When One Side, the Center, or the Edges Stay Wet
One Wet Edge
A single wet edge gives a clear location signal.
Watch whether the wet area moves when the strip shifts sideways.
If it follows the physical strip edge, inspect:
- edge wave or edge damage;
- camber;
- liquid collecting along that edge;
- the strip entry angle.
If it stays on the same machine side, inspect:
- left-right loading;
- bearing and mounting condition;
- side-to-side roll alignment;
- one-sided drainage;
- local wear or damage on the roll face.
A strip entering the pair at an angle may reach firm contact on one side first. The other side remains slightly open and carries more liquid through.
In that situation, compare the entry path and nearby Guide Rollers before changing the squeeze-roll specification.
Center Wet Band
Look at the strip before it reaches the rolls.
A liquid stream already running through the center can remain visible after squeezing. Correct the incoming liquid distribution first.
When no center stream is present, compare different strip widths and grades.
A band that follows a loose or raised center in the strip points toward strip shape. A band that remains at the machine center and becomes stronger on wider strip points toward weaker middle contact.
At that point, inspect:
- roll bending under load;
- actual working width;
- roll support and bearing condition;
- center-to-end diameter profile;
- recent grinding or roll replacement;
- the loading arrangement across the roll face.
A center band that consistently grows with strip width or loading gives a stronger reason to inspect the squeeze rolls.
Wet Bands Near Both Edges
Wet bands beside the physical strip edges often follow edge wave or open edge contact. Liquid squeezed from the middle may also move outward and collect at the edges.
Compare several strip widths.
If the bands stay beside the physical strip edges, strip shape remains the stronger direction.
If one band stays at the same roll-face position across different widths, inspect that position for:
- a shiny or polished track;
- local wear;
- a groove or cut;
- a local diameter change;
- an old repair.
The wider roller context around pickling, rinsing, guiding, and steel-strip handling is covered on the Steel & Metallurgy Rubber Rollers page.
When the Top and Bottom Differ—or Wet Patches Repeat
One Surface Stays Wetter
The upper and lower strip surfaces may carry different amounts of liquid before they reach the squeeze rolls.
Spray direction, gravity, drainage, tank-exit geometry, and strip path can all create this difference.
Inspect both surfaces immediately before and after each squeeze pair.
If the difference becomes smaller after the pair, that pair is reducing an upstream imbalance.
If a new difference appears after one pair, inspect:
- the upper and lower roll surfaces;
- drainage around each roll;
- strip entry angle;
- splashback or liquid returning after contact;
- local wear or contamination.
Stop at the first pair where the difference appears. Later pairs may only carry the same condition forward.
Periodic Wet Patches
Measure the distance from one wet patch to the next.
Compare that distance with the circumference of every nearby roll that touches the strip.
A close match points toward one angular position on a roll. Turn the roll and inspect the complete circumference for:
- a cut, dent, blister, or raised area;
- one contaminated or polished patch;
- local swelling;
- uneven wear;
- a repaired section;
- diameter variation.
The damaged area may be underneath the roll when the line stops.
When the repeat does not match a roll circumference, make a controlled line-speed change.
A roll-related pattern stays connected to roll rotation. A pump or spray pulse keeps a time cycle, so the distance between wet patches changes with line speed.
