Hydrogen Brazing
Here at Altair Technologies most of our products are for high vacuum applications and we therefore do most of our brazing in Hydrogen Gas or in a high vacuum atmosphere. During the braze run, while assemblies are being heated up to braze temperature, the furnace “bell” sees a steady flow of Hydrogen gas. This process continues until parts are below a certain temperature at which time the bell is backfilled with Nitrogen gas. Products or assemblies that are commonly hydrogen brazed include X-Ray Tubes, Traveling Wave Tubes, Linear Accelerators for medical, research and security applications and similar ion or electron beam devices. For reasons to be explained below, Hydrogen brazing is arguably the best process for bonding metals and ceramics regardless of the application. Read the rest of this entry »

Braze alloy penetrates full thickness of cavity wall

When fabricating complex geometries, whether it’s by die casting, e-beam welding, or 5- axis machining, there can be distinct advantages when brazing is used as a means of creating the final assembly.  Manufacturing of cavity structures utilizing standard brazing principles, for example, is becoming a current trend.
 
Structures with internal cavities are used in many applications including RF power, fuel cells, heat exchangers, cryogenic systems and chemical processing.  These arrangements are fabricated from many types of materials including copper, stainless steel, niobium, Inconel, titanium and alumina.

• Brazing vs. E-beam welding (EBW)

Orbital EBW is often used to bond two hemispheres together in order to produce a cavity; however, due to the limits in the amount of penetration possible with EBW, there are limits on possible wall thicknesses of the cavity (typically 2” in soft vacuum machines and 6” in hard vacuum machines).  With brazing, there is virtually no limit on wall thickness.  Read the rest of this entry »

The term “wetting” is commonly used to describe the flow of braze alloy or braze filler across a surface. However, before we get more into wetting, let’s recap the brazing process: First, two components are placed very close to or in contact with each other and a braze filler metal is placed in contact with BOTH parts. The filler and components are heated to just past the melting temperature of the filler braze alloy. The filler alloy “wets” the parts and capillary forces draw the braze alloy between the mating components, making up what is called the braze joint. The assembly is then cooled, solidifying the braze joint.

Good wetting occurs when the surface is clean & metallic and is Read the rest of this entry »

Laser Beam Welding (LBW) is a high energy welding process that continues to expand into modern industries and new applications because of its many advantages.  Some of the advantages of laser welding versus arc-welding are:

• High power density: deep weld penetration with minimal Heat Affected Zone (HAZ)
• Automation: easily automated using robotic machinery or CNC
• Accessibility: non-contact nature allows normally inaccessible areas to be welded along a “line of sight” or through thin parts as in the case of a cover plate (see Laser Welding page on our Website for more info)
• Versatility: capable of welding steels, aluminum, titanium, kovar, precious and refractory metals
• “Laser brazing”: high degree of accuracy allows melting of a filler metal placed within a joint without affecting the base material
• Laser welders can also be used for precision cutting and engraving

From a furnace brazing standpoint, laser welding is an important process used to reduce cost and increase productivity.  Read the rest of this entry »

Most of the brazing we do at Altair Technologies occurs between 800° C – 1270° C. Finding a suitable braze-alloy or “filler” to melt in this temperature range is not difficult. However finding a braze alloy, or even base materials, that will withstand operation over 1000° C can be tricky. One of the first questions to ask is what is the operating atmosphere or environment (high vacuum, air or?) and what are the base materials? At those elevated temperatures, many unwanted phenomena can occur. Read the rest of this entry »

Here at Altair Technologies we don’t maintain in-house plating capability and in general we try to avoid the use of plating(s) due to its additional costs and lead-times as well as yield issues associated with poor process controls. However, the plating of base material can benefit the operational performance and reliability of certain applications, benefit the brazing process and even assembly. Read the rest of this entry »