The atomic weight of molybdenum is 95.94. The outer electronic structure is 4d5s, with a melting point of 2615 ℃, a boiling point of 4610 ℃, and a density (20 ℃) of 10.2g/cm. The binary phase diagram of molybdenum and iron is shown in Figure 1. Molybdenum and iron formationα Andγ Two solid solutions and two intermetallic compoundsε (Fe7Mo6) andσ (FeMo) phase. Industrial ferromolybdenum contains about 60% Mo, with a melting temperature of 1800~1900 ℃; The density is about 9.0g/cm.

The role of molybdenum in steel can be summarized as improving hardenability, improving thermal strength, preventing temper brittleness, improving residual magnetism and coercive force, as well as corrosion resistance in certain media, and preventing pitting corrosion tendency. Due to the various beneficial effects of molybdenum in steel, it has been widely used in a series of steel grades, such as structural steel, spring steel, bearing steel, tool steel, stainless acid resistant steel, heat-resistant steel (also known as hot strength steel), magnetic steel, etc. Molybdenum is very effective in improving strength and toughness in cast iron. When the addition amount is 0.25%~1.25%, it can also form a pearlite matrix structure for castings with medium and large cross-sections. Commonly used for rolls and other wear-resistant castings.