A2 Steel: Engineered for Toughness and Precision

Experience superior wear resistance and stability with A2 steel from Aobo Steel – quality you can rely on.

Reliable A2 Tool Steel for High Performance and Durability

At Aobo Steel, we provide factory-direct A2 tool steel crafted for manufacturers who demand durability, precision, and quality. Engineered with exceptional toughness and wear resistance, A2 tool steel is a trusted choice for cold work tooling and versatile industrial applications.

what is a2 steel? A2 tool steel is a deep-hardening, air-hardening tool steel. Due to its air-hardening properties, the deformation caused by hardening is about one-fourth that of tungsten-based oil-hardening tool steel. Its wear resistance is between chromium-type and high-carbon high-chromium-type tool steels, but its toughness is superior. This makes it especially suitable for applications requiring good wear resistance, toughness, and dimensional stability. It is widely used in blanking dies, forming dies, rolling dies, punch dies, calendering dies, thread rolling dies, and specific cutting blades.

A2 steel Applications

A2 steel excels in producing precise stamping dies, such as drawing dies, stretching dies, and forming dies, and can withstand repeated impact loads and wear.

Blanking Dies:
A2 steel’s toughness and wear resistance balance are ideal for blanking dies used in stamping and cutting operations.
Forming Tools:
Its toughness ensures long service life, making A2 perfect for forming tools that endure mechanical stress.
Punches and Shear Blades:
A2 steel’s wear resistance allows for producing durable punches and shear blades that withstand repeated use.
Plastic Molds:
A2 offers excellent dimensional stability and resistance to stress, making it a top choice for precision plastic injection molding.

Aobo Steel: Your A2 Tool Steel Expert

Aobo Steel stands out as your A2 tool steel supplier, providing steel renowned for its durability and wear resistance. A2 steel’s excellent toughness makes it ideal for applications like punches and dies, ensuring high performance under stress. Trust Aobo for quality and reliability in every piece.

Introduction to A2 steel

A2 tool steel chemical composition

Element	Carbon (C)	Chromium (Cr)	Molybdenum (Mo)	Vanadium (V)	Manganese (Mn)	Silicon (Si)	Phosphorus (P)	Sulfur (S)
Percentage (%)	0.95 – 1.05	4.75 – 5.50	0.90 – 1.40	0.15 – 0.50	0.40 – 1.00	0.30 – 0.90	≤ 0.03	≤ 0.03

A2 steel equivalent

Region	Standard	Equivalent Grade
America	AISI/ASTM A681	เอ2
Europe	EN ISO 4957	X100CrMoV5 (1.2363)
Japan	JIS G4404	สกด12
China	GB/T 1299	Cr5Mo1V
Germany	EN ISO 4957

A2 steel properties

1. Critical Point Temperature

Critical Point	Temperature (Approximate) / °C
Ac₁	795
Accm	—
Ms	168

2. Linear Expansion Coefficient

Temperature / °C	Linear Expansion Coefficient α / × 10⁻⁶ °C⁻¹
20 ~ 100	8.2
20 ~ 300	11.3
20 ~ 500	12.4
20 ~ 700	12.9

3. Other Physical Properties

Property	Value
Density (g/cm³)	7.84
Elastic Modulus E (Room Temperature) / MPa	203,000
Specific Heat Capacity c_p / [J/(kg·K)]	460.55

A2 steel Heat Treatment

1. Pre-Heat Treatment Process Specifications

Pre-Heat Treatment Plan	Process Parameters
General Annealing, after Forging	Heating temperature: 840 ~ 870℃, holding time: 2 ~ 3h; furnace cooling to below 550℃, air cooling, hardness ≤248HBW
Isothermal Annealing after Forging	Heating temperature: 830 ~ 850℃, holding time: 2h; isothermal temperature: 710 ~ 730℃, holding time: 2 ~ 4h, furnace cooling to 500℃, air cooling to room temperature, hardness ≤248HBW

2. Quenching

Recommended Quenching Process

Scheme	First Preheating Temperature (°C)	Second Preheating Temperature (°C)	Quenching Temperature (°C)	Cooling Method	Hardness (HRC)
I	300 ~ 400	800 ~ 850	940 ~ 960	Air or Oil Cooling	62 ~ 63
II	300 ~ 400	800 ~ 850	980 ~ 1010	Air or Oil Cooling	62 ~ 65

Effect of Quenching Temperature on Hardness

Quenching Temperature (°C)	875	900	960	980	1020	1050
Hardness (HRC)	46.5	54	64.5	64.5	63	58

3. Tempering

Recommended Tempering Process

Tempering Scheme	Tempering Temperature (°C)	Number of Tempering Cycles	Hardness (HRC)
I	180 ~ 220	1	60 ~ 64
II	510 ~ 520	2	57 ~ 60

Hardness and retained austenite as a function of tempering

The graph illustrates the trade-off between hardness and retained austenite in A2 tool steel during tempering.

