Thermal—Mechanical Fatigue Behavior and Life Analysis of Cast Ni—base Superalloy K417

In-phase(IP) and out-of-phase(OP)thermal-mechanical fatigue(TMF) behavior of cast Ni-base superalloy K417 was studied.All experiments were carried out under total strain control with temperature cycling between 400-850℃.Both in-phase and out-of-phase TMF specimens exhibited cyclic hardening followed by cyclic softening at the minimum temperature.Besides,they cyclically hardened in the early stage of life followed by cyclic softening at the minimum temperature.Besides,they cyclically hardened in the early stage of life followed by cyclic softening at the maximum temperature.OP TMF life was longer than of IP TMF.Various damage mechanisms operating in different controlled strain ranges and phasing were discussed.A few life prediction methods for isothermal fatigue were used to handle TMF fatigue and their applicability to superalloy K417 was evaluated.The SEM analysis of the fracture surface showed that transgranular fracture was the principal cracking mode for both IP and OP TMF.Oxidation was the main damage mechanism in causing shorter fatigue life for IP TMF compared with OP TMF.     

提高连续油管使用寿命的方法

从采用软件跟踪疲劳寿命 ,截断法 ,变径连续油管 ,反转使用连续油管 ,防止连续油管损伤 ,合理配置设备 6个方面讨论了控制管串疲劳 ,提高连续油管使用寿命的方法 ,并得出结论 :控制管串疲劳的方法中 ,最有效的方法是实际作业截断法。指出要尽量减少连续油管在带内压下工作 ,也要研究开发降阻性能好的工作液 ,以延长连续油管使用寿命、降低作业风险。     

振动时效及其应用

振动时效技术主要是利用共振消除和均匀金属构件内部残余应力，走到增强结构件抗变形能力，稳定尺寸精度，在很大程度上替代传统的热时效和自然时效工艺，因此大大节省了能耗，降低了成本。文章介绍了振动进效的作用，特点，机理及工艺和发展应用。     

高压金属软管开裂分析

某系统在进行寿命试验时，一根高压软管开裂，经检验，软管在试验前已产生微裂纹，在试验中微裂纹呈疲劳扩展，裂纹的起源与工艺微裂有关，建议对软管的加工及热处理工艺进行改进。     

异种钢焊接接头熔合线附近腐蚀疲劳性能的研究

1 前言 异种钢焊接技术于30年代已用于锅炉制造行业。在随后的使用中发现,异种钢焊接接头的失效几乎总是发生在铁素体钢一侧的热影响区(HAZ),靠近熔合线,实际上是HAZ中的脱碳区。碳在熔合线附近的迁移导致在接头处0.5mm的间隔内显微硬度有240HV的差异,特别是当熔合线两侧分别为铁素体和奥氏体组织时,碳迁移将更为显著。     

汽轮机轴瓦龟裂原因探讨及改进

本文介绍了对汽轮机轴瓦龟裂原因的分析，解决的技术措施和操作方法，以及取得的良好效果。     

大中型风力发电机组可靠性研究

研究了大中型风力发电机组的可靠性，讨论了可靠性指标的分配，可靠性设计的四个重要方面、可靠性试验计算机模拟。