| High-effective welding is the development trend of modern welding production, however, high strength low alloy steel (HSLA) are unadaptable to high heat input. How to give consideration to the high Strength-Toughness and weldability of HSLA has become a key to design steel structure. Effect of welding thermal analysis and assessment of the accuracy are the foundation and prerequisite of metallurgical analysis, stress deformation analysis, welding process control and weld microstructure transformation.Early results showed that the ship with 1ONiCrMoV steel has significant correlation exists and heat input sensitivity. The subject take 1ONiCrMoV steel as research object, using combination methods of numerical simulation, physical simulation, welding manufacturability test, mathematical statistics to do a system research on the thermal effect of HSLA in double wire welding. The specific conclusions are as follows:Multi-channel welding colorimeter was developed. The laws of double-wire welding thermal and pool features of HSLA were studied. In the heat input for 21.7-43.9KJ/cm, the double-wire welding heat cycle and characteristic parameters were affected by wire spacing directly. The measured values of t8/5 were closely related to the distance between welding wires.Simulation program of twin-wire welding through the secondary development of ANSYS software is designed, Full use of basic operation of the array vector to provide new ideas for speeding up the calculation of simulation. Algorithm which is double-wire moving heat source to calculation loading was proposed. This algorithm can shorten the computing time as well as simplify the loading operation of moving heat source, mainly took an array of storage and related operations of vector as support. This calculation model can be easily extended to the calculation of multiple-wire welding.Analysis the numerical simulation results in weld temperature field of twin-wire welding, first study the rules among parameters of twin-wire welding, state of the molten pool, size of the molten pool, thermal cycling parameters such as peak temperature (Tp) and cooling times from 800℃to 500℃(t8/5):Firstly, there is a critical relationship between parameters of twin-wire welding and the position where the two arc of the twin-wire began to form two independent molten pool. With Current, voltage constant and the increase of welding speed, the common molten pool state is terminate early and the two separate pool is arrival early; the weld width and penetration that formed by the arc of first wire is maintained constant values; while the weld width and penetration that formed by the arc of second wire reach the maximum when the molten pool is going to be separated. Secondly, the tp gradually decreased with the increase of welding speed under the same distance between welding wires, and the impact of heat input (E) is much greater than the distance between two wires as to value of tp of the same point, while the tp value at the same point are not always rise with E increasing, however, some decline appeared when the heat input of first wire is lower than the heat input of second wire(E1 |
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