How to Extend the Service Life of Vacuum Furnace Heat Treatment Fixtures?

How to Extend the Service Life of Vacuum Furnace Heat Treatment Fixtures/ Toolings? Junteng Fanghu Reveals 3 Practical Tips

The service life of vacuum furnace fixture/ tooling directly affects the stability of heat treatment processes, the qualification rate of workpieces, and the comprehensive production cost of enterprises. For high-value scenarios such as aerospace, semiconductor, and high-end fixture/ tooling die heat treatment, frequent replacement of fixture/ tooling not only increases procurement costs but also leads to production downtime and quality fluctuations. Based on years of R&D and on-site service experience, Junteng Fanghu has summarized 3 highly operable practical tips for extending the service life of vacuum furnace fixture/ tooling, helping enterprises maximize the value of their furnace fixture/ tooling investments.

Tip 1: Standardize Pre-Use Preparation – Eliminate Hidden Risks from the Source

The service life of fixture/ tooling is closely related to pre-use preparation. Ignoring details such as cleanliness and inspection may cause irreversible damage to fixture/ tooling during high-temperature and high-vacuum processes. Junteng Fanghu recommends the following standardized operations:

1. Strict Cleanliness Treatment
Before putting the fixture into the furnace, thoroughly remove surface contaminants such as oil, moisture, oxides, and workpiece residues. For heat-resistant steel fixture, use a high-pressure air gun to blow off surface dust, and then clean it with a neutral detergent to remove oil stains; for graphite and ceramic tooling, avoid using corrosive cleaners, and use a soft brush to gently brush off surface attachments. Residual contaminants will volatilize violently in the vacuum environment, forming corrosive gases that erode the fixture surface and reduce its structural strength.
2. Comprehensive Pre-Use Inspection
Conduct a visual inspection of the tooling’s appearance to check for cracks, deformation, or loose components. For load-bearing structures such as fixture brackets, use a micrometer to measure key dimensions and confirm that the deformation amount is within the allowable range. For fixture with coatings, check whether the coating is intact and free of peeling or blistering. If hidden defects are found, stop using the tooling immediately for maintenance or replacement to avoid further damage during use.
3. Reasonable Pre-Heating Procedure
For large-scale or thick-walled fixture, avoid direct heating to high temperatures. Adopt a step-by-step pre-heating procedure (e.g., 200℃ for 30 minutes, 500℃ for 30 minutes, 800℃ for 30 minutes) to gradually raise the temperature. This can reduce the thermal stress caused by rapid temperature changes, prevent cracking or deformation of the fixture, and extend its service life. Junteng Fanghu’s technical team can customize a pre-heating curve matching the fixture material and structure according to the enterprise’s furnace type and process requirements.

Tip 2: Optimize In-Use Operation – Avoid Damage Caused by Improper Use

Improper operation during the use of fixture is one of the main reasons for shortened service life. Junteng Fanghu emphasizes that enterprises must standardize operation processes and avoid the following common mistakes:

1. Control Load Within the Rated Range
Overloading is a key factor leading to tooling creep deformation and fracture. Different materials of fixture have different load-bearing capacities at high temperatures: for example, heat-resistant steel fixture can bear a load of 500kg/m² at 1200℃, while graphite fixture can only bear a load of 200kg/m² at the same temperature. Enterprises must strictly control the workpiece weight according to the rated load of the fixture, and avoid uneven load distribution (e.g., placing heavy workpieces only on one side of the tooling). Junteng Fanghu can provide a load-bearing capacity test report for customized fixture, clarifying the safe load range under different temperature conditions.
2. Ensure Uniform Heating and Cooling
In the vacuum furnace, heat transfer mainly relies on radiation. Uneven heating will cause local overheating of the fixture, leading to thermal fatigue and cracking. Enterprises should reasonably arrange the placement position of workpieces (e.g., avoid direct contact between workpieces and heating elements) and use heat reflection screens or heat insulation layers to optimize the thermal field. During the cooling stage, avoid rapid cooling (e.g., direct air cooling after high-temperature treatment), and adopt a step-by-step cooling procedure to reduce thermal stress. Junteng Fanghu’s customized fixture adopts a special structural design (such as heat dissipation holes and reinforcing ribs) to improve the uniformity of heating and cooling, further reducing the risk of damage.
3. Avoid Chemical Reactions Between Tooling and Workpieces
In high-temperature environments, chemical reactions may occur between tooling and workpieces, leading to mutual contamination and damage to the fixture surface. For example, carbon-containing fixture (such as graphite fixture) will cause carbon pollution to titanium alloys and nickel-based superalloys; metal fixture may react with ceramic workpieces at high temperatures. Enterprises must select tooling materials that are chemically compatible with the workpiece materials. For carbon-sensitive materials, Junteng Fanghu’s carbon-free heat-resistant steel tooling or high-purity ceramic tooling can be used to avoid chemical reactions and extend the service life of both the tooling and the workpieces.

