Cold-Work Tool Steel Properties

Propriedades do aço para ferramentas A2

A2 tool steel is an air-hardening cold work tool steel with good wear resistance, medium-to-good toughness, excellent dimensional stability, and common working hardness around 57–62 HRC after heat treatment.

A2 is widely used for punches, dies, forming tools, shear blades, thread-rolling dies, gages, precision tooling, and cold-work components that require a practical balance between wear resistance, toughness, machinability, and heat-treatment stability.

Suprimentos de aço Aobo A2 air-hardening cold-work tool steel for dies, punches, blades, gages, forming tools, and precision tooling applications.

Barra de aço ferramenta A2

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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.

A2 Tool Steel Properties Summary

PropriedadeTypical A2 Tool Steel BehaviorSignificado prático
Tipo de açoAir-hardening cold work tool steelUsed for precision cold work tooling
Main equivalents1.2363, SKD12, Cr5Mo1V, UNS T30102Useful for international sourcing
Dureza de trabalho típicaAbout 57–62 HRCDepends on tempering temperature and application
Dureza após recozimentoAbout 201–229 HBSuitable for machining before hardening
Resistência ao desgasteBomBetter than O1 and S-series steels, lower than D2
RobustezMedium to goodBetter than D2, lower than S7
Estabilidade dimensionalMuito bomLow movement during air hardening
UsinabilidadeAbout 60% of 1% carbon tool steel baselineMais fácil de usinar do que o D2.
Heat treatment responseAir hardening, double tempering recommendedHelps reduce distortion and brittleness
Resistência à corrosãoNot stainlessRequires rust protection
Main applicationsPunches, dies, forming tools, shear blades, gagesUsed for many cold work tooling applications
Main limitationNot a hot work or high-speed steelNot suitable for hot forging dies or high-speed cutting tools

A2 Tool Steel Equivalent Grades

Padrão/SistemaGrau equivalente
AISI / ASTMA2
ONUT30102
DIN / W-Nr.1.2363
DIN / EN nameX100CrMoV5
JISSKD12
GBCr5Mo1V
BSBA2
AFNORZ100CDV5
SS2260

Users should still confirm the chemical composition, delivery condition, hardness requirements, inspection standard, and heat-treatment route before ordering.

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.

ElementoFaixa típica
Carbon, C0,95–1,05%
Chromium, Cr4,75–5,50%
Molybdenum, Mo0,90–1,40%
Vanadium, V0,15–0,50%
Manganese, MnAté 1.00%
Silicon, SiUp to 0.50%
Nickel, NiUp to 0.30%

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.

Dureza do aço para ferramentas A2

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.

CondiçãoDureza típica
Condição de recozimentoAbout 201–229 HB
Maximum annealed hardnessOften around 235 HB, depending on specification
condição após têmperaAbout 63–65 HRC
Dureza de trabalho comumAbout 57–62 HRC
Common range for many cold work toolsAproximadamente 58–60 HRC

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.

Resistência ao desgaste, tenacidade e estabilidade dimensional.

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

Boa resistência ao desgaste

A2 usually provides better wear resistance, deeper hardening, and better dimensional stability than O1, but it does not match D2 in severe abrasive wear.

Useful Toughness

A2 has better toughness than D2 because it contains fewer large carbides, but it is not as tough as S7 under heavy impact or sudden breakage.

Low Distortion

Because A2 hardens in air, it cools more slowly than oil-quenched or water-quenched steels, helping reduce quenching stress and distortion.

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.

CondiçãoMechanical Property ReferenceNota prática
Annealed A2Tensile strength about 100 ksi / 710 MPaReference for soft delivery condition
Annealed A2Yield strength about 50 ksi / 350 MPaNot representative of hardened tool performance
Hardened and tempered A2Strength depends on final hardness and tempering conditionConfirm data under the required heat-treatment condition
Engineering calculationTensile, yield, impact, or compressive data should match the actual heat-treated stateDo not use generic values without 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.

