News Center
11
2022
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11
The foundry would like to introduce the precautions in precision casting and how to improve the quality of castings.
I believe most people now know about stainless steel investment casting, also known as lost-wax casting, which is widely used in various castings, but a series of problems will inevitably be encountered during the casting process. The foundry will introduce the precautions in investment casting and how to improve the quality of castings.
Most people now know about stainless steel precision casting, also known as investment casting or lost wax casting, which is widely used in various castings. However, a series of problems are inevitable during the casting process. The foundry will introduce the precautions in precision casting and how to improve the quality of castings.
First of all, the foundry says that it is necessary to choose an optimized plan and process to improve the process yield rate of precision castings. On the premise of ensuring the quality of precision castings, the import and export rate can usually be improved by changing the gating system and using heated insulation risers. If the export rate can be increased from 60% to 70%, the energy consumption can be reduced by 14.3%.
Second, use a molding machine with high compactness and modern core-making technology to minimize casting quality and machining allowance. The foundry believes that using high-pressure molding can reduce the casting quality by 3%-5% compared with manual molding and ordinary machine molding, and the machining allowance can be maintained at 2-3 mm. Reducing weight not only saves energy in the precision casting workshop, but also reduces energy consumption in subsequent processing.
Third, the foundry says that to choose an energy-saving process flow for castings, production should be arranged reasonably. For example, replacing clay sand dry molds with self-hardening resin sand or externally dried molds can save energy consumption for dry molds; strictly proportioning, determining suitable casting components, adopting beneficial inoculation schemes, eliminating white spots or hard spots on as-cast castings, and canceling graphitization annealing processes; promoting as-cast ductile iron, requiring elongation after fracture below 12% in the as-cast state; try to choose frequency harmonic vibration aging process to remove stress and reduce thermal aging process.
Fourth, save materials and strive for reuse. Because the production of any material requires energy consumption.
Fifth, the scale production of steel casting enterprises, that is, the output of each casting unit is more than 5,000 tons. The foundry believes that due to the large output of the enterprise and the long working hours of the furnace, the heating energy consumption of the furnace itself can be evenly distributed to each ton of precision castings, which can be greatly reduced.
Sixth, improve management level and reduce the rejection rate. For example, for a precision casting factory with an annual output of 5000t, every 1% decrease in the rejection rate is equivalent to an increase of 50t of precision castings. Calculated at 400 GJ of energy consumption per ton, 20 tons of standard coal can be saved in one year, which means reducing the energy consumption of each ton of precision castings by 4 GJ.
The foundry says that the methods to improve the quality of stainless steel precision castings are as follows:
1. Process planning: Strictly control the process. The foundry believes that before closing the box, ensure that the molding and sand core are in a warm state to ensure the fluidity of the molten steel during pouring. For places with rough and damaged appearance, apply alcohol-based zircon powder coating and then ignite and bake to lubricate the appearance of the mold.
2. Mold planning: The appearance treatment list of stainless steel castings starts from the mold, clean the appearance of the mold, that is, wipe the surface with sandpaper, and then apply nitro paint. For high-precision castings, choose metal or plastic molds to improve the smoothness of the mold appearance.
3. Fillet planning: The foundry believes that in order to avoid white spots in stainless steel forging, in addition to taking technical measures, the wall thickness of stainless steel should not be too thin. When the wall thickness is greater than 15mm, use fillets at the corners of castings forged with metal molds.
4. Polishing plan: Remove burrs and sharp edges during polishing, and over-lubricate uneven surfaces. For heat-treated castings, choose grinding and polishing. Steel shot grain size is 0.85~1.4mm, hardness is HRC40-50, and hardness error is large HRC3.0.
5. Wall thickness planning: Since metal molds dissipate heat quickly, the small wall thickness of stainless steel forgings should be greater than that of sand forgings, and the small wall thickness of various forging alloys is different from that of large and small forgings.
6. Material planning: Starting from raw materials, the appearance and core making adopt 75-150 mesh zircon sand resin sand, and choose thermosetting resin. The mixed sand has high fire resistance, smooth appearance, good collapsibility, and simple sand removal.
Foundry
Shandong Gongchen Machinery Technology Co., Ltd.
Contact QQ: 258506508
Mobile Number:15621618888
Phone:0536-7691368 7691229
Fax: 0536-7691229
Contact Email:guisongzhng8@gmail.com
Website:www.shandonggongchen.com Gongchen.China Valve Castings.China
Address: Mucun Town, Fangzi District, Weifang City, Shandong Province
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