ThePipingMart Blog Grades L6 Low Alloy Steel (UNS T61206) – Composition, Properties, and Uses

L6 Low Alloy Steel (UNS T61206) – Composition, Properties, and Uses

AISI L6 Tool Steel

AISI L6 is a versatile and popular tool steel widely used in various industries. Its toughness, wear resistance, and machinability have made it a top choice for cutting and forming tools, dies, punches, and other industrial applications. If you want to use AISI L6 tool steel for your project or want to learn more about its properties and applications, this blog post is for you.

What is AISI l6 Tool Steel?

AISI L6 tool steel is a low, high-carbon alloy with excellent wear and impact resistance. Its machinability is superior to other tool steel grades, making it an ideal choice for hot work applications where strength and durability are essential. It also has a good heat treatment response, permitting increased hardness and dimensional stability after hardening.

AISI L6 Tool Steel Composition

AISI L6 is low-alloy, high-carbon steel with a composition that includes chromium, nickel, and tungsten. The exact composition may vary depending on the manufacturer, but it typically contains around 0.7-0.8% carbon, 0.5-0.7% manganese, 0.4-0.6% silicon, 0.8-1.2% chromium, 0.8-1.2% nickel, and 0.9-1.3% tungsten. In addition, it may also contain small amounts of other elements, such as sulfur and phosphorus. This unique composition gives AISI L6 its outstanding toughness and wear resistance, making it suitable for heavy-duty applications.

Element Content (%)
Nickel, Ni 1.25-2.00
Chromium, Cr 0.60-1.20
Carbon, C 0.65-0.75
Silicon, Si 0.5
Molybdenum, Mo 0.5
Manganese, Mn 0.25-0.80
Vanadium, V 0.20-0.30 (a)
Copper, Cu 0.25
Phosphorus, P 0.03
Sulfur, S 0.03
Iron, Fe Balance

AISI L6 Tool Steel Mechanical Properties

The mechanical properties of AISI L6 tool steel can vary depending on the heat treatment and processing conditions. It has high strength and toughness, with a hardness range of 55-60 HRC. It also has excellent wear resistance and compression strength, making it ideal for cold work applications. Compared to other tool steels, AISI L6 has lower wear resistance but higher toughness, making it a good choice for applications that require impact resistance and toughness.

Properties Metric Imperial
Poisson’s ratio 0.27- 0.30 0.27- 0.30
Elastic modulus 190-210 GPa 27557-30457 ksi

AISI L6 Tool Steel Physical Properties

AISI L6 tool steel has a density of 7.85 g/cm³ and a melting point of 1380-1420°C. It has a thermal conductivity of 24.2 W/m·K and a specific heat capacity of 460 J/kg·K. The coefficient of thermal expansion is 13.0 µm/m·K, and it has a modulus of elasticity of 210 GPa. These physical properties make AISI L6 tool steel suitable for high-temperature and thermal shock applications.

Properties Metric Imperial
Density 7.86 g/cm³ 0.284 lb/in³
Melting point 2590°F 1421°C

AISI L6 Tool Steel Equivalents

  • UNS T61206
  • ASTM A681
  • DIN 1.2713
  • SAE J437
  • SAE J438

AISI L6 Tool Steel Uses

AISI L6 tool steel is commonly used in various industrial applications. Its excellent properties make it suitable for cutting and forming tools, dies, punches, blades, and other parts that require high toughness, wear resistance, and machinability. It is often used to manufacture air hammers, hammer dies, forging dies, shear blades, and trimming dies. It is also used to produce plastic moulds and extrusion dies and to construct heavy-duty machinery and equipment.

AISI L6 Tool Steel Corrosion Resistance

AISI L6 tool steel has moderate to good corrosion resistance due to the presence of chromium and nickel in its composition. However, it is not recommended for use in highly corrosive environments or with acidic substances. Proper maintenance and cleaning can extend the service life of the tool steel and prevent corrosion.

AISI L6 Tool Steel Heat Treatment

AISI L6 tool steel can be heat treated to improve its properties and increase its hardness, toughness, and wear resistance. The heating and cooling process should be carefully controlled to achieve the desired properties. The typical heat treatment process involves annealing, quenching, and tempering. Annealing occurs at 760-790°C, followed by slow cooling to reduce internal stresses. Quenching is done between 810-840°C, and tempering is done at a temperature between 540-600°C.

AISI L6 Tool Steel Machining

AISI L6 tool steel can be machined easily with conventional methods, but it requires careful attention to cutting parameters, tool wear, and heat generation. The tool steel should be preheated before machining to reduce thermal shock and improve dimensional stability. Carbide and diamond tooling are recommended for high-speed machining operations, while high-speed steel tooling suits slower machining speeds.

AISI L6 Tool Steel Welding

AISI L6 tool steel can be welded using conventional welding methods such as gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW). However, preheating the tool steel before welding is essential to prevent cracking and improve weld quality. Low hydrogen welding electrodes are also recommended to ensure proper fusion and avoid porosity.


AISI L6 tool steel is a versatile and reliable material with various applications in various industries. Its unique composition and exceptional properties make it an ideal choice for cutting and forming tools, dies, punches, and other industrial parts. By understanding the composition, properties, and uses of AISI L6 tool steel, you can decide whether it is suitable for your project or application. If you need assistance selecting the right tool steel or machining your tools, contact an expert in the field for guidance.

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