There are significant differences between white cast iron and gray cast iron in terms of chemical composition, microstructure, physical and mechanical properties, and application areas.
Appearance differences
White cast iron and gray cast iron have obvious differences in appearance. The fracture of white cast iron is white (the “white” in white cast iron means that all the carbon in the cast iron exists in the form of infiltrated carbon (Fe3C). Because the fracture is bright white and the cross section is relatively flat, it is called white cast iron. In addition, the formation of white cast iron is mainly due to the fact that there is no graphite precipitation during the crystallization process, and all carbon exists in the form of infiltrated carbon, and it can be forged during processing. So this is also a distinct feature from gray cast iron, which cannot be forged.
Gray cast iron is gray , the cross section is relatively rough. This is because the carbides in white cast iron are spherical, resulting in a smooth fracture, while the carbides in gray cast iron are flaky, resulting in a rough fracture.
Performance Differences
1. Hardness and Strength: The hardness and strength of white cast iron are higher than those of gray cast iron. This is because the carbides in white cast iron are stable and evenly distributed, while the carbides in gray cast iron are unstable and unevenly distributed.
2. Toughness: The toughness of gray cast iron is better than that of white cast iron, because gray cast iron The carbide in the cast iron is in the form of flakes, which makes it have better toughness.
3. Wear resistance: White cast iron has better wear resistance than gray cast iron, because the carbide in white cast iron is in the form of spherical, which makes it have better wear resistance.
Application difference
The application range of white cast iron and gray cast iron is also different. Generally speaking, white cast iron is used to make some parts that require higher strength and hardness, such as engine cylinder block, cylinder head and more; while gray cast iron is used to make some parts that require better toughness and wear resistance, such as machine tool bed, automobile brake drum and more. In addition, common sewer pipes, underground pipes, street lamp poles are also gray cast iron products.
Of course, the two types of cast iron parts are currently widely used in the market, and professional casting factories also have mature cast iron processes. If you need to customize cast iron parts in large quantities, you can choose Mulan Metal. Mulan Metal has 12 years of metal casting experience, serving customers in more than 30 countries, with complete certificates, and can meet the OEM needs of customers in different countries.
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