ThePipingMart Blog Grades H43 Tool Steel (UNS T20843) – Composition, Properties and Uses

H43 Tool Steel (UNS T20843) – Composition, Properties and Uses

Tool Steel H43

Tool Steel H43 is an alloy steel that is known for its durability and strength. H43 Tool Steel steel is often used for heavy-duty applications such as machining, heat treatment, and corrosion resistance. H43 Tool Steel, also known as UNS T20843, is a high-speed steel with a reputation for delivering exceptional performance in demanding applications. With its excellent combination of strength, toughness, and wear resistance, H43 is an ideal choice for cutting tools, dies, taps, punches, and other components requiring long tool life and high levels of precision. Its unique composition includes significant amounts of tungsten, chromium, and molybdenum, contributing to its outstanding hardness and resistance to wear and deformation under extreme conditions. In addition, this steel has good machinability and can be heat-treated to achieve a wide range of hardness levels and other properties to meet specific application requirements. For these reasons, H43 Tool Steel is a top choice for manufacturers and designers who require high-quality materials that meet the rigours of demanding applications. In this blog post, we will discuss the uses of UNS T20843, its corrosion resistance, its heat resistance, the different types of heat treatment available, and how to machine it properly.

What Forms of H43 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

H43 Tool Steel Composition

Element Content (%)
Molybdenum, Mo 7.75-8.5
Chromium, Cr 3.75-4.5
Vanadium, V 1.8-2.2
Carbon, C 0.5-0.65
Silicon, Si 0.2-0.45
Manganese, Mn 0.15-0.4
Phosphorus, P 0.03
Sulfur, S 0.03

H43 Tool Steel Physical Properties

Properties Metric Imperial
Density 7.7 g/cm3 0.278 lb/in3
Melting point 1450-1510°C 2642-2750°F

H43 Tool Steel Mechanical Properties

Properties Metric Imperial
Tensile strength 650-880 MPa 167.95 ksi
Elongation 8-25% 15%
Modulus of elasticity 190-210 GPa 27557- 30457 ksi
Poisson’s ratio 0.27-0.3 0.27-0.3

H43 Tool Steel Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient 10 µm/m°C 5.5 µin/in°F
Thermal conductivity 25 W/mK 173².°F

H43 Tool Steel Uses

Tool Steel H43 has a wide range of uses due to its durability and strength. It’s often used in automotive, aerospace, and construction industries, where high-performance materials are needed. It is also used in industrial manufacturing processes such as forging and casting. Additionally, it can be used in mold-making for injection molding and die-casting processes.

H43 Tool Steel Uses in Industries

Automotive Industry

H43 tool steel is commonly used in the automotive industry for its high strength and wear resistance. It is often used to make parts such as gears, crankshafts, and bearings. The high hardness of H43 tool steel makes it ideal for withstanding the harsh conditions of engines and transmissions.

Aerospace Industry

The aerospace industry also utilizes H43 tool steel for its strength and durability. It is commonly used to make critical components such as landing gear, engine mounts, and turbine blades. The high toughness of H43 tool steel allows it to withstand extreme temperatures and pressures in flight.

Oil and Gas Industry

In the oil and gas industry, H43 tool steel makes drilling equipment such as drill bits and pipes. Its high wear resistance is ideal for withstanding abrasive materials in drilling operations. Additionally, its strength allows it to withstand the high torque forces involved in drilling.

Construction Industry

H43 tool steel is also utilized in the construction industry for its strength and toughness. It can be found in tools such as hammers, chisels, and saw blades due to its ability to withstand heavy impact without breaking or chipping. It is also commonly used in machinery parts for construction equipment.

H43 Tool Steel Corrosion Resistance

Tool Steel H43 offers excellent corrosion resistance when compared to other types of tool steels. It can withstand harsh chemicals and environments that would quickly corrode other metals or alloys. This makes Tool Steel H43 an ideal choice for applications with critical corrosion resistance, such as aerospace components or oil industry equipment.

H43 Tool Steel Heat Resistance

Tool Steel H43 also offers superior heat resistance when compared to other tool steels due to its high chromium content. This allows it to be used in applications that require extreme temperatures without losing its properties or becoming brittle over time. Additionally, its excellent wear resistance makes it an ideal choice for parts that must endure high friction levels or abrasion over long periods.

H43 Tool Steel Heat Treatment

Different types of heat treatment can be applied to Tool Steel H43 depending on what properties are desired from the material after treatment has been completed. Cold working can be used to increase the hardness or wear resistance, while hot working can be employed to achieve increased ductility or toughness in the material after treatment has been completed. The type of heat treatment chosen will depend on what properties are desired from the material after the treatment has been completed.

H43 Tool Steel Machining

When machining Tool Steel H43, certain precautions should be taken into consideration to ensure optimal performance from your finished part or component. Proper speeds and feeds should always be employed when machining any type of tool steel material but especially with regards to Tool Steel H43, given its superior hardness and wear resistance properties which must be taken into account during the machining process in order for optimal results to be achieved from your finished part or component.


As you can see, Tool Steel H43 is a versatile alloy steel that offers superior strength and durability over many other types of tool steels available on the market today, making it an ideal choice for a wide variety of applications requiring maximum performance under varying conditions. Its exceptional corrosion, heat, and wear-resistant properties make it well-suited for use in extreme conditions while providing excellent results each time. With proper machining techniques, this type of tool steel can provide reliable components with outstanding performance characteristics every time.

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