Rolling method for optimizing the surface quality of hot-rolled steel sheets

Abstract

The invention discloses a rolling method for optimizing the surface quality of a hot rolled steel plate, comprising phosphorus removal before continuous casting roughing and roughing control, wherein the total deformation of roughing is 70-85%, and rolling reduction of each pass in roughing control is in progressive increase. By taking the steel surface quality as the factor of influencing load distribution, a load distribution method in which the rolling reduction of each pass in roughing control is in progressive increase is adopted, so that oxide scale thickness is effectively reduced, possibilities of oxide scale press-in and red ironhide can be reduced, the surface quality of a hot rolled steel plate is improved, and steel plate components, tissue uniformity and mechanical property can be ensured while the oxide scale thickness is reduced. According to the method, the rolling power of a rolling mill can be fully utilized on the premise of not influencing the yield of energy consumption, and the method can be widely used in production of hot rolled steel plates. According to the method, additional facility and input are not increased, the investment is low, rapid effect is achieved and the operation is convenient.

Description

Technical field

[0001] The invention relates to a steel rolling process control technology, in particular to a rolling method for optimizing the surface quality of a hot rolled steel sheet. Background technique

[0002] With the development of modern industry, users have higher and higher requirements for the surface quality of steel products. Surface quality defects such as red rust and iron sheet pressing often appear on the surface of hot-rolled products, which seriously hinder the improvement of steel product quality.

[0003] After the hot-rolled slab comes out of the heating furnace, it is rough-rolled after descaling by high-pressure water and other methods. During the rough-rolling process, secondary oxide scale is produced on the surface of the steel plate. The secondary oxide scale has good high-temperature plasticity and is together with the steel plate during rough rolling. Deformation and poor peelability. If the secondary scale cannot be completely removed by sprayin...

Examples

Embodiment 1

[0067] The roughing mill consists of two roughing mills, R1 and R2. R1 is a two-high rolling mill that only rolls one pass, and R2 is a four-high reversible roughing mill with vertical rolls, rolling 7 passes, the largest rolling mill The pressure is 5000t, and the main drive motor capacity is 2×7500kW. The thickness of the continuous casting slab is 200~250mm, the width is 1600mm, the length is 10000mm, the thickness of the intermediate slab is 20~60mm, and the total rough rolling deformation is 85.1%. In the fifth pass, a rough rolling descaling is performed, except for the first pass and the last pass. Except for one pass, the reduction of the remaining passes is controlled to increase linearly from pass to pass. The rolling data of the continuous casting billet of Example 1 in each pass is shown in Table 1.

[0068] Another example of rolling by the conventional rough rolling method is set as Comparative Example 1 of Example 1. First, the continuous casting slab is descaled w...

Embodiment 2

[0076] The roughing mill is a four-high reversing mill with a maximum rolling pressure of 58854kN, a maximum rolling torque of 5493kJ, and a main drive motor capacity of 2×4600kW; the thickness of the continuous casting slab is 200mm, the width is 1550mm, the length is 3100mm, the thickness of the intermediate slab is 60mm, and the width 2600mm.

[0077] First, the continuous casting slab is subjected to conventional descaling; then, the rough rolling is carried out. The rough rolling pass is set to 7 passes. The width of the slab is first cross-rolled to make the width of the slab equal to the width of the steel plate, and then the slab is rolled to the end by 90°, except for the first pass. Except for the last pass, the reduction of each pass is controlled to increase linearly from pass to pass, and the total rough rolling deformation is 70%. The rolling data of the continuous casting billet of Example 2 in each pass is shown in Table 3.

[0078] Another example of rolling by the...

Embodiment 3

[0085] The roughing unit is a semi-continuous roughing mill composed of a two-high irreversible rolling mill and a four-high reversing rolling mill. The work roll diameter of the two-high mill is 1200~1350mm, the maximum rolling pressure is 3000t, and the main drive motor capacity is 2×5000kW; the work roll diameter of the four-high mill is 1100~1200mm, the maximum rolling pressure is 4500t, and the main drive motor The capacity is 2×7500kW; the thickness of the continuous casting slab is 200-250mm, the width is 1400mm, the length is 11900mm, the thickness of the intermediate slab is 38mm, and the width is 1289mm. The total deformation of rough rolling is 84.3%.

