The free forging equipment commonly used by forging plants are: air hammer, air steam hammer and hydraulic press forging equipment. The nominal parameters of the air hammer are 65kg, 100kg, 150kg, 250kg, 400kg, 560kg and 750kg. The air hammer is simple in structure, easy to operate, easy to maintain, low in equipment investment and small in tonnage. It is suitable for the production of small forgings.
The tonnage of the air steam hammer ranges from 0.5 to 5t, the steam pressure of the steam hammer is 0.7 to 0.8MPa, and the compressed air pressure is 0.6 to 0.8MPa. The mechanism has good stability, the weight of the falling part of the hammer can be significantly increased, and the hammering energy can be improved. The air steam hammer needs a set of auxiliary equipment, such as air compressor and steam boiler. It is more complex than the air hammer, and is suitable for forging medium or large forgings. It is widely used in machine manufacturers.
The hydraulic press has a large tonnage, generally more than 500t, and the current maximum tonnage can reach 75000t. The hydraulic press has a slow down speed during forging, and the static pressure with less impact acts on the blank to deform the metal. The vibration and noise during working are small. The working conditions are good, the pressure action time is long, and it is easy to reach a larger forging depth. The forging with the whole section of fine grain structure can be obtained. The hydraulic press forging is the main equipment for forging large forgings, A set of water supply system and control system is required, with huge equipment and high cost.
Free forging raw materials mainly include forging billet, hot rolling billet, cold rolling billet, ingot, etc.
The contents of the free forging forging process mainly include: drawing the forging drawing according to the part drawing; Determine the material, quality and size of the blank; Formulate deformation process and forging and striking times; Design step diagram; Select auxiliary tools for each forming step; Formulate forging temperature range and heating and cooling specifications; Determine the forging heat treatment specification; Select equipment and arrange production; Propose technical requirements and inspection requirements for forgings; Fill in the process procedure card.
Free forging is divided into manual free forging and machine free forging. Manual forging mainly depends on the use of simple tools to forge billets, change the shape and size of billets, and obtain the required forgings. This method is mainly used to produce small forgings, with low productivity. Machine free forging relies on free forging equipment to forge, change the shape and size of billets, and obtain the desired forgings. During free forging, except that the metal part in contact with the hammer head and anvil iron is restrained, the metal blank can flow freely in all other directions without external restrictions.
Free forging is characterized by simple tools, strong versatility and short production preparation cycle. The mass range of free forging is wide, from less than 1kg to hundreds of tons. For large forgings, free forging is the only forging method, which makes free forging play a particularly important role in the manufacturing of heavy machinery. For example, the main shaft of hydraulic turbine, multi crank crankshaft of large ships and ships, large connecting rods, important gears and other parts all bear great loads when working, requiring high mechanical properties. The method of free forging is often used to produce blanks.
Because the shape and size of free forging forgings are mainly controlled by manual operation, the forging accuracy is low, the machining allowance is large, the labor intensity is large, and the productivity is low.