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This new welding technique is PATENTED and has been successfully applied to several pickle line Combination Flash Butt Welders. The results have been extremely favorable, and on
most grades, weld quality achieved has been comparable to weld quality achieved in low carbon steels. In all grades, quality shows significant improvement over welds made in the conventional manner.
HSLA
steels had been termed "difficult to weld" or "unweldable" since they had a tendency to develop "flat" spots at the interface of the weld which represent a lack of fusion. This
condition is neither uniform nor universal, and in some grades it is more severe than on others.
Taylor-Winfield has found that this condition can be eliminated or minimized through use of a technique
whereby the oxygen in the flash area is depleted through the use of a combustible type gas introduced during the flashing cycle. In addition, a lower overall flashing voltage is utilized.
The result is a
practical, low cost means of improving weld quality with a minimal change to the welder.
A secondary advantage is obtained through the ability to sustain flashing at a lower flashing voltage. This lower
flashing voltage results in a less violent weld with smaller craters during the flashing action and smaller flash particles. Users of this system have witnessed considerable reduction in the flash that adheres to
the die faces.
The combination of oxygen depletion and low voltage flashing are both required to weld many grades of HSLA to insure that the weld interface zone is fully upset without "flat spots".
Therefore, it is mandatory on welders wider than 52" size that the welding transformers be reworked to allow flashing at a lower voltage when using the Oxygen Depletion System.
Our users report that rolling results show significant improvement from this technique.
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