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In this paper an implant reheat cracking test by stress relaxation was introduced 文中提出了一种插销再热裂缝应力释放试验法,并对14MnMoNbB、BHW38、15MnVNCu三种压力容器用钢的再热裂缝敏感性进行了评定。可以采用:1.最低临界初应力;2.再热裂缝“C”形曲线上的最短断裂时间;作为两种判裂准则,来评定钢材的再热裂缝的敏感性.试验表明,14MnMoNbB 钢的过热粗晶区具有较强的再热脆化倾向,BHW38钢次之.而15MnVNCu 钢具有很小的再热脆化倾向,实际上很少会出现再热裂缝. In this paper a stress relief implant method for testing reheat cracking in welding has been recommended and the reheat cracking susceptibility of three pressure vessel steels 14MnMoNbB BHW38 and 15MnVNCu has been compared.Reheat cracking susceptibiliy is evaluated on the basis of two fracture criterions:the minimum initial critical stress and minimum time to fracture on"C"curve of reheat cracking. The test results have shown that the coarsegrain region of the 14MnMoNbB steel is the most sensitive to reheat... In this paper a stress relief implant method for testing reheat cracking in welding has been recommended and the reheat cracking susceptibility of three pressure vessel steels 14MnMoNbB BHW38 and 15MnVNCu has been compared.Reheat cracking susceptibiliy is evaluated on the basis of two fracture criterions:the minimum initial critical stress and minimum time to fracture on"C"curve of reheat cracking. The test results have shown that the coarsegrain region of the 14MnMoNbB steel is the most sensitive to reheat embrittlement with that of the BHW 38 steel following not far behind. The 15MnVNCu steel has the least susceptibtibility to reheat embrittlement and it is hardly possible in practice for reheat cracking to appear in this type of steel. 本文提出了一种插销再热裂缝应力释放试验法.并对14MnMoNbB、BHW38、15MnvNCu三种压力容器用钢的再热裂缝敏感性进行了评比. 本文采用:一、最低临界初应力,二、再热裂缝“C”形曲线上的最短断裂时间,作为两种判裂准则,来评定钢材的再热裂缝的敏感性。试验表明:14MnMoNbB钢的过热粗晶区具有较强的再热脆化倾向,BHW38次之,而15MnVNCu具有很小的再热脆化倾向,在实际上很少可能会出现再热裂缝. Theoretical studying has indicated that the behaviour of surrounding medium of water has a large effect on the stress corrosion process of fracture in rock. So far, experiments made for stress corrosion in rock have been done under the situation of static water. In this experiment, the subcritical develop characteristics of fracture caused by stress corrosion n Yuennan marble samples under the situation of static and flowing distilled water have been studied respectively. The results show that flowing of the... Theoretical studying has indicated that the behaviour of surrounding medium of water has a large effect on the stress corrosion process of fracture in rock. So far, experiments made for stress corrosion in rock have been done under the situation of static water. In this experiment, the subcritical develop characteristics of fracture caused by stress corrosion n Yuennan marble samples under the situation of static and flowing distilled water have been studied respectively. The results show that flowing of the medium of water around fracture may accelerate the stress corrosion process of the end of fracture. It is perharps of great signifieanse to the study of earthquake source process and the precursor just before earthquake. 理论研究[1]表明,环境水介质的动态对岩石中裂缝的应力腐蚀过程有很大的影响。但迄今为止,岩石的应力腐蚀实验都是在水介质静止情况下作的。本实验对比研究了蒸馏水静止和流动情况下云南大理岩试件应力腐蚀引起的亚临界裂缝扩展特征。结果表明,裂缝周围水介质的流动会加速裂缝端部的应力腐蚀过程,这对于震源过程及临震前兆的研究可能有重要意义。样品采用紧凑拉伸试件,同时测量了断裂韧性K_(Ic)=(1.41±0.013)kg·mm~((-3)/2),并对人工狭窄锯口与天然初始裂缝的试件进行了对比测量,认为对于云南大理岩的紧凑拉伸试件可以用人工狭窄锯口代替天然初始裂缝。
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