H13

H13 Die Steel

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Product Description

H13 Hot Work Die Steel
Equivalent grades: 4Cr5MoSiV1/SKD61/DAC/DH31/1.2344/1.2343/8407/W302

Introduction

Chromium hot-work tool steels are classified as group H steels by the AISI classification system. This series of steels start from H1 to H19.
H13 chromium hot-work steel is widely used in hot and cold work tooling applications. Due to its excellent combination of high toughness and fatigue resistance H13 is used more than any other tool steel in tooling applications.
This article will give an overview of H13 chromium hot-work steels.

Chemical Composition

The following table shows the chemical composition of H13 tool steels.

 Element  Content (%)
 Chromium, Cr  4.75-5.50
 Molybdenum, Mo  1.10-1.75
 Silicon, Si  0.80-1.20
 Vanadium, V  0.80-1.20
 Carbon, C  0.32-0.45
 Nickel, Ni  0.3
 Copper, Cu  0.25
 Manganese, Mn  0.20-0.50
 Phosphorus, P  0.03
 Sulfur, S  0.03

Physical Properties

The physical properties of H13 tool steels are given in the following table.

 Properties  Metric  Imperial
 Density (@20°C/68°F)  7.80 g/cm3  0.282 lb/in3
 Melting point  1427°C 2600°F

Mechanical Properties

The mechanical properties of H13 tool steels are tabulated below.

 Properties  Metric  Imperial
 Tensile strength, ultimate (@20°C/68°F, varies with heat treatment)  1200 – 1590 MPa  174000 – 231000 psi
 Tensile strength, yield (@20°C/68°F, varies with heat treatment)  1000 – 1380 MPa  145000 – 200000 psi
 Reduction of area (@20°C/68°F)  50.00%  50.00%
 Modulus of elasticity (@20°C/68°F)  215 GPa  31200 ksi
 Poisson’s ratio  0.27-0.30 0.27-0.30

Thermal Properties

The following table shows the thermal properties of H13 tool steels.

 Properties  Conditions
 T (ºC)  Treatment
 Thermal expansion  10.4 x 10-6/ºC  20-100  -
 Thermal conductivity  28.6 W/mK  215 -

Other designations that are equivalent to H13 tool steels include:

•AFNOR Z 40 COV 5
•DIN 1.2344
•UNI KU
•JIS SKD61
•SS 2242
•B.S. BH 13
•ASTM A681
•FED QQ-T-570
•SAE J437
•SAE J438
•SAE J467
•UNS T20813
•AMS 6408

Fabrication and Heat Treatment

Machinability

The machinability rate of H13 tool steels is nearly 75% of that of the W group tool steels.

Forming

H13 tool steels are formed by using conventional methods.

Welding

H13 tool steels are readily weldable.

Heat Treatment

H13 tool steels are preheated to 816°C (1500°F). Then the steels are directly heated by increasing the temperature to 1010°C (1850°F) followed by holding for 15 to 40 mins. The steels are then air-quenched.

Forging

H13 tool steels are forged at 1079°C (1975°F). For this type of steels, forging below 898°C (1650°F) is not preferable.

Cold Working

Cold working may be carried out on H13 tool steels using conventional methods.

Annealing

H13 tool steels are annealed at 871°C (1600°F) and slowly cooled at 4°C (40°F) in the furnace.

Tempering

Tempering is carried out in H13 tool steels from 538 to 649°C (1000 to 1200°F) to obtain Rockwell C hardness of 53 to 38. Double tempering can also be performed in these steels for every one hour at the preferred tempering temperature.

Applications

H13 tool steels are suitable for forming extrusion dies.