SIMULATED WELD HAZ OF VANADIUM MODIFIED 2.25CR-1MO STEEL

The effect of the weld heat affected zone (HAZ) on microstructure, mec hanical properties and hydrogen embrittlement susceptibility of vanadi um modified 2.25Cr-1Mo steel (V-Mod Steel) has been studied to examine the viability of using V-Mod steel for reactor applications. The weld HAZ was simulated on the assumption that the submerged are welding wa s made for the V-Mod steel with input heat of about 40 kJ/cm. When the weld HAZ was heated to 1123 K, the strength was somewhat decreased, w hile the 0.2 % proof strength exceeded considerably the critical value (415 MPa) established for reactors. Heating the weld HAZ in the regio n of 1173 to 1473 K had a beneficial effect on the strength and ductil e-to-brittle transition temperature. Compared to the base metal, the w eld HAZ heated in the region of 1123 to 1673 K exhibited equal or supe rior hydrogen charged and initial mechanical properties. The results i llustrate that the weld HAZ for the V-Mod steel has not only sufficien t mechanical properties which could withstand the operation under seve rely stressed conditions but also beneficial effects on hydrogen embri ttlement susceptibility.