Daido Steel DH31-EX™
High performance hot work tool steel. Made in Japan.
DH31-EX Features
DH31-EX is a high performance hot work tool steel with a modified chemical alloy of 1.2367 double melted (ESR) with very high toughness and a very homogeneous structure.
DH31-EX provides homogeneous hardness and toughness values up to the center, especially in large-sized high-pressure and low-pressure die casting (HPDC-LPDC) molds. In this way, heat checking resistance, wear resistance and metal erosion properties are very high. DH31-EX can be used in many applications such as hot forging dies, aluminum extrusion dies, etc.
Hot Work Tool Steels Performance Chart
- Heat checking resistance 90%
- High temperature wear resistance 90%
- Toughness 100%
- Aluminum erosion resistance 90%
- Homogeneity 100%
- Machinability 80%
The information given above is only for comparison with OTHER HOT WORK TOOL STEELS. For detailed technical information and information about material selection, please contact our technical team.
DH31-EX Chemical Composition
The chemical composition of DH31-EX is contractually confidential, but it is a modified alloy of DIN 1.2367 hot work tool steel.
Other information;
About Daido Steel
Daido Steel Co. Ltd., since its founding in Japan in 1916, has extensive skills in combining scrap steel with other materials to achieve strength, machinability, and other properties to meet stringent requirements. As one of the world's largest producers of special steel, Daido Steel offers value-added steels such as automobile transmissions and engine parts, as well as components used in ships, aircraft, and electric generators. Tool steel is among its core products and the company has a wide range of products for cold work tool steels, hot work tool steels, high speed tool steels, and plastic mold steels. Daido Steel continues to provide its customers with quality products and high performance technical support.
Mold Performance
High hardenability; DH31-EX, which can be hardened to a maximum of 54 HRC, maintains the same hardness until the center even in very large molds. Thanks to the high toughness of the steel, it can be used comfortably even at high hardnesses.
High strength at high temperature; high heat checking and wear resistance.
Double melting (ESR) provides homogeneous and nearly isotropic mechanical properties.
Ease of Mold Making
Homogeneous structure allows easy control of dimensional changes after heat treatment.
Machinability; Machinability is very homogeneous and high due to double melting (ESR). The hardness of DH31-EX in its raw form is below 235 HB.
Optical Microstructure
Please refer to the catalog for DH31-EX microstructure.
Ease of Heat Treatment (Parameters)
DH31-EX reaches a hardness of 52-54 HRC by austenitizing at 1030°C followed by tempering at 2×520°C, the most common tool steel hardening. Same as other hot work tool steels, no need to wait for a special charge.
Hardening (Austenitizing, Quenching) temperature: 1000-1050°C, air cooling.
Tempering temperature: 520-650°C, air cooling, at least twice.
Annealed hardness: ≦235HB
Hardness after quenching and tempering: 35-54 HRc
Stock Information
- Up to 910×420 mm as flat bars,
Stock is kept continuously. As it is a new steel, the stock is increasing rapidly. Please contact for current sizes.
We continuously diversify and strengthen our stocks in order to offer more suitable size options to our customers.
DH31-EX Usage Areas
- Al, Zn, Mg die casting,
- Hot metal extrusion,
- Hot metal cutting,
- In hot forging molds,
DH31-EX is widely used. The world's leading industrial organizations prefer DH31-EX. Please contact us for references.