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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 are the quality requirements for slabs for hot-rolled steel strips for packaging steel strips?
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. An excessively large positive difference increases the temperature difference of the section of the slab produced, which is easy to induce rolling failures, and the control accuracy of the final rolling temperature of the thin strip steel is reduced; when rolling the limit material of the coil diameter, it will cause the unloading operation to 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 ±30.0mm. Excessive deviation affects the cantilever amount of the slab on the beam in the furnace, and scratches the fire-shooting material wrapped on the beam; when the rolling mill is empty, it is too large.
difference will affect the tracking judgment of the draw 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 of the furnace 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 the trimmed timber or the width of the finished sheet.
(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. The side of the slab is allowed to have indentations not greater than 10.0mm. 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. An excessively large positive difference increases the temperature difference of the section of the slab produced, which is easy to induce rolling failures, and the control accuracy of the final rolling temperature of the thin strip steel is reduced; when rolling the limit material of the coil diameter, it will cause the unloading operation to 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 ±30.0mm. Excessive deviation affects the cantilever amount of the slab on the beam in the furnace, and scratches the fire-shooting material wrapped on the beam; when the rolling mill is empty, it is too large.
difference will affect the tracking judgment of the draw 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 of the furnace 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 the trimmed timber or the width of the finished sheet.
(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. The side of the slab is allowed to have indentations not greater than 10.0mm. The surface defects on the side of the slab are allowed to be cleaned, and the cleaning depth shall not be greater than 10mm.
