Smelt In Casting Process

Common cast metals

1. Gray cast iron
2. Nodular cast iron
3. Malleable cast iron
4. Cast steel

Commonly used cast non-ferrous metals

1. Brass
2. Tin bronze
3. Wuxi bronze
4. Aluminum alloy

Smelting of cast non-ferrous alloys

The smelting process has a great influence on the properties and defects of non-ferrous alloy castings. Most non-ferrous alloys are prone to pores and inclusions, especially titanium alloys, aluminum alloys, magnesium alloys and certain copper alloys. The general smelting process is:

1. According to the alloy grades specified in the technical requirements of castings, the chemical composition range of the alloy can be found, and the chemical composition can be selected from it;
2. According to the burning loss rate and composition requirements of the elements, the batching calculation is carried out to obtain the added amount of various charge, and the charge is selected. If the charge is contaminated, it needs to be treated to ensure that all the charge is clean, rust-free, and preheated before feeding;
3. Check and prepare chemical equipment, apply paint, and preheat to prevent pollution by gas, inclusions and harmful elements;
4. Feeding. The general order of feeding is: recharge, intermediate alloy and metal material, and metal materials with low melting point and easy to oxidize, such as magnesium, are added after the charge is melted;
5. In order to reduce the gas absorption and oxidation pollution of the alloy liquid, it should be melted as soon as possible to prevent overheating. According to the needs, some alloy liquids must be protected by a covering agent;
6. After the charge is melted, refining is carried out to purify the alloy liquid and to check the refining effect;
7. Perform deterioration treatment and sub-organization treatment as needed to improve performance, and check the treatment effect;
8. Adjust the temperature and perform pouring. Some alloys must be stirred before pouring to prevent segregation of specific gravity..

Refractory

High-quality refractory materials are inseparable from the process of metal smelting and casting in the casting process. The quality of the melting furnace and the intermediate iron/ladle refractory materials will directly affect the chemical composition of the metal liquid, which will cause the overall quality of the castings to be irresistible. Recover the adverse effects.
Classification of refractory materials commonly used in the casting and smelting process:

Refractory bricks: siliceous bricks, high alumina bricks, corundum bricks, magnesia bricks, magnesia alumina bricks, magnesia carbon bricks, etc.

Unshaped refractory materials: ramming materials, castables, refractory cement, silica sand, magnesia, smears and light insulation materials, etc.

Informatization

Casting is an important basic industry of the machinery industry. With the rapid development of information nowadays, improving the production and processing efficiency and production quality of casting will be a problem that the majority of foundry workers must face.

The high scrap rate of cast blank products has always been a common problem of various casting methods in the industry. How to better control the entire casting process is particularly important!

Therefore, the emergence of casting process simulation software will gradually solve this problem in the casting industry. The next step How to optimize the simulation process into a more accurate measurement tool, how to network, how to use cloud computing to better handle a large amount of parameter data so that the majority of casting technicians can better share these public data,

China Foundry Association, China Foundry Society, and China Foundry Network are all investing in research and development efforts for the informatization of the foundry industry.

Four qualities

Innovation is the fundamental source of the development and growth of an industry and the foundation of an enterprise’s inexhaustible power. Therefore, the foundry industry must vigorously develop scientific research and innovation forces. The foundry industry is composed of various foundry companies, so innovation must be implemented. , The task falls on the shoulders of various foundry companies. For foundry companies to innovate, they must possess four qualities.

The foundry industry of our country should build an innovative enterprise with “Four Haves”, that is, with innovative ideas, innovative plans, innovative systems and systems, and innovative working methods. Innovation is a scientific system. Therefore, my country’s foundry companies must have a complete innovation system in order to be able to innovate better. Foundry companies formulate their innovation plans under the impetus of innovative ideas, and under the innovation system and system and guarantee Implement innovation plans and provide overall guidance in a scientific way of work to promote the development of enterprise innovation.

Therefore, the “Four Haves” is not only the original driving force for the foundry enterprises to innovate, but also the guiding principle for the foundry companies to better carry out innovative work. Therefore, innovative foundry enterprises should have the quality of the “Four Haves”.

Type of casting

The most used material for casting technology.

Sand casting method

Using sand as a mold material, sand with different compositions can be subdivided into Green Sand Mold, Dry Sand Mold, etc., but not all sand can be used for casting.

The advantage is that the cost is lower, because the sand used in the mold can be reused; the disadvantage is that the production of the mold is time-consuming, the mold itself cannot be reused, and the finished product can only be obtained after destruction.

Die Casting

Use a metal with a higher melting point than the raw material to make a mold. Among them, it is subdivided into gravity casting method, low pressure casting method and high pressure casting method.

Subject to the melting point of the mold, the metal that can be cast is also limited.

Lost-wax casting (Investment Casting, Lost-wax casting)

This method can be the outer film casting method and the solid casting method.

First copy the object to be cast with wax, then immerse it in a ceramic-containing bath and wait to dry, so that the wax replica is covered with a ceramic outer film, and the steps are repeated until the outer film is sufficient to support the casting process (about 1/ 4 inch to 1/8 inch), then melt the wax in the mold and pull out of the mold. After that, the mold needs to be heated many times to increase the hardness before it can be used for casting.

This method has good accuracy and can be used for casting high melting point metals (such as titanium). However, due to the high price of ceramics, and the need for multiple heating and complicated production, the cost is quite expensive.