ThePipingMart Blog Grades A8 Tool Steel – Composition, Properties and Uses

A8 Tool Steel – Composition, Properties and Uses

Tool Steel A8

Tool Steel A8 is a form of tool steel that has high wear resistance and strength, making it an ideal choice for a wide range of applications. A8 Tool Steel is a versatile material widely used in the manufacturing industry for its exceptional properties. This steel is an air-hardening grade that belongs to the ASTM A681 specification and has a chemical composition of 0.5% Carbon, 5% Chromium, 8% Molybdenum, and 1.5% Vanadium. A8 Tool Steel exhibits excellent toughness and wear resistance, making it appropriate for various tooling applications such as punches, dies, and gauges. It has a maximum working hardness of 62 HRC and offers good dimensional stability during heat treatment. Per the UNS T30108 designation, A8 Tool Steel is a top choice for tool-making needs. In this blog post, we’ll discuss the uses, corrosion resistance, heat resistance, heat treatment, and machining of A8 Tool Steel.

What Forms of A8 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

A8 Tool Steel Composition

Element Content (%)
Chromium, Cr 4.75-5.50
Molybdenum, Mo 1.15-1.65
Tungsten, W 1.00-1.50
Silicon, Si 0.75-1.10
Carbon, C 0.50-0.60
Manganese, Mn 0.5
Nickel, Ni 0.3
Copper, Cu 0.25
Phosphorus, P 0.03
Sulfur, S 0.03

A8 Tool Steel Physical Properties

Properties Metric Imperial
Density 7.87 g/cm³ 0.284 lb/in³

A8 Tool Steel Mechanical Properties

Properties Metric Imperial
Poisson’s ratio 0.27-0.30 0.27-0.30
Elastic modulus 190-210 GPa 27557-30457 ksi
Bulk Modulus (typical for steels) 140 GPa 20300 ksi
Shear modulus (typical for steels) 80 GPa 11600 ksi
Hardness, Rockwell C 48 – 57 48 – 57
Machinability (based on carbon tool steel) 65 65

A8 Tool Steel Equivalents

  • ASTM A681
  • FED QQ-T-570
  • UNS T30108

A8 Tool Steel Uses

Tool Steel A8 is most commonly used in dies and tools for the manufacturing industry. It can be used for stamping and forming operations, such as forming automotive components or other parts with intricate configurations. This tool steel also has good thermal properties, making it an ideal material for hot work applications such as forging dies or hot extrusion dies.

A8 Tool Steel Uses in Industries

Automotive Industry

A8 tool steel is commonly used in the automotive industry due to its high strength and wear resistance. It is often used to make components such as gears, shafts, and bearings, which are essential for the smooth operation of vehicles.

Aerospace Industry

The aerospace industry also relies on A8 tool steel for its durability and ability to withstand extreme temperatures. It is commonly used to manufacture aircraft engine parts, landing gear components, and other critical parts that require high strength and toughness.

Oil and Gas Industry

In the oil and gas industry, A8 tool steel is used for drilling tools such as drill bits, reamers, and stabilizers due to its high hardness and resistance to wear. It can withstand the harsh drilling conditions into the earth’s surface.

Construction Industry

A8 tool steel is used in the construction industry for structural components such as beams, columns, and support brackets due to its high tensile strength and toughness. It can withstand heavy loads without deforming or breaking under pressure.

A8 Tool Steel Corrosion Resistance

Tool Steel A8 also has excellent corrosion resistance due to its high chromium content. This makes it suitable for use in environments that may be exposed to moisture or other corrosive elements. Its ability to withstand exposure to these elements makes it highly versatile and resilient when used in harsh working conditions.

A8 Tool Steel Heat Resistance

Tool Steel A8 is extremely heat resistant due to its high carbon content. This makes it a great choice for applications requiring long periods of operation at elevated temperatures without losing strength or shape. The material’s structural stability also allows it to resist thermal cycling or shock-loading distortion during use.

A8 Tool Steel Heat Treatment

Tool Steel A8 can be heat treated by hardening at 44-50 HRC and tempering at 400-600ºF (204-316ºC). When tempered at this temperature range, the material will gain toughness while retaining its hardness and wear resistance. After tempering, the steel should be cooled down slowly in order to avoid any chance of cracking or warping during the cooling process.

A8 Tool Steel Machining

The machinability of Tool Steel A8 is average compared to other tool steels due to its higher carbon content; however, some lubricants can help improve machining performance if needed. The steel should be machined at low speeds with heavy feeds in order to achieve optimal results. Cutting tools should also be kept sharp in order to reduce cutting forces and increase tool life during operations involving this material type.


Tool Steel A8 is an extremely durable tool steel with many uses across numerous industries due to its outstanding wear, strength, corrosion, heat, and machinability properties. Its ability to resist distortion from thermal cycling or shock loading during use makes it suitable for applications such as forging dies or hot extrusion dies where long periods of operation at elevated temperatures are required without sacrificing performance or quality standards. With proper heat treatment and machining techniques applied accordingly, this type of tool steel can provide exceptional performance even under the harshest working conditions!

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