Country: India

Company: Thermax, Ltd.

Material: Mild steel

Job: Small boiler tubes - 51 mm dia / 3.7 mm wall

Problem

TIG welding small boiler tubes was time-consuming due to lengthy set-up times, hindering productivity.

Solution

Due to Lincoln's STT process' low heat input and excellent heat control, Thermax is able to use a joint with no root face and no gap and still get excellent penetration.

Results

Welding a 50mm tube takes a mere 60 seconds, which increased productivity dramatically.

Thermax, Ltd., manufactures temperature indicators and strips, thermal fluid heaters, and other products used to monitor and record equipment temperature fluctuations in the food, medical, automotive, aerospace industries, among others.

 Thermax has switched from TIG to the STT process for welding small boiler tubes used in thermal fluid heaters. Because fit-up has to be perfect when TIG welding, set-up time was too long, and productivity was slowed. With STT's low heat input and excellent heat control, they are able to use a joint with no root face and no gap and still get excellent penetration. Two long seamless tubes are joint prepared and fixtured in a lathe. The tubes are rotated and welding proceeds in the 1G position.

After each root bead, the capping pass is welded with the same parameters as the root pass by weaving the torch to fill up the joint. This operation has been automated to start the weaving automatically upon completion of the root pass. With STT, penetration is outstanding with an excellent back bead, and a smooth, polished finish on the cap pass is obtained.

Thermax is now welding a 50mm tube in a mere 60 seconds. Their goal is zero defects in the first year of operation, as well as Six Sigma.