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Chromium hot-work tool steels are designated as group H steels according to the AISI classification system. This series of steels start from H1 to H19. The most commonly used chromium hot-work steels are H11, H12, and H13, which can be air hardened in 150 mm thick sections. The steels are subjected to minimal distortion during hardening due to their balanced alloy content. The tools produced from chromium hot-work steels can be cooled using water without damage as these steels have low carbon and alloy contents.

This article will give an overview of H11 chromium hot-work steels, which have low carbon content and good toughness. These steels can be deep hardened by heat treatment and air-quenching.

Chemical Composition Physical Properties

The physical properties of H11 tool steels are given in the following table.

Mechanical Properties

The mechanical properties of H11 tool steels are tabulated below

Thermal Properties

The following table shows the thermal properties of H11 tool steels.

Other Designations

Other designations that are equivalent to H11 tool steels include

Chromium hot-work tool steels are designated as group H steels according to the AISI classification system. This series of steels start from H1 to H19. The most commonly used chromium hot-work steels are H11, H12, and H13, which can be air hardened in 150 mm thick sections. The steels are subjected to minimal distortion during hardening due to their air-hardening and balanced alloy content. The tools produced from chromium hot-work steels can be cooled using water without damage as these steels have low carbon and alloy contents.

This article will give an overview of H13 chromium hot-work steels, which contain strengthening agents such as vanadium and molybdenum. These steels are resistant to softening at elevated temperatures due to the presence of chromium content.

Chemical Composition

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

Physical Properties

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

Mechanical Properties

The mechanical properties of H13 tool steels are tabulated below.

Thermal Properties

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

Other Designations

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

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.

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.