Effect of Tempering Temperature on Hardness

	Hardness (HRC)
Tempering Temperature (°C)	100	200	300	400	450	500	520	580
954°C Quenching	64.5	62	58	57	56	59	56	51
982°C Quenching	65	62	58	58	56	58	57	51.5

Hot Forging Process Specification

Forging Process Specifications

Item	Heating Temperature (°C)	Initial Forging Temperature (°C)	Final Forging Temperature (°C)	Cooling Method
Steel Ingot	1100 ~ 1150	1050 ~ 1100	850 ~ 900	High-temperature annealing, pit cooling, or sand cooling
Steel Billet	1050 ~ 1100	1000 ~ 1050	850 ~ 900	Pit cooling or sand cooling

A2 VS O1 Steel: A brief look at their differences and uses

1. Heat Treatment

A2 steel:
Austenitizing temperature: 945-995°C (1730-1750°F)
Typical tempering process: 205-540°C (400-1000°F) double tempering
Hardness range: 46-63 HRC
O1 Steel:
Austenitizing temperature: 790°C (1450°F) Oil quenching
Typical tempering process: Single tempered at 205°C (400°F)
Hardness range: 58-62 HRC

2. Mechanical Properties Comparison

O1’s peak torsional strength is lower than that of A2’s. A2’s impact toughness is stronger than that of O1’s, and A2’s wear resistance is stronger than that of O1’s.

3. Comparison of typical applications

A2 steel applications:
High-precision punching dies (e.g., automotive nut punching dies)
Shear tools requiring toughness
Complex-shaped dies (using air-quenching properties)
O1 steel applications:
Small punches/thimbles (e.g. nut split pins)
Gauges/jigs (simple shaped parts)
Low-load cutting tools

4. Cost vs. machinability

In terms of machinability, O1 steels are superior to A2 steels, which are more costly than O1 steels because of the need for secondary tempering and because of the Mo element in their composition.

5. Suggestions for selection:

เอ2: high hardenability, complex shaped tools, high toughness requirements of the occasion
โอวัน: Simple shaped parts, cost-sensitive applications, small cross-section size tools

Your Trusted Partner for A2 Tool Steel

When precision, durability, and performance matter, choose A2 tool steel from Aobo Steel. Join countless satisfied manufacturers who’ve streamlined their production with our unmatched quality and service.

A2 Tool Steel Equivalents: DIN 1.2363 and JIS SKD12

In the German and Japanese standard systems, A2 steel is equivalent to DIN 1.2363 and JIS SKD12 grades, respectively. They can be substituted for each other. They are all cold work die steels and air-hardening chromium steels. The steel has evenly distributed carbides, possessing a certain impact toughness and good wear resistance. It also has good air-quenching performance, small dimensional deformation during air quenching, uniform and fine carbides, good toughness, and high wear resistance.

Introduction to DIN 1.2363 steel

1.2363 Chemical composition

Carbon (C)	Chromium (Cr)	Manganese (Mn)	Silicon (Si)	Vanadium (V)
0.95 – 1.05	4.75 – 5.50	0.60 – 1.00	0.10 – 0.40	0.15 – 0.50

1.2363 steel Physical properties

Density: Approximately 7750 kg/m³ at room temperature

Coefficient of Thermal Expansion: 6.5 × 10⁻⁶ per °F from 68°F, or 11.6 × 10⁻⁶ per °C from 20°C

Thermal Conductivity: at 20°C: 15.9 W/(m·K), at 350°C: 26.8 W/(m·K), at 700°C: 29.2 W/(m·K).

Specific Electrical Resistivity: 0.33 μΩ·m at 24°C

Introduction to JIS SKD12

SKD12 Chemical composition

Carbon (C)	Chromium (Cr)	Molybdenum (Mo)	Vanadium (V)	Manganese (Mn)	Silicon (Si)	Phosphorus (P)	Sulfur (S)
0.95 – 1.05	4.75 – 5.50	0.90 – 1.20	0.15 – 0.50	0.50 – 0.70	0.10 – 0.40	≤ 0.030	≤ 0.030

SKD12 steel Physical properties

Property	Value
Density	7.8 g/cm³
Thermal Conductivity	25.0 W/m·K
Hardness (After Heat Treatment)	58 – 62 HRC
Elastic Modulus	210 GPa
Tensile Strength	1570 MPa
Melting Point	1450°C (2642°F)

FAQs

What is A2 steel?
A2 steel is an air-cooled, medium-alloyed cold work tool steel known for its high wear resistance, good toughness, and small heat treatment deformation. It is commonly used in the manufacture of a variety of cold work molds.
Is A2 a good knife steel?
A2 steel is a good knife steel because of its combination of high wear resistance, good toughness, and easy heat treatment. It is so commonly used in the production of cutting tools.
Is A2 steel better than A4?
A4 steel generally has slightly better wear resistance than A2 steel and can be hardened at lower austenitizing temperatures, but both have good toughness and low heat treat distortion.
Is A2 better than D2 steel?
D2 steel has better wear resistance than A2 steel but is less tough than A2 steel.
Does A2 rust?
A2 steel will rust, but its resistance to rust is somewhat better than ordinary carbon steel because it contains a moderate amount of chromium.