- The ball and seat materials of metal hard-sealed ball valves are generally made of stainless steel or corrosion-resistant materials. Otherwise, the bonding layer between the carbide and the valve seat (or ball) is easily corroded by the medium, and the carbide layer will fall off, affecting the life of the ball valve. In addition, the appropriate quenching process should be selected for different valve seat (or ball) materials.
- Duplex stainless steel materials are widely used in the coal chemical industry. Duplex stainless steel materials have good resistance to corrosion fatigue and wear and corrosion. Duplex stainless steel is a steel with both ferrite and austenite structures.
- Ferrite and austenite structures each account for about 50%, and the two-phase structures are independent of each other. Its performance characteristics combine the characteristics of austenitic stainless steel and ferritic stainless steel.
- Among the characteristics of ferritic stainless steel, when the temperature is in the range of 400-500°C, strong embrittlement will occur during long-term heat preservation. This phenomenon is generally called 475°C embrittlement; when the temperature exceeds 400-500°C, the properties of duplex stainless steel will be destroyed.
- If the duplex stainless steel material adopts the spray welding or surfacing cemented carbide process, the melting process of the cemented carbide and the matrix (the temperature is generally greater than 900°C) will destroy the metallographic structure of the duplex stainless steel, so the duplex stainless steel is not suitable for spray welding. The hardening process of welding (or surfacing) cemented carbide. The surface hardening process of duplex stainless steel is suitable for the supersonic spraying process. The hardening process must ensure that the metallographic structure of the duplex stainless steel matrix is not destroyed.