Blanks used in machining contain castings, forgings, profiles and welding parts. Different types of blanks and their accuracy, blankness and hardness have a direct impact on machining process. There are four factors we need to consider when selecting valve blanks:
 
1. Valve parts materials and the requirements of their organization and performance. Parts materials specified on the design drawing largely determine the kind of blank. For example, valve parts made of cast iron must be produced by casting methods. For steel parts, we should consider the mechanical performance of materials when choosing blanks. For instance, parts for high-pressure valves should be forging or welding parts to ensure good mechanical properties of materials.
 
2. Structure shape and dimensions of valve parts. Structure switch of valve parts is an important factor affecting the choice of blanks. For example, valves with complex structure switches can be made of castings. For large size valves, sand castings can be applied. While small size ones should be adopted investment casting.
 
3. The scale of production program. The greater the production program is, the better of economic results through high precision and high efficiency blank manufacturing will be.
 
4. The condition of blank manufacturing. Choose blanks based on the equipment and technology level, and gradually adopt advanced manufacturing methods in consideration of the development prospects