ThePipingMart Blog Grades T8 Tool Steel (UNS T12008) – Composition, Properties and Uses

T8 Tool Steel (UNS T12008) – Composition, Properties and Uses

Tool Steel T8

UNS T12008 is a type of steel alloy that is used for various applications. It has a unique chemical composition and physical properties making it ideal for certain kinds of projects. This article will look at the chemical composition, mechanical properties, physical properties, corrosion resistance, heat resistance, heat treatment, machining and welding of Tool Steel T8.

T8 Tool Steel Chemical Composition

The main components of UNS T12008 are Carbon (C), Chromium (Cr), Manganese (Mn), Molybdenum (Mo), Nickel (Ni) and Vanadium (V). These elements contribute to its strength and durability.

Element Content (%)
Tungsten, W 13.25-14.75
Cobalt, Co 4.25-5.75
Chromium, Cr 3.75-4.5
Vanadium, V 1.80-2.40
Carbon, C 0.75-0.85
Molybdenum, Mo 0.4-1
Nickel, Ni 0.3
Copper, Cu 0.25
Manganese, Mn 0.2-0.4
Silicon, Si 0.2-0.4
Phosphorus, P 0.03
Sulfur, S 0.03

T8 Tool Steel Chemical Properties

UNS T12008 has an outstanding chemical composition, making it an ideal metal alloy for metalworking. This type of tool steel contains carbon, tungsten, molybdenum, and cobalt components, giving it superior properties such as excellent hardness and wear resistance at high temperatures. Considering the versatile applications and demands for industrial tools, the unique characteristics of T8 make it suitable for tools used in heavy-duty environments such as construction equipment or automotive manufacturing plants. Metallurgists may also appreciate the machinability of this tool steel which allows toolmakers to shape precise parts with fewer delays in production.

T8 Tool Steel Mechanical Properties

This type of steel has excellent tensile strength and hardness. It is also very resistant to wear and tear due to its high abrasion resistance. Additionally, it offers good shock absorption capability as well as impact resistance.

Properties Metric Imperial
Tensile strength 1158 MPa 167.95 ksi
Elongation 15% 15%
Modulus of elasticity 190-210 GPa 27557- 30457 ksi
Poisson’s ratio 0.27-0.3 0.27-0.3

T8 Tool Steel Physical Properties

The main physical property of Tool Steel T8 is its density which ranges from 7.75-7.85 g/cm3 at room temperature. Another important property is its melting point which ranges from 1495-1520 ℃ depending on the alloying elements present in it.

Properties Metric Imperial
Density 8.43 g/cm3 0.267 lb/in3

T8 Tool Steel Thermal properties

Properties Metric Imperial
Thermal expansion co-efficient 16-17 µm/m°C 8.8-9.4 µin/in°F
Thermal conductivity 16 W/mK 110².°F

T8 Tool Steel Equivalent

  • ASTM A600
  • FED QQ-T-590
  • SAE J437
  • SAE J438

T8 Tool Steel Uses

UNS T12008 is a tough, shock-resistant steel alloy with numerous uses due to its superior strength and resilience. Its primary use is in producing machine tools, such as drills, taps, reamers and saws. It also is used to construct hand tools needed for everyday use, like hammers and wrenches. T8’s hardness makes it ideal for accurately cutting through harder metals or drilling into harder materials. Its strength makes it perfect for punches and dies regularly subjected to high pressure. Tool steel T8 provides the performance needed for any demanding application, and no job is too tough for this resilient alloy.

Corrosion Resistance

The corrosion resistance properties of this type of steel depend upon its chromium content; the more chromium it contains, the better the corrosion resistance will be. The higher levels of nickel also provide additional protection against oxidation and other forms of corrosion.

Heat Resistance

This type of steel’s heat resistance properties depend upon its molybdenum content; the more molybdenum it contains, the better the heat resistance will be. Additionally, its vanadium content also helps improve its temperature tolerance capabilities up to 800 degrees Celsius without any significant reduction in performance or structural integrity being observed.

Heat Treatment

Tool Steel T8 can be hardened by quenching in water or oil followed by tempering at temperatures between 600-650 degree Celsius for maximum hardness or between 200-350 degrees Celsius for increased toughness with increased toughness and reduced hardness level accordingly.


This type of steel can be machined using conventional methods such as drilling, tapping or turning due to its high machinability rating compared to other materials like stainless steel or aluminium alloys.


Due to its low carbon content, tool steels like T8 can be welded easily without any risk of cracking or embrittlement when appropriately done with proper techniques. Preheating should also be done before welding to reduce thermo-mechanical stresses during cooling.


Tool Steel T8 is an excellent choice for applications where strength and durability are required because of its unique composition and properties. Its excellent mechanical properties, such as tensile strength, impact & shock absorption, and good wear & abrasion resistance, make it suitable for various industrial projects. Furthermore, its corrosion & heat-resistant features add value to this material, making it an even more attractive choice for many applications. For these reasons, tool steels like T8 should seriously be considered whenever you need strong & durable material for your project needs.

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