Germiston-based Efficient Engineering has invested in state-of-the-art orbital welding technology from France, to help meet its growing workload in heat exchangers.

The welding of the tube to tubesheet connections is a challenging task in the construction of heat exchangers, explains Efficient Engineering quality manager and welding engineer Dries Vandezande. To manage its increasing orders of heat exchangers while raising its production standards, the company has invested in orbital tube-to-tubesheet technology from European original equipment manufacturer Polysoude.

“These welds are very demanding, and require a level of welding skill which is in short supply in South Africa,” says Vandezande.

The orbital welding machine enables the whole weld to be conducted in one pass, compared to a manual operation that involves interruptions as both sides of the weld are completed, which can produce defects such as pinholes.

The quality result is ensured by a pre-programmed welding procedure, explains Vandezande. The procedure qualification record (PQR) ensures that, as long as the base material and joint preparation is consistent, the same high level of results will be achieved.

The units can weld a range of material from stainless steel, carbon steel and low alloys and different welding heads can be applied to exotic materials such as titanium. Among the key features of the orbital welding machine is its arc voltage control, which helps to achieve a consistent weld bead. After pre-programming, the arc voltage control keeps the weld pool constant to deliver the welds predicted in the PQRs. With the use of different accessories, the advanced orbital welding machines can also be applied to header boxes where there is limited access through holes.

The new machines also enhance safety, especially related to the pre-heating of the pieces to be welded. Certain alloy materials could require pre-heating up to 150 ^oC to 250 ^oC, and the orbital welding machine allows the operator to remain at a safe distance from the test piece.

“This is very novel technology, which opens up a new world for Efficient Engineering,” asserts Vandezande. “When there is market demand, we will be able to apply welding techniques that deliver the best results. This overcomes the challenge that with manual welding the risk of defects and the challenge to repair them is high.”