There are significant differences between valve castings and forgings in terms of manufacturing processes, performance characteristics, and application scenarios. Here is a detailed comparison between the two:

1、 Manufacturing process

Valve castings

Definition: Valve castings are made through casting processes, which involve melting metal into a liquid that meets the requirements and pouring it into a specified valve model. After cooling, solidification, and cleaning, the resulting valve has a predetermined shape, size, and performance.

Characteristics: The casting process has relatively low requirements for materials and can manufacture valves with complex shapes, including irregular body structures and flow channels. The casting process can be molded in one go, and as long as the technology is up to standard, it can even cast large-diameter valve bodies.

Valve forgings

Definition: Valve forgings are made through forging processes, which use forging machinery to apply pressure to metal valve blanks, causing them to undergo plastic deformation, thereby obtaining forgings with certain mechanical properties, shapes, and sizes.

Characteristics: The forging process has high requirements for materials, but the stress distribution inside the forging has directionality and good density. However, for flow channels and shapes that are too complex, forgings often cannot be formed in one go and need to be modularized, forged separately and welded together, thus limiting the size of forgings to a certain extent.

2、 Performance characteristics

Valve castings

Strength: The strength of castings usually depends on the type of material and the level of casting process. Compared to castings and forgings made of the same material and with the same wall thickness, forgings usually have better strength and crystal structure. But castings can improve their strength by optimizing casting processes and heat treatment.

Pressure resistance: For cast valves of the same weight class and material, their wall thickness is usually thicker than that of forgings, but their pressure resistance strength is equal to that of forgings.

Defects: The main defects of castings include sand holes, bubbles, etc. These defects may affect the sealing and service life of the valve.

Valve forgings

Strength: The strength of forgings is usually higher than that of castings because the metal undergoes plastic deformation during the forging process, refining the grains and improving the mechanical properties of the material.

Resilience: Forgings have good mechanical properties such as plasticity and toughness, which enables them to exhibit better performance when subjected to impact loads.

Defects: The main defects of forgings include large grains, cold hardening phenomenon, cracks, fissures, etc. These defects may be prevented and controlled through strict heat treatment and testing methods.

3、 Application scenarios

Valve castings

Advantages: fast manufacturing speed, low cost, and large usage.

Application scenario: Suitable for pipeline systems with low performance requirements but high quantity requirements, as well as valves that require complex shapes and structures.

Valve forgings

Advantages: Superior performance, suitable for harsh working environments such as high pressure, high temperature, and strong corrosion.

Application scenario: Suitable for some high-performance pipeline systems, such as key parts in industries such as petroleum, chemical, and power.

In summary, there are significant differences between valve castings and forgings in terms of manufacturing processes, performance characteristics, and application scenarios. When selecting valves, comprehensive consideration should be given to specific usage environments, medium characteristics, pressure and temperature factors to ensure that the selected valves can meet usage requirements and have good performance.