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RapidDirect Heat Treatment Services
Alter the physical and mechanical properties of your products without changing their shape with heat treatment finish services. Enhance strength, durability, and performance to meet your industry's demands.
What's Heat Treatment?
Heat treatment is a custom metal finishing process involves heating and cooling a metal to precise temperatures. It is a well-controlled precision thermal process that changes the part’s microstructure, improving its hardness, strength, and toughness.
Precision heat treatment involves heating the metal to a specific temperature to change its microstructure, maintaining the temperature, and cooling it back to room temperature at a particular rate.
There are also four types of heat treatment: hardening, tempering, annealing, and normalizing. Hardening makes the metal stronger but reduces its ductility. It involves slowly heating the part to a high temperature, maintaining the temperature for a specified time, and quenching (rapid cooling by plunging it into water or oil)
Tempering has steps like hardening, although they occur at lower temperatures, and the cooling occurs in air and not a liquid. It involves relieving the internal stress that occurs due to the hardening process.
Annealing is the opposite of hardening as it increases the ductility of the metal part, relieves stress, and softens the metal. It involves slowly heating the metal to a specified temperature, maintaining the temperature, and slow air cooling.
Lastly, normalizing is applicable in relieving internal stresses created during machining. It is like the annealing process, with the difference being that the parts are removed from the furnace for air cooling after heating and maintaining the temperature.
Vacuum Heat Treatment
Vacuum heat treatment is a heat treatment solution that involves heating metal parts in a vacuum furnace to achieve precise temperature control and eliminate surface contamination. A vacuum heat treated part has uniform heating, reduced oxidation, and improved mechanical properties.<span></span>
| Applicable Materials | Visual Appearance | Industrial Applications | Overall Hardness |
|---|---|---|---|
| Steel, Cast Iron | A black film may appear on the part. | Aerospace components, automotive parts, tooling and die segments, heavy machinery parts, and high-wear equipment. Precision parts requiring enhanced wear resistance and dimensional stability also benefit greatly. | 48-62 HRC (depending on the material). |
Advantages
- Precise temperature control ensures consistent results.
- Elimination of surface contamination leads to higher purity of the treated parts.
- Enhanced mechanical properties, including improved hardness and strength
- Uniform heating throughout the part minimizes distortion and warping.
Notes
- If a metal-colored surface is preferred, an additional grinding process is required.
- Parts undergo high-temperature treatment, cooling, and tempering three times in a vacuum furnace to achieve stable hardness. It is ideal for parts that need to provide strong support properties.
Bright Heat Treatment
Bright heat treatment or gas carburizing, is a heat treatment process used to improve metal parts' surface hardness and wear resistance. It involves heating the parts in a controlled atmosphere to diffuse carbon into the surface, followed by quenching and tempering.
| Applicable Materials | Visual Appearance | Industrial Applications | Overall Hardness |
|---|---|---|---|
| Steel, Cast Iron | Uniform, shiny finish free of oxidation. | Automotive engine components, precision tooling, cutlery, and decorative hardware. Applications demanding aesthetic appeal along with hardness. | 42-58 HRC |
Advantages
- Increased surface hardness and wear resistance.
- Improved fatigue strength and toughness
- Longer lifespan
- Enhanced dimensional stability
- Uniform case depth and hardness distribution for consistent performance.
Notes
- No tempering treatment, only case hardening, keeping a bright external surface, generally suitable for cosmetic parts with hardening needs.
- The core of the part cannot be fully hardened and is unsuitable for parts responsible for strong support.
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FAQs
Heat tolerance for heat treatment typically ranges between ±5°C and ±15°C, depending on factors such as temperature level, material, and specific process requirements. For instance, in the case of tempering steel at 200°C, a tolerance of ±5°C ensures consistent mechanical properties. Conversely, for processes like annealing aluminum at 500°C, a broader tolerance of ±15°C may be acceptable.
Yes, the heat treatment process can indeed impact the surface finish of a part, especially in processes involving rapid heating and cooling, such as quenching. Rapid temperature changes can cause thermal stresses, distortion, and the formation of surface imperfections like cracks or scale. However, with precise process control and post-treatment finishing techniques such as grinding or polishing, it is possible to minimize any adverse effects on the surface finish. Additionally, selecting appropriate heat treatment parameters and materials can help maintain or even improve the surface finish, ensuring the desired quality and performance of the final part.
Firstly, it allows for precise temperature control, ensuring uniform heating and cooling throughout the part. Secondly, the absence of air in the vacuum chamber eliminates the risk of surface contamination, resulting in cleaner and purer parts. Additionally, vacuum heat treatment can enhance mechanical properties such as strength, hardness, and toughness, leading to improved performance. Moreover, the reduced oxygen content minimizes oxidation, resulting in less distortion and warping of the parts.
The duration required to heat treat blades typically ranges from 20 to 60 minutes, depending on various factors such as material, size, and specific heat treatment process. For example, a high-carbon steel blade might require austenitizing at around 800°C for 30 minutes, followed by quenching and tempering at a lower temperature for another 20 to 60 minutes to achieve the desired hardness and toughness. Stainless steel blades might require longer durations, such as 45 minutes to an hour, at different temperatures due to their unique properties.
Over-burning is the possible culprit if the surface of the piece is dark gray, there are small bubbles on the workpiece surface, cracks appear, and the crack fracture is rough
Heat treatment is necessary to prevent deformation because machining and forming process build residual stresses into parts. Techniques like annealing can relieve these stresses, thereby improving dimensional stability and reducing the risk of deformation during subsequent use.
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