1. Casting

Parts blanks with complex shapes should be manufactured by casting method. At present, most of the castings are cast with sand mold, which is divided into wood mold manual molding and metal mold machine molding. Wood mold manual molding casting has low precision, large processing surface allowance and low production efficiency, which is suitable for single small batch production or large parts casting. The metal mold machine has high molding productivity and high casting accuracy, but the equipment cost is high, and the weight of the casting is also limited, which is suitable for small and medium-sized castings in mass production. Secondly, a small number of small castings with high quality requirements can be used for special casting, such as pressure casting, centrifugal manufacturing and investment casting.

2. Forgings

Steel parts with high mechanical strength requirements generally use forging blanks. There are two kinds of forgings: free forged forgings and die forgings. Free-forged forgings can be obtained by hand forging (small blanks), mechanical hammer forging (medium blanks) or press forging (large blanks). This kind of forgings have low precision, low productivity, large machining allowance, and the structure of the parts must be simple, suitable for single piece and small batch production, as well as manufacturing large forgings. The precision and surface quality of die forgings are better than free forgings, and the shape of forgings can be more complex, so that the machining allowance can be reduced. The production efficiency of die forging is much higher than that of free forging, but it requires special equipment and forging dies, so it is suitable for small and medium-sized forgings with large batches.

3. Profiles

Profiles can be divided into round steel, square steel, hexagonal steel, flat steel, angle steel, channel steel, I-beam and other profiles of special section according to the cross-section shape. There are two types of profiles: hot rolled and cold drawn. Hot rolled profiles have low precision, but are cheap and are used for blanks of general parts; The cold-drawn profile size is small, the precision is high, and it is easy to realize automatic feeding, but the price is higher, and it is mostly used for the production of larger batches, which is suitable for automatic machine tool processing.

4. Weldments

Welded parts are combined parts obtained by welding method, the advantages of welding are simple manufacturing, short cycle, material saving, the disadvantage is poor vibration resistance, large deformation, and mechanical processing can be carried out after aging treatment.