| Duplex stainless steel has developed to now,because of its good oxidation resistance,mechanical properties and corrosion resistance,more and more applied to oilfield platform,maritime,chemical industry and other fields.Especially in the field of chemical industry.because of the good resistance to chloride corrosion performance,the duplex stainless steel is not only get used in acids,polymers,and other products,but also widely used in the pressure vessel,reactor and heat exchanger equipment.SAF2205 duplex stainless steel as the most commonly used duplex stainless steel,because of its good corrosion resistance and welding performance,often use GTAW,SMAW and SAW for welding.But in the process of welding,because of welding thermal cycle,led to the precipitated phase and welding stress,affect the performance of the welded joint.Therefore,research on different welding method and heat treatment process on the performance impact of SAF2205 duplex stainless steel welding joint,for its application in the actual production has a certain theoretical and practical significance.The article use the gas tungsten arc argon arc welding(GTAW)and manual arc welding(SMAW)two kinds of different welding method,by comparing the two kinds of welding methods of SAF2205 duplex stainless steel the pros and cons of various performance impact,analysis of different welding method to weld the influence of mechanical properties and corrosion resistance;Late to different process of heat treatment,welding specimen by comparing the different heat treatment temperature and holding time after welding joint of the mechanical properties and corrosion resistance,heat treatment was studied in two different welding method of welding joint stress relieving effect,the change of mechanical properties and influence on corrosion resistance,finally get the following main results:(1)GTAW and SMAW welding method has a little impact on tensile strength and bending strength,and they are both higher than the parent metal.But the impact toughness of the weld area are lower than the parent metal,and SMAW was much lower than that of GTAW.Metallographic test showed that the weld zone of coarse grains is the main cause of its impact toughness reduce.(2)GTAW and SMAW welding zone has a more excellent corrosion resistance than the parent metal.This is because the weld area has a good phase ratio.(3)after the heat treatment,the test results show that the annealing temperature and holding time,both the tensile strength and the bending strength not have obvious changes;Impact test results show,because of the high temperature heat treatment,the impact absorbing energy in both the weld zone and heat affected zone are evidently lower.As a result,the annealing temperature can not be more than 350 ?.(4)The result of the welding sample of corrosion test after heat treatment showed that,the corrosion rate of the sample is increased with the increase of annealing temperature and the extension of heat preservation time;In the lower 280 ? annealing,heat preservation time which will not influence the corrosion rate of sample.(5)The welding stress is mainly concentrated in the weld heat affected zone.Annealing at 280 ?,welding stress will decline with the extension of heat preservation time.The test show that heat preservation 6h the welding stress can fell by 7.7%,heat preservation 12 h the welding stress can fell by 14.5%. |
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