scope:

Part 1 details the investigations conducted by Bethlehem-Lukens Plate into the behavior of ASTM A5 16 Grade 70 steel plate subjected to post-weld heat treatment (PWHT). Those studies characterize the effects of PWHT on hardness and notch toughness of welded joints. Inherent in the scope of these efforts was some work on the behavior of the base metal. However, the reports generated from those studies in¬cluded little definitive discussion on the effects of PWHT on base metal properties. They further suggested that the amount of scatter in the limited amount of data made it difficult to establish trends, especially pertaining to any parametric analysis such as correlation with Larson-Miller Parameter (LMP). The results of earlier internal work by Lukens Steel dem¬onstrated a well-defined correlation between base metal strength, toughness and time-temperature relationships. Additional investigations have been continued by Bethlehem-Lukens Plate to improve normal¬ized base metal toughness and improve internal guidelines for predicting properties of post-weld heat-treated material conforming to A516 Grade 70. These new data reinforce previous conclusions that PWHT has a detrimental and predictable effect on base metal properties that needs to be considered when evaluating application of PWHT.

Part 2 reports compiled data on A 516 Gr. 70 and A 537 Cl. 1 base metal and welded joints in the initial (as-welded) and in the PWHT condition using data provided by Chi¬cago Bridge & Iron Company (CBI) from past welding procedure qualifications tests and other tests to assess the effect of PWHT on notch toughness (Charpy V-notch val¬ues) and hardness of base metal and heat affected zones (HAZ). Tables list the average Charpy V-notch data and the maximum hardness values from this data. The data in Tables is tabulated with respect to the mate¬rial, thickness, welding position, PWHT temperatures and hold times (in terms of Larson-Miller parameter). The results are presented in Figures which plot the changes in Charpy V-notch impact test values (delta CVN, %, and delta CVN, ft-lbs) and hardness due to PWHT versus Larson-Miller parameter (LMP). Except for the base metal data, all data was taken from past welding qualification tests. As such, it includes data on plates from various steel produc¬ers in various thicknesses and heat treat conditions, as from welds made with various welding processes and differ¬ent heat inputs