Study On Heat Treatment And Resistance Spot Welding Process Of Independent Welded Grinding Bimetal Band Saw Blade

The bimetal band saw blade is a necessary and efficient tool for metal cutting.It is known as the"hand of a craftsman".It is mainly used to cut various steel and non-ferrous metals.It has the characteristics of high cutting accuracy,good surface quality,and high cutting efficiency.It is widely used In the manufacturing fields of machinery manufacturing,mold processing,rail transit,aerospace and so on.The thesis aims at the problem of low utilization rate of high-speed toothed steel in the production process of traditional bimetal band saw blades,and the overall heat treatment of tooth back material is difficult to take into account the different process requirements of the two.Based on the new technology of independent welding grinding,study on resistance spot welding process of B318 high strength steel with back material.The main research results obtained in the paper are as follows:(1)Through a series of experimental studies on quenching and tempering,the effect of quenching temperature and subsequent tempering temperature of ASP2051high-speed steel on its structure and properties was explored.It shows that when the quenching temperature is lower than 1190?,M₆C carbonization in high-speed steel If the quenching temperature is higher than 1230?,the grain size will grow obviously.At a quenching temperature of 1210?,full solid solution of ASP2051 steel secondary carbide can be achieved while maintaining a relatively fine grain size.During the tempering process,when the tempering temperature is lower than 570?,the residual austenite cannot be completely transformed,and the amount of secondary carbide precipitation is also small.When the tempering temperature is higher than 570?,it will cause the dissolution of M₂C carbides.After three tempers at 570?+30min,the best secondary hardening effect can be achieved,and the hardness reaches 902HV.(2)By comparing the experimental research of nickel-plated and non-nickel-plated welding of high-speed steel particles,it is shown that nickel plating can effectively improve the electrical conductivity of the particles and avoid the occurrence of resistance heat radiation between the high-speed steel particles and the electrodes.At the same time,nickel plating can significantly reduce the voids and defects of the welded joint during welding.(3)Through a series of welding experiments,the effect of resistance spot welding process parameters on the performance and failure mode of ASP2051 particles/B318high-strength steel welded joints was explored.It was found that the heat input of the welded joints determines the failure mode of the welded joints under shear.When the heat input is low,the strength of the welding interface is low and the interface is broken.When the heat input is high,the strength of the high-strength steel softening zone decreases and the heat-affected zone breaks.When the welding interface strength and the softening zone strength are similar,it is the best heat input value,the welded joint has the highest strength.Combined with orthogonal analysis,the best welding process is welding current 900A,welding pressure 100N,welding time 100ms;based on the best process parameters,the 400?+30min annealing process after welding can be used to obtain uniform performance,suitable for follow-up Processed welded joints.