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What quality requirements does the packaging steel strip have for the slab for hot-rolled strip steel?
by：Hongmei
2021-03-15
What quality requirements does the packaging steel strip have for the slab for hot-rolled strip steel?
Answer: The quality requirements for slabs for hot-rolled strip steel are as follows:
(1) The chemical composition should meet the requirements of the corresponding steel number standard.
(2) Dimensional deviation. among them:
1) The thickness deviation is ±5.0mm. An excessively large negative difference will reduce the output of the heating furnace and increase the heat energy consumption. Excessive positive difference increases the temperature difference of the section of the slab produced, which is easy to induce
Rolling failure, the control precision of the final rolling temperature of the thin strip steel is reduced; when rolling the limit material of the coil diameter, the unloading operation will be difficult.
2) The width deviation is ±10.0mm. An excessively large negative difference will cause the gap between the furnace slabs to increase, and the corners of the slabs heated at high temperature for a long time will easily produce overheating or overburning; reduce the output of the heating furnace; increase the heat energy consumption. Excessive positive difference can easily induce VSB mill failure and reduce the width accuracy of strip steel.
3) The length deviation is: ±30.0. Excessive deviation affects the amount of cantilever of the slab on the beam in the furnace and scratches the refractory material wrapped on the beam; when the rolling mill is empty, the excessive positive deviation will affect the tracking judgment of the R2 even pass.
(3) Requirements for the shape of the slab. Up and down bends and sickle bends: one row of materials is 50mm; the second row of materials is 25mm. Excessive up-and-down bending affects the positioning of the slab in the furnace; the slab is prone to deviation in the furnace; the downward-bending slab is easy to scratch the refractory material of the furnace inner beam; it affects the bite of the R1 rolling mill. Excessive side bend affects the gap between the slab in the furnace; affects the centering of the strip when passing through the slab; affects the setting of the opening degree of the side guide or scrapes the edge of the strip; induces a sickle bend in the strip and a tower shape in the coil ; Affect the trimming quality of trimmed timber or finished board
The width of the material.
(4) Surface quality requirements. The surface of the slab must not have cracks, corner cracks, pull cracks, scars and inclusions; pores, cracks, scratches, and scratches with a depth of not more than 2.0mm are allowed.
pits and pits, and vibration water ripples with a depth not greater than 4.0mm. The end face of the slab cut shall not have shrinkage holes and visible internal cracks. No more than indentation is allowed on the side of the slab. The surface defects on the side of the slab are allowed to be cleaned, and the cleaning depth shall not be greater than 10mm.
Answer: The quality requirements for slabs for hot-rolled strip steel are as follows:
(1) The chemical composition should meet the requirements of the corresponding steel number standard.
(2) Dimensional deviation. among them:
1) The thickness deviation is ±5.0mm. An excessively large negative difference will reduce the output of the heating furnace and increase the heat energy consumption. Excessive positive difference increases the temperature difference of the section of the slab produced, which is easy to induce
Rolling failure, the control precision of the final rolling temperature of the thin strip steel is reduced; when rolling the limit material of the coil diameter, the unloading operation will be difficult.
2) The width deviation is ±10.0mm. An excessively large negative difference will cause the gap between the furnace slabs to increase, and the corners of the slabs heated at high temperature for a long time will easily produce overheating or overburning; reduce the output of the heating furnace; increase the heat energy consumption. Excessive positive difference can easily induce VSB mill failure and reduce the width accuracy of strip steel.
3) The length deviation is: ±30.0. Excessive deviation affects the amount of cantilever of the slab on the beam in the furnace and scratches the refractory material wrapped on the beam; when the rolling mill is empty, the excessive positive deviation will affect the tracking judgment of the R2 even pass.
(3) Requirements for the shape of the slab. Up and down bends and sickle bends: one row of materials is 50mm; the second row of materials is 25mm. Excessive up-and-down bending affects the positioning of the slab in the furnace; the slab is prone to deviation in the furnace; the downward-bending slab is easy to scratch the refractory material of the furnace inner beam; it affects the bite of the R1 rolling mill. Excessive side bend affects the gap between the slab in the furnace; affects the centering of the strip when passing through the slab; affects the setting of the opening degree of the side guide or scrapes the edge of the strip; induces a sickle bend in the strip and a tower shape in the coil ; Affect the trimming quality of trimmed timber or finished board
The width of the material.
(4) Surface quality requirements. The surface of the slab must not have cracks, corner cracks, pull cracks, scars and inclusions; pores, cracks, scratches, and scratches with a depth of not more than 2.0mm are allowed.
pits and pits, and vibration water ripples with a depth not greater than 4.0mm. The end face of the slab cut shall not have shrinkage holes and visible internal cracks. No more than indentation is allowed on the side of the slab. The surface defects on the side of the slab are allowed to be cleaned, and the cleaning depth shall not be greater than 10mm.