PropriedadeTypical Reference ValueSignificado prático
DensidadeAbout 7.75–7.86 g/cm³Used for weight calculation
Specific gravityAbout 7.87General reference for material density
Módulo de elasticidadeAbout 190–207 GPaUseful for engineering stiffness reference
Condutividade térmicaAbout 26 W/m·K near 95°CAffects heat transfer during service and heat treatment
Coefficient of thermal expansionAbout 10.6 µm/m·°C from 20–260°CImportant for dimensional change under temperature
Calor específicoAbout 460 J/kg·°CHeat-treatment and thermal calculation reference
Comportamento magnéticoGenerally magneticA2 is an iron-based tool steel
Resistência à corrosãoNot stainlessRequires rust protection

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.

Annealed PropertyTypical Behavior
DurezaAbout 201–229 HB
UsinabilidadePractical for milling, drilling, turning, and grinding before hardening
ForçaLower than hardened and tempered A2
Resistência ao desgasteNot the final working performance
Objetivo principalMachining before final heat treatment

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.

Heat-Treated PropertyTypical Behavior
dureza após têmperaAbout 63–65 HRC
Dureza de trabalho comumAbout 57–62 HRC
Resistência ao desgasteGood for general cold work tooling
RobustezBetter than D2, lower than S7
Estabilidade dimensionalVery good compared with many oil-hardening grades
Final performanceDepends on hardening temperature, quenching control, tempering temperature, and section size

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.

EtapaTypical PracticeFinalidade
RecozimentoHeat slowly to about 845–899°C, then furnace coolAmaciar o aço para usinagem
Alívio do estresseOften around 649–677°C after rough machiningReduzir o estresse de usinagem
Pré-aquecimentoAround 650°CReduza o choque térmico antes do endurecimento.
AustenitizaçãoAround 950–970°CPrepare o aço para têmpera.
ResfriamentoCool in still air or controlled airHarden with lower distortion risk
TêmperaDouble tempering recommendedReduce brittleness and stabilize the structure

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.

ProcessoPractical Point for A2 Tool Steel
MachiningA2 machines reasonably well in annealed condition
Usinagem brutaUsually done before hardening
Alívio do estresseUseful after heavy rough machining
MoagemMust be controlled after hardening to avoid overheating and grinding cracks
EDMCan be used on hardened A2, but recast layer and heat-affected zone should be removed for demanding tools
SoldagemPossible, but crack-sensitive; preheating and post-weld stress relief may be required

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.

AplicativoWhy A2 Is Used
Matrizes de corteGood wear resistance with lower chipping risk than D2
Piercing and trimming diesUseful toughness and edge stability
Forming and bending toolsGood dimensional stability after heat treatment
Desenho morreResistência ao desgaste e tenacidade equilibradas
Matrizes de cunhagem e estampagemHolds detail with controlled distortion
PunçõesSuitable when both wear and chipping are concerns
Lâminas de corte e facas de corte longitudinalSuitable for light to medium cutting duty
Matrizes de laminação de roscasGood compressive strength and wear resistance
Gages and measuring toolsLow movement supports precision
Plastic mold componentsCan be machined in annealed condition and hardened later
Machine componentsUsed where wear resistance and durability are required

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.

ComparaçãoChoose A2 WhenChoose the Other Grade When
A2 vs D2You need better toughness and easier machiningChoose D2 when abrasive wear is the main problem
A2 vs O1You need better hardenability and dimensional stabilityChoose O1 for simpler, lower-cost tools
A2 vs S7You need better wear resistance than shock steelChoose S7 when heavy impact is the main problem
A2 vs DC53You need a standard, widely available air-hardening steelChoose DC53 when improved D2-type performance is required

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.

Need A2 Tool Steel for Cold-Work Tooling?

Aobo Steel supplies A2 tool steel round bar and flat bar for dies, punches, forming tools, shear blades, gages, and precision tooling. Share your grade, size, quantity, hardness target, and application for a practical supply suggestion.

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