Tool steel
Date:2026-08-26
Tool steel is a type of high-quality steel specifically designed for manufacturing various tools (such as knives, molds, and measuring tools). Its core characteristics are high hardness, high wear resistance, and a certain degree of toughness.
Based on chemical composition and performance characteristics, tool steels are mainly divided into the following three categories:
1. Carbon Tool Steel: An Economical and Basic Choice
This is the most basic and cheapest type of tool steel. Its high hardness is primarily achieved through a high carbon content (typically between 0.65% and 1.35%).
Core Advantages: Good machinability; surface hardness after quenching can reach HRC66-67; excellent wear resistance.
Main Limitations:
Low hardenability: Water quenching can only effectively harden small tools with a diameter of approximately 8-15mm, making it unsuitable for large or complex tools.
Poor heat resistance (poor red hardness): Hardness and wear resistance decrease sharply when the working temperature exceeds 200℃-250℃, making it unsuitable for high-speed cutting.
Application Scenarios: Used for manufacturing tools with simple shapes, small sizes, and low operating temperatures. For example, T7/T8 is often used for chisels and hammers; T10/T11 is suitable for taps, drills, files, etc.
2. Alloy Tool Steel: The Main Force for Performance Improvement
Based on carbon tool steel, alloying elements such as chromium (Cr), tungsten (W), silicon (Si), and manganese (Mn) are added, significantly improving hardenability, wear resistance, and tempering stability.
Representative Grades and Applications:
Cutting Tool and Measuring Tool Steels: Such as 9SiCr and CrWMn. These steels have good hardenability, minimal heat treatment deformation, and high wear resistance, and are commonly used to manufacture precision tools such as taps, dies, reamers, and gauges.
Impact Tool Steels: Such as 5CrW2Si and 6CrW2Si. With a lower carbon content (0.35%-0.65%), they have exceptionally high toughness and are suitable for tools subjected to strong impact loads, such as pneumatic chisels and punches.
Cold work die steels: The most typical are high-carbon, high-chromium steels Cr12 and Cr12MoV. They possess extremely high wear resistance and minimal deformation after quenching, making them the preferred choice for manufacturing heavy-duty, high-volume cold stamping dies.
Hot work die steels: Such as 5CrMnMo, 5CrNiMo, and 4Cr5MoSiV. These steels maintain high strength, hardness, and resistance to thermal fatigue at high temperatures, and are used to manufacture forging dies, die-casting dies, etc., that work on hot metals.
3. High-speed tool steel: Cutting-edge materials in the cutting field.
This is the most alloyed and highest-performance type of tool steel, commonly known as "high-speed steel." It uses tungsten (W), molybdenum (Mo), chromium (Cr), and vanadium (V) as main alloying elements and is a key material for manufacturing high-speed cutting tools.
Core advantage: Excellent red hardness, meaning it maintains high hardness (HRC63-70) even at temperatures above 600℃, thus allowing for extremely high cutting speeds.
Representative Grades and Applications:
General-Purpose High-Speed Steel: The most common types include W18Cr4V (tungsten-based) and W6Mo5Cr4V2 (tungsten-molybdenum-based, abbreviated as M2). These offer good overall performance and are used to manufacture general-purpose cutting tools such as lathe tools, drills, and end mills.
High-Performance High-Speed Steel: Such as W2Mo9Cr4VCo8 (cobalt-containing high-speed steel, M42). These steels have higher hardness and red hardness, making them suitable for machining difficult-to-cut high-strength materials.
