Tribological and Mechanical Aspects of the Welding and Postweld Heat Treatment of High Strength, Wear-Resistant Martensitic Boron Steel

Abstract In the article, the microstructural, mechanical, and tribological properties of welded joints of high-strength martensitic boron steel are presented. Industrial practice showed the occurrence of significant technological problems during its welding, which impelled the authors to carry out a series of technological tests aimed at improving the conditions and parameters of welding 450-HBW grade steel to obtain better tribological, mechanical, and plastic properties. On the grounds of the performed research, a method of welding and postweld heat treatment of this steel is suggested. The developed method involves the use of submerged arc welding (SAW), which ensures greater repeatability of results compared to manual welding techniques, reducing the risk of defects in the welded joint. Additionally, the postweld heat treatment process was optimized to refine the microstructure, relieve residual stresses, and enhance the mechanical properties of the joint. This approach led to a 25% reduction in wear in the abrasive soil mass compared to the as-welded state. Moreover, the tests performed in the presence of loose abrasive showed an increase in the value of the coefficient of relative abrasion resistance kb from 0.92 to 1.14. The tensile strength of the welded joint is Rm = 1245 MPa, which accounts for 85% of the strength of the base material.