System designed for underwater welding

April 12, 2005

Specialty Welds Ltd.'s Hammerhead™ system is designed to enable wet welds in nil visibility, without the need for skilled welder-divers.

The system creates a spot/plug weld rather than depositing a fillet weld within a specified joint. It involves a simple lap joint and reduces the need for cleaning the joint area extensively. The one-shot approach eliminates multiple passes; one electrode produces one spot/plug weld.

Other than the control system and electrodes, all other equipment is the same as that used in conventional SMAW. The control unit is connected to the welding power source by the remote control facility and powered by a 110-V supply. All welding leads pass through a 400-amp Piranha safety switch before going to the diver.

A high-current setting allows the electrode to pierce through the materials and create a hole through which both materials are joined together. A timer limits the penetration depth to prevent bursting through the base material. After the first weld cycle is completed and the penetration depth is achieved, a second, lower current automatically initiates and fills the hole, creating a spot/plug weld that penetrates both materials and creates a weld nugget.

The system's electrode offers a tensile strength of 650 N/mm2 (94 KSI) and a shear strength of approximately 520 N/mm2 (75 KSI).

The process remains a manual welding operation and is not defect free, the manufacturer says. Trials were limited to flat bar/plate stock welded in the flat and vertical positions.

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