J.L. Li
,
K.F. Wang
,
J. Li
,
Z.M. Yao and W. Ke(Fushun Petroleum Institute
,
Fushun 113001
,
China)(Department of Chemical Engineering
,
Zhejiang University
,
Hangzhou 310027
,
China)(Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shengyang 110015
,
China)
金属学报(英文版)
Influence of hydrogen attack on mechanical and fatigue properties of 1020, 15CrMo and 2.25Cr-1Mo steels has been studied, which were exposed to gaseous hydrogen at pressure of 18MPa and 300-480℃ for up to 480h. The results of fatigue test showed that hydrogen attack (HA) resulted in an obvious change in fatigue properties of 1020 and 15CrMo steels, however, 2.25Cr-1Mo steel showed a lower susceptibility to hydrogen attack due to the addition of Cr and Mo. Fatigue crack behaviour for 1020 steel is attributed to hydrogen attack damage and the crack closure induced by the rough cracking surface, which lead to a valley on △Kth～HA% plot. The change in the fatigue behaviour of 15CrMo steel is possibly caused by severe surface decarburization.
关键词:
hydrogen attack
,
null
,
null
,
null
LI Xiaogang CHEN Hua YAO Zhiming LI Jin KE Wei Institute of Corresion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China lecturer
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The hydrogen attack of austenitic stainless steel 304 exposed to hydrogen under the pressure of 5 MPa at 733 K for 2×10~4 h in service was detected.The microstructure has been studied by SEM and TEM.Hydrogen was determined with molten samples which had tempered at.573,673,773,873,and 973 K for 6 h.The results showed that hydrogen attack in this steel was due to methane bubbles which resulted in occuring of Cr_(23)C_6.Thermodynamic analysis of hydrogen attack for stainless steel 304 was discussed.
关键词:
hydrogen attack
,
null
,
null
,
null
董超芳
,
李晓刚
,
陈华
,
李明
中国腐蚀与防护学报
对含氢腐蚀裂纹的碳钢进行1000℃、10h的再热循环处理后，SEM和TEM观察表明，氢蚀裂纹发生完全愈合.Fe和C在γ-Fe中的快速扩散是碳钢中氢蚀裂纹愈合的必要条件.氢蚀裂纹愈合的动力是氢蚀气泡长大导致的塑性变形能Es，在Fe、C和氢原子扩散都足够快的情况下，氢蚀裂纹的愈合条件是Es2γ/r(γ为界面表面张力，r为裂纹半长).TEM观察表明，氢蚀裂纹形成使晶界发生严重的塑性变形，位错密度高且相互缠绕，氢蚀裂纹的愈合过程伴随着亚晶长大、晶界滑动的高温回复过程甚至再结晶，位错回复低密度、整齐排列的低能态，片层状珠光体的出现也表明基体组织发生修复.
关键词:
碳钢
,
hydrogen attack
,
crack healing
,
TEM
董超芳
,
徐景
,
李晓刚
中国腐蚀与防护学报
利用高温显微镜，对碳钢氢腐蚀裂纹的愈合过程进行原位、 实时观察，通过录象记录了整个裂纹愈合实验过程.结果表明，裂纹在加热到630℃左右时， 发生明显愈合而变小变细.实验中造成的CH4气体散失和内部裂纹表面化使得实验结果与真 实情况有一定的偏差，观察得到裂纹闭合的临界温度630℃低于实际裂纹闭合温 度.发生氢蚀裂纹愈合的机制是热扩散，动力是氢蚀气泡长大导致的塑性变形能Es.在 Fe、C和H原子扩散足够快的情况下，氢蚀裂纹愈合的条件是Es大于2γ/r(γ为界面 表面张力，r为气泡半径或裂纹半长).
关键词:
高温显微镜
,
in-situ
,
hydrogen attack
,
crack
,
healing
董超芳
,
李晓刚
中国腐蚀与防护学报
采用热压愈合的实验方法，对碳钢氢腐蚀裂纹的愈合行为进行研究.结果表明，在热塑性变形条件下，经1000℃、压下率为40%、15 min短时间处理，能够基本消除碳钢试样内的氢蚀裂纹，局部未修复裂纹呈现为尺寸4 μm～8 μm的透镜状.与单纯高温愈合处理(1000℃循环热处理10 h)的实验结果相比，塑性形变可大大缩短裂纹愈合所需要的热处理时间。热塑性变形下的裂纹愈合进程及程度加大，且氢蚀裂纹内高压甲烷气体的分解不是裂纹愈合过程的控速步骤.
关键词:
碳钢
,
hydrogen attack
,
crack
,
healing
