Research Of Twin-wire Narrow Gap SAW Welding Technology On Q690E High Strength Steel Plate

With the development of marine engineering,the application of thick plate is more and more extensive,the welding quality and efficiency of a higher demand.Narrow gap submerged arc welding has a high deposition rate,excellent mechanical properties of joints,smaller heat input,marine engineering equipment to become a thick plate welding development trend.The twin-wire submerged arc welding as an efficient welding method,by adjusting the front and rear wire current value,control the welding line energy input,to meet the requirements in different conditions of use.Low alloy high strength steel is widely used in bridge construction,engineering machinery,shipbuilding,marine structure and other fields.Aiming at the problem of poor welding condition and cold crack tendency of Q690E high strength steel for offshore platform,this paper presents a method of twin-wire narrow gap submerged arc welding and the narrow gap submerged arc welding process of Q690E high strength steel is studied.Equipment is a key factor in ensuring the stability of the welding process.The HSS-350W welding head,ARSTOR AC-DC 1000 welding power supply,PEK process controller and heavy-duty column-beam manipulator were used to build a narrow-gap submerged arc welding test platform and optimized from the aspects of structure.Based on this,the control variable method is used to study the technology of twin-wire narrow gap welding.The influence of welding current,welding speed and wall spacing on the formation of twin-wire narrow gap submerged arc welding is studied.Only in the reasonable process parameter range within the weld to meet the requirements of forming.In the case of welding methods to determine the welding material on the weld chemical composition,organizational structure has an important impact.Based on the above process test,two kinds of welding wires were used to study the twin-wire narrow gap submerged arc welding of 60 mm deep groove Q690E high strength steel.The twin-wire narrow gap weld with good macroscopic defects was obtained.Excellent performance and meet the requirements of the welding consumables.The influence of different welding heat input on the microstructure and properties of the welded joint was studied by the mechanical properties test and microstructure analysis of the welded joint.