During the welding of tanks, chambers and vessels, an uneven root profile can cause product entrapment that may contaminate a process as well as interrupting flow characteristics. Many weld joints require a controlled underbead profile of the first root pass.
Where manual welding cannot control the weld root profile sufficiently, or when an automatic weld process is unable to reach satisfactory speeds while still obtaining satisfactory underbeads, it is common to use a method of backing below the weld. A cost-effective way to provide support for molten metal below a weld joint, is to use Weld Backing Tape.
Huntingdon Fusion Techniques HFT have a range of Backing Tape to support all welding currents, from 80 amps, up to as high as 600 amps, providing the support to produce perfect weld underbeads.
Georgia Gascoyne, CEO for HFT said: “Weld Backing Tape is a glass fibre weld backing system that supports and protects the weld root from oxidation. It will trap the inert gas from the weld torch to hold the gas surrounding the weld pool, effectively providing a back purge facility. We manufacture four grades of Weld Backing Tape for use up to 80, 160, 240 or 600 Amps.”
“Each tape comprises a 3 in. (75mm) wide aluminum adhesive tape backing strip, in the centre of which is a 1 in. (25mm) wide band of woven glass fibre matting running down the centre. The glass fibre matting has differing thicknesses to match the welding current in use.”
“Once the tape is positioned with the glass fibre matting under the centre of the weld joint, the welders can start their arc. The welding torch argon flow has plenty of space to move between the pores of the matting, which allows the welding arc to stabilise and start forming the weld root.”
Using Backing Tape it is possible to weld with MIG, TIG (GTAW) or Plasma (PAW) techniques for the joining of all weldable metals without change to the chemistry or metallurgy of the weld.
Read the article online at: https://www.worldpipelines.com/equipment-and-safety/24052017/hft-improving-weld-root-profiles-with-back-tape/