Stainless steel casting belongs to investment casting or precision casting. It is a casting process with little or no cutting, and is an excellent process technology in the foundry industry. So what should be paid attention to in stainless steel casting?
1. In order to prevent white mouth during casting of stainless steel, in addition to taking measures from the stainless steel casting process, the wall thickness must not be too thin. (Some information points out that when the wall thickness is more than 15mm, the corners of the metal mold casting must be rounded)
2. Due to the inability of the metal mold and the core, in order to facilitate the removal of the casting and the extraction mold, the casting slope of the stainless steel casting should be appropriately larger than that of the sand casting, generally 30%-50% larger.
3. The thickness of the inner wall and inner rib of the stainless steel casting should generally be 0.6-0.7 of the thickness of the connected outer wall, otherwise, because the inner wall (rib) cools slowly, cracks are likely to occur at the junction of the inner and outer walls when the casting shrinks.
4. Due to the fast heat dissipation of the metal mold, the minimum wall thickness of custom stainless steel casting should be larger than that of sand casting, and the minimum wall thickness of various casting alloys and different sizes of casting.
Whether the quality of stainless steel castings is up to standard and pouring are inseparable. In order to better obtain standard stainless steel castings, the pouring operation procedures of the castings should be strictly implemented, and the pouring temperature and pouring speed of the stainless steel castings should be controlled.
1. Pouring temperature. Different pouring temperatures have a particularly great influence on the quality of stainless steel castings. Therefore, it is necessary to establish and determine the appropriate pouring temperature according to the alloy type, casting structure and mold characteristics of the stainless steel casting to be poured.
Under normal circumstances, the pouring temperature established by everyone when pouring stainless steel castings should be between 1540-1580 °C;
2. Pouring speed. The speed of pouring is related to the speed of forming of stainless steel castings. Therefore, different pouring speeds should be adopted for stainless steel castings of different standards under the condition of ensuring that the gas in the cavity is discharged more smoothly.
Under normal circumstances, we should adopt a faster pouring speed for standard simultaneous solidification stainless steel castings, and we should adopt a slower pouring speed for stainless steel castings that achieve sequential solidification;
3. When pouring large and medium-sized stainless steel castings, everyone should pay attention that the molten steel needs to stand for 2 minutes before pouring;
4. After the stainless steel casting is successfully poured, it is necessary to remove the weight iron and box card immediately after the casting is solidified, otherwise the stainless steel casting will form cracks.