Laser brazing organization and properties of hard alloy and W2Mo9Cr4VCo8 high speed steel

There exists a great difference between hard alloy and high speed steel in physical and chemical properties. The weld between hard alloy and high speed steel can be achieved effectively by using the high- energy laser beam. Using negative defocus amount △f =- 3mm,when laser scanning speed is too small( v 7mm / s),and power is too large( P 1500W),such tissue defects like the pores and micro cracks will be raised in base metal because of losing a large amount of Co. While laser scanning speed is too large( v 7mm / s),power is too small( P 1500W),Cu and base metal is immiscible,it will lead to the poor joint tissue fusion. So v = 7mm / s,P = 1100W,brazed joint forms equiaxed structure with good performance. Then tests about the distribution of its elements and micro- Vickers hardness are made. The result shows that: except Cu there also exists other elements such us Co,Mo,and Cr including in base metal,which indicates that base metal and solders are well fused. While the micro hardness of joint organization and heat affected zone changes smallest,the maximum average micro hardness of 941. 7HV and 778HV are obtained respectively.