forging

forging materials are mainly carbon steel and alloy steel of various components, followed by aluminum, magnesium, copper, titanium and their alloys. The original state of the material is bar stock, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of the metal before deformation to the cross-sectional area after deformation is called the forging ratio. Correct selection of forging ratio, reasonable heating temperature and holding time, reasonable starting and final forging temperature, reasonable deformation and deformation speed have a great relationship to improve product quality and reduce costs. General small and medium-sized forgings use round or square bars as blanks. The grain structure and mechanical properties of the bar are uniform and good, the shape and size are accurate, and the surface quality is good, which is convenient for mass production. As long as the heating temperature and deformation conditions are reasonably controlled, forgings with excellent performance can be forged without large forging deformation. Ingots are used only for large forgings. The ingot is an as-cast structure with large columnar crystals and loose centers. Therefore, it is necessary to break the columnar crystals into fine grains through large plastic deformation, and compact loosely to obtain excellent metal structure and mechanical properties. Powder metallurgy preforms formed by pressing and sintering can be made into powder forgings by non-flash die forging in the hot state. Forging powder is close to the density of general die forgings, has good mechanical properties, and has high precision, which can reduce subsequent cutting. Powder forgings have uniform internal organization and no segregation, and can be used to manufacture small gears and other workpieces. However, the price of powder is much higher than that of general bars, and its application in production is limited. , Apply static pressure to the liquid metal poured in the mold bore to solidify, crystallize, flow, plastic deformation and shape under pressure, and you can obtain the required shape and performance of the die forging. Liquid metal die forging is a forming method between die casting and die forging, especially suitable for complex thin-walled parts that are difficult to form in general die forging. Different forging methods have different processes. Among them, the process flow of hot die forging is the longest, and the general sequence is: forging blank blanking; forging blank heating; roll forging preparation; die forging forming; trimming; punching; correction; intermediate inspection, Check the size and surface defects of forgings; heat treatment of forgings to eliminate forging stress and improve metal cutting performance; cleaning, mainly to remove surface oxide; correction; inspection, general forgings should be checked for appearance and hardness, and important forgings should be tested for chemical composition analysis, mechanical properties, residual stress, etc. and nondestructive testing. In addition to the usual materials, such as carbon steel and alloy steel of various components, followed by aluminum, magnesium, copper, titanium and their alloys, iron-based high-temperature alloys, nickel-based high-temperature alloys, cobalt-based high-temperature alloys The deformed alloys of alloys are also completed by forging or rolling, but because these alloys have relatively narrow plastic zones, the forging difficulty will be relatively large, and the heating temperature of different materials, both the open forging temperature and the final forging temperature have strict requirements.