A STUDY OF RULES OF MATERIAL GROUPINGS IN ASME Ⅸ QW-420 BY DECISION TREE METHOD

摘要

Based on ASME Ⅸ QW-420, each base metal is assigned a P-No., which is a critical material parameter and used extensively in the ASME Codes, including welding procedure qualification, qualification of welder and welding operator, preheat and post weld heat treatment., etc. However, unlike EN and ISO standards, ASME Code doesn't explicitly specify the rules of material grouping, which brings inconvenience in some circumstances. In this study, the 1872 base materials in ASME Ⅸ QW-420 (2007 Edition) are investigated from the point of view of material chemical composition, mechanical properties and weldability, with the aid of decision tree method. Through the study, a complete set of rules is given to classify a certain material into a P-No. , which provides an aspect to understand ASME material grouping and facilitates use of the Code, and more importantly, helps to implement the principle of ASME Code in local standards.