Stainless Steel Precision Casting
Stainless steel precision casting can effectively ensure good fluidity of the melt during injection to a certain extent. The temperature selection of stainless steel precision casting should be effectively determined based on factors such as the distance and process of injection, cooling, and flow rate.
Stainless steel precision casting by silica sol precision casting manufacturer has good mechanical properties due to its small transition zone size, which can meet its flowability and prevent the formation of bright crystals to a certain extent. The general temperature is 715-740 ℃. Stainless steel precision casting flat ingots have a high tendency for hot cracking, and the precision casting temperature of stainless steel is relatively low, generally between 680~735 ℃.
The cracking tendency of stainless steel precision cast round ingots is relatively low, which can effectively ensure that the alloy has good exhaust and shrinkage capabilities to a certain extent, create favorable conditions for its order, and improve density. The casting temperature is generally higher, and the casting temperature for ingots with a diameter of over 350mm is generally 730-750 ℃.
Key Points for Temperature Control in Stainless Steel Investment Casting
In the stainless steel investment casting process, temperature control is a key factor in determining casting quality, directly impacting the fluidity of the molten metal, the stability of the mold shell, and the mechanical properties of the casting. Considering the characteristics of investment casting, the key temperature parameters and control logic for stainless steel investment casting are as follows:
Metal melting temperature is the primary control point in stainless steel investment casting. Different grades of stainless steel (such as 304, 316, and 17-4PH) have significantly different melting temperatures due to their alloy composition. The melting temperature of ordinary austenitic stainless steel (such as 304) is typically between 1500°C and 1560°C, while 316 stainless steel, which contains higher amounts of molybdenum and nickel, requires a temperature of 1520°C to 1580°C to ensure sufficient dissolution of alloying elements and prevent precipitation of low-melting-point phases. Martensitic stainless steel (such as 17-4PH) requires strict control between 1480°C and 1540°C to prevent coarsening of grains due to excessive temperatures. The matching of the mold shell preheating temperature and the molten metal pouring temperature directly impacts the filling quality and internal quality of the casting. For thin-walled, complex stainless steel castings, the mold shell must be preheated to 800°C-1000°C. At this point, the molten metal pouring temperature can be appropriately lowered (20°C-50°C below the melting temperature). This utilizes the mold shell’s residual heat to maintain molten metal fluidity and avoid defects such as cold shuts and under-pouring. For thicker castings, the mold shell preheating temperature is typically controlled between 400°C and 600°C. This minimizes the temperature difference between the molten metal and the mold shell, reducing internal stress in the casting.
The solution treatment temperature is a key subsequent process for improving the corrosion resistance of stainless steel castings. Austenitic stainless steel requires solution treatment at 1050°C-1100°C to fully dissolve and evenly distribute carbides within the matrix, followed by rapid water cooling to achieve a single-phase austenite structure. Martensitic stainless steel, on the other hand, requires heating at 1020°C-1060°C, followed by oil cooling, quenching to form martensite, and then tempering at 200°C-450°C to adjust hardness and toughness.
Temperature control requires extremely high precision, typically keeping melting temperature fluctuations within ±10°C and mold preheating temperature fluctuations within ±20°C. Currently, the industry generally uses medium-frequency induction furnaces coupled with infrared temperature measurement systems for real-time monitoring of melting temperatures, while mold preheating utilizes fully automatic electric heating furnaces for precise temperature control. This technology aligns with the intelligent temperature control technology employed by Ningbo Suijin Machinery Technology Co, Ltd. in its digital investment casting production line, reliably ensuring the high quality of stainless steel precision castings.
