第1部分:锅炉和压力容器用钢的热处理报告——Cr-Mo焊接件中的碳迁移对冶金结构和机械性能的影响研究了Cr-Mo焊接件中碳剥蚀“软”区的出现和行为，以确定其对机械性能和使用性能的影响。进行了室温拉伸试验、蠕变断裂试验和云纹干涉法评估，以表征铬钼焊接件中这一独特区域的行为。该区域是由焊缝金属和母材金属之间的铬水平差造成的。使用OLM、SEM和STEM技术完成了广泛的金相分析。我们的结果表明，脱碳“软”区的出现是由于碳迁移，这是由焊缝金属和母材之间的元素差异（尤其是铬）驱动的。 碳迁移的程度取决于焊后热处理时间表。OLM特征表明，在2¼Cr-1Mo焊接金属和2¼Cr-1Mo母材焊接件中，A&T条件下的“软”区最宽。下一个最宽的是N&T条件，其中只有几个晶粒宽，而PWHT条件下的“软”区非常窄（宽一个晶粒）。在9Cr-1Mo焊缝金属和2¼Cr-1Mo母材焊接件中，热影响区（HAZ）重叠区域内的“软”区发展在焊后热处理（1350°F时小于1小时）后的短时间内开始，然后随着温度的升高沿整个熔合线扩散。第2部分:锅炉和压力容器用钢的热处理报告——ASME焊后热处理实践:解释性报告本报告的目的是审查现行ASME规范要求，找出不一致之处，提供变更建议，并推荐应作为焊后热处理（PWHT）实践进一步变更基础的研究。 根据对焊后热处理实践和现行规范规则影响的审查，得出结论，现行规范规则通常适用于无缺口韧性要求的高碳钢。对于具有韧性和增强焊接能力的现代钢，现行规范规则可能会施加不必要的要求，并且对于某些钢，可能会对钢的性能产生不良影响。对与时间和温度相关的具体要求的审查表明，一些要求与文献数据不一致，需要修订。我们建议修订规范规则，将焊后热处理要求与缺口韧性和无损检测考虑因素联系起来，前提是由于外部因素（即。 e、 ，环境影响）。这样的修改将允许在一些压力容器的制造中利用高韧性对使用性能的影响。本文还介绍了作为代码需求变更基础的具体研究。

Part 1: Reports on Heat Treatment of Steels Used in Boiler and Pressure Vessel Applications - Carbon Migration in Cr-Mo Weldments Effect on Metallurgical Structure and Mechanical PropertiesThe occurrence and behavior of a carbon denuded "soft" zone in Cr-Mo weldments was studied to determine its influence on mechanical properties and in-service behavior. Room temperature tensile tests, creep rupture tests and Moire interferometry evaluations were performed in order to characterize the behavior of this unique zone in Cr-Mo weldments. The zone is brought about by chromium level differentials between the weld metal and base metal. Extensive metallography was accomplished using OLM, SEM and STEM techniques.Our results show that the occurrence of the carbon denuded "soft" zone is due to carbon migration, which is driven by elemental differences (especially in chromium) between the weld metal and base metal. The extent of carbon migration depends on the PWHT schedule. OLM characterizations show that in 2 ¼ Cr - 1Mo weld metal and 2 ¼ Cr - 1Mo base metal weldments the "soft" zone is widest for the A & T condition. Next widest is the N & T condition where it is only a few grains wide, while the "soft" zone is very narrow (a grain wider) for the PWHT condition. In a 9 Cr - 1Mo weld metal and a 2 ¼ Cr - 1Mo base metal weldment the "soft" zone development begins a short time after PWHT (less than 1 hr at 1350°F) in the overlapped region of the heat-affected zone (HAZ), and then spreads along the entire fusion line as time at temperature increase.Part 2: Reports on Heat Treatment of Steels Used in Boiler and Pressure Vessel Applications - ASME Post-Weld Heat Treating Practices: An Interpretive ReportThe purpose of this report is to review the present ASME Code requirements, identify inconsistencies, provide recommendations for changes and recommend research that should be the basis of further changes in post weld heat treatment (PWHT) practices.Based on a review of the effects of PWHT practices and the present Code rules, it is concluded that present Code rules are generally applicable to high carbon steels produced without notch toughness requirements. For modern-day steels that exhibit toughness and enhanced weld-ability, the present Code rules might impose unnecessary requirements and, for certain steels, might actually produce undesirable effects on the properties of the steel.A review of specific requirements related to time and temperature indicate that some are not consistent with literature data and are in need of revision.We propose that revisions be made to the Code rules to relate the PWHT requirements to notch toughness and nondestructive examination considerations when a PWHT is not required because of outside considerations (i.e., environmental effects). Such revisions would permit economies in the fabrication of some pressure vessels to take advantage of the effect of high toughness on service performance. Specific research that would be the basis of changes in Code requirements is presented.