H13 Steel Hardness

At Aobo Steel, we know that achieving the correct H13 steel hardness is vital for your tools and dies. This guide provides essential technical information on H13 tool steel‘s hardness characteristics to help you optimize your die casting, forging, and plastic molding operations.

We offer a free download of the technical data of the H13 steel hardness PDF at the bottom of the page.

1. H13 Steel: An Overview

H13 is a chromium-molybdenum-vanadium (Cr-Mo-V) hot-work tool steel, known for its excellent red hardness, toughness, and thermal fatigue resistance. It’s a medium-alloy air-hardening steel used for:

• Die-casting dies
• Plastic-injection-mold tooling
• Forging tools
• Extrusion dies

The final hardness is determined by its composition and heat treatment.

2. What is H13 Steel Hardness?

Hardness measures a material’s resistance to permanent deformation, like indentation. For H13 steel, it’s typically reported in Brinell (HB) or Rockwell C (HRC). Optimal hardness balances wear resistance, toughness, and heat resistance, crucial for tool longevity and factory productivity.

3. Typical H13 Steel Hardness Values

H13 steel hardness varies with its metallurgical state, mainly due to heat treatment.

3.1. Annealed Hardness

In its fully annealed condition, H13 steel has a maximum hardness of approximately 220 HB. This softer state is ideal for machining before hardening.

3.2. As-Quenched Hardness

After austenitizing and air cooling, H13 develops its as-quenched hardness:

• A 1-inch (25mm) cube typically reaches about 53 HRC.
• Larger sections (e.g., a 330 mm/13 in. diameter bar cooled from 1010 °C/1850 °F) might be around 45 HRC.

Higher austenitizing temperatures can increase the as-quenched hardness in smaller sections. Slower cooling in heavy sections can result in lower hardness. H13 is deep hardening, capable of hardening through sections up to about 2-1/2 inches (63.5 mm) in diameter with air quenching.

3.3. Tempered Hardness

The final working hardness comes from tempering after quenching. As a secondary hardening steel, H13 develops optimal properties when tempered above approximately 510 °C (950 °F), which also provides stress relief. A secondary hardening peak occurs around 540 °C (1000 °F) due to vanadium-rich MC carbide precipitation. Double tempering is recommended.

The achievable tempered H13 steel hardness ranges from 38 to 57 HRC.

It’s critical to select tempering parameters to balance hardness with toughness; for instance, tempering around 500°C (930°F) is often avoided as it can lead to high hardness but low toughness, risking premature cracking.

4. Optimizing Hardness for Applications

Correct H13 steel hardness is key to tool performance. For more information, please click H13 tool steel applications.

4.1. Controlled Tempering for Desired H13 Steel Hardness

Tempering fine-tunes H13 steel hardness to balance wear resistance, toughness, and stability at operating temperatures.

4.2. Recommended Hardness Ranges

Application	Recommended Hardness (HRC)	Notes
General Die Casting Dies	42–52 HRC	47 HRC often preferred for aluminum.
Die Casting Inserts, Cores, Slides	46–52 HRC	Higher wear resistance.
Die Casting Plungers	46–50 HRC	Good wear and thermal shock resistance.
Die Casting Shot Sleeves	44–48 HRC	Resistance to wear and erosion.
Die Casting Nozzles	32–42 HRC	Improved toughness.
Die Casting Tooling (Optimal)	44–48 HRC	General working range.
Tooling Requiring Shock Resistance	40–44 HRC	Enhanced toughness.
Forging Dies (Hammers/Presses)	47–56 HRC	Maximize wear resistance; 53-56 HRC (min. severity), 47-49 HRC (max. severity).
Extrusion Punches and Dies	48–52 HRC	High wear resistance at elevated temperatures.
Plastic Mold Applications	40 HRC+	Often 48-54 HRC or 54-56 HRC; may be nitrided.

4.3. Surface Treatments for Enhanced H13 Steel Hardness

• Nitriding: Can achieve surface hardness near 1100 HV (>70 HRC) with a typical layer of 0.1-0.3 mm. The core (often ~45 HRC) remains tough. Ideal for hot wear applications.
• Boriding: Can produce surface microhardness around 1800 HV, significantly harder than standard hardened or nitrided H13.

5. The Basis of H13 Steel Hardness and Wear Resistance

Heat-treated H13’s wear resistance comes from:

1. The hardness of its martensitic matrix.
2. The presence of hard, undissolved alloy carbides (Vanadium-rich MC, Molybdenum-rich M6C, Chromium-rich M23C6). MC carbides can be around 84 HRC.

These carbides resist wear, especially at high temperatures.

6. Consistent H13 Steel Hardness with Aobo Steel

Achieving the target H13 steel hardness requires precise heat treatment control (austenitizing, quenching, tempering). While Aobo Steel supplies high-quality H13, we emphasize collaboration with experienced heat treaters to optimize your components for maximum life and efficiency.

For questions or to source H13 steel, contact Aobo Steel.