Horizontal bright stripe of galvanized roll

The possibility of horizontal stripes, and their characteristics

DX51D+Z environmental protection passivated galvanized coil head out of horizontal bright stripes, this stripe thick is not easy to determine whether it is crease print, roller print, mill vibration stripes, horizontal stripes, etc., as shown in the figure below:


Learn more product information from defect photos, warranty, brand, specifications, implementation standards, defect morphology, appearance and other aspects, then eliminate other defects from multiple perspectives, and then narrow the scope of possibility from several features.

Defect description

The DX51D+Z zinc-friendly passivating coil has a continuous horizontal bright stripe defect, and only the upper surface has a horizontal bright stripe, the lower surface does not.

Defect possibility analysis

We exclude several possibilities from several aspects:

First, it is impossible to be a crease print, the crease print should appear on the thick specification, and should be in the inner ring, and this is the direct delivery futures, the specification is 0.8*1250, the thickness is relatively thin, the possibility of producing crease print is not large, and the direct delivery, the possibility of rewinding crease print found in the inner ring is not large.In addition, the crease print should be the top and bottom, not a single side.

Second, it is not rolling, flat roll printing, if it is rolling, it should be periodic, and may be rolled out, and the bright streak is a continuous number of a straight 40m, so also excluded.

Third, the mill vibration stripe is not, because this defect is also mostly double-sided, single-sided possibility is very small.

Finally, horizontal streaks produced by the coating spores of the coated passivator are more likely because the two surfaces are coated separately during the coating process, so the single bright streaks are most likely to be produced.If the bright streaks have a raised feel, and if you sandpaper the passivated film, it will disappear with the polishing, that’s very likely.

Can you raise the quality objection?

According to the steel mill enterprise standard, the surface quality grade of FB is allowed to have streaks, among which horizontal streaks also belong to streaks.

Can I use it?

So can we use this 40-meter material?From the perspective of use, if it is the horizontal stripe caused by passivating liquid coating, the uneven coating will not affect the corrosion resistance, but it is not very good-looking, but there is a problem with the single side, the side can be used as the inner surface, or can be used.

Of course, if the passivating liquid is not applied, then another, so we want to see is raised or sunken, raised is passivating liquid is applied too much, sunken should be tested, whether to apply.

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