By Ethan Rejto, Director of Marketing at Mantle

INTRO TO H13 TOOL STEEL:

If you’re a plastic injection molder or toolmaker, you know the importance of using the right tooling material in each molding scenario. Often considered the workhorse of tooling materials, H13 tool steel has established itself as a common injection mold tooling material, known for its high hardness, excellent thermal fatigue properties, and ability to be easily heat treated.

WHAT IS H13 TOOL STEEL?

H13 tool steel is a chromium-molybdenum-vanadium hot work steel known for its excellent toughness, wear resistance, and thermal fatigue resistance. As wrought, H13 tool steel typically has a hardness of around 35-42 HRC. However, after heat treatment, the hardness can increase significantly, typically reaching a range of 50-60 HRC. it’s widely used in plastic injection molding, where it’s essential to have a material that can withstand high temperatures, pressures, and wear from abrasive resins, has a long lifetime to last millions of cycles, and can withstand repeated thermal cycling as the tool is constantly heated and cooled.

FEATURES AND BENEFITS OF H13 TOOL STEEL:

1. SUPERIOR TOUGHNESS:

Toughness refers to a material’s ability to withstand stress and deformation without breaking or cracking. H13 tool steel has outstanding toughness, which ensures minimal risk of cracking or breaking during the high pressures of the injection molding process. The microstructure of H13 tool steel typically consists of tempered martensite, which is a very hard and strong crystalline structure. However, this microstructure is also very tough and ductile, which allows the material to absorb energy without breaking or cracking. This toughness translates to long tool life and H13 tools not needing repair as often as less tough tools.

2. EXCELLENT WEAR RESISTNACE:

Wear resistance refers to a material’s ability to resist damage from contact with other surfaces or materials. The wear resistance of H13 tool steel helps maintain crisp features and sharp edges on your tool, improving molded part quality and reducing the mold tools need for maintenance.

H13 tool steel wear resistance results from a combination of its chemical composition, microstructure, and heat treatment. H13 is a chromium-molybdenum-vanadium hot work steel. The chromium content in H13 provides improved hardening and resistance to softening at high temperatures, while molybdenum enhances strength and hardenability. Vanadium contributes to the formation of hard, stable carbides that increase wear resistance.

The microstructure of H13 tool steel plays a crucial role in its wear resistance. The presence of hard carbides, such as vanadium carbides, dispersed within the steel matrix increases its ability to resist wear. These carbides improve hardness and provide a barrier against abrasive wear, reducing the rate of material loss during use.

Proper heat treatment is essential for achieving the desired wear resistance in H13 tool steel. Through a combination of hardening and tempering processes, the steel develops a tempered martensitic microstructure with a fine distribution of carbides. (Martensitic microstructure is a crystalline structure that forms when austenite, a high-temperature form of iron, is rapidly cooled.)

3. THERMAL FATIGUE RESISTANCE:

H13 tool steel’s high thermal fatigue resistance means it can withstand the constant temperature fluctuations experienced during injection molding. The thermal fatigue resistance is due to a high amount of alloying elements, primarily chromium, molybdenum, and vanadium.

The chromium in H13 steel forms a stable oxide layer on the material’s surface, which helps protect it from oxidation and corrosion at high temperatures. The molybdenum and vanadium improve the high-temperature strength and toughness of the material by forming hard carbides and nitrides in the steel’s microstructure.

This high thermal fatigue resistance prevents premature failure due to thermal stress and contributes to a longer mold life.

4. POLISHING & SURFACE TREATMENT COMPATIBILITY:

H13 tool steel can be polished to a high level of surface finish, which is crucial for producing high-quality plastic parts. Additionally, it’s compatible with various surface treatments, such as nitriding and coatings, further enhancing its performance.e.

WHY 3D PRINT H13 TOOL STEEL?

While H13 tool steel offers many advantages for mold tooling, it can be very challenging to fabricate. Its high hardness makes machining challenging, requiring highly skilled machinists using carbide cutting tools with high cutting speeds and low feed fates. Additionally, since the material is so hard, a small depth of cut is required to additionally help reduce heat build-up and tool wear. The challenges of machining it, combined with other rigorous steps of the toolmaking process (EDM, grinding, etc.), make H13 mold tools expensive and time-consuming to produce.

Mantle’s innovative metal 3D printing technology takes the benefits of H13 tool steel to the next level by alleviating the challenges of producing H13 tools traditionally. With the push of a button, users can print H13 tools faster and more affordably than with traditional manufacturing.

Mantle’s TrueShape technology produces H13 inserts with the accuracy, surface finish, and tool steel properties that toolmakers demand. Additionally, printing unlocks the ability to create molds that were previously impossible with traditional manufacturing methods, incorporating things like conformal cooling to reduce cycle times and part defects.

ABOUT ETHAN:

Ethan has extensive experience in technical marketing for manufacturing products. He previously ran the technical marketing team at Desktop Metal, a 3D printing manufacturer focused on volume production. Ethan has a master’s degree in engineering from Boston University and a degree in mechanical engineering from the University of Colorado.