Coated Sand Casting Parts
China Coated Sand Casting Parts Manufacturers Factory Suppliers
We specialize in producing all kinds of Coated Sand Casting Parts products, mainly High Strength Steel Casting, High Tensile Strength Castings, etc.
HANRUI STEEL CUSTOMIZATION was established in 2009, boasting over 10 years of manufacturing experience, can provide customers with perfect solutions.
Our market is mainly concentrated in countries such as the United States, Australia, Canada, Finland, Belgium, Bulgaria, Germany, Japan, United Kingdom, Netherlands, Sweden, etc. We have established long-term cooperative relationships with customers around the world.
Company Advantages
Well-Experienced
HANRUI STEEL CUSTOMIZATION was established in 2009, boasting over 10 years of manufacturing experience. With a dedicated team casting engineers, and mechanical designers, we are committed to offering solutions to the steel accessory challenges faced across various industries.
Large Scale
With shares in two investment casting bases, one sand casting base, and two forging bases, we offer comprehensive one-stop services to our customers. From initial design and development to the delivery of flawless steel parts, we ensure a seamless and efficient process.
Advanced Production Equipment
We are a full-service company providing complete design, R&D, production and sales services. Our production workshop is equipped with the most advanced equipment. Innovation, powerful technology, and expertise make our equipment highly automated with various parameters that can be adjusted to meet the needs of most applications in the industry.
24-hour Online Customer Service
We have an experienced and professional customer support team to provide flexible service to customers around the world. Our customer service is available online 24 hours a day. After receiving the service information or feedback from the customer, we will reply and address the feedback in the shortest time.
Global Sales Network
Our market is mainly concentrated in countries such as the United States, Australia, Canada, Finland, Belgium, Bulgaria, Germany, Japan, United Kingdom, Netherlands, Sweden, etc. We have established long-term cooperative relationships with customers around the world. In addition, we also provide OEM/ODM manufacturing services to many customers.
Customized Services
We welcome product customization, and our team is capable of developing new products or providing technical solutions tailored to customer requirements. lf you have any special request, pls send us the details.
Introduction to Coated Sand Casting Parts
Coated sand casting is a casting method that uses chemical components added to molding sand, which is then hardened by heating. The sand is mixed with new sand and recycled sand, and creates high-quality products. Coated sand casting is becoming more common and is often used to replace clay green sand casting.
The process involves heating sand to a certain temperature, then mixing with resin, Hexamethylenetetramine solution and Calcium stearate respectively, then cooling, crushing and sieving. The resin coated sand mold could be solid into a strong shell after heating of just at the room temperature (no-bake or self-hardening process), which is different from the green sand casting process.
Coated sand is one of the best moulding sands for cars, tractors and hydraulic parts. It produces a casting of high precise dimensions, smooth surface, free of blow holes and devoid of casting defects.
Coated Sand Casting has the following advantages:
1. The pollution is small, and the worksite environment is obviously improved. Since the clay sand is added with a large proportion of coal powder, which is a combustion-supporting material, it is mainly used to increase the appearance quality and air permeability of the workpiece. The coal powder added to the sand cannot be reused, resulting in a waste of resources. Ash residues after combustion have a great impact on the quality of our working environment. At the same time, the reducing gas and PM2.5 produced during combustion cause serious pollution to the atmosphere. Although the molding method based on coated sand also has a certain impact on the environment, after all, it uses a small amount of sand, and at the same time, all the waste sand after use is recycled. The worksite is clean and free of dust pollution.
2. The sand coating layer is thin, the dosage is small, the production cost is low, the waste is small, and the used molding sand can be recycled and reused. Due to the thin sand coating layer of this molding method, 5-10mm coating sand layer is usually designed according to the wall thickness of the live piece, while the minimum sand coating amount for clay sand molding is usually 30-50㎝, and the amount of sand used is 10-20 mm of coated sand. times. Although clay sand can also be recycled for the second time, the high content of coal powder, bentonite and other additional raw materials have been basically consumed, and the quality of the sand has been greatly reduced, which affects the appearance quality of the product. After the molding sand of coated sand is roasted at high temperature, the expansion is greatly reduced, the process steps of pickling are reduced in the secondary use, and the addition amount of solid resin and curing agent is also greatly reduced, which reduces the production cost.
3. Change the appearance quality of the blank, reduce the cutting allowance, the process yield is high, and the quality is stable. Due to the low hardness of the clay-sand molding sand and the large concessionality, the casting defects such as box expansion, sand expansion, sand loss, porosity, shrinkage and other casting defects are serious, which not only cause poor product appearance but also have many internal casting defects, which are serious and serious. The service life of the product is affected, and the scrap rate is high. The aggregate in coated sand molding is pickled or calcined at high temperature, which reduces the expansion of the sand mold after combustion, and has many advantages such as high strength and small gas generation after curing. Appearance quality, inherent casting defects, and product size accuracy are far superior to those produced by clay sand molding.
