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Extremely thin cold rolled steel strip flatness defect control measures

Feb 22, 2017

Very thin cold rolled steel strip of high value, but the production is difficult, prone to various problems in the production, product quality improvement. Following reasons easily very thin cold rolled steel strip flatness defect:
1, fluctuation of bending force.
HC reversing cold rolling through six roller bending force improve the Strip shape quality if bending force fluctuations, not conducive to the steel strip flatness control.
2, the heat expansion.
Steel strip rolling process will produce a lot of hot deformation, if roller preheating time too short, this deformation and thermal heat expansion, and altering the original roll to roll type, affecting the shape quality.
3, rolling pressure, not conducive to the adjustment of the shape.
At the time of rolling thin steel coil, view the rolling force, finished product pass rolling pressure exceeds the 7800kN value, leading edge defects.
4, roll the large amount of steel.
With the extension of work roller in rolling mill (steel quantity), between working roll and strip roll wear due to friction, leading roll gap of irregular shape, resulting in defects of plate form.
Control measures:
1, reducing the bending force fluctuations
Hydraulic oil for test of large particulate matter exceeded the filter through the oil filter, precision grade 6 oil. The filter cartridge is replaced, ensure the accuracy of bending roll stand oil. Servo valve zero point deviation using the roll servo valve coil resistance measurements, to replace an excessive resistance. Bending force fluctuations under control, thereby reducing fluctuation of bending force caused by the defects of plate form.
2, improve uniformity of roll thermal expansion
Optimum rolling speed (< 400m/min) and adjustment warm-up time (>25min), roll to achieve uniform thermal expansion effect, improve the quality of the shape.
3, optimal rolling, annealing parameters
Used in production of ultra thin cold rolled steel strip rolling work roll of hardness ≥ 93HSD, 1.0%~2.0% of emulsion concentration of conventional products by rolling up to 1.8%~2.5%. During the second rolling annealing temperature optimization to 640 from 620 ℃ ℃, time 8h.
4, to ensure that the rollers of roller-type precision
950 mill rolling very thin steel with Shi, work roll of had steel volume by original of 80 tons reduced to 60 tons within, Middle roll of had steel volume by original of 120 tons reduced to 100 tons within, production very thin cold rolled steel with Shi support roll roll surface concave pit area Michael Jackson 50mm2, concave pit number not over 3 a, to guarantee roll of roll type precision.