High-cycle fatigue and wear performance of low-carbon steel plates remanufactured with wire arc additive manufacturing

This paper examines the fatigue and wear performance of low-carbon steel plates remanufactured with ER70S-6 steel wire using GMAW (gas metal arc welding) -WAAM (wire arc additive manufacturing). The repair technique involves filling pre-fabricated trapezoidal grooves that simulate defects in flat plate test coupons. Fatigue testing is conducted on both base and repaired plates, with high-cycle fatigue and fully reversed conditions employed for performance analysis. Wear characteristics, including wear rate, mechanisms, and friction coefficients, are evaluated for both the base plate and the WAAM-repaired plate. Despite showing higher tensile strength, WAAMrepaired coupons exhibit lower fatigue strength and life compared to base plate coupons. The S-N curve, derived from the Marin equation with correlation factors, aligns closely with fatigue test results, showing better agreement for base plate coupons than WAAM-repaired ones. Fractography reveals cracks in WAAM-repaired coupons due to surface imperfections, edges, and internal pores, indicating stress concentrations and defects impacting fatigue life. Crack initiation in base plate coupons consistently occurs at the edge ends, particularly at the end of the gauge length near curvature, due to high-stress concentrations. The WAAM-repaired zone is found to have a lower wear rate and higher coefficient of friction than the base plate, with adhesive wear predominating in both specimens.