Study On The Welding Technology For The Fusion Penetration Of T Type Joint Plate

At present, most of the steel structure fabrication plant the general process of full penetration level of weld seam is as follows:backing weld first welding seam weld (combination) adopted the submerged arc welding welding specification, then use the method of carbon arc air gouging back clear root, removal of weld defects, and use of submerged arc welding in the welding sequence. But this method exists defects:(1) the first welding surface submerged arc welding seam with large welding specification. Welding defects, mainly is the welding crack.(2) clear root plane dropped a blunt edge, makes the blunt edge during welding the limitation on the lateral contraction function completely lost, on the residual stress under the action of further contraction.(3) after the air gouging welding, the welding metal heating many times (positive reverse welding, opposite gouging, welding) on the microstructure and mechanical properties of heat affected zone, joint performance degradation.(4) the plane on both sides of the base has to be when gas, and air gouging carbon surface when there is a clip when its carbon content is high, the impact on performance of weld metal.(5) manual operation is difficult, production efficiency is low, auxiliary materials consumption is high, the cost is high.(6) the work environment is poor, gouging produce dust, noise is big, the occupational health hazards.We are in the original technology through the experiment on the basis of trial and error, summarizes the five measures to improve:(1) web redesign in the form of groove(2) tire frame welding position to readjust(3) the welding deformation control measures(4) the selection of welding process parameters(5) using CO2gas shielded welding backing before submerged arc weldingThe purpose of these new technology measures to improve the adjustment:(1) the adjustment of the groove Angle, the purpose is to increase the weld cross section shape coefficient of the wide depth ratio, reduce the risk of hot cracking formation. (2) the groove size adjustment, the purpose is to reduce the amount of filling molten metal, reduce the heat input value, control of welding deformation.(3) the workpiece on the gantry Angle adjustment, the purpose is to ensure the penetration Angle, so as to avoid partial welding.(4) using CO2gas shielded welding, the purpose is to prevent first submerged arc welding welding leakage breakdown, the back from the root.The implementation of these measures from the point of actual effect, not only can achieve full penetration level of weld seam quality requirements, and carbon arc air gouging clear root from the working procedure, to achieve the goal.Usually at the same time, the double wire welding heat input is larger also easy to make hot cracking in welding seam.This paper mainly studies how to use the double wire double arc of submerged arc welding equipment, welding plate T combination of h-beam welding seam, to the quality levels of full penetration level, and was relieved from the clear root technology process on the back. After a lot of research and trial and error, and gradually found out the various Angle of groove forms, the assembling gap, welding in the welding process of full penetration weld, the effect of gradually mastered the thickness from12to25mm between commonly used web full penetration process parameters, enhances the crack resistance of the weld, solve the first full penetration welding surface, joint on the back of the root problem, technology improves welding efficiency greatly. System of the double wire double arc welding welding don’t use black root technology can also achieve full penetration weld quality of technological process. Promote the use of the process effectively to improve the labor productivity, reduce the production cost, improve the working conditions of the workers, by the vast number of staff and technical staff.The application of welding technology improves the production efficiency, reduce production costs, ensure product quality, reduce labor intensity, reduce environmental pollution. Inspection qualified rate has improved larger than before,12-25mm thickness of web qualified rate above96%, satisfying the requirements of the quality of the product. For medium thickness plate manufacture of steel structures, provides the technical support.