What are The Differences Between Cast Steel Valves and Forged Steel Valves?

Cast steel is a kind of casting alloy, and forged steel is produced by forging method, its quality is better than cast steel, so the quality of forged steel valve is generally better than cast steel valve. The following describes the specific differences between the cast steel valves and the forged steel valves.

Introduction of Forging

Forging is a kind of machining method which uses forging machine to exert pressure on metal billet to produce plastic deformation to obtain forgings with certain mechanical properties, certain shape and size. Forging is one of the two major components of forging and pressing, and the important parts with high load and severe working conditions are made of forgings. Parts of simpler shape can be made from weldment. By forging, the welding holes and as-cast looseness of metal materials can be eliminated. Choosing the forging ratio correctly can improve the quality of the product and reduce the cost. The forging materials are mainly carbon steel, stainless steel and alloy steel.

Introduction of Casting

Casting is a hot metal process. The castings have good comprehensive mechanical properties. The casting has a wide application range and the cost of its blank is low. It is suitable for manufacturing parts with complex shape, especially with complex internal structure. Casting is the basic technology of modern machinery manufacturing industry. Casting is to melt the metal into liquid and pour it into the casting mould, and then take out the castings after cooling and solidification to get the castings with predetermined size and shape and mechanical properties. However, harmful gases and dust will be produced when casting, and these substances will pollute the environment.

The cast steel can be divided into cast carbon steel, low alloy cast steel and special cast steel. The cast carbon steel is cast steel with carbon as the main element and contains a small amount of other elements. The low alloy cast steel is a cast steel containing alloying elements such as manganese, chromium and copper. The special cast steel is a kind of alloy cast steel, which is made to meet special needs, with a wide variety and usually contains one or more alloy elements to obtain some special properties.

The Differences Between The Cast Steel Valves and The Forged Steel Valves

The forged steel valves are of better quality than cast steel valves, can withstand greater impact force, and have higher mechanical properties in plasticity, toughness and other aspects than cast steel valves. The forging process can improve the internal structure of the workpiece, which has good mechanical properties. But the nominal size of forged steel valves is relatively small, generally below the DN50. The cast steel valves have lower pressure levels, and the nominal pressure of PN16, PN25, PN40 and 150LB-900LB are commonly used. The nominal pressure grades of forged steel valves are PN100, PN160, PN320 and 1500 LB-3500LB, etc. The cast steel is mainly used to make some parts with complex shape, which are difficult to forge or cut to form, but require high strength and plasticity.