Process Parameters Optimization And Numerical Simulation Study Of ZL114A Fabricated By GTA Arc Additive Manufacturing

In recent years,the application of cast aluminum alloys has become more and more extensive.ZL114 A is a kind of Al-Si alloy,which has the characteristics of high strength and high toughness.ZL114 A alloy is widely used in modern manufacturing industries such as ordnance,aviation,and transportation due to its good casting properties and mechanical properties.Additive manufacturing technology has received widespread attention worldwide due to the characteristics of efficient and low-cost manufacturing.The combination of welding technology and additive manufacturing technology has become a new development direction.Arc additive manufacturing technology came into being,which has the advantages of low heat source cost and easy access.Arc additive manufacturing technology quickly became a hot research topic.This article combines arc additive manufacturing technology with cast aluminum alloys,uses GTA arc additive to manufact ZL114 A parts,optimizes parameters through process tests,and studies the temperature and stress fields in the additive process through finite element numerical simulation based on ABAQUS software.The self-designed additive manufacturing platform was used for process testing.To study the influence of process parameters on the forming of ZL114 A by GTA additive manufacturing,orthogonal test was used.The results found that the effect of wire feed speed on the melting height was greatest,and the effect of walking speed was lowest.The effect of walking speed on the weld width was greatest,and the effect of wire feed speed was lowest.Controlled variable test was used to study the influence of process parameters on forming.It was found that the weld width and the welding current showed an approximately proportional relationship.The weld width is approximately inversely proportional to the walking speed and wire feed speed.The weld seam height decreases with increasing welding current and walking speed.Welding seam height tends to increase with increasing wire feed speed,and is approximately linearly proportional to wire feed speed.The inflection point will appear in the curve of the melt width with the welding current,walking speed,wire feed speed.And the inflection point will also appear in the curve of melt width with welding current and walking speed.The inflection point corresponds to the value of welding current 140 A,walking speed 100 mm/min,wire feed speed 100 cm/min,which was the optimal parameter.ABAQUS software was used for the establishment of three-dimensional finite element model and the calculation and analysis of temperature field.FORTRAN language was used to define heat source subroutine.PYTHON language was used to edit model change.The temperature field calculation results show that the subsequent weld bead has heat treatment effect on the first weld in the additive process.But the effect gradually weakens and tends to be stable at 400 ?.The thermal cycle curves of the arc starting end and the arc ending end of the first weld are quite different.Peak temperature difference is nearly 100?.The heating and cooling speeds at the starting arc end are faster than at the closing arc end.As the current increases,the peak temperature of the thermal cycle curve at the arcing end and the arcing end of the first weld increases.But the difference between the two temperatures remains basically unchanged at 300 ?.Increasing the current does not improve the unevenness of the additive structure.The stress field model was established on the basis of the temperature field,selecting the sequence coupled thermal stress program.The calculation results of the stress field show that during the first welding process,the equivalent stress value in the area in front of the molten pool is the largest.When adding to the third layer,the equivalent stress of the substrate gradually stabilizes.When the additive finishes cooling to room temperature,the residual stress value of the part where the accumulation layer contacts the substrate is the largest.he points on the accumulation layer undergo a stress cycle state,and the latter layer has a heat treatment effect on the previous layer,which plays a role in stress relief.After the additive finishes cooling to room temperature,the most severe positions of the substrate and the accumulation layer deformation are located near the arc end.