[0086] First, the continuous casting billet is subjected to conventional descaling; then, rough rolling is carried out. The rough rolling pass is set to 6 passes, among which, the two-high rolling mill rolls 1 pass, the four-high rolling mill rolls 5 passes, except for the first pass Except for the last pass, the reduc...

Technical field

[0001] The invention relates to a steel rolling process control technology, in particular to a rolling method for optimizing the surface quality of a hot rolled steel sheet. Background technique

[0002] With the development of modern industry, users have higher and higher requirements for the surface quality of steel products. Surface quality defects such as red rust and iron sheet pressing often appear on the surface of hot-rolled products, which seriously hinder the improvement of steel product quality.

[0003] After the hot-rolled slab comes out of the heating furnace, it is rough-rolled after descaling by high-pressure water and other methods. During the rough-rolling process, secondary oxide scale is produced on the surface of the steel plate. The secondary oxide scale has good high-temperature plasticity and is together with the steel plate during rough rolling. Deformation and poor peelability. If the secondary scale cannot be completely removed by sprayin...

Examples

Embodiment 1

[0067] The roughing mill consists of two roughing mills, R1 and R2. R1 is a two-high rolling mill that only rolls one pass, and R2 is a four-high reversible roughing mill with vertical rolls, rolling 7 passes, the largest rolling mill The pressure is 5000t, and the main drive motor capacity is 2×7500kW. The thickness of the continuous casting slab is 200~250mm, the width is 1600mm, the length is 10000mm, the thickness of the intermediate slab is 20~60mm, and the total rough rolling deformation is 85.1%. In the fifth pass, a rough rolling descaling is performed, except for the first pass and the last pass. Except for one pass, the reduction of the remaining passes is controlled to increase linearly from pass to pass. The rolling data of the continuous casting billet of Example 1 in each pass is shown in Table 1.

[0068] Another example of rolling by the conventional rough rolling method is set as Comparative Example 1 of Example 1. First, the continuous casting slab is descaled w...

Embodiment 2

[0076] The roughing mill is a four-high reversing mill with a maximum rolling pressure of 58854kN, a maximum rolling torque of 5493kJ, and a main drive motor capacity of 2×4600kW; the thickness of the continuous casting slab is 200mm, the width is 1550mm, the length is 3100mm, the thickness of the intermediate slab is 60mm, and the width 2600mm.

[0077] First, the continuous casting slab is subjected to conventional descaling; then, the rough rolling is carried out. The rough rolling pass is set to 7 passes. The width of the slab is first cross-rolled to make the width of the slab equal to the width of the steel plate, and then the slab is rolled to the end by 90°, except for the first pass. Except for the last pass, the reduction of each pass is controlled to increase linearly from pass to pass, and the total rough rolling deformation is 70%. The rolling data of the continuous casting billet of Example 2 in each pass is shown in Table 3.

[0078] Another example of rolling by the...

Embodiment 3

[0085] The roughing unit is a semi-continuous roughing mill composed of a two-high irreversible rolling mill and a four-high reversing rolling mill. The work roll diameter of the two-high mill is 1200~1350mm, the maximum rolling pressure is 3000t, and the main drive motor capacity is 2×5000kW; the work roll diameter of the four-high mill is 1100~1200mm, the maximum rolling pressure is 4500t, and the main drive motor The capacity is 2×7500kW; the thickness of the continuous casting slab is 200-250mm, the width is 1400mm, the length is 11900mm, the thickness of the intermediate slab is 38mm, and the width is 1289mm. The total deformation of rough rolling is 84.3%.

[0086] First, the continuous casting billet is subjected to conventional descaling; then, rough rolling is carried out. The rough rolling pass is set to 6 passes, among which, the two-high rolling mill rolls 1 pass, the four-high rolling mill rolls 5 passes, except for the first pass Except for the last pass, the reduc...

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