The properties of steel depend not only on the chemical composition but also on the metallographic structure. Through the process of heating, holding and cooling to get different metallographic structure and desired property is heat treatment. Common heat treatments include normalizing, quenching, tempering, and annealing. Normalizing treatment: The steel is heated to 30 ° C ~ 50 ° C above the AC3...

With the rapid development of science and technology, the continuous improvement of production processes and product structures, ball valves have been increasingly applied in thermal systems in recent years. It has the advantages of no fluid resistance, light weight, zero leakage sealing performance, fast opening and closing switch, no medium erosion on the sealing surface, and long service life. ...