For many years pipe fabrication have been searching for a faster,easier method to make single-sided low hydrogen open root welds. It is difficult even for skilled welders to weld open root pipe and inflexible positioning makes pipeline welding more difficult, time consuming and expensive.
Higher Strength pipe steels are driving a requirement to achieve a low hydrogen weld metal deposit. GTAW has been only available process capable of achieving the quality requirements but GTAW root welds are very expensive to make. The GMAW process has been avoided because of side-wall fusion and lack of penetration.
Lincoln Electrics has developed and proven the Surface Tension Transfer process to make single-sided root welds on pipe. STT is a patented controlled short-circuit transfer GMAW process made possible by Linchon Electrics exclusive waveform control technology.
STT produces a low hydrogen weld deposit and makes it easier to achieve a high quality root weld in all positions. The STT process as a field proven quality record. STT eliminates the lack of penetration and poor sidewall fusion problems encountered when using the traditional short-arc GMAW process.
Advantages:
Penetration control: Provides reliable root pass, complete back bead and ensured sidewall fusion
3. Low heat input: Reduces burn through, cracking and other weld defects.
4. Low hydrogen weld metal deposit: Hydrogen levels meet the requirements for use on high strength pipe steels
5. High quality open root welds at faster rate travel speed than GTAW
6. Allow operator to control the heat input into the weld puddle
7. Its easy to operate.
Higher Strength pipe steels are driving a requirement to achieve a low hydrogen weld metal deposit. GTAW has been only available process capable of achieving the quality requirements but GTAW root welds are very expensive to make. The GMAW process has been avoided because of side-wall fusion and lack of penetration.
Lincoln Electrics has developed and proven the Surface Tension Transfer process to make single-sided root welds on pipe. STT is a patented controlled short-circuit transfer GMAW process made possible by Linchon Electrics exclusive waveform control technology.
STT produces a low hydrogen weld deposit and makes it easier to achieve a high quality root weld in all positions. The STT process as a field proven quality record. STT eliminates the lack of penetration and poor sidewall fusion problems encountered when using the traditional short-arc GMAW process.
Advantages:
Penetration control: Provides reliable root pass, complete back bead and ensured sidewall fusion
- Cost Reduction: Use 100% CO2 the lowest cost gas, when welding carbon steel
3. Low heat input: Reduces burn through, cracking and other weld defects.
4. Low hydrogen weld metal deposit: Hydrogen levels meet the requirements for use on high strength pipe steels
5. High quality open root welds at faster rate travel speed than GTAW
6. Allow operator to control the heat input into the weld puddle
7. Its easy to operate.
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