Experimental determination of the effect of titanium nanoalloy on mechanical properties of girth welding on Iranian natural gas transmission pipelines

Titanium is one of the most important microalloy elements of high strength low-alloy steels used in gas transmission industry. In this paper, titanium nano -oxide and titanium nano- carbide were added to two separate samples in the binding point. Then the Shielded metal arc welding (SMAW) was performed on high-strength low alloy (HSLA) steel with high grade of X-65 according to the special welding method of the National Iranian Gas Company. The results show that the percentage of titanium in both nano-alloy samples has been increased compared to the microalloy. The percentage of titanium in the sample of titanium carbide nanoparticles has increased more than that of titanium oxide nanoparticles. The charpy test results show that in the sample containing titanium oxide nanoparticles compared to the sample containing titanium carbide nanoparticles, has been increased by 70%. Also, the final strength (sample containing titanium carbide nanoparticles compared to the sample containing titanium oxide nanoparticles) has been increased by 40%.