Tip 3: Strengthen Post-Use Maintenance and Repair – Extend Service Life Through Regular Care

Regular maintenance and timely repair are crucial for extending the service life of fixture. Many enterprises ignore post-use maintenance, leading to the accumulation of damage and premature scrapping of fixture. Junteng Fanghu recommends the following maintenance measures:
1. Timely Cleaning After Use
After each furnace run, clean the tooling in a timely manner to remove workpiece residues, oxides, and other contaminants on the surface. For heat-resistant steel fixture/ tooling, use a wire brush to remove surface scale, and then apply anti-rust oil to prevent oxidation during storage; for graphite fixture, use compressed air to blow off dust, and avoid water washing (to prevent cracking caused by water absorption and expansion). For fixture with serious contamination, Junteng Fanghu provides professional cleaning services, using vacuum heating degreasing or sandblasting to restore the fixture’s surface state.
2. Regular Maintenance and Coating Repair
For fixture with surface coatings (such as anti-oxidation coatings for heat-resistant steel fixture and SiC coatings for graphite tooling), regularly inspect the coating state and repair peeling or damaged parts in a timely manner. The coating can effectively isolate the fixture from corrosive gases and high-temperature oxidation, extending the service life by more than 50%. Junteng Fanghu provides coating repair services for its customized fixture, using the same coating material and process as the original to ensure the maintenance effect.
3. Scientific Storage Management
Store the fixture in a dry, ventilated, and dust-free environment to avoid moisture, oxidation, or mechanical collision. For large-scale tooling, place it on a dedicated support frame to avoid deformation caused by long-term stacking; for precision fixture, store it in a sealed box to prevent dust contamination. Junteng Fanghu can provide storage guidelines for different types of fixture, helping enterprises standardize storage management and avoid unnecessary damage during storage.

Junteng Fanghu’s Value-Added Service: One-Stop Tooling Life Extension Solution

In addition to the above three practical tips, Junteng Fanghu also provides one-stop fixture life extension solutions for enterprises, including:

• Tooling Health Diagnosis: Regularly conduct on-site inspections of the fixture, analyze the damage causes, and provide targeted improvement suggestions.
• Customized Maintenance Plans: According to the enterprise’s production capacity and process characteristics, formulate a personalized maintenance plan to reduce maintenance costs and downtime.
• Tooling Repair and Renovation: For damaged tooling, provide professional repair and renovation services to restore its performance, avoiding the waste of scrapping intact parts.

Summary
Extending the service life of vacuum furnace tooling is a systematic project that runs through the entire process of pre-use preparation, in-use operation, and post-use maintenance. Enterprises must establish a complete management system and avoid ignoring details. Junteng Fanghu’s three practical tips are highly operable and can help enterprises effectively extend the service life of tooling, reduce production costs, and improve the stability of heat treatment processes.
Whether you use graphite, heat-resistant steel, refractory metal, or ceramic tooling, Junteng Fanghu can provide targeted life extension suggestions and services according to your tooling type and application scenario.