Why vacuum brazing? A short overview

Vacuum brazing enables development engineers and production persons in charge to design and manufacture parts in a modular way. Starting with simple pre-products complex shaped parts can be realized cost-effectively and/or with minimized effort for pre- and post-machining. Given flexibility in terms of combining components with strong difference in weight, wall thickness and shape and the utilization of different materials properties in terms of function and costs can be enlarged significantly. Parts guiding gases or liquids can be realized with an internal complex channel structure.

A broad range of materials is usable, starting with mild steels across high-alloyed cold and hot work steels up to super alloys. As well non-ferrous metals like copper and titanium and even ceramics, hard metals and the superhards CBN and diamond can be brazed. Using vacuum brazing no flux is required which results in strength values close to the bulk material. Even at high brazing temperatures no oxidation occurs.

Today vacuum brazing is applied in many application areas, from simple mass production up to complex, heavily loaded turbine parts.

Pros & Cons of vacuum brazing

Vacuum brazing is characterized by versatility and flexibility by the following advantages:

• nearly no limitation in materials (base material and brazing alloy)
• low distortion due to homogeneous furnace heating
• high joint quality due to vacuum atmosphere and prevention of flux
• high reproducibility due to excellent temperature uniformity and convenient control system of recent furnace facilities incl. process documentation
• combined heat treatment possible, brazing and hardening
• low environmental pollution

Disadvantages are:

• in most case batch operation, continuous processes only with very expensive manufacturing equipment
• high effort for component fixation because component cannot be manipulated within furnace
• heating of entire component which results in hardness loss of already hardened/tempered or cold worked materials
• high capital costs