METHOD FOR WELDING A PROTECTIVE COATING ON THE INNER SURFACE OF A PIPELINE ELBOW Russian patent published in 2023 - IPC B23K9/04 F16L43/00 

FIELD: pipe production.

SUBSTANCE: manufacture of bimetallic curved pipe elements in the form of elbows and bends from heat-resistant steels for superheated steam supply pipelines. The fixed surfacing head is placed inside the elbow in the middle of its bend and the protective coating metal beads are deposited on one half of the elbow from the middle to the end, and after reinstallation, surfacing is carried out on its other half. During surfacing of the protective coating metal bead, the elbow is rotated at the speed of surfacing around the center of its bending to obtain a bead parallel to the longitudinal curvilinear axis of the elbow. After the end of the passage, the elbow is rotated relative to its longitudinal curvilinear axis by the width of the bead, then the elbow is rotated relative to the center of its bend in the opposite direction to the starting point of the fixed surfacing head in the middle of the bend of the elbow, and the surfacing process is repeated until the entire surface of the half of the elbow is filled. When surfacing, pre-welded production rings are used with their subsequent removal. Perform electroslag facing with a strip electrode 25-100 mm wide.

EFFECT: high quality of bimetallic pipe elbows by applying protective anti-corrosion coatings after bending the elbows and their high-temperature heat treatment.

2 cl, 8 dwg