Yttrium (element symbol Y) is a heavy rare earth metal element. Yttrium is an important heavy rare earth metal because its physical and chemical properties are similar to those of other rare earth metals and often coexist with rare earth minerals of other rare earth metals. Yttrium metal has many applications in non-ferrous alloys, steel, rare earth permanent magnets and military industry. The application of iron and steel is as follows:
1. In molten steel at high temperature, Y reacts with S, O 2, P, C and N to form YS, Y2O3, YP, YC and YN, which improves the service performance of steel.
2. In molten steel, Y_reacts with inclusions such as Al2O3 and MnS to form Y2O3 and YS, while Al2O3 and_MnS change to Mn and Al, which improves the comprehensive properties of steel.
3. Sometimes Y can be alloyed with steel to form new compounds, which is beneficial to the improvement of steel properties.
4. The eutectic temperature and solid solubility of cast iron can be improved by adding Y < 1.0% to cast iron.
5. Adding Y_0.015-0.07% to 18-8 stainless steel can obviously improve the pinhole corrosion resistance and be beneficial to the requirements of application environment.
6. When Y_0.3% is added to heat-resistant steel, the oxidation rate of steel at different temperatures can be significantly reduced, the oxidation increment can be reduced and the service life can be prolonged.
7. When Y is added to the production of seamless steel pipe for petroleum, quenching crack and forging crack can be reduced, and heat treatment process can be simplified.