Optimisation of parameters influencing cold crack resistance of SAE 950A steel

• Published in: Sadhana (Bangalore) Vol. 46; no. 3
• Main Authors: Manivelmuralidaran, V, Senthilkumar, K, Ebby, Jacob, Prabhu, T Ram
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.09.2021; Springer Nature B.V
• Subjects: Cold; Crack propagation; Engineering; Fracture surfaces; Heating; High strength low alloy steels; Impact strength; Low temperature resistance; Nucleation; Optimization; Process parameters; Response surface methodology; Surface analysis (chemical); Vanadium oxides; Weld defects; Welding parameters; Cold crack; response surface methodology; Box–Behnken design; acicular ferrite; preheating
• ISSN: 0256-2499; 0973-7677
• DOI: 10.1007/s12046-021-01673-6

The effect of process parameters on cold crack susceptibility during welding of high strength low alloy steel SAE 950A is the subject of this study. The aim of this study is to use response surface methodology to optimise welding parameters in order to improve cold crack resistance. Preheating temperature, oxide particle content, and heat input are the welding parameters studied in this research. The optimum response parameters for achieving high impact strength are 200°C preheating temperature, 0.02 wt.% vanadium oxide particles, and a high heat input of 4.76 kJ/mm. The results show that the preheating temperature and heat intake have a greater effect on the weld's impact strength than the presence of oxide particles. The model's accuracy was evaluated using a validation experiment, and the discrepancy between the expected and observed value was only 2.67 percent. The fracture surface analysis and scanning electron microscopy revealed the fracture modes and the effects of oxide particles on nucleation of acicular ferrite microstructure which increases the cold crack resistance.