Introduction to Pressure Components of American Standard Alloy Cast Steel
Cast steel is widely used in mechanical manufacturing. In order to meet the needs of various mechanical products, various alloys are added to the steel to make alloys with better strength and toughness. Alloy cast steel is the commonly used cast steel. It has higher strength, toughness, thermal stability and wear resistance. The pressure worthy components of the American Standard are usually made of alloy cast steel. This alloy cast steel is a low alloy steel that contains several key alloying elements such as molybdenum, nickel, chromium, manganese, titanium and carbon.
Molybdenum increases the strength and hardness of the alloy, increases the overall corrosion resistance of the steel, and improves the toughness of the steel. The 0.25-0.5% molybdenum alloy steel has better machinability and weldability. Nickel increases the strength and hardness of the alloy, and can increase the temperature resistance, corrosion resistance and toughness of the steel. The alloy steel with 0.3-0.7% nickel has high strength and good machinability and weldability. Chromium increases the hardness, strength and toughness of the alloy, and the resistance to thermal fatigue and thermal stress is improved. The chromium content is generally 0.4-1.2%. Manganese improves the strength and hardness of steel, and increases the machinability and weldability. Ti to stabilize carbon and nitrogen, it also improves the strength and toughness of steel. In general, the content varies from 0.15-0.6%. The carbon content of the alloy steel is slightly higher than that of ordinary carbon steel. The tensile strength is higher. Generally, the carbon content is 0.3-0.8%.
The American standard pressure-bearing components are mainly made of AISI 4130 and 4140 alloy steel. AISI 4140 is a chromium-molybdenum low alloy steel with a chromium content of 0.85–1.2%. The molybdenum content is 0.15–0.25%. The carbon content is 0.40–0.45%. The yield strength, tensile strength, elongation, toughness and hardenability are relatively high. AISI 4130 is a chromium-molybdenum low alloy steel that contains 0.80–1.10%Cr and 0.15–0.25%Mo. The carbon content is 0.28–0.33%. It has higher strength, good toughness and weldability.
The commonly used grades of alloy steel for American standard pressure-bearing components are 4130, 4140, 4330V, 4340, 6150 and 8620. These grades of alloy steel have different properties and are suitable for different parts. AISI 4330V is a low alloy chromium-nickel-molybdenum alloy steel. The composition is 0.20-0.27%C, 0.45-0.75%Si, 0.70-1.00%Cr, 0.05-0.15%Mo, 0.35-0.45%Ni and 0.30-0.50%Mn. AISI 4340 has higher strength and toughness and is used for components subjected to larger loads. The chemical composition is 0.38-0.43%C, 0.20-0.40%Si, 0.70-1.00% Cr, 0.15-0.30%Mo, 0.70-1.00%Ni and 0.60-0.80%Mn. AISI 6150 is a chromium-silicon-vanadium low alloy steel with a high strength and excellent wear resistance. The chemical composition is 0.48-0.53%C, 0.15-0.35%Si, 0.80-1.10% Cr, 0.90-1.20%V and 0.15-0.25%Mo. AISI 8620 is a low alloy NiCrMo steel with good machinability and wear resistance. The chemical composition is 0.17-0.23%C, 0.90-1.10%Cr, 0.15-0.25%Mo, 0.70-0.90%Ni and 0.40-0.60%Mn.
The use of alloy cast steel as pressure worthy components of the American standard requires excellent strength, toughness and machinability. The American standard alloy steel parts meet these needs. Different grades of alloy cast steel can be chosen according to their different properties and materials. The performance and service life of the components have been significantly improved.
Conclusion
The American Standard recognizes the use of alloy cast steel for pressure worthy components. These alloy steels have higher strength, toughness, wear resistance, and better machinability and weldability. AISI 4130, 4140, 4330V, 4340, 6150 and 8620 are among the commonly used grades of alloy steel for American Standard pressure components. These alloy steels have different properties and can be selected according to their materials. The use of alloy cast steel for the pressure components of the American Standard has greatly improved the performance and service life of the components.
