The Influence Of A7N01P-T4 Aluminum Alloy Hot Cracking Sensitivity And The Joint Properties With Different Welding Metal

A7N01P-T4 aluminum alloy has been widely used in our country's high-speed trains manufacturing at present.In this paper,according to the needs of domestic practical production of high-speed railway train,we analysis the hot cracking sensitivity,conventional mechanical properties,stress corrosion sensitivity and fatigue performance of the A7N01P-T4 aluminum alloy welded joint,which is welded by ER5356 and ER5087 respectively.We comprehensive assessment the results,to provide relevant test data for choose the reasonable welding material of the production.Hot cracking sensitivity test use the T weld joint and the Houldcroft method,Houldcroft test shown that the solidification cracks appeared in the test plate welded by both of the welding wire.The crack rate is approximately 50%,means they have the same hot cracking sensitivity.Conventional mechanical properties research including the tensile properties of the welding metal and the joint,the bending property,hardness of the welded joint.The test results showed that the welded joints with ER5087 have the higher yield strength and tensile strength.The welded joints with the two kinds of welding wire have shown the well bending property.We use the pulsation of the axial tensile cyclic stress fatigue test,according to the results made the S-N curve.We know that the fatigue strength of the ER5087 joint is 21%higher than the welding joint of ER5356.Observation the microstructure of the joint welded by ER5356 and ER5087 respectively,we find that the Al3Zr particle exist in the weld seam of ER5087,this maybe the reason why the tensile properties of the ER5087 is higher than ER5356 joint.Both the welded joint of ER5356 and ER5087 didn't have stress corrosion cracking on the condition of 90%of the yield strength stress.