Pneumatic valve forging and casting

forging is the use of pressure forging machinery for metal blank, make its produce plastic deformation, in order to obtain a certain mechanical properties, a certain shape and size of forging processing method. Forging and stamping belong to plastic processing properties, generally referred to as the forging press.
forging forming method is commonly used in mechanical manufacturing. Can eliminate the as-cast loose metal through forging, welding and holes, general is better than that of the same material of the casting on the mechanical properties of the forgings. Mechanical load is high, the working conditions of severe important parts, in addition to a simpler shape rolling plate, profile or welding parts are available, use forging more.
the temperature of the forging press blank when processing can be divided into hot forging and cold forging. Cold forging is commonly processed at room temperature, hot forging is on above the recrystallization temperature of billet metal processing. Sometimes will also be in heating condition, but the temperature is less than the recrystallization temperature of forging called warm forging. But this classification in production is not unified.
the recrystallization temperature of steel is about ℃, but generally used ℃ as a dividing line, is higher than that of ℃ hot forging; Between ℃ ~ called warm forging or hot forging.
forging press forming method can be divided into free forging, die forging, cold heading, radial forging forming, extrusion, rolling, forging, rolling, etc. Billet produced by deformation under pressure basic not restricted by external said free forging, also calls the open-die forging; Other forging method of billet deformation are subject to the conditions of the mold, forging as patterns. Forming rolling, roll forging, and rolling forming relative rotation between tools and blank, blank for point by point and asymptotic pressurized and forming, so it is also known as rotary forging.
forging materials are mainly components of carbon steel and alloy steel, followed by aluminum, magnesium, copper, titanium and its alloys. Material of the original state has a bar, ingot casting, metal powder and liquid metal.
general of small and medium-sized forgings with round or square bar as a blank. Bar uniform grain of organization and mechanical properties, good, accurate shape and size, surface quality is good, is advantageous for the organization batch production. As long as reasonable control heating temperature and deformation conditions, do not need large forging deformation can be forged out of the excellent performance of forgings. Ingot is used only for large forgings. Ingot is the as-cast organization, the larger the columnar crystal and the center of the osteoporosis. Therefore must through large plastic deformation, breakage of the columnar crystal for fine grained, will loose compaction, excellent metal organization and mechanical performance can be achieved.
the repression and burning of powder metallurgy blocking, under the thermal state by without flash forging die forging can be made into powder. Close to the density of general die forgings forging powder, has good mechanical properties, and high accuracy, can reduce the subsequent machining. Powder forging internal organization even, no segregation, can be used to make the small gear and other artifacts. But powder price is much higher than generally the price of the bar, its application in production.
in casting mould chamber of liquid metal ShiJiaJing pressure, make its solidification and crystallization under pressure, flow, plastic deformation and forming, can obtain the required shape and properties of die forgings. Liquid metal forging is between the die casting and die forging forming method, especially suitable for common die forging is difficult to forming the complex thin-walled parts.
different forging method has a different process, in which hot die forging process, the longest general order: forging stock of material; Forging billet heating; Roll forging billet prepared; Die forging forming; Trimming; The size of the intermediate inspection, forging and surface defects; Forging, heat treatment to eliminate forging stress, improve performance of metal cutting; Cleaning, main is to remove surface scale; Correction; Check, general forging passes through appearance and hardness test, and important forging pass chemical composition analysis, mechanical properties, such as residual stress test and NDT.
casting is a metal liquid molding process, namely the molten alloy liquid injection preparation beforehand good formed after cooling solidification mold casting. By casting technology method can be subdivided into sand mold casting, pressure casting, investment casting, shell mold casting, lost foam casting, low pressure casting, gravity casting, etc.
pneumatic valve castings generally refers to the part is made of casting forming, this kind of parts do you usually refers to pneumatic valve, pneumatic valve cover and the handwheel. Casting is generally larger parts, or cost savings, but the premise that conform to the standards and design requirements. As opposed to a casting and forging molding process, generally used in smaller pneumatic valve, or special industries, or the owner requirements.
the main parts include: pneumatic valve, pneumatic valve, pneumatic valve cover, pneumatic valve stem, pneumatic disc ( Ram, according to the standard requirement of pneumatic valve stem is forging, of course, there are some manufacturers in order to save costs of rolling bar instead of, according to the experience of use in low pressure state pneumatic valve is acceptable to do so. The pneumatic disc ( Ram and pneumatic valve, pneumatic valve cover smaller is processed directly with forging even bar is ok. Large size is to use the casting. We usually pneumatic valve casting material can be divided into: carbon steel, alloy steel, and stainless steel. Carbon steel: WCA, WCB, WCC; Alloy steel: WC, WC. Stainless steel: CF, CFM, CF, CFM. Of course there are also some special casting materials: copper, pure titanium, titanium alloy and so on.