What application of stainless steel precision casting in precision casting proce2020-04-23 00:00:00
Simply put, metallurgy (melting)
1) Tapping temperature: Stainless steel is higher than carbon steel;
2) Liquidity of molten steel: stainless steel is worse than carbon steel;
3) Molten steel oxidation: stainless steel is easier to oxidize than carbon steel;
4) Solidification method: stainless steel is solidified in paste form, and carbon steel is solidified sequentially.
For sand casting, mass production factories should create conditions to adopt technologically advanced modeling and core-making methods. The old-fashioned shock-type or shock-type molding machine production line is not high enough in productivity, the labor intensity of the workers is high, the noise is large, and it is not suitable for the requirements of mass production. For small castings, a boxless high-pressure moulding machine production line with horizontal or vertical parting can be used. The production efficiency of solid moulding is high and the floor space is small; for middle parts, various boxed high-pressure moulding machine production lines and gas can be used. Punching molding line to meet the requirements of fast, high-precision molding production line, core-making methods can be selected: cold core box, hot core box, shell core and other efficient core-making methods. Medium-volume large castings can consider the application of resin self-setting sand molding and core making.
At present, among the precision casting parts produced by precision casting companies, about 60 to 70% of the precision casting parts are produced with sand molds, and about 70% of them are produced with clay sand molds. The reason why sand precision casting accounts for the majority is because of low gas cost and simple process. Therefore, all precision casting parts for auto parts are made of sand precision casting parts.
Low-pressure precision casting, die casting, centrifugal precision casting and other casting methods are not easy to mass-produce, mainly because the production cost is expensive.
For heavy-duty precision castings produced in small batches, manual modeling is still an important method. Manual modeling can adapt to various complex requirements and is more flexible and does not require a lot of process equipment. Water glass sand molds, vrh method sodium silicate sand molds, organic ester water glass self-setting sand molds, clay dry molds, resin self-setting sand molds and cement sand molds can be used; for single-piece heavy precision castings, the pit molding method is low cost. Production is fast. Mass production or long-term production of shaped products are more suitable to adopt multi-box modeling and split-box modeling. Although the initial investment in molds and sand boxes is high, it can be compensated by saving modeling man-hours and improving product quality.
Generally speaking, for medium and large precision castings, iron castings can be produced with resin self-hardening sand molds, and stainless steel precision castings can be produced with water glass sand molds. Castings with precise dimensions and smooth surfaces can be obtained, but the cost is higher. Of course, the precision, surface finish, material density, metallographic structure, and mechanical properties of castings produced by sand precision casting are often poor. Therefore, when these castings require higher performance, other casting methods, such as investment ( Lost wax) casting, die casting, low pressure casting, etc.
