Evaluation of preheating impact on weld residual stresses in AH-36 steel using Finite Element Analysis

Shipbuilding industry is a valuable and profit earning industry which plays a vital role in country’s economic development. Ships have crucial impact on country’s trade due to necessary support for maritime transportation. Moreover, ships can be utilized for protecting coastal area. Steel chiefly utilized for ships construction due to its good strength and durability. This study emphasizes on residual stress analysis of AH-36 shipbuilding steel. Abaqus software is utilized for finite element analysis to evaluate residual stresses. Mitigation of these residual stresses is very essential; hence preheating technique is discussed in this study. Preheating was conducted at three temperatures i.e., 100ºC,150ºC and 200ºC. Results indicate that Von Mises stresses were decreased effectively due to preheating. 12.6%, 21% and 45.6% reduction were observed at preheating temperatures 100ºC, 150ºC and 200ºC respectively. Further evaluation of stresses revealed that due to preheating of base plate, longitudinal stresses reduced to 21.3%, 44% and 52.4% by increasing preheating temperature from 100ºC,150ºC and 200ºC, respectively. Mitigation of thermal gradient between weld zone and base plate resulted in reduction in overall stresses of base plate.