Vacuum Brazing and Heat Treatment

The process of brazing involves taking two separate metal surfaces and joining them together through the flow of a molten filler to achieve a strong and reliable seal. This process is vital to the production of PWR’s heat exchangers and continuous development has ensured we remain at the forefront of brazing innovation. Home to four styles of brazing and heat-treating furnaces: a vacuum brazing furnace, two continuous belt CAB furnaces, a single batch CAB furnace and a solution heat-treating furnace, PWR is a NADCAP accredited heat treat facility capable of brazing in accordance with AWS C3.7 standard as well as solution treating and artificial ageing in accordance with AMS2770.

Vacuum Brazing Furnaces

Vacuum Brazing is a fluxless brazing process that is performed under high vacuum in a heated chamber using pre-placed clad filler material. Vacuum brazing is best known for its ability to produce clean, precise braze connections without oxidisation, resulting in high quality and reliable assemblies. This process is used in aerospace, automotive and other markets for joining complex heat exchange components such as cold plates. Advantages of Aluminium Vacuum Brazing include, but are not limited to:

  • High strength joints in heat treatable aluminium alloys that enable light weight heat exchangers to be manufactured with superior structural integrity;
  • Fluxless brazing meaning no potentially harmful residues or contaminates;
  • Excellent conductivity, both thermal and electrical, providing exceptional heat rejection characteristics while maintaining electrical integrity;
  • Greater freedom in design of products with intricate internal fluid passages or thin wall applications;
  • Greater reliability and durability in high stress design application compared to bolted or adhesive bonded applications; and
  • Relatively low-cost solutions for high end designs.

While PWR focuses largely on producing high-end aluminium heat exchanging products, our Vacuum Brazing capability is not limited to Aluminium materials with experience using a wide range of other exotic metals such as Titanium, Nickle and Chromium based metals like Inconel, and Heat Resistant Stainless Steels paired with alloy fillers such as Silver, Nickle, and Gold to provide superior joint interfaces.

Controlled Atmosphere Brazing (CAB) Furnaces

Controlled Atmosphere Brazing processes are performed in a Nitrogen purged atmosphere where pre-fluxed assemblies are joined together with aluminium clad fillers producing strong, leak-free joints in lower strength aluminium alloys for applications such as Radiators, Oil Coolers, Intercoolers and Heat Exchangers. PWR extends its brazing capability with three Controlled Atmosphere Brazing (CAB) furnaces two of which feature a continuous belt for rapid and continuous heat exchanger production while the third is a single batch style furnace for controlled braze cycles with less volume.

PWR Australia recently received and installed a new Universal Batch CAB Furnace from the SECO/WARWICK Group. This new batch furnace is designed for short production runs of industrial products and specialised orders. The main production advantage of this furnace comes from the ability to braze products in both horizontal and vertical positions. This eliminates any limitations caused by the heat exchanger configuration.

Solution Heat Treatment Furnace

In association with Aluminium Vacuum Brazing, returning heat treatable brazed workings to a tempered state through Solution Heat Treatment and Artificial Aging is key to the performance and structural integrity of high stress components. This is achieved in the specially designed PWR Solution Heat Treatment Furnace. This specialised equipment incorporates PLC controlled heating cycles with an automated, programmable, integral spray quench system that reduces residual stress during the quenching operation resulting in stable, high-quality post braze components ready for final machining processes. Applications for Aluminium Vacuum Brazed and Heat-Treated components include, but are not limited to the following:

  • Cold plates – for both land based and aeronautical applications, cooling electronic components and power units;
  • Formula 1 and Formula E race-car platforms;
  • Battery cell cooling/heating for electric vehicles;
  • Airborne electronics and enclosures;
  • Radar installations and other military applications.