CN104070