1.4852 Universal Heat Treatment Fixtures for Brazing Furnaces, Gas-Cooled at 1150°C

Brazing/Soldering Furnace Heat Treatment Fixtures & Toolings

Brazing/soldering furnace heat treatment fixtures are specialized support and positioning devices used in controlled atmosphere (e.g., hydrogen, nitrogen-hydrogen mix, vacuum) furnaces for brazing assembled workpieces.

Unlike heat treatment fixtures that emphasize "load-bearing and quenching," the core tasks of brazing fixtures are "precision assembly positioning" and "preventing workpiece deformation due to self-weight or filler metal melting." They must also ensure the filler metal can wet and fill the entire joint gap through capillary action.

I. Core Functions and Special Challenges
1. Precise Positioning and Maintaining Gap: This is the primary task. The parts to be joined (e.g., honeycomb structures, multi-layer sheets, complex flow channels) must be held in precise relative positions, maintaining the brazing gap as per design requirements (typically 0.02-0.2 mm). The parts must retain their designed geometry and dimensional accuracy after brazing.

2. Resisting High-Temperature Deformation: At brazing temperatures (typically 30-100°C above the filler metal's liquidus temperature), workpiece material strength decreases. The fixture must provide sufficient support to prevent workpiece warping, sagging, or collapse from self-weight or thermal stress.

3. Avoiding Reactions with Workpiece/Filler Metal: The fixture material must not undergo harmful alloying, sticking, or dissolution with the workpiece (e.g., stainless steel, superalloys, ceramics) or the molten filler metal (e.g., silver-, copper-, nickel-based) at high temperatures. This prevents post-braze separation difficulties or joint contamination.

4. Matching Coefficient of Thermal Expansion (CTE): The CTE of the fixture and workpiece should be as close as possible to prevent the fixture from imposing excessive constraining stress on the workpiece during heating or cooling, which could cause deformation or cracking.

5. Not Interfering with Atmosphere and Thermal Field: The fixture structure must not block the cleaning action of the protective atmosphere on the workpiece surface nor significantly disrupt the uniformity of the furnace's thermal field.

II. Key Points for Material Selection

Material selection for brazing fixtures is critical to their success.

1. Common Metallic Materials:

• Austenitic Stainless Steels: E.g., AISI 304, 316. Used for medium-to-low temperature brazing (<900°C). Low cost, easy to machine.
• Heat-Resistant Steels and Alloys: E.g., AISI 310 (2520), 330, Inconel 600/601. Used for high-temperature brazing (>900°C). Excellent oxidation and creep resistance. The first choice for most high-temperature brazing (e.g., of stainless steels, superalloys).
• Molybdenum, Tungsten: Used for very high-temperature (>1300°C) vacuum brazing. Low CTE, but oxidize easily, can only be used in vacuum or pure hydrogen.

2. "Non-Stick" Coatings/Treatments:

• Purpose: Apply a barrier at the contact surface between fixture and workpiece to prevent high-temperature sticking.
• Methods:

01. Spraying: Plasma-sprayed alumina, zirconia coatings.

02. Deposition: Chemical Vapor Deposition (CVD) boron nitride coating.

03. Pastes: Application of yttria- or boron nitride-based anti-stick pastes.

3. Core Selection Principles:

• The fixture's maximum service temperature must be significantly higher than the brazing temperature.
• The fixture material and workpiece material should not form low-melting-point eutectics at the brazing temperature.
• Prefer materials with a CTE matching the workpiece.

III.  Application Examples

Typical Applications:

• Plate-Fin Heat Exchangers: Require massive clamping systems composed of multi-layer pressure plates, side plates, and high-strength bolts to maintain tight contact between all layers throughout the thermal cycle.
• Aero-Engine Blades/Stators: Use precision-cast or machined superalloy jigs to accurately position dozens or even hundreds of blades.
• Electronic Devices (Vacuum Brazing): Use precision trays made of molybdenum, graphite, or ceramics to position microwave components, power modules, etc.

Brazing furnace heat treatment fixtures act as the "precision jigs" and "shape-retaining frameworks" of the brazing process. They vividly embody the industry consensus that "brazing success depends 30% on filler metal and 70% on fixtures". An excellent brazing heat treatment fixture design is the product of the deep integration of three disciplines: mechanical design (precision and rigidity), materials science (high-temperature compatibility), and brazing technology (gap control and deformation prediction). Its value lies not only in producing qualified brazed joints, but also in ensuring the precision connection of complex components under stress-free or low-stress conditions—an irreplaceable core role in fields such as aerospace and high-end manufacturing.

Material Grade Table:

FAQ:

Q: How to give inquiry ?

A: Step 1, please give us some details about your furnace,operating temperature,cooling method,loading weight of your furnace and so on;

Step 2, it's better to provide 3D drawings;

Step 3, when we have enough details, we may design the products drawings and quote accordingly;

Q: When can I get the price?

A: We usually quote within 24 hours after we get your inquiry(Except weekend and holidays). If you are very urgent to get the price, please email us or contact us in other ways so that we can offer you a quote.

Q: When will make delivery ? /What is the delivery Time?

A: -Sample Order: 35 days after receipt of the full payment.

-Stock Order: 10 days after receipt of the full payment

-OEM Order: 30 days after receipt of the deposit.

Q: What's your after-sales service?

A: 1 year warranty for all kinds of products;

If you find any defective accessories first time, we will give you the new parts for free to replace in the next order, as an experienced manufacturer, you can rest assured of the quality and after-sales service.

Q: What's your payment condition?

A: T/T

Payment<=USD10000, 100% in advance. Payment>USD10000, 50% T/T in advance ,balance before shipment.

Q: What is the shipping method?

A: Transported by DHL, UPS, EMS, Fedex,Air freight, sea freight or train freight.