ThePipingMart Blog Grades D2 Tool Steel (UNS T30402) – Composition, Properties, and Uses

D2 Tool Steel (UNS T30402) – Composition, Properties, and Uses

Die Steel D2

Die steel D2 is a type of steel used to make dies and other components. This type of steel has a high carbon and chromium content, granting it superior strength and durability. It is also highly resistant to corrosion and heat, making it a great choice for many applications. In this article, we will cover the composition, chemical properties, mechanical properties, physical properties, uses corrosion resistance, heat resistance, heat treatment, and machining of 1.2379.

What is D2 Tool Steel?

D2 Tool steel is a high-carbon, high-chromium metal that has been air or oil-hardened. It combines extreme hardness and wear resistance with relatively good toughness, making it an ideal material for metalworking tools. Not only is D2 tool steel incredibly durable, but it also offers excellent corrosion resistance as well as outstanding abrasion resistance when properly hardened and heat treated. These characteristics make D2 an exceptional choice for applications such as dies, forming tools, trimming punches, engine components and thread rolls. To maximize its performance potential, D2 must be tempered at precise temperatures following heat treatment – the condition in which its properties can be tailored to the requirements at hand.

What Forms is D2 Tool Steel Available at Piping Mart?

  • D2 Tool Steel Bar
  • D2 Tool Steel Bolt
  • D2 Tool Steel Pipe
  • D2 Tool Steel Screw
  • D2 Tool Steel Tubing
  • D2 Tool Steel Valves
  • D2 Tool Steel Washers

D2 Tool Steel Composition

Steel D2 contains 1.4% carbon, 0.6% silicon, 12% chromium, and 0.7% molybdenum by weight. It also contains small amounts of manganese and vanadium and trace amounts of phosphorus and sulfur.

Element Content (%)
C 1.40 – 1.60
Mn 0.60
Si 0.60
Co 1.00
Cr 11.00 – 13.00
Mo 0.70 – 1.20
V 1.10
P 0.03
Ni 0.30
Cu 0.25
S 0.03

D2 Tool Steel Chemical Properties

Due to its high chromium content (12%), UNS T30402 has excellent resistance to oxidation in comparison with other steels with lower chromium concentrations. This makes it an ideal material for use in hot working environments such as forging operations or die-casting processes where oxidation may occur if the wrong material is chosen.

D2 Tool Steel Mechanical Properties

The mechanical properties of die steel D2 are quite impressive due to its combination of high carbon content (1.4%) and high chromium content (12%). It has a very high yield strength (1300 MPa) as well as d2 tool steel tensile strength tensile strength (1550 MPa). These properties make it ideal for use in applications that require superior strength, such as injection molds or dies for metalworking operations.

Mechanical Properties Metric Imperial
Hardness, Knoop (converted from Rockwell C hardness) 769 769
Hardness, Rockwell C 62 62
Hardness, Vickers 748 748
Izod impact unnotched 77.0 J 56.8 ft-lb
Poisson’s ratio 0.27-0.30 0.27-0.30
Elastic modulus 190-210 GPa 27557-30457 ksi

UNS T30402 Tool Steel Physical Properties

The physical properties of die steel D2 are largely determined by its composition, which includes a significant amount of carbon (1.4%), silicon (0.6%), chromium (12%), and molybdenum (0.7%). Because of this composition, die steel D2 has excellent wear resistance, which makes it ideal for use in applications where wear occurs frequently, such as dies used in metalworking operations or injection molds used in plastic injection molding processes. Additionally, the presence of chromium gives Die Steel D2 outstanding corrosion resistance making it suitable for use in corrosive environments that would otherwise damage other materials quickly over time, such as coastal areas or areas with acidic soils or waters containing large amounts of chlorine or sulfates.

Properties Metric Imperial
Density 7.7 x 1000 kg/m3 0.278 lb/in3
Melting point 1421°C 2590°F

D2 Tool Steel Equivalent

  • DIN 1.2379
  • NI KU
  • B.S. BD 2
  • ASTM A681
  • FED QQ-T-570
  • SAE J437
  • SAE J438
  • UNS T30402

D2 Tool Steel Specifications

AISI ASTM A681 DIN 17350 BS EN ISO 4957

1.2379 Tool Steel Uses

Die Steel T30402 is becoming increasingly popular among industries due to its amazing characteristics. This high-carbon tool steel exhibits excellent wear resistance, hardness retention, strength at elevated temperatures, and great toughness, making it ideal for tooling applications. Moreover, its hardenability enables the use of molds with intricate designs without compromising on their durability. Some of the most common uses for Die Steel D2 include producing blanking dies, progressive dies, and forming tools for a wide range of industrial materials such as plastic, rubber, and aluminum.

