Italy-based oil and gas producer Bonatti has selected EFD Induction’s post-weld heat treatment (PWHT) solution for the construction of 13% Cr onshore pipeline.

The gas pipeline is being constructed as a part of In Salah Southern Fields project in the Algerian Sahara desert, which in turn is a part of the In Salah Gas (ISG) project.

A joint venture between Statoil, BP and Sonatrach, the ISG project is said to be Algeria’s third largest gas development program with a current production capacity of about nine billion cubic meters, claimed Bonatti.

EFD Induction’s PWHT solution is accepted across the industry as a safe method to minimize the chances of hydrogen induced stress cracking (HISC), which is caused by the presence of hydrogen in the pipe’s heat affected zone.

The PWHT solution will be used on the corrosion resistant alloy pipelines to reduce the risk of HISC, due to the high temperature in the Sahara desert.

EFD Induction’s Stefano Migliavacca said that it is a technically advanced work to weld the heterogeneous materials.

"But when used in conjunction with PWHT, such welding offers tremendous benefits," Migliavacca added.

"13% Cr pipe, for example is extremely cost-effective because its strength means that lighter wall thicknesses can be used. Duplex on the other hand is extremely resistant to corrosion."

As a part of the contract, EFD Induction will provide two complete PWHT systems for on-site operation in the Saharan desert.

Each system is truck-mounted, and comprises an EFD Induction ‘Minac’ 70/110 power source, specially designed induction coils for 8in -12in and 16in pipe, and chiller and quench units.

The two PWHT systems will be used to weld the 13% Cr to duplex steel. PWHT of 13% CR and duplex flowlines is necessary to decrease the HISC risk.