ThePipingMart Blog Grades A3 Tool Steel (UNS T30103) – Composition, Properties and Uses

A3 Tool Steel (UNS T30103) – Composition, Properties and Uses

Tool Steel A3

Tool Steel A3 is a high-carbon, air-hardening steel that has excellent wear and abrasion resistance. It is also highly corrosion-resistant and heat-resistant, making it an ideal choice for a variety of industrial applications. A3 Tool Steel, or UNS T30103, is a versatile material used in various industrial applications. With a high carbon content, A3 Tool Steel boasts exceptional hardness and wear resistance. It also has good toughness and can withstand high stress and impact. A3 Tool Steel is primarily composed of iron, carbon, chromium, and small amounts of other elements such as manganese and silicon. AISI Type A3 Tool Steel is often preferred for its excellent machinability and ability to be easily heat treated for optimal performance. Whether in the automotive industry, machinery manufacturing, or metalworking, A3 Tool Steel is a reliable and durable choice for various applications. In this blog post, we’ll explore the features of Tool Steel A3, its uses, corrosion resistance, heat resistance, and how to machine it properly.

What Forms of A3 Tool Steel is Available at Piping Mart?

  • Nut
  • Bar
  • Bolt
  • Pipe
  • Screw
  • Tubing
  • Valves
  • Washers
  • Flanges
  • Fasteners
  • Electrodes
  • Stud Bolts
  • Sheet Plates
  • Pipe Fittings
  • Forged Fitting
  • Instrumentation Fittings

A3 Tool Steel Composition

Element Content (%)
C 1.20-1.30
Mn 0.40-0.60
Si 0.50
Cr 4.75-5.50
Ni 0.30
Mo 0.90-1.40
V 0.80-1.40
Cu 0.25
P 0.03
S 0.03

A3 Tool Steel Physical Properties

Properties Metric Imperial
Density 7.86 g/cm3 0.284 lb/in3

A3 Tool Steel Mechanical Properties

Properties Metric Imperial
Machinability (based on carbon tool steel) 65% 65%
Shear modulus (typical for steels) 80.0 GPa 11600 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Elastic modulus 190-210 GPa 27557-30457 ksi

A3 Tool Steel Equivalents

  • ASTM A681
  • FED QQ-T-570
  • UNS T30103

A3 Tool Steel Uses

Tool Steel A3 can be used in a wide range of applications due to its versatility. It is often used for dies and moulds as well as other cutting tools such as shear blades, punches, taps and reamers. It is also commonly used in cold forging, and hot press forming operations where strength and wear resistance are required.

A3 Tool Steel Uses in Industries

Automotive Industry

A3 tool steel is commonly used in the automotive industry for components such as gears, shafts, and bearings. The high strength and wear resistance of A3 make it ideal for these types of applications, where durability and reliability are crucial.

Aerospace Industry

The aerospace industry relies heavily on A3 tool steel for its strength and toughness properties. It is commonly used in aircraft engine components, landing gear parts, and other critical components that require high performance under extreme conditions.

Manufacturing Industry

In manufacturing, A3 tool steel is often used to make moulds for plastic injection moulding or die-casting processes. Its ability to maintain shape and resist wear makes it popular for creating complex shapes with tight tolerances.

Tooling Industry

As its name suggests, A3 tool steel is widely used in the tooling industry to make various cutting tools such as drills, taps, reamers, and milling cutters. Its high hardness and wear resistance make it suitable for these applications where tools must withstand heavy use.

Construction Industry

In the construction industry, A3 tool steel is commonly used to produce heavy-duty equipment such as bulldozers, excavators, and cranes. Its toughness and ability to withstand impact make it an essential material for these types of machinery subjected to heavy loads daily.

A3 Tool Steel Corrosion Resistance

Tool Steel A3 has excellent corrosion resistance properties due to its high carbon content. This makes it ideal for use in wet environments or areas with significant exposure to acids or alkalis. It also resists rusting better than other steels, which makes it perfect for outdoor applications where the steel will be exposed to rain or snow.

A3 Tool Steel Heat Resistance

Tool Steel A3 has excellent heat resistance up to 1000°F (538°C). This makes it an ideal choice when working with high temperatures, such as welding operations or heat-treating processes. Additionally, it can be hardened by heating it at 1650°F (899°C) followed by cooling in oil or air quenching. This ensures optimal performance even under extreme temperatures.

A3 Tool Steel Machining

Machining Tool Steel A3 requires patience and precision due to its hardness which increases machinability but also increases the risk of tool breakage if not done properly. To avoid this problem, use carbide tools instead of HSS tools when machining this steel type and always make sure your tools are sharp before using them on the material. Additionally, using coolant while machining will help reduce friction and ensure a smooth finish on your pieces.


Tool Steel A3 is an ideal choice for a variety of industrial applications thanks to its excellent wear and abrasion resistance combined with its corrosion-resistance and heat-resistance properties. Its versatility makes it suitable for various tasks, including hot press forming operations where strength and wear resistance are required for cold forging operations or even outdoor applications that require rust protection from rain or snow exposure. Additionally, proper machining practices should be followed when working with this type of steel to ensure optimal performance without tool breakage risk from improper handling techniques. With these tips in mind, you’ll have no trouble taking full advantage of the benefits that come with using Tool Steel A3!

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