Hardening
Hardening is a heat treatment process used to increase the hardness and strength of metals, such as steel. Most materials consist of different crystal lattice structures, each with distinct properties. Hardening is a process in which these structures are altered to achieve the desired properties.
HARDENING PROCESSES
vacuum hardening
In vacuum hardening, your component is heated in a vacuum and then quenched using nitrogen under positive pressure. High-alloy materials are typically vacuum-hardened.
Protective gas hardening
In gas-protective hardening, the metal component is heated to the hardening temperature in a protective gas atmosphere and then rapidly cooled in an oil bath. Low-alloy materials are typically heat-treated in this manner.
induction hardening
In induction hardening, the areas to be hardened are heated using an induction current and then quenched with a water spray if necessary.
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Silvio Stranek
Sales, Technical Consulting / Quotes (Upper Austria, Tyrol, Salzburg, Vorarlberg, Bavaria, South Tyrol)
Email. s.stranek@htr.at
Phone: +43 (0) 664 / 88 92 78 10
Thomas Stadlober
Sales, Technical Consulting / Quotes (Styria, Vienna, Lower Austria, Carinthia, Slovenia)
Email. t.stadlober@htr.at
Phone: +43 (0) 664 / 88 64 15 06
A COMPARISON OF HARDENING PROCESSES
| Criterion | vacuum hardening | Protective gas hardening | induction hardening | Case Hardening |
|---|---|---|---|---|
| Medium | Vacuum (without oxygen) | Nitrogen, argon, methane | Induction coil (electric field) | Carbon-rich gas / medium |
| Temperature range | approx. 900–1,250 °C | approx. 750–950°C | Surface temperature: 800–1,000 °C | Carburizing: 850–950 °C, Hardening: ~800 °C |
| Penetration Depth / Layer Depth | Full curing (through and through) | Full curing | 0.5–5 mm (depending on the coil and time) | 0.2–2 mm (diffusion layer) |
| Can the depth of hardening be controlled? | Limited (depending on the material) | Limited | Highly precise control | Yes, regarding the carburizing time |
| Distortion / Dimensional Stability | Very low | Low to moderate | Low | Medium to high |
| Typical hardness | >60 HRC (depending on the steel) | 50–64 HRC | >55 HRC (edge hardness) | ~60–65 HRC (surface layer) |
| Typical applications | Tools, Precision Parts, Molds | Machine Components, Mass Production | Gears, shafts, bearing housings | Transmission parts, crankshafts, piston pins |
| Surface quality | Very good, shiny | Good (low-oxygen possible) | Rough; may require further processing | May be oxidized; often requires rework |
| Environmental friendliness | Very high (no emissions) | Medium | High (locally limited) | Medium (gaseous emissions) |
| Special Features | No scale formation, clean components | Cost-effective for mass production | Fast, selective, energy-efficient | Ideally combines hardness and toughness |
Our CORE COMPETENCIES
As one of the leading hardening companies,we are your reliable partner for industrial heat treatment. For over 25 years we have been hardening steel and other metals using state-of-the-art processes – dimension-stable, wear-resistant, and reproducible. Whether individual parts or series production: we combine expertise, state-of-the-art equipment, and process controlto achieve the highest hardness quality and warp resistance .
48-hour service
Thanks to our unique organizational structure and customer-focused flexibility, we have been delivering top-quality hardened parts in record time for over 25 years.
Quality assurance
With a state-of-the-art control system, we keep an eye on all important parameters at all times and ensure that only flawless products are delivered.
Pick-up and delivery service
As part of our worry-free service package, our company-owned transport fleet enables daily pickups and deliveries in the central region of Upper Austria.
Knowledge transfer
In customized seminars, you will learn which combination of materials and hardening processes can reduce the costs of your project while achieving optimal component properties.
Your Questions, Answered
We have compiled a list of frequently asked questions to help you better understand our services.
What exactly is hardening?
Hardening is a heat treatment process used to increase the hardness and strength of metals, such as steel. Most materials consist of various crystal lattice structures, each with different properties. Hardening is a process in which these structures are altered to achieve the desired properties. Hardening can be performed in various ways; each method has its own advantages and limitations and is selected based on the specific requirements and properties of the material.
Why should I harden my materials?
Materials are hardened to improve their properties. Hardening alters the internal structure of the material, resulting in increased strength, hardness, toughness, and wear resistance. This enables the material to perform better under stress and wear. Hardening is therefore an important process in many fields, such as the manufacture of tools, machine parts, and automotive components.
What materials can I harden?
Steel: Steel is the most commonly hardened material and is frequently used in tools, machinery, and automotive parts.
Aluminum: Aluminum can be hardened through heat treatment to make it more resistant to damage.
Copper: Copper alloys can be hardened through heat treatment to make them more suitable for specific applications, such as electrical conductors.
Titanium: Titanium can be hardened through heat treatment to make it more resistant to corrosion and abrasion.
Nickel-based alloys: Nickel-based alloys are often heat-treated in high-temperature applications to increase their strength and hardness.
What is the curing process like?
Hardening is a process in which a material—usually steel—is heated and then rapidly cooled to increase its hardness and strength. Here is an overview of the hardening process:
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Pre-treatment: Before the hardening process begins, the material is typically cleaned and pre-treated to ensure that it is ready for hardening. This may involve removing rust, oil, and other contaminants, as well as grinding or sanding the material.
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Heating: The material is heated to a specific temperature. The exact temperature depends on the type of material and the desired degree of hardness.
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Cooling: After heating, the material is quickly cooled to achieve the desired hardness. This can be done by immersing it in oil, air hardening, or cold hardening.
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Quenching: After cooling, the material is typically quenched to stabilize its hardness.
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Inspection: Finally, the harder material is inspected to ensure that it has reached the desired hardness level.
Overall, hardening is a complex process that requires careful monitoring and control. However, performing the hardening process correctly can help improve the performance and durability of tools and machines.
What are the benefits of hardening?
- Increased Hardness and Strength: Hardening alters the material's crystal lattice structure, thereby increasing its hardness and strength, which makes it more suitable for higher loads and stresses.
- Improved Wear Resistance: Hardening increases the surface hardness of the material, which improves its resistance to abrasion, damage, and wear.
- Extended Service Life: By improving hardness and strength, heat treatment extends the service life of the material and increases its reliability.
- Increased corrosion resistance: Some heat treatment processes also improve the material's corrosion resistance by forming a protective layer on the surface.
- Increased thermal stability: Hardening can also increase the material's thermal stability, making it more suitable for high temperatures and varying thermal conditions.
- Reducing Tolerances and Warpage: Hardening can also improve the precision and accuracy of the material by reducing tolerances and warpage.