Test methods for spiral submerged arc welding pipe
Metallographic Metallographic method (or etching method) is polished bead cross-section, showing the inside and outside weld bead after welding performed partial measurement method. Showing that the method can be intuitively apparent bead offset, which can easily be welded deviating measurements. Metallographic welding deviating measurements each pipe manufacturers actually used, and can be summarized in three centerline method, arc deviation method and ridge line method.
Centerline on the sampling method can block containing bead, polished bead profile, weld deviating measured under an optical microscope; you can also use 5% (by volume) in the steel pipe end flat after nital wipe containing welding Road site, clearly show the weld bead after partial measurement. Inside, from the outside bead toe is the welding wire centerline partial amount.
The method generally arc deviation method after welding shop inspection post or carried out the final inspection posts, may, after etching outlined arc weld bead profile weld partial measurement of the amount over the top of the arc after the draw vertical lines, also You can use the optical microscope welding deviating measurements. Inner and outer bead wire through the arc and weld toe from the vertical line is the welding of the partial amount.
Ridge line method which is the use of distance measuring crystal bead inside and outside the ridge line to measure the amount of internal and external weld bead bias in double wire or wire welding, the straight ridge line is not the rule many times, so in Drag actual application of this method of measurement is less, crystal bead and outside the ridge line is the welding deviating distance.