Showing 3 results for Sabokrouh
M. Sabokrouh, M. Saroghi,
Volume 4, Issue 2 (Journal OF Welding Science and Technology of Iran 2019)
Abstract
High strength low alloy steels are widely used in gas industry, so shield metal arc welding in pipelines to transport natural gas from Iran is of great importance. For experimental investigation of seam weld and integrity of girth weld, destructive and non-destructive tests are required. In this article the effects of normal heat treatment on properties of multi pass welding in different situations (6-7:30 , 7:30-9 , 9-10:30 , 10:30-12) with 36 in outside diameter is evaluated by chemical, metallography, tensile, toughness and hardness. The result shows that normalizing increases ferrite ratio in root pass and weld cap pass respectively 24 and 6 percent than base steel. Also the increase rate of ferrite in root, hot, filler, and the cap pass are respectively 32, 14, 12 and 7 percent before than normalizing. The elongation weld of was increased ratio than before the heat treatment in base metal respectively 65 and 5 percent. The impact energy alignment to weld (9-10:30) had a rate of 70 percent increase before the heat treatment. The increase rate of C, V and Ti in the weld zone according to base metal in situation of 6-7:30 are respectively 0.01, 0.003 and 0.005.
M. Sabokrouh,
Volume 5, Issue 1 ((Journal OF Welding Science and Technology 2019)
Abstract
Shield metal arc welding on the high strength low alloy steels in pipelines to transport natural gas from Iran is of great importance. In this article the effects of annealing heat treatment on properties of multi pass welding in different situations (6-4:30 , 4:30-3 , 3-1:30 , 1:30-12) with 36 in outside diameter is evaluated by chemical, metallography, tensile, toughness and hardness. Tensile test results showed the lowest yield strength (Vertical to weld and in position 6-4:30) equal to 348 MPa, and the lowest energy impact (Vertical to weld and in position 1:30-3) equal to 108J. The impact energy alignment to weld had a rate of 12 percent increase before the heat treatment. The amount of hardness variation in different areas and positions is negligible (less than 5 percent). Images of metallographic test made by light and electron microscopes demonstrated that the amount of perlite cap pass weld and heat affected zone near the weld metal were decreased compared to main metal to respectively 29 and 8 percent. The elongation weld of was increased ratio than before the heat treatment in base metal respectively 75 and 23 percent. The increase rate of C, V and Ti in the weld zone according to base metal in situation of 3-4:30 are respectively 0.02, 0.003 and 0.006.
M. Sabokrouh ,
Volume 5, Issue 2 ((Journal OF Welding Science and Technology) 2020)
Abstract
In this article the effects of carburizing heat treatment on girth weld with containing titanium oxide and titanium carbide nanoparticles (X-65 grade of gas pipeline) is evaluated. The charpy results show that in the carburized sample containing titanium oxide and titanium carbide nanoparticles compared to the no heat treatment sample (containing titanium carbide and titanium carbide nanoparticles), has been respectively increased by 6% and 42%. Also, the ultimate strength carburized sample containing titanium oxide nanoparticles and titanium carbide nanoparticles compared to the no heat treatment sample (containing titanium oxide and titanium carbide nanoparticles) has been respectively increased by 20% and 28%. The results show that the fatigue life in both carburized nano-alloy samples has been increased. The fatigue life in the carburized sample of titanium carbide nanoparticles has increased more than that of titanium oxide nanoparticles. The fatigue test results show that in the carburized sample containing titanium carbide nanoparticles compared to the tempered sample containing titanium oxide nanoparticles, fatigue life (150-N force) has been increased by 20%. In this loading the fatigue life (tempered sample containing titanium carbide nanoparticles compared to the no heat treatment sample) has been increased by 31%. The results show that the residual stress in both carburized nano-alloy samples has been decreased The hole drilling strain gage results show that in the tempered sample containing titanium oxide oxide nanoparticles and titanium carbide nanoparticles compared to the no heat treatment sample (containing titanium oxide nanoparticles and titanium carbide nanoparticles), hoop residual stresses has been respectively decreased by 9% and 6%.
