A2 공구강의 특성

Confirmed A2 Is the Right Grade?

Aobo Steel supplies A2 in annealed condition, ready for machining and heat treatment. Send your sizes and quantity, or check full product specifications and stock condition.

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A2 Tool Steel Properties Summary

A2 Tool Steel Equivalent Grades

A2 Tool Steel Chemical Composition

A2 tool steel is a chromium-molybdenum-vanadium alloyed cold work tool steel. Its composition provides better hardenability and dimensional stability than simple oil-hardening grades, while maintaining better toughness and machinability than high-carbon, high-chromium grades such as D2.

A2 tool steel is not stainless steel. Its chromium content supports hardenability and wear resistance, but it is not high enough to provide stainless corrosion resistance. A2 should be protected from rust during storage, machining, shipping, and service.

A2 Tool Steel Hardness

A2 tool steel is normally supplied in an annealed condition, then machined, hardened, and tempered to the required working hardness. The final hardness depends on the heat-treatment process, section size, tempering temperature, and tool application.

Higher hardness can improve wear resistance, but it also increases the risk of chipping. Lower hardness can improve toughness, but it may reduce edge life.

For many punches, forming tools, trimming dies, gages, and cold-work components, A2 is often used at 58–60 HRC. Cutting tools and thin-edge tools may require a different hardness range depending on the material being processed and the risk of edge chipping.

내마모성, 인성 및 치수 안정성

A2 is usually chosen because it offers a balanced combination of wear resistance, toughness, and dimensional stability.

A2 is often the better choice when the tool must resist both wear and chipping. This is common in punches, trimming tools, forming dies, shear blades, and precision cold work tooling.

A2 Tool Steel Mechanical Properties

The mechanical properties of A2 tool steel depend strongly on delivery condition and heat treatment. In the annealed condition, A2 is supplied soft enough for machining. After hardening and tempering, its strength, hardness, wear resistance, and tool performance increase significantly.

A2 tool steel’s tensile strength and yield strength are not fixed values. They depend on hardness level, tempering temperature, section size, test method, and heat-treatment condition.

For tool design, hardness, toughness, wear resistance, compressive strength, and dimensional stability are usually more important than a single tensile or yield strength value.

A2 Tool Steel Physical and Thermal Properties

Physical and thermal properties are useful for weight calculation, heat-treatment planning, precision tooling, and engineering reference. Values can vary slightly by data source, condition, temperature, and product form.

A2 is usually considered dimensionally stable during heat treatment, but that does not mean it has no size change. Precision tools should still allow for grinding, lapping, or finishing after hardening when tight tolerances are required.

A2 Tool Steel Annealed Properties

A2 tool steel is usually supplied in an annealed condition for machining. In this state, it has lower hardness, better machinability, and lower internal stress than hardened material.

The final properties of A2 tool steel are obtained only after proper hardening and tempering, not in an annealed condition.

Heat-Treated A2 Tool Steel Properties

After hardening and tempering, A2 tool steel can reach high hardness, good wear resistance, useful toughness, and excellent dimensional stability.

A2 is normally double tempered after hardening. Double tempering helps reduce brittleness and stabilize the structure, especially when retained austenite may transform after the first temper.

A2 Tool Steel Heat Treatment Overview

A2 must be heat-treated correctly to reach its final working properties. The basic process includes annealing, stress relieving when needed, preheating, austenitizing, air quenching, and tempering.

A2 should be protected from oxidation and decarburization during heat treatment. A vacuum furnace, controlled-atmosphere furnace, neutral salt bath, or stainless-foil wrapping may be used, depending on the heat-treatment facility.

This page only gives a property-level overview. A dedicated A2 heat-treatment guide should cover soaking time, furnace protection, tempering curves, size-change behavior, and hardness selection in greater detail.

A2 Tool Steel Machinability

A2 tool steel has relatively good machinability among air-hardening cold work tool steels. In the annealed condition, its machinability is commonly rated around 60% compared with a 1% carbon tool steel baseline of 100.

A2 is usually easier to machine than D2. A2 is often selected when the tool needs better machinability than D2 but more wear resistance and dimensional stability than O1.

The safest manufacturing route is to machine A2 in annealed condition, control stress after heavy rough machining, and perform final hardening and tempering after most shaping work is complete.

If EDM, heavy grinding, or welding is required after hardening, the surface condition and residual stresses should be carefully controlled, as they can affect tool life.

Common Applications of A2 Tool Steel

A2 is used in cold-work tooling where the tool must resist wear, maintain its shape, and avoid brittle failure. It is especially useful when O1 lacks stability or wear resistance, while D2 may be too brittle or difficult to machine.

A2 vs D2, O1, S7, and DC53 Tool Steel

A2 is often compared with D2, O1, S7, and DC53 because these grades are also used in cold work tooling.

A2 is tougher and easier to machine than D2, more dimensionally stable and wear-resistant than O1, and more wear-resistant but less shock-resistant than S7.

Compared with DC53, A2 remains a standard, widely available air-hardening cold-work steel, while DC53 may be selected when improved D2-type performance is required.