When it comes to stainless steel investment castings, several factors influence the formation of its casting defects. For this reason, every stainless-steel casting manufacturer needs to pay close attention to the following aspects of quality control during the production process.
Raw Material Control
The surface quality of stainless-steel production castings is highly dependent upon the surface layer material due to its direct contact with the melted alloy. Your supply of raw alloy material and auxiliary materials must have a stable channel and strict control of the charging materials must be observed. Furthermore, it is necessary to ensure that your charging materials are clean and free of rust before they are subjected to heat. Lastly, basic operating procedures must be strictly followed to steer clear from the introduction of impurities into the melted alloy.
Coating and Dewaxing Control
Strict coating slurry quality control must be conducted and the binder extract’s gelation time in the coating slurry must be regularly monitored. Aside from the fact that it’s highly important to make sure that the shell’s thermal conductivity and permeability are in excellent condition, you must also make sure that the wax mold’s surface layer melts before the wax mold itself expands. Since this wax mold expansion generates tension that could cause the shell to crack, extra measures must be taken to relieve this tension. Keep in mind that the strength of the shell depends on the shell’s drying rate. When the shell retains less residual moisture, it can withstand the pressure and the tension that’s caused by wax mold’s expansion when it is being subjected to dewaxing.
Roasting, Smelting, and Pouring Control
Ensure sufficiency of deoxidation and slag removal treatment during alloy smelting. If necessary, sprinkle sawdust into the cast shell that was just poured. Prevent non-metallic inclusions into the molten steel by not adding excessive deoxidizers.
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