Simplified Mathematical Modeling of Implant Limit Stress and Maximum HAZ Hardness.

Hydrogen-induced cracking (HIC) susceptibility in the heat-affected zone (HAZ) was investigated and modeled using implant static tensile limit stress (σ_imp) and maximum hardness of the HAZ (HV_10MAX). C-Mn and high-strength low-alloy (HSLA) steels were used as base metals with a carbon equivalent (CE) ranging from 0.38 to 0.48% and 0.52 to 0.69%, respectively. The shielded metal arc welding (SMAW) and gas metal arc welding (GMAW) processes with CO₂ shielding gas were used. The diffusible hydrogen (H) content was varied taking the values between 2 and 40 mL/100 g. σ_imp and HV_10MAX were the two measures used to evaluate the weldment susceptibility to HIC. Using Pearson's product-moment coefficient (P_pm) and the developed analysis of HIC susceptibility, two simplified models were developed using simple mechanistic models, linear and logarithmic, to simulate σ_imp and HV_10MAX. σ_imp was modeled as a function of HV_10MAX and H, while HV_10MAX was modeled as a function of CE and t_800/500. The two new simplified models were capable of accurately simulating both simp and HV_10MAX. The newly developed models form a simplified tool that can be used to assess HIC susceptibility in steel weldments. [ABSTRACT FROM AUTHOR]