour of three 7xxx aluminium alloys

The purpose of the paper is to compare hardenability and aging precipitation behaviour of three 7xxx aluminium alloys (7150, 7055 and 7056). The hardenability has been studied by Jominy test. The aging precipitation behaviour has been investigated according to their hardness and electrical conductivity after over-aging treatment. The micro-structural characterisation has been observed by scanning electron microscope and transmission electron microscope. These results show that AA7056 has the highest hardenability and sensitivity to over-aging treatment compared with AA7150 and AA7055. The highest w(Zn)/w(Mg) ratio and the lowest Cu content of AA7056 are beneficial for inhibiting quench precipitates and decreasing the stability of meta-stable η′ phase.     

T91和P9取热管异种钢焊接

分析T91、P9取热管的焊接性能,针对其淬硬性强,冷裂纹倾向大的特点,采取焊前预热、严格控制层间温度、焊后及时消氢等工艺措施,避免冷裂纹产生,确保焊接接头性能,并成功应用在生产实践中。     

45钢热处理组织异常原因分析与控制

45钢在使用过程中热处理组织出现晶粒粗大、淬透性差的问题。经检验发现多个炉次生产的产品均出现了此问题，因此分析认定这是一个系统的质量缺陷问题，钢水中杂质含量较多且分布不均、轧制温度较高是造成该问题的主要原因，并对此提出了解决的方案与方法。     

浅析淬透性和淬火介质

通过对淬透性的介绍和分析,引出淬火介质,通过对淬火介质的详细分析及其适用范围的具体阐述,指出了两者之间的关系。