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Go to Editorial ManagerDue to the extremely complicated thermal cycle for the welding process, the fusion zone and heat-affected zone (HAZ) produce irreversible elastic-plastic deformation and residual stresses. The differential heating of the pipes caused by the weld heat source causes residual stress as a result of the welding process. However, the strength and lifetime of the component are also decreased as a result of residual stresses in and around the weld zone. The objective of this research is to analyze the residual stresses created during the welding process and select the best welding parameters that give the lowest residual stresses in 316SS pipes with 50 mm diameter and 4 mm thickness that were manually welded by used (316) welding wire and using shielded metal arc welding (SMAW) in a single-pass butt joint with the various values for each of current (58 , 68 , 78 , 88) amperes and voltage (22 , 23 , 24 , 25 , 26) volts. The shielded metal arc welding process involves heating, melting, and solidifying the parent metals and filler material in a localized fusion zone by a transient heat source to create a junction between the parent metals. The welding process free from preheating and heat treatment will be obtained. ANSYS Finite Element methods are used to calculate the welding residual stress distribution. The mechanical and thermal models were used to carry out the theoretical analysis. In general, the numerical study found that the residual stress distribution at the weld zone’s center is continuous, rising, and has a value of about (1738 MPa). Additionally, the residual stress at the boundary between the heat-affected zone and the weld zone climbs to a maximum value of around (3799 . 6 MPa). On the other hand, the magnitude of the residual stress in the heat-affected zone of the weld reduces significantly and achieves a minimum value at a position of (20 mm) with a value near zero.
The welding process involves a very complex thermal cycle, resulting in irreversible elastic-plastic deformation, and residual stresses in and around fusion zone and heat-affected zone (HAZ). A residual stress due to welding arises from the differential heating of the pipes due to the weld heat source. However, the presence of residual stresses in and around the weld zone reduces the strength and life of the component. The objective of this work is to measure the welding residual stress in ASTM (A-106 Gr. b) steel pipes with 4" diameter and 6 mm thickness welded manually (SMAW) in a three-pass butt joint. The shielded metal arc welding process consists of heating, melting, and solidification of parent metals and a filler material in a localized fusion zone by a transient heat source to form a joint between the parent metals. The welding process was carried out without preheating and heat treatment. This measurement of residual stress occurs by using the hole-drilling strain gauge method according to (ASTM E-873), and the experimental results for residual stresses obtained from welded carbon steel pipes are used to provide validation for finite element simulations. The welding process and welding residual stress distribution is calculated by Ansys Finite Element techniques. Theoretical considerations can be assessed by a mechanical model. Overall, there is good agreement between the predicted and measured distributions of residual stress, but the magnitude of predicted stress tends to be greater in the welding region.
One of the major problems in industry are new welding trainees cost, it drains the budget of many companies, particularly in industrialized countries, through raw material costs for preparation, welding wires, electric and fumes in addition to time spent. Recently a new technique was appeared; it is called virtual welding training system (VWTS) to reduce the training cost. In the present work a VWTS technique was built, a simulation of electrode motion is upgraded by using LVDT to represent the welding arc length while a DC motor with gearbox connect to the steel rode is used to represent welding electrode consumption. A 2D graphs with touch screen monitor are used to represent welding process. All sensors were calibrated to generate a VWTS. Accepted results obtained in training new welding trainees in the shielded metal arc welding (SMAW) training.