Non-metallic inclusions in 16MnR steel (hot-rolled)
Non-metallic inclusions are constituents that may be present in steel. These inclusions are essentially mineral particles or oxidation products of various origins. In steel, non-metallic inclusions have both beneficial and detrimental effects on its physical properties such as dimensional stability, fatigue and corrosion resistance. In order for steel products to have good quality, it is essential that non-metallic inclusions be properly controlled.
16MnR steel is a Chinese hot rolled medium and low alloy steel, commonly known as GB/T 712-2000 standard. This alloy is a kind of manganese-containing steel specially used in various building structures, engineering structures, super-long concrete structures, agricultural machinery, ships and bridges. 16MnR steel contains elements such as manganese, carbon, silicon and phosphorus, in addition to non-metallic inclusions. The content of non-metallic inclusion in hot-rolled 16MnR steel can be determined by metallographic analysis.
Some common non-metallic inclusions found in 16MnR steel include oxides, sulfides, nitrides, carbides, silicates and nitroxides, which are formed during the process of smelting, casting, rolling and heat treatment. The formation of these non-metallic inclusions can have a negative effect on the mechanical properties of 16MnR steel. By controlling the content of non-metallic inclusions during the smelting, casting, rolling and heat treatment processes, the quality of 16MnR steel can be improved.
During the smelting process, furnace conditions such as temperature, gas atmosphere, fluxes and additions should be carefully controlled in order to reduce the content of non-metallic inclusions in the steel. During the casting process, the temperature of the steel should be kept low and the rate of solidification should be properly adjusted. Thorough mixing of charge and use of deoxidizers should also be ensured. During the rolling process, temperature control, roll wear and cooling should be properly done in order to reduce non-metallic inclusions. In addition, it is important to note that the addition of a variety of refractory materials during the reheating and heat treatment should be avoided.
Finally, it is worth noting that non-metallic inclusions can also negatively affect the corrosion resistance of 16MnR steel. This is because corrosion products are usually present in non-metallic inclusions, which increases the risk of corrosion. Therefore, it is important to keep the content of non-metallic inclusions in 16MnR hot rolled steel as low as possible in order to maintain good corrosion resistance.
