| 摘要 |
A method and apparatus are disclosed for marking hot workpieces which are particularly useful in marking weld defects on hot continuous welded pipe immediately after fabrication. The method involves the application of a controlled flow of glass particles to the workpiece which melt and produce a fusion coating on the workpiece. This glossy fusion coating absorbs the iron scale, penetrates to the base metal and adheres well to the hot workpiece. The coating will remain on the workpiece during cutting, sizing and initial cooling operations. Further cooling causes the coating to crack and expose the base metal leaving a bright metal mark resembling a galvanized surface. An improved glass bead dispensing gun having a modified nozzle and marking tube is used to apply the glass particles. The nozzle and marking tube enables the user to deposit an even flow of glass particles onto the workpiece and shield the gun from the hot workpiece. The gun is preferably designed so that a continuous flow of air can be provided for cooling the nozzle and marking tube and preventing clogging, during non-marking periods.
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