Influence of preheat temperature on the impact energy and tensile properties of the HSLA-70 steel

In the present work, API-5L X70 (HSLA) steel plates were uniformly preheated at different temperatures before the welding process (SMAW). E7010, E8018 and E7024 electrodes are used to weld the butt joint of API -5L X70 steel plates with 20mm thickness. Tensile and Charpy impact tests were performed on the samples according to AWS and ASTM standards. The results show that by increasing the preheat temperature, tensile strength of the HAZ was decreased and the impact energy was increased. This behavior in mechanical properties of the HAZ is due to the stress relief along with the microstructural modification of HAZ.

Keywords:

Preheat temperature , HAZ , SMAW , tensile strength , impact energy