| Summary: | 碩士 === 國立虎尾科技大學 === 創意工程與精密科技研究所在職專班 === 101 === Welding residual stress is due to the welding process the welding heat generated on the workpiece uneven and Rapid heating and cooling, so that the molten weld metal and surrounding base metal parts of the thermal strain produced by this thermal strain and the formation of the thermal
stress sub, leading to the welding residual stress generated.The welding then the residual stress generated on the workpiece itself will bring onthe structure
and material: the cold cracking, thermal cracking, should Stresscorrosion, the possibility of brittle fracture and other safety hazards.
This willbe he finite element method software package SolidWorks Simulation, according to ASTM A36 steel material set for casing in welded rectangular steel pipe fittings, its welding residual stresses.The size and distribution of power to do related simulation analysis, and try to linear
analysis and weld surface heat fixed output Into the methods and use of steady-state thermal analysis and thermal stress analysis of steady-state thermal conditions set solid structure coupling analysis determined to obtain the welding residual stresses. In order to simplify the calculations in the software simulation of welding parameters in its. The complexity of theconditions set, only the necessary heat transfer conditions only do its associated parameter
settings, in addition to Conditions in three types of simulation analysis differences: different welding heat input temperature difference; different materials heat transfer coefficient difference; different bi thick casing size difference. Do their welding residual stress analysis model corresponds comparison of the proposed application. By the simulation results that: welding heat input temperature is higher, relative to the overall welding Parts of
the welding residual stress values also will increase. Another parent material for different workpiece materials related differences in heat transfer coefficient compared to the simulation results, the thermal conductivity is
lower, will be making Welding residual stress of the over all value becomes higher. The higher coefficient of thermal expansion, the overall number of welding residual stress Value becomes high. Thick casing bi thick as the
difference between the thickness increases, the casing outside, off-welding Road farther then the welding residual stress values will subsequently decline, but the inside of the casingis the opposite of the situation in terms of conditions, that is, its value inside the whole welding residual stresses will be with thick bi increases with thethickness. And although the conditions set by
linear analysis of simulation results, representing not fully simulate the actual overall Welding residual stress values, but on the welding residual stress value curve towards trends,still meet the reasonable On the numerical curve welding residual stresss tate distribution. And is located in the heat-affected zone around the weld with in Residual stress, still quite close to simulate the welding residual stress, and therefore the welding residual stress Analysis purposes, the results should still provide a certain degree of reference.
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