TPT May 2022


Post scarf inspection on tube mills with the Xiris weld inspection system

to measure its depth. In this case, the scarf tool may be less than or equal to the maximum width of the weld bead and may cut too far into the weld bead so that the scarfed surface is below the surface of the edges of the parent material. Like the scarf width defect, this defect can occur if the scarf tool has not been properly set up to remove the right amount of weld bead, or if for some reason the tube height bounces around and the tube gets pushed into the scarfing tool, causing the tool to cut deeper than normal. A scarf cut defect can occur due to flank wear in which the portion of the scarf tool in contact with the welded tube erodes over time sometimes causing a ridge to be left behind in the scarf zone; or as crater wear, in which chips of weld bead erode the rake face of the tool causing an uneven cut surface. When this happens, the effectiveness of the scarfing process is reduced as the resulting scarf surface changes from a clean, smooth cut to a rough surface with ridges left behind by the damaged scarf tool. The scarf defect measurement will measure the largest offset from a nominal surface as a way of indicating how non-smooth the scarfed surface of the tool is. If the scarfing process is not performed properly, the tube may not meet end user customer specifications or can be the primary contributor to creating a leak path on a compression fitting. As a result, tube fabricators must monitor the quality of their scarfing process to meet the expectations of their customers. Does the scarfing tool cut too deeply, or not enough? Is the tool damaged? Is

MEASURING and monitoring the variables in an ERW tube welding process is the first step to controlling and improving weld quality. To do so, tube fabricators can employ laser-based weld inspection systems such as the Xiris WI-2200/3000 weld inspection system, which can be placed after the scarfing process to detect scarf-related defects. Post scarf, the weld inspection system can be used to accurately measure defects such as mismatch, scarf width, scarf depth or a scarf defect. Mismatch is the difference in position of the parent material on either side of the weld seam, as measured by the position of the parent material outside of the scarf area. The uneven joining of the two strip edges of the tube material could be a result of incorrect forming setup, edge break issues or some twisting in the strip feed into the rollers. If mismatch is present, significant thinning of one side of the tube wall following the scarfing process can occur, causing a scarf related issue. Scarf width is a measurement defined as the length of the “flat” portion of the tube that appears after the weld bead has been removed by scarfing. The scarf width can grow larger than desired if the scarf tool has been set up to remove too much material. In addition, sometimes the support rollers used to hold the tube can get dirty with metal chips from the scarfing material and cause the tube to lift when the debris gets caught between the roller and the tube. When this happens, the tube will get pushed into the scarfing tool and remove too much material. Scarf depth is an alternative to measuring the width of the scarf cut is

Scarf width, scarf depth and scarf defect and mismatch

the scarf cut a consistent amount? All these questions can be addressed by installing a weld inspection system after scarfing on the tube mill. Measuring the quality of the scarfing process requires an inspection tool that can deliver precise measurements useful for keeping the tube mill in control. The above defects are just some of the defects that can be monitored to find these defects using an inspection system such as the Xiris WI-2200/3000 weld inspection system.

Xiris Automation

Innovative machines for welding pipes MTC BAMIEH Srl, a company that specialising in supplying coil processing lines, welded pipelines and complete production facilities, has started the production of a new machine to produce decorative pipes and poles. The new machine will produce spiral shapes on already welded pipe or pole, which could be created in two directions to produce diamond effect. MTC Bamieh Srl also MTC Bamieh Srl

produces an automatic pipe packing machine.


MAY 2022

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