Selecting the best AISI steel grades and their proper heat treatment process by integrated entropy-TOPSIS decision making techniques

Steel is a primary component in the majority of engineering applications. The strength, hardness, and durability of any design and structure to withstand an external force are primarily determined by the steel grades. As a result, selecting the required AISI steel grades is crucial in the engineering sector. There are numerous factors present that influence its proper selection, rendering it qualified to be considered a multi-criteria decision making (MCDM) issue. The aim of this study is to select the best AISI grades of steel and their appropriate heat treatment process using an integrated Entropy-TOPSIS decision making methodology based on five mechanical properties (criteria) i.e., tensile strength, yield strength, elongation percent, reduction in area percent and hardness. Seven AISI grades are chosen for this reason, and four different heat treatment processes at various temperatures are chosen for each grade. Entropy is used as a criterion weightage calculation tool in this case, while TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) is used to choose the best choice (alternative). The selection process is carried out in three stages. Initially, suitable quenching temperature is selected followed by the proper heat treatment for all seven alternative AISI grades and finally, the best AISI grades is proposed using the integrated MCDM system. The final result demonstrates that quenched and tempered AISI 1137 steel grade at 1200F is the best option, while quenched and tempered AISI 1144 steel grade at 1200F is the worst option in the category.