A comparison of different experimental approaches in the determination of dynamic fracture toughness (J_1d) behavior for RHA steel cost sustainable MMAW weldments

Abstract

In the present investigation, the low hydrogen ferrite consumable weldment (weldment-1) and austenitic stainless steel consumable weldment (weldment-2) of rolled and homogenous armor steel (RHA) have been prepared with manual metal arc welding (MMAW). Further, the influence of weldments (weldment-1 and weldment-2) microstructure on the dynamic fracture toughness (J_1d), strength, ductility and hardness has been evaluated and compared. The three different approaches have been utilized to estimate J_1d for RHA weldments. Further, all three approaches’ outcomes have been compared with the elastic-plastic fracture mechanics (EPFM) approach through J_p-R curve. The results revealed that weldment-1 (yield strength 504.24 MPa and ultimate tensile strength 763.03 MPa) exhibited 26.93 and 25.07% more yield and tensile strength respectively than weldment-2 (yield strength 384.55 MPa and ultimate tensile strength 593.05 MPa). Further, the elongation of weldment-2 (elongation 42%) is 26.72% more than weldment-1 (elongation 32.10%). The joint efficiency and fusion zone hardness of weldment-1 are 5.85 and 57.56%, respectively more than weldment-2. The EPFM approach has good agreement with the correction factor approach (approach 2) and the compliance change rate approach (approach 3) with less than 7% difference in the estimation of dynamic fracture toughness of base metal and weldments (weldment-1 and weldment-2). Further, the percentage difference between maximum load point approach (approach 1) and the EPFM approach is more than 15% difference. The fractographic investigation confirms the ductile fracture in all under-investigated materials.

Keywords:

• RHA steel
• MMAW
• J_1d behavior
• EPFM approach
• crack initiation energy
• compliance change rate

Acknowledgment

No funding is available with this article.

Ethical approval

This article does not contain any studies with human and animal subjects performed by any of the authors.

Author contributions

Ambuj Saxena: Conceptualization, methodology, validation, investigation. Tarun Kumar Gupta: Data curation, writing – original draft. Rishi Srivastava: Software, data curation. Ashish Kumar Srivastava: Formal analysis, visualization, writing - review & editing. Ajay Kumar: Final editing.

Disclosure statement

No potential conflict of interest was reported by the the author(s).