The hydrogen assisted cracking susceptibility of Modified 9Cr–1Mo steel weld is evaluated by implant test by determining lower critical stress for different preheating and combination of pre, post heating conditions. The diffusible hydrogen present in the implant specimens for different test conditions is estimated. Residual stress distribution in the weld for different heating condition is estimated using SYSWELD software. For a combination of pre + post heating at 200°C, the diffusible hydrogen content of the weld comes down to 1.17 from 4.7 mL/100g and the lower critical stress of the implant specimen increases from 250 to 370 MPa. Preheating + post heating also brings down the peak tensile residual stress level in the weld joints and lowers the cracking susceptibility.

中文翻译：

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预热和后加热对降低改性9Cr-1Mo钢扩散氢含量和氢致裂纹敏感性的影响

通过植入试验，通过确定不同预热和预、后加热条件组合的较低临界应力来评估改性 9Cr-1Mo 钢焊缝的氢辅助开裂敏感性。估计不同测试条件下植入物样品中存在的扩散氢。使用 SYSWELD 软件估计不同加热条件下焊缝中的残余应力分布。对于 200°C 的预加热和后加热的组合，焊缝的扩散氢含量从 4.7 mL/100g 降至 1.17，并且植入物样品的下临界应力从 250 MPa 增加到 370 MPa。预热+后加热还降低了焊接接头中的峰值拉伸残余应力水平并降低了开裂敏感性。