Carbon raiser, also known as carbon additive, is a material that is added to molten metal during casting to improve the quality of the final product. Carbon raiser is typically made from petroleum coke or anthracite coal, and it is used to increase the carbon content of the metal being cast.

The addition of carbon raiser has several benefits in casting. First, it helps to reduce the amount of porosity in the final product. Porosity is a common issue in casting, and it occurs when tiny air bubbles become trapped in the metal as it cools. These air bubbles can weaken the metal and make it more prone to cracking or breaking under stress. By adding carbon raiser, the carbon in the material reacts with the oxygen in the air bubbles, causing them to dissipate and reducing the overall porosity of the final product.

In addition to reducing porosity, carbon raiser can also improve the strength and durability of the metal being cast. Carbon is a hard, strong material, and when it is added to molten metal, it can help to reinforce the structure of the final product. This is particularly important in applications where the metal will be subjected to high stress or wear, such as in automotive or aerospace components.

There are several different types of carbon raiser that can be used in casting, each with its own characteristics and benefits. Petroleum coke-based carbon raiser is a common choice, as it is relatively inexpensive and readily available. However, it can also contain impurities that may affect the quality of the final product. Anthracite coal-based carbon raiser is another option, and it is known for its high purity and consistent quality. However, it can be more expensive than petroleum coke-based carbon raiser.

When using carbon raiser in casting, it is important to carefully control the amount that is added to the molten metal. Adding too much carbon raiser can lead to over-carburization, which can cause the metal to become brittle and prone to cracking. Conversely, adding too little carbon raiser may not have a significant impact on the final product.

Overall, the use of carbon raiser in casting can help to improve the quality, strength, and durability of the final product. By carefully controlling the amount of carbon raiser that is added, manufacturers can produce high-quality castings that meet their specific requirements.