M4 is a high carbon molybdenum high vanadium type high-speed steel, the steel is on the basis of M2 to improve the carbon content and vanadium content, its main properties (surface hardness, high temperature hardness, wear resistance, heat resistance) have been improved. It has the advantages of small carbide non-uniformity and high toughness, and is easy to overheat, so the quenching heating temperature should be strictly controlled, and the protection requirements for heat treatment are stricter. Due to its good hardness and wear resistance, it is often used to manufacture tools for cutting materials that are difficult to cut.
Chemical composition of M4 high-speed steel:
| element | C | Cr | Mo | W |
| content | 1.25～1.40% | 3.75～4.75% | 4.25～5.50% | 5.25～6.50% |
| V | Si | Mn | S | P |
| 3.75～4.50% | 0.20～0.45% | 0.15～0.40% | ≤0.030% | ≤0.030% |
M4 high speed steel application scope:
Can produce various types of general tools, such as turning tools, planing tools, tap, drill, forming milling cutter, broach, scraper, hob, thread comb, hexagonal head forming die, tap, punch, etc., suitable for processing high-strength steel, high-temperature alloy and other difficult to process materials. Because of the general grinding performance, it is not suitable to manufacture high-precision complex tools. Similar to PM23 high speed steel
