Assessment of the behaviour of fatigue loaded HSLA welded steel joint by applying fracture mechanics parameters

Abstract

In discussion of the welded joints from fracture mechanics point of view, it is assumed that the welded joint is pre-cracked and that therefore fatigue life of the pre-cracked structure is determined by the period of crack growth under variable loading. Experimental data obtained by testing provide a substantial foundation for better understanding and explanation of the phenomenon of fatigue of a material. Low-cycle fatigue (LCF) occurs during charging and discharging of the reactors, pressure vessels and pipelines; it can be accelerated by additional negative effect of temperature variation and aggressive effect of vessel contents during exploitation of the equipment in processing industry. In present paper, the results of measurement of J-integral of weld metal made of low-alloy high-strength steel, used for manufacture of the pressure vessels in the process of powder welding, at LCF have been presented.