Abstract Scope |
The Hybrid Induction Arc Welding process utilizes a concentrated heat source ahead of the motion of the arc welding torch. The heat source has two primary purposes: 1) significantly reduce or completely eliminate weld distortion; and, 2) increase the welding speed by up to 5X. This patented welding process is being applied to shipbuilding and to the on-site production of UltraTall Wind Towers.
Weld distortion costs the U.S. Navy and Navy shipbuilders an estimated 20 million dollars, conservatively, annually. As an example, ship decks are produced by welding T-Stiffeners to the underside of the deck plate, in order to achieve the stiffness and overall strength to support the various loads on the deck of a ship. The stiffeners are joined to the deck plate using a two-sided T-fillet weld, produced by robotic/automated arc welding. Weld distortion causes the deck plate to bend downward on either side of the stiffener weld joint. The result is a "washboard" surface on the deck.
This unflat surface condition can have several negative impacts on the final ship product: 1) The depressions of the surface of the deck between the stiffener welds can accumulate water -- in the case of some of the decks, this may be highly corrosive sea water -- which can result in deterioration of the protective coating on the deck surface; 2) The resulting uneven deck surface can present a tripping hazard for Navy personnel who are assigned to that ship, which can have catastrophic consequences in any battle engagement situation as well as during normal operations; and 3) The non-flat deck surface is unacceptable for aircraft operations, on ships which have aerial combat, or non-combat, mission requirements. Both rotary wing and fixed wing aircraft often have to traverse a deck surface in preparation of, and during take-off and landing operations.
Common practice is to "straighten" the deck sections after the stiffeners have been welded to the underside of the deck. It is not uncommon for the labor cost to exceed 1-2 million dollars per shipyard annually, for deck plate straightening. EnergynTech, Inc. has produced a automated/robotic deck plate straightening portable/mobile robot, which can reduce the straightening cost by 80%, but the overall cost to the Navy even using the straightening robot is still many millions of dollars annually.
By strategically applying the induction heating using a specially designed induction coil, the patented "HyDep" Welding process completely eliminates the weld distortion on ship deck sections. The induction heating is strategically placed in advance of the welding arc, to counter the forces created by the weld distortion, so that the resulting deck section is completely flat.
The induction heating also raises the weld joint surfaces to, or near, the melting point, so that the primary heating by the welding arc is just to melt the wire. Consequently, welding travel speed can be increased substantially. Tests conducted on Navy Destroyer Ship decks have shown that the welding process can increase welding speed, and therefore welding productivity, by a factor of 5.
Because of the stringent flatness requirements of decks on Aircraft Carriers, the patented HyDep Welding process will result in saving the shipyard millions of dollars annually. But, any structural weld, even outside of the shipbuilding industry, will be made with substantially higher productivity and lower cost with the HyDep Welding Process.
Metallurgical testing of welds produced with the HyDep Welding Process have shown that HyDep Welds are sound and meet all of the fairly stringent Navy metallurgical requirements. Consequently, this can process produces welds which meet the requirements of AWS Standards such as D1.1, and others. As required by the standards, all welding procedures must undergo testing as proscribed, before the HyDep Welding process can be used to produce a welded structure.
The published paper and technical presentation, will include images and data showing that the process meets or exceeds multiple welding standards. EnergynTech, Inc. is the only licensed provider of the patented HyDep Welding process systems, and can provide consulting, and procedure development assistance for implementation of the process, and the most efficient implementation in production.
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