The rotary kiln tyre is one of the key components supporting the stable operation of the rotary kiln. During the operation of the kiln, tyres will be subject to temperature difference stress, bending stress, and contact stress. Therefore, they must be made of high-quality materials to ensure they will not be easily cracked and damaged during use.
As a professional supplier of rotary kiln equipment and parts, our company has summarized materials that are very suitable for the manufacturing of rotary kiln tyres through years of experience accumulation and technical research, so that our rotary kiln tyres have excellent quality and longer service life.
To improve the properties of the tyre manufacturing steel, the most effective way is to add a small number of alloy elements.
Add Chromium
Chromium can improve the hardenability and tempering resistance of steel without reducing plasticity. It can also slow the precipitation and aggregation of carbides in steel during tempering.
Because chromium is dissolved in ferrite, it can strengthen without reducing plasticity, so ZG40Cr has higher mechanical properties after quenching and tempering treatment. However, the thermal conductivity of chromium steel is poor, and coarse dendrites are easily to be obtained in the primary crystallization, which will increase the hot cracking tendency of the casting and have temper brittleness. Therefore, a small amount of Mo should be added to large steel castings to improve this property and the high-temperature strength of steel.
Add Manganese
Adding manganese to steel can reduce grain boundary carbides, and refine pearlite and ferrite grains, thus improving the toughness, yield limit, and low-temperature resistance of the material.
In addition, the sulfur in the steel is easy to delaminate the steel. When FeS is synthesized from sulfur and iron, the blue brittleness of steel during hot working will be caused. If proper manganese is added, manganese can be combined with sulfide to form harmless MnS. However, excessive MnS will lead to a reduction in the plasticity of steel.
Add Silicon
Silicon can improve the yield strength of steel by strengthening ferrite. Adding 1% silicon in medium carbon steel can increase the strength of steel by 15% to 20% after quenching and tempering, and the toughness will not be significantly reduced. In addition, a proper combination of silicon and manganese can reduce the tendency of heat treatment of manganese steel to grain growth.
Steel materials are polycrystalline, the smaller the grain diameter, the more grain boundaries; Dislocation cannot pass through the grain boundary, so the grain boundary can strengthen the yield strength. The addition of silicon in steel can reduce the grain diameter and improve the yield strength. Adding silicon and manganese to low-alloy steel at the same time can significantly improve the hardness of the material without reducing plasticity. Adding silicon can also improve manganese steel’s wear resistance and corrosion resistance.
Add Molybdenum
Adding molybdenum to steel can bring a variety of advantages, for example, it can improve the hardenability of steel; The matrix can be strengthened by solid melting; It can improve the high-temperature mechanical properties of steel; It can bring excellent temper brittleness resistance to the steel; It can increase the density of the hardened phase, etc. Therefore, cast steel with Cr and Mo is easy to manufacture large or complex-shaped castings.
Because molybdenum has a low solid melting degree in cementite and can separate out carbide (fine carbide with uniform distribution precipitated by martensite tempering), it can improve the creep resistance and the ability to prevent the fracture of steel. In addition, molybdenum has high density, high melting point, and low affinity with oxygen, so the oxidation resistance and high-temperature strength of molybdenum steel are very good.
Conclusion
The reasonable addition of the above elements to the steel used to manufacture the rotary kiln tyre can effectively improve the service performance of the steel, thus improving the durability of the tyre and extending its service life.