Developed New Welding Process

Developed New Welding Process

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reduced product cost with Innovative solenoid tube welding process

Fig1: New Solenoid Tube Welding Process


My Employer’s Top management decided that introduction of a new high-pressure series of solenoids was strategically important to the company and should be given high priority.

The solenoid had to be highly efficient magnetically. That meant that it would have to be multi-section, with the center section being a non-permeable flux break. The problem was that existing tube joining methods did not fit our cost, capital and performance requirements. We determined that we would have to develop the joining technology ourselves.


We quickly decided that welding was preferable to other methods from a strength and reliability standpoint, but welding presents its own difficulties – namely weld integrity and brittleness. After a significant amount of basic research, we found that a key determinant in producing leak free welds was to prevent the metals from transitioning through the liquidus line. When this occurred, alloying elements in the base metals tended to migrate into the grain boundaries at the weld joint resulting in brittle welds. In other words, we needed a method of welding that didn’t melt the metals being joined.

We researched over twenty welding methods and determined that projection welding could be adapted to our needs.  We demonstrated feasibility and used    designed experiments (DOE) to optimize the process.


For $30,000 we modified off-the-shelf equipment to reliably produce low cost, high strength, leak free welds. Our testing indicated 0.99 minimum reliability at 95% confidence based on success run theorem.

Tube welded using new welding process

Fig 2: Welded tube (before machining)

welding process reduced product cost and produced pore free welds

Fig 3: Welded zone Inherently Free of Voids