Effect of alloying elements W, Ti, Sn on microstructure and mechanical properties of gray iron 220

Abstract

Experiments were carried out to observe the variation in microstructure and mechanical properties of gray cast iron by adding pearlite promoting alloying elements such as Ti, Sn and W. Results show that adding Sn, Ti, and W with different concentrations improve the microstructure, Brinell hardness and tensile strength of gray cast iron. With the increase of alloying element concentration, the average graphite length and graphite content increase linearly. At the same time, average cell size and the maximum graphite length also decrease linearly. Brinell hardness and tensile strength of gray cast iron also increase with an increase in alloying elements contents, and attain the maximum when Ti = 0.561%, Sn = 0.561% and W = 0.945%. However, at higher concentrations of Ti = 0.810%, Sn = 0.631% and W = 1.351%, the tensile strength decreases from 333 MPa to 297 MPa and the Brinell hardness decreases from 248 HB to 225 HB. The decrease in tensile strength and Brinell hardness at the higher concentration level is attributed to the formation of coarse and thick graphite flakes.