If the used high frequency tube mills refers to the chemical composition and mechanical properties of welded tube blanks that require certain inspection methods to be known as invisible defects; then, those defects that can be seen only by vision are called tube blanks. Overt defect.

The dominant defects of the welded tube blank of the used high frequency tube mills generally include cracked edges, broken edges, sawtooth, pitting, scratches, roll marks, dark spots, edge burrs, sickle bends, wrinkles, waves, edge warping, and points. Layers, warped skins, pinholes, sticky rolls, soft spots, rust, oxide layers, towers, loose rolls, etc. Let me introduce you to the causes of cracked edges and the effect of cracked edge billets on welded pipes.

Cracked edge

Edge cracking refers to the existence of fine cracks of different widths on the edge of the tube blank, which mainly occur at the edge of the cold-rolled tube blank, and can be divided into unilateral, bilateral, continuous and intermittent.

Causes of cracked edges:

(1) The edges of hot-rolled steel strips are prone to chemical composition segregation, and the segregated edges are prone to embrittlement during the cold rolling process.

(2) The cold rolling process is unreasonable. The single-pass reduction is too large, resulting in rapid hardening of the sheet and a sharp decrease in elongation. Under the action of subsequent rolling and extension and longitudinal tension, cracks or even cracks occur at the weakest edge of the sheet.

(3) The amount of trimming is too small, and there are still wide or narrow cracks on the edge of the slitting tube.

The influence of cracked edge billet on the production of welded pipe:

(1) During the forming process, the edge cracks of the tube blank will crack under the action of longitudinal tensile stress.

(2) The tightness of the weld cannot be guaranteed.

(3) The weld strength cannot be guaranteed, and it cannot withstand deformations such as bending, flaring, flattening, and flanging.

Regarding the defects of welded pipe blanks of used high-frequency tube mills(1) The introduction of cracked edges and the influence of cracked edges on the quality of welded pipes, I hope it can help you.

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