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Forming Performance Of Valve Castings Forming performance of valve castings: The pouring temperature is 1540, the casting formability is good, and the shrinkage rate of castings is generally 2.5%. It is necessary to consider the design of pressure, the arrangement of pouring riser and the selection of moulding materials. When the casting dimension is biased, it can be corrected after heat treatment, and the heat treatment should be carried out after rectification. Compared with other gray iron castings, the manufacturing process of valve castings has the following characteristics: Shan Valve Castings manufacturing process and inspection process is more complex. The blank of the valve castings is a complex thin-walled shell. Its castings require a smooth surface, cast clarity, especially a tight defect. In order to meet the above requirements, casting should take a series of technological measures, such as the selection of high refractory molding materials and control of sand water, molding should be layered to ensure that the sand hardness, the use of a reasonable cap-and-mouth system and strict control of the pouring speed and temperature. Due to high technical requirements, The casting process of valve castings is much more complicated than that of general castings. In addition, the valve castings in addition to inspection size, location accuracy and appearance, and some also for metallographic structure, mechanical properties, corrosion resistance and nondestructive testing and other testing, so the valve castings inspection process is also more complex. Shan valve castings are difficult to install on machine tools The structure and shape of valve castings are complex, and some parts belong to thin wall, slender parts and poor rigidity. When machining on machine tools, locating and clamping are difficult, so complex special fixture is often needed. Some valve parts, positioning base surface accuracy is lower, surface roughness is higher, and sometimes even the use of non machined surface positioning. and the processing of the cover and other parts of the precision and surface roughness requirements are very high, it is difficult to ensure the quality of processing. Therefore, in order to meet the needs of the process, it is often necessary to improve the precision of the positioning base surface and reduce surface roughness, or on the surface of the machining of the location of the base surface, which increases the complexity of the valve manufacturing process. Shan machining is difficult. As a result of various types of valve material castings, in addition to a variety of cast iron, carbon steel, the majority of its high-strength, corrosion-resistant and hard material cutting performance is very poor, it is difficult to achieve the required machining precision and surface roughness. The geometrical precision and surface roughness of the sealing surface of the valve castings are very high, so the machining difficulty of the valve castings is increased. At the same time, the cutting performance of the valve casting material is poor, and it brings many new problems to the processing method of the valve castings, the tool material, the cutting dosage, the process equipment and so on.
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Oblikovanje performansi odljevaka ventila: Temperatura izlijevanja je 1540, oblikovanje lijevaka je dobro, a stupanj stezanja od lijevanja je općenito 2,5%. Potrebno je uzeti u obzir oblik tlaka, raspored izbošenja i izbor materijala za kalupljenje. Kada je dimenzija lijevanja pristrana, može se ispraviti nakon toplinske obrade, a toplinska obrada mora se provesti nakon ispravljanja. U usporedbi s drugim odljevima od sivog lijeva, proizvodni proces odljevaka ventila ima sljedeće karakteristike: Shan Valve Castings proces proizvodnje i inspekcije proces je složeniji. Prostor od lijevanja ventila je složena ljuska tankih stijenki. Njegovi odljevci zahtijevaju glatku površinu, jasnu jasnoću, osobito čvrstu grešku. Da bi se ispunili gore navedeni zahtjevi, lijevanje treba poduzeti niz tehnoloških mjera, kao što je odabir visokih vatrostalnih materijala za kalupljenje i kontrolu pijeska, oblikovanje treba biti slojevito kako bi se osiguralo da tvrdoća pijeska, I usta i strogu kontrolu brzine i temperature ulijevanja. Zbog visokih tehničkih zahtjeva, Proces lijevanja odljevaka ventila mnogo je složeniji od onih općih odljevaka. Osim toga, odljev ventila pored veličine inspekcije, točnosti i izgleda položaja, a neke također za metalografsku strukturu, mehanička svojstva, otpornost na koroziju i ispitivanje bez razaranja i druga ispitivanja, tako da je proces nadzora odljevaka ventila također složeniji. Valjni odljevni ventili teško se mogu postaviti na alatne strojeve Struktura i oblik odljevaka ventila su složeni, a neki dijelovi pripadaju tankom zidu, vitkim dijelovima i slabom krutost. Prilikom strojne obrade na alatnim strojevima, teško je locirati i pričvrstiti, pa je često potrebno složeno specijalno učvršćenje. Neki dijelovi ventila, preciznost površine temeljne pozicije je niža, hrapavost površine je veća, a ponekad i uporaba neobrađenog pozicioniranja površine. A obrada pokrova i ostalih dijelova zahtjeva preciznosti i površinske hrapavosti vrlo je visoka, teško je osigurati kvalitetu obrade. Dakle, kako bi se zadovoljile potrebe procesa, često je potrebno poboljšati preciznost osnovne površine za pozicioniranje i smanjiti hrapavost površine ili na površini strojne obrade položaja osnovne površine što povećava složenost Postupak proizvodnje ventila. Strojno struganje je teško. Kao rezultat raznih vrsta odljevaka ventila, pored raznovrsnog lijevanog željeza, ugljičnog čelika, većina njegovih čvrstoće, otpornosti na koroziju i rezanja tvrdom materijalom vrlo je loša, teško je postići potrebne Preciznost obrade i hrapavost površine. Geometrijska preciznost i površinska hrapavost brtvene površine odlivaka ventila su vrlo visoka, pa se povećava poteškoća u strojnoj obradi odljevaka ventila. Istodobno, značajka rezanja materijala za lijevanje ventila je loša i donosi mnoge nove probleme metodi obrade odljevaka ventila, materijala alata, doziranja rezanja, procesne opreme i tako dalje.