Local post-weld heat treatment (PWHT) is the only option for heat treating field welded joints. Quite often, the success of local PWHT in alleviating the residual stress and tempering the material within the soak band (SB) is dependent on the ability to achieve the required heat treatment temperature and maintain through-thickness temperature gradient (TTG) within the specified limits at the end of heating cycle, whence soaking begins. Field observations reveal the inadequacy of AWS D 10.10 specified parameters viz. rate of heating (ROH), heat band (HB) and insulation band width in not achieving the required TTG for certain pipe dimensions. Although prior works have attempted to address this issue by widening the HB, the capacity of the heating equipment often pose a limitation. In such cases, reducing ROH is a plausible alternative. With, no such prior studies seen in literature, an exhaustive finite-element analysis simulating the local PWHT on 81, SA106GrC pipe samples (diameter and thickness varied in 9 levels each) was performed, thrice. First as per AWS recommendations, second by halving the code deduced ROH and third by doubling the code deduced HB. The trend of important outcomes (TTG, power source rating and energy consumption) with great significance to the heat treatment industry were also compared and analysed. Two nomograms were developed to serve as a ready reckoner for field heat treater in not only assessing the adequacy of heat treatment parameters but also with possible alternatives in achieving the desired TTG using field-available power source.

中文翻译：

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将管道尺寸与局部热处理的成功相关联：开发列线图来推导热处理参数

局部焊后热处理 (PWHT) 是现场焊接接头热处理的唯一选择。通常，局部焊后热处理在减轻残余应力和在均热带 (SB) 内对材料进行回火方面是否成功取决于能否达到所需的热处理温度并将全厚度温度梯度 (TTG) 保持在指定范围内在加热周期结束时，浸泡开始。现场观察揭示了 AWS D 10.10 指定参数的不足之处。对于某些管道尺寸，加热速率 (ROH)、加热带 (HB) 和保温带宽度未达到所需的 TTG。尽管先前的工作已尝试通过加宽HB来解决这个问题，但加热设备的容量通常会造成限制。在这种情况下，降低 ROH 是一个可行的替代方案。由于文献中没有此类先前研究，因此对 81 个 SA106GrC 管道样品（每个直径和厚度在 9 个级别上变化）进行了三次详尽的有限元分析，模拟局部 PWHT。首先按照 AWS 建议，其次通过将代码减半推导出 ROH，第三通过将代码加倍推导出 HB。并对对热处理行业具有重要意义的重要成果（TTG、电源额定值和能耗）的趋势进行了比较和分析。我们开发了两个列线图，作为现场热处理人员的现成计算工具，不仅可以评估热处理参数的充分性，还可以提供使用现场可用电源实现所需 TTG 的可能替代方案。