4. Improve the internal quality of products. Due to the fast cooling rate of the coated sand during casting, the graphite morphology of the casting is greatly improved, the mechanical properties of the product are improved, and the service life of the product is increased. The products produced by coated sand molding, especially ductile iron, are far superior to those produced by clay sand molding regardless of spheroidization level, matrix structure, hardness, tensile strength, yield strength, etc. Invisibly improve the inherent quality of the product. It increases the service life of the product and indirectly provides a strong guarantee for meeting customer needs.
5. Coated sand molding adopts automatic production line operation, which improves production efficiency, reduces the labor intensity of workers, and shortens labor time. The traditional clay sand molding adopts manual molding or molding machine molding. The labor intensity of workers is high and the work efficiency is low, which is 1/3 to 1/4 of the molding efficiency of the production line.
Types of Coated Sand Casting
Coated sand casting has various derived variants and improvements in practical applications. These variant processes can be selected based on different requirements and material characteristics. Two common variants are:
Cold-box coated sand casting
In this process, the coating material is directly sprayed onto the surface of the cold, hard mold without the traditional hot mold pre-treatment. This process is suitable for materials with poor heat dissipation or special casting requirements. It significantly reduces the process temperature, improves production efficiency, and saves energy.
Continuous coated sand casting
This process combines continuous sand belts with coating equipment to achieve continuous production. The sand is continuously coated with the coating material as it moves along the conveyor belt, forming a continuous sand mold. The advantage of this process is high production efficiency, making it suitable for large-scale and continuous production requirements.
Applications of Coated Sand Casting Parts
The coated sand casting method is prevalent in a wide range of applications. The popular products from coated sand castings are pistons and valves, engine blocks, cams, bearings, bearing balls, hydraulic pumps and housings, agricultural equipment, automotive equipment, lever arms and pulleys, and electrical equipment appliances parts, railroad equipment, petrochemical engineering equipment, construction machinery.
Although based on different complexity, the type of metal casting may vary. The popular industries it serves are medical, agricultural, automotive, defense, marine, mining, power plants, etc.
Process of Coated Sand Casting Parts
The process of coated sand casting mainly includes the following steps:
Preparation of cores
Prepare the required cores according to product requirements.
Preparation of molds
Mix the coated sand with a binder to prepare the mold used for casting. The coated sand is uniformly applied to the mold surface.
Coating treatment
After applying the coating to the mold, use a dedicated coating machine or other methods to process the mold to form a uniform and strong coating layer.
Pouring of metal liquid
After the coating layer is dried, pour the metal liquid into the mold to fill the entire cavity.
Cooling and solidification
After the metal liquid cools down, the mold and cores gradually solidify, forming the overall structure of the castings.
Shakeout
After solidification is complete, shake and remove the mold, then remove the sand cores, resulting in the castings.
Post-processing
Inspect the castings for dimensions, surface quality, etc., and then perform necessary post-processing such as deburring and trimming.
Precautions of Coated Sand Casting
Here are some precautions for coated sand casting:
Treatment of old sand
Old sand treatment is important for the
casting elements of coated sand.
Use high-purity quartz sand
Use high-purity quartz sand instead of 45–75 mesh coarse quartz sand.
Ensure SiO2 content is higher than 96%
For bucket tooth steel castings with high pouring temperatures, the SiO2 content of raw sand should be higher than 96%.
Minimize dust generation
Minimize the generation and accumulation of dust.
Our Factory
We have a fully automatic CNC production line, and are committed to providing customers with the best products and services.
Frequently Asked Questions
Q: What are the differences between Coated Sand Casting VS Resin Sand Casting?
Coated sand mould casting and resin sand mould casting are two casting methods that are more and more widely used. In actual casting production, they are increasingly used to replace clay green sand casting.
Although there are some similarities between resin sand and coated sand, for example, chemical components are added to the molding sand. Both of them could be divided into sand casting process. However, their difference is also very obvious. Resin sand is self-hardening sand, cold hardened, and hardened with a curing agent or catalyst; while coated sand is thermal hardened and hardened by heating.
Coated Sand Casting:
The surface of the sand particles of the coated sand is covered with a layer of solid resin film molding sand or core sand before making mould. Preheat the sand to a certain temperature, add resin to melt, stir to coat the surface of the sand particles, add urotropine aqueous solution and lubricant, cool, crush, and siev to obtain coated sand with enough hardness to withstand the molten metals.
Resin Sand Casting:
Resin sand casting is to mix raw sand, resin and curing agent evenly and put them into the sandbox and pattern to make the core. It uses furan resin and curing agent to make the sand compact and hard enough. Then close the box for casting.
Q: What is the basic principle of Coated Sand Casting Parts?
The basic principle of the coated sand casting parts process is to cover the traditional sand mold with a layer of coating material, which can be a special thermoplastic or thermosetting material. This coating forms a protective layer during the casting process, preventing direct contact between the metal liquid and the mold material, and protecting the sand core material from being eroded by the metal liquid, thereby improving the surface quality of the castings.
Q: What are the characteristics of Coated Sand Casting?
The coated sand casting process has good strength performance;
Good fluidity, the produced sand mold and sand core have a clear outline and dense organization, and can produce complex sand core;
The sand mold (core) has good surface quality, the surface roughness can reach Ra=6.3～12.5μm, and the dimensional accuracy can reach CT7～CT9 level;
The disintegration is good, and the castings are easy to clean.
The coated sand can be used to make both casting molds and sand cores. The coated sand molds or cores can be used together with other sand molds (cores);
It can be used not only for metal-type gravity casting or low-pressure casting, but also for iron-type sand-covered casting, but also for thermal centrifugal casting;
It can be used not only for the production of cast iron and non-ferrous alloy castings but also for the production of steel castings.
Q: What are the disadvantages of Coated Sand Casting?
The coated sand casting method produces higher porosity defects in the castings than other metal casting methods. Therefore, it would be best if you decide the porosity level of your metal casting applications.
Another casting defect often found in coated sand casting is surface inclusion. In the casting process, the molten metal picks up loose sand from the molds. As a result, it creates surface inclusions in the form of sand grains.
We know that coated sand casting requires less tooling cost. However, on the other hand, it ultimately increases the labor cost as the process is manual.
Coated Sand Casting requires special cleaning and additional machining to minimize the dimensional tolerances.
This casting method is not suitable for large order quantities. In those cases, reusable permanent molds are prevalent in most foundries.
Q: What Are The Different Types of Sand Used in Coated Sand Casting?
Green sand: Green sand consists of sands (75-85%), bentonite clay (5-11%), water (2-4%), and other materials (3-5%).
Sodium-silicate or Water glass: Sodium silicate mainly consists of metasilicate. It is ideal for fire protection. Besides, this sand is also popular in the textile industry, lumber handling, and silica gel production.
Resin sand: Resin sand is a mixture of quartz sand and resin. It provides good fluidity and accessible compaction properties.
Q: How to Choose The Best Sand for Coated Sand Casting?
Temperature refractoriness: The most critical factor you should consider is the ability of the sand that withstand the high molten temperature of the liquid metal.
Gas permeability: The ability of sand to allow gas to pass through the sand. During the casting process, some gas may dissolve in the liquid metal. However, when it starts solidification, this gas tries to come out of the mold. In that case, the gas permeability of the sand is the most crucial factor to consider.
Fluidity: The sand's ability to compress to a compact density allows the molten liquid to pack around the pattern.
Contractibility: Collapsibility or contractibility refers to the ability of the sand to collapse after solidification.
Adhesiveness: The ability of the sand allows the sand particles to stick to other materials.
Strength: The ability of the sand allows the sand particles to stick to each other.
Q: What is Coated Sand Casting Process steps?
First Step: Mold Creation
Mold-making is the most critical step, which ensures the precision of the final casting dimension. A container filled with specialized sand includes the pattern of the original object. In this case, a casting pattern replicates the actual product. It can be made of wax or other materials. However, the sand mold container's top and bottom halves are called cope and drag, respectively.
Second Step: Mold Preparation
After the sand mold is ready, the operator prepares to pour the molten metal. In this case, lubrication on the surface of the cavity is necessary. Each metal type differentiates the lubricate type. Later, the operator closes the two halves of the container and clamps them together. Clamping is also a critical step where proper precautions are taken for defect-free metal casting.
Third Step: Pouring Molten Metal
The gating system is one of the essential terms in this step. The operator pours the molten metal through these gates. In this case, gating refers to the gap between the casting cavity and the mold outside.
Fourth Step: Cooling
After pouring metal into the casting cavity, the operator puts the container into the cooling chamber. In this case, an appropriate cooling temperature is necessary to minimize the shrinkage defects of the casting. When the liquid metal turns into solid metal and comes to a moderate temperature, it is now ready to be removed.
Fifth Step: Remove The Cast From The Mold
At this stage, the operator breaks the sand mold and removes the casting from the mold. In Dawang casting, the expert operator uses a vibrating machine that gently removes the sand from the casting. Finally, the hot blasting method removes the remaining sand and the oxide layer which was stuck on the surface of the casting.
Sixth Step: Machining
It is important to note that coated sand castings have higher dimensional tolerances. At this stage, proper machining is necessary to make it precise. Some excess material might be attached to the surface, which needs to be removed to get the original shape of the castings.
Seventh Step: Finishing
After trimming and other machining stages, the casting goes to the finishing stage. The finishing stage includes polishing, painting or powder coating. The type of finishing depends on the casting materials and application.
Q: What are the differences between coated sand casting vs. investment casting?
Q: What Metal & Alloys Does Your Coated Sand Casting Foundry Mainly Cast?
Q: What Casting Tolerances Could Your Sand Castings Achieve?
DCT Grade by Green Sand Casting: CTG10 ~ CTG13
DCT Grade by Shell Mold Casting or Furan Resin Sand Casting: CTG8 ~ CTG12
GCT Grade by Green Sand Casting: CTG6 ~ CTG8
GCT Grade by Shell Mold Casting or Furan Resin Sand Casting: CTG4 ~ CTG7
Q: How long does coated sand casting take?