Structure and properties of H70 silver-containing cast brass alloy

The as-cast silver-containing H70 brass were prepared by adding different contents of silver. The structure and properties of the casting materials were analyzed by means of optical microscope, hardness test, linear polarization curve and electrochemical impedance. The results show that the low magnification of the samples are composed with columnar crystal and equiaxed crystal regions. The addition of silver element can significantly refine the grain size, and the grain size is the smallest when the silver content is 0.1%. With the increase of silver content, the precipitation phases gradually decrease and the degree of dendrite segregation increases in the metallographic structure. The hardness value increases first and then decreases, reaching the maximum value of 80.8 HV when the silver content is 0.1%. The electrochemical test of artificial sweat shows that the self-corrosion current density is the lowest and the pitting tendency is the smallest when the silver content is 0.5%. The R_p value of H70 is the largest and its corrosion resistance is the best.