Tee weld job report
Before turning the welder on I made sure that it was in a safe working condition, this involves checking any connections were secure, checking that there was no live wires showing through the cables and checking that the valve on the gas cylinder was secure.
The material that I used for this job was 1.6mm mild steel sheet, I used two pieces of 50x150mm. The first step in the tee-weld is to tack weld them into place, this involves securing the top plate at a 90 degree angle from the bottom plate. I placed one tack weld in the centre of the plates and then I quickly added a tack onto each end of the material to minimise distortion. After this I then placed small tack welds (small enough so that they will not be seen after the weld has been complete) with equal distances of around 20mm across the length.
Before final welding I checked that the joint was accurate, this involved checking that the plates were square on the ends and that the top piece of material was 90 degrees from the other piece of material. After I have ensured that the tack welds were accurate and that the material was in the correct place for the type of weld I prepared for the final weld. This involved making sure that I had enough filler wire at hand and that I had a sharp tungsten tip. Once I had made these checks, I then began the weld making sure that the heat from the tungsten was split evenly between the two pieces of material so that there would be significant penetration on each piece of material.
After completing the weld with at least one stop and start, I performed visual inspections on the weld to make sure that the uniformity was to standard. I then cut 2 inches from the middle of the weld (including the stop and start) using a band saw so that I could perform the nick-break test. I cut along the weld on this 2 inch section using a hack saw and then began tapping it back and forth until the weld snapped completely. After the weld had broken I was then able to measure for penetration, to do this I measured the marks on the thickness of the material to identify and measure how much penetration had gone into the material.
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Dye-penetrant test
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Destructive test along weld join after break
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The non-destructive test that I carried out on the weld was a dye-penetrant test. This involves using 3 different substances, these are a cleaner, a dye and a developer. The first step is to clean the weld, making sure to remove any dirt and oil. The next step is the application of the dye penetrant for this you spray the dye on the surface of the weld and wait for it to settle into any seams that may be there, you should wait between 5 and 30 minutes for this step. After the dye had settled you can then wipe off any excess on the surface and spray on the developer, the developer draws out the dye to the surface and is white so it makes the red dye very visible so you can easily recognise flaws in the weld.
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Another view of the destructive test for penetration |
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