Sand Casting Auto Parts
The sand mold material must have a certain bond strength so that it can be molded into the desired shape and resist the scour of the high-temperature molten iron without collapsing. In order to form a cavity in the sand mold that matches the shape of the casting, a model must first be made of wood, which is called a wood mold.
Qinhuangdao Zhongwei Precision Machinery Co., Ltd. mainly produces various grades of gray iron castings, high-quality mechanical parts such as gray iron castings, steel castings, castings of various materials and row numbers. In the process of automobile manufacturing, cast iron is used. There are many parts of the blank, accounting for about 60% of the weight of the whole vehicle, such as cylinder block, transmission case, steering gear housing, rear axle housing, brake drum, various brackets, etc. Sand molds are usually used to make iron castings. The raw material of the sand mold is mainly sand, which is mixed with binder, water, etc., which is called sand casting.
Basic Situation Of Sand Casting Auto Parts
1. Implementation standards: The company strictly implements ISO9001 & TS 16949 certification.
2. Product material standards: ISO, GB, ASTM, SAE, ISO, EN, DIN, JIS, BS
3. Main processes: sand casting, silica sol investment casting, water glass investment casting,
shell casting,deburring, sand blasting, machining, heat treatment, leak testing, surface treatment, etc.
4. Available materials:
Gray iron, ductile iron, cast iron, cast steel, cast aluminum, cast copper, alloy steel, etc. are customized according to customer requirements.
Casting Process
The sand mold material must have a certain bond strength so that it can be molded into the desired shape and resist the scour of the high-temperature molten iron without collapsing. In order to form a cavity in the sand mold that matches the shape of the casting, a model must first be made of wood, which is called a wood mold. After the hot molten iron is cooled, the volume will be reduced. Therefore, the size of the wooden mold needs to be increased according to the shrinkage rate on the basis of the original size of the casting, and the surface that needs to be machined is correspondingly thickened. Hollow castings need to be made into sand cores and corresponding core wood molds (core boxes). With the wooden mold, the cavity sand mold can be made. When making sand molds, it is necessary to consider how to separate the upper and lower flasks to take out the wooden mold, and also consider where the molten iron flows in and how to fill the cavity to obtain high-quality castings. After the sand mold is made, it can be poured, that is, pouring molten iron into the cavity of the sand mold.
When pouring, the temperature of molten iron is 1250-1350 degrees, and the temperature is higher during smelting. Then it has to go through the process of sand removal, repair, grinding, etc., before it can become a qualified casting.
Moisture control method of old sand of foundry sand casting
Almost all foundries check and control the moisture content of mixed sand, however, many foundry leaders and technicians still lack sufficient understanding of the importance of strictly controlling the moisture content of used sand. The moisture content of the old sand entering the mixing sand is too low, and the impact on the quality of the sand mixing may be no less than that the sand temperature is too high. Both experimental studies and experience have shown that it is much more difficult to wet dry bentonite with water than to lubricate wet bentonite. The bentonite and water in the molding sand are not simply mixed together, but they must be kneaded to make them plastic. This is like making pottery with clay and water. The combination of water and soil is loose and has no bonding ability; after rubbing and beating, each grain of soil fully absorbs water and becomes a plastic state. Can be shaped to make pottery blanks.
After the mold is poured, due to the influence of hot metal, the soil-water adhesive film on the surface of many sand grains is dehydrated and dried, and it is very difficult to add water to make it absorb water to restore plasticity. The lower the moisture content of the used sand, the longer it will take to add water to the mixer to achieve the required properties. Since the time for sand mixing in production is limited, the lower the moisture content of the used sand, the worse the overall quality of the mixed sand. At present, foundry workers in various countries have reached such a consensus: the moisture content of the used sand entering the mixer can only be slightly lower than that of the mixed sand. A better practice is: in the cooling process of the old sand, the water content after fully adding water to cool is slightly lower than that of the mixed sand. In this way, there is still a long period of time from the sand cooling to entering the sand mixer, and the water can fully wet the bentonite on the surface of the old sand grains. A better approach is to set up a sand mixer in the system to premix the used sand, and add water to the premixed sand mixer to premix the cooled used sand to improve the mixing state of bentonite and water in the used sand. In foreign countries, some foundries will add all the additional materials such as new sand, bentonite and coal powder that need to be added when premixing. Qinhuangdao Zhongwei Precision Machinery Co., Ltd. uses the EiRich sand mixer made in Germany to premix. After pre-mixed old sand, the amount of water added after entering the sand mixer is very small, only slightly adjusted. The bentonite and water in the molding sand are further modulated in the sand mixer, and the performance of the molding sand is more stable and consistent.
Post Casting Process
1. Heat treatment: annealing, carbonization, tempering, quenching, normalizing, surface tempering
2. Sand casting auto parts processing equipment: CNC, WEDM, lathe, milling machine, drilling machine, grinder, etc.;
3. Surface treatment: powder spraying, chrome plating, painting, sandblasting, nickel plating, galvanizing, blackening, polishing, bluing, etc.
Moulds and Inspection Fixtures
1. Mold service life: usually semi-permanent. (except for lost foam)
2. Mold delivery time: 10-25 days, (according to product structure and product size).
3. Tooling and mold maintenance: Zhongwei is responsible for precision parts.
Available Materials List:
Grey iron and ductile iron
Other materials: cast iron, cast steel, cast aluminum, cast copper, alloy steel, etc. can be customized according to customer requirements.
Quality Control
1. Quality control: the defective rate is less than 0.1%.
2. Samples and trial run will be 100% inspected during production and before shipment, sample inspection for mass production according to ISDO standards or customer requirements.
3. Testing equipment: flaw detection, spectrum analyzer, golden image analyzer, three-coordinate measuring machine, hardness testing equipment, tensile testing machine;
4. Provide after-sales service.
5. The quality can be traced back.
Sand Casting Auto Parts Application Range
1. Engine parts
2. Auto parts
3. Mechanical parts
4. Railway train parts
5. Truck parts
6. Tractor accessories
7. Construction equipment
8. Agricultural equipment
9. Machine tool equipment
10. Other industrial fields
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