热输入对2.25Cr1MoV钢粗晶热影响区再热裂纹敏感性的影响

发布时间：2018-02-10 06:08

  本文关键词： .CrMoV钢 焊接粗晶热影响区 热模拟 再热裂纹敏感性　出处：《机械工程学报》2015年06期 　论文类型：期刊论文

【摘要】：再热开裂曾多次在2.25Cr1MoV钢反应器的焊接粗晶热影响区(Coarse-grained heat affected zone,CGHAZ)部位发生,却很少在"斜Y型坡口再热裂纹试验"中出现。考虑两者之间的热输入差异,通过Gleeble热模拟试验研究热输入对2.25Cr1MoV钢CGHAZ再热裂纹敏感性的影响,并结合显微组织观察、硬度测定及断口分析,讨论热输入、组织和性能之间的关系。结果表明,在5~100 kJ/cm的热输入范围内,CGHAZ的再热裂纹敏感性随热输入的升高而增大,当热输入为35 k J/cm时,CGHAZ在675℃对再热开裂"高度敏感",限制热输入在25 kJ/cm以内,将有效降低其再热裂纹敏感性。综合分析发现,模拟CGHAZ的高温塑性与其在高温拉伸试验后硬度的变化规律之间存在良好的对应关系。当软化现象发生时,拉伸试样的断裂模式为穿晶与沿晶的混合型断裂,具有较高的断面收缩率(Reduction of area,Ro A),当二次硬化现象发生时,其断裂模式为均一的微孔聚集型沿晶断裂,RoA显著降低。试验结果从二次硬化的角度反映了高热输入条件下CGHAZ的再热脆化机理。
[Abstract]:Reheat cracking occurred many times in the coarse-grained heat affected zonezon CGHAZ site of the 2.25Cr1MoV steel reactor, but rarely in the "inclined Y groove reheat crack test". The effect of heat input on the sensitivity of CGHAZ reheat crack of 2.25Cr1MoV steel was studied by Gleeble thermal simulation test. The relationship among heat input, microstructure and properties was discussed by means of microstructure observation, hardness measurement and fracture analysis. The reheat crack sensitivity of CGHAZ increases with the increase of heat input in the heat input range of 5 ~ 100 kJ/cm. When the heat input is 35 kJ/cm, it is "highly sensitive" to reheat cracking at 675 鈩，

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