Nickel iron is a nickel iron alloy with a nickel content of 20% -60%. The melting point of nickel iron is 1430-1480 degrees, and the density is 8.1-8.4. Mainly used as a nickel additive in steelmaking and cast iron. According to international standards (ISO), nickel iron is divided into FeNi20 (15%~25% Ni), FeNi30 (25%~35% Ni), FeNi40 (35%~45% Ni), and FeNi50 (45%~60% Ni) based on its nickel content. It is further divided into high carbon (1.0%~2.5% C), medium carbon (0.030%~1.0% C), and low carbon (<0.03% C); Low phosphorus (<0.02% P) and high phosphorus (<0.030% P) nickel iron.