Forging is an article in which metal is pressed to shape the required shape or suitable compression force through plastic deformation. This force is typically achieved by using a hammer or pressure. The forging process creates a refined granular structure and improves the physical properties of the metal. In the practical use of components, a correct design can make the particle flow in the direction of the main pressure.
Each piece of forging shall be consistent without any porosity, excess space, inclusion or other defects. The components produced by this method have a high ratio of strength to weight. These elements are often used in aircraft structures.
The forging has the advantages of expandable length and contractible cross section; Retractable length, extensible cross section; Variable length, variable cross section. The types of forgings include: free forging/hand forging, hot die forging/precision forging, upset forging, roll forging and die forging.
Type of Forging
Aircraft forging
By weight, about 85% of the components on the aircraft are forgings. Turbine disk, rear journal (hollow shaft), blade, wing beam of wing, rib plate of fuselage, wheel bracket, inner and outer cylinder of landing gear of aircraft engine are all important forgings related to aircraft safety. Aircraft forgings are usually made of high strength, wear-resistant, corrosion resistant aluminum alloy, titanium alloy, nickel base alloy and other precious materials. In order to save materials and energy, aircraft forgings are mostly produced by die forging or multi direction die forging press. According to weight, 71.9% of forgings are found on automobiles. General automobile forgings are composed of 15 parts, such as body, trunk, engine, front axle, rear axle, frame, gearbox, transmission shaft and steering system. They are characterized by complex shape, light weight, poor working conditions and high safety requirements. For example, the crankshaft, connecting rod, camshaft, front beam and knuckle required by the front axle, axle shaft, axle sleeve and transmission gear in the axle box used by the rear axle used by the automobile engine are all key forgings related to the safe operation of the automobile
Diesel engine
Diesel engine is a kind of power machinery, which is often used as an engine. Taking a large diesel engine as an example, there are more than ten kinds of forgings used, including cylinder head, main journal, crankshaft flange output shaft, connecting rod, piston rod, piston head, crosshead pin shaft, crankshaft drive gear, gear ring, intermediate gear and dye pump body.
Marine forging
Marine forgings are divided into three categories: main engine forgings, shafting forgings and rudder system forgings. The forging of main engine is the same as that of diesel engine. Shafting forgings include thrust shaft, intermediate shaft, stern shaft, etc. Rudder system forgings include rudder stock, rudder post, rudder pin, etc.
Weapon forging
Forgings play an extremely important role in the weapon industry. By weight, 60% of tanks are forgings. The gun barrel, muzzle brake and gun tail in artillery, rifled gun barrel and three edged bayonet in infantry weapons, rocket and submarine deep-water projectile launcher and fixed seat, stainless steel valve body for nuclear submarine high-pressure cooler, shells, shells, etc. are forging products. In addition to steel forgings, weapons are made of other materials.
Petrochemical industry
Forgings are widely used in petrochemical equipment. Such as manhole and flange of spherical storage tank, various tube plates required by heat exchanger, integral forged cylinder (pressure vessel) of butt welding flange catalytic cracking reactor, cylinder joint used by hydrogenation reactor, top cover, bottom cover and head required by fertilizer equipment are all forgings.
Mine forging
According to the weight of equipment, the proportion of forgings in mining equipment is 12-24%. Mining equipment includes: mining equipment, winch equipment, crushing equipment, grinding equipment, washing equipment and sintering equipment.
Nuclear forging
Nuclear power is divided into pressurized water reactor and boiling water reactor. The main large forgings in nuclear power plants can be divided into two categories: pressure shells and reactor internals. The pressure shell includes: cylinder flange, nozzle section, nozzle, upper cylinder, lower cylinder, cylinder transition section, bolts, etc. The reactor internals work under severe conditions such as high temperature, high pressure, strong neutron radiation, boric acid water corrosion, scouring and hydraulic vibration, so 18-8 austenitic stainless steel shall be selected for fabrication.