Cutting Tools

T30402 tool steel is a popular choice for use in the manufacturing of cutting tools. This type of steel is incredibly hard and durable, making it ideal for applications such as drill bits, saw blades, chisels, and other cutting tools. The high hardness of D2 tool steel also makes it resistant to wear and tear, allowing it to retain its sharp edge for longer periods of time.

Moulds and Dies

D2 tool steel is also often used to produce moulds and dies. This type of steel is highly resistant to heat and corrosion, making it an ideal material for creating molds and dies that can withstand extreme temperatures and pressure without deforming or becoming damaged. Additionally, the high hardness 1.2379 prevents wear on the moulds or dies over time.


steel D2 is commonly used in the manufacturing of knives due to its superior strength and durability. This type of steel can be hardened to create incredibly sharp knives that will retain their edge even after extended use. D2 steel is also corrosion-resistant, making it an excellent choice for producing knives that will last a long time with proper maintenance.

Automotive Parts

D2 tool steel is also often used to produce automotive parts such as gears, shafts, axles, cams, valves, springs, etc. This type of steel’s superior strength and durability make it well-suited for these applications, as they must withstand extreme pressures without failing or becoming damaged over time. Additionally, D2 tool steel has excellent wear resistance which helps to prolong the life span of automotive parts made from this material.

Hand Tools

Finally, D2 tool steel is also often used to manufacture hand tools such as hammers, wrenches, pliers, screwdrivers, chisels, files, etc.. These types of tools require a material that can withstand repeated impacts without breaking or becoming damaged over time, which D2 tool steel excels at providing due to its superior strength and durability properties.

UNS T30402 Welding

Die steel D2 welding is a complex process that requires the utmost precision and skill. The success of the weld depends on various factors, such as preheating, proper selection of shielding gas and electrode, using appropriate welding current, pre-post treatments, etc. Improperly done welds can lead to welding defects such as slag inclusion or inadequate weld penetration. An experienced welder must understand all aspects of die steel D2 welding to achieve the desired outcomes. While the process may be difficult, those who have mastered it are highly sought after by many industries due to the high-quality welds they can produce.

D2 Tool Steel Corrosion Resistance

Die Material, particularly steel D2, are renowned for their outstanding corrosion resistance. It can last a lifetime, even in the harshest of industrial environments and extreme heat conditions. Due to its unique composition, it can also resist pitting, cracking, and crevice corrosion. Its superior hardening capability, along with its superior alloying elements, makes it one of the top-choice steels for complex manufacturing processes. In addition to its impressive corrosion resistance properties, D2 steel is easy to work with and has tremendous machinability. These features make it an ideal option for various uses, such as dies, molds, and other complex components in heavy industrial settings.

D2 Tool Steel Heat Resistance

Die steel D2 is a popular choice for tool and die makers due to its tough construction and abrasion resistance. Another huge benefit of D2 steel is its heat resistance, which makes it the ideal material for cutting and shaping when exposed to high temperatures. Working with different metals can often lead to warping or deformation of tools when subjected to intense heat; however, D2’s international reputation for quality has made it sought after in many industries. This remarkable heat resistance provides the steel with unique properties that make it permissible in many places around the world and highly sought after by manufacturers in search of reliable yet sturdy solutions.

D2 Tool Steel Heat Treatment

Heat-treating D2 die steel requires precision and knowledge, as even small changes to the treatment can have drastic effects. The correct ratio of carbon and chromium must be found when changing the temperatures, as too little or too much of either can create cracking or brittleness. The base structure 1.2379 consists mainly of ferrite and large carbides, which influence its final characteristics after heat treatment. Depending on the desired hardness of the component parts being manufactured, D2 may require several different levels of hardening and tempering to reach optimal strength. Experienced technicians understand how to combine heat treatments such as carburization and austenitization with quenching and tempering to reach exceptional results.

D2 Tool Steel Machining

Machining dies steel D2 requires expert knowledge of tool and workpiece materials and precision temperature and feed rate controls. Toolholders must exert the right hold force, while cutter geometry and speeds must be meticulously designed and precisely maintained. High-pressure coolant systems are often needed for chip evacuation and to provide better component lifespans. Special attention must also be given to vibration damping through specialist cutting techniques, allowing machinists to achieve high precision with repeatable results. To maximize the potential of die steel D2 machining, it is important to consult an experienced manufacturing supplier with experience designing an optimized process solution.


As you can see from this article, die steel D2 is an ideal choice for many different types of applications due to its strong mechanical properties combined with its exceptional wear resistance and corrosion resistance qualities thanks to its unique composition that consists primarily of carbon, silicon, chromium, and molybdenum plus small amounts of manganese and vanadium along with trace amounts of phosphorus and sulfur added during the alloying process at the mill during production. Die Steel D2 can be heat treated using various techniques depending on the application at hand; these techniques allow engineers to tailor the mechanical characteristics according to their specific needs, ensuring optimal performance every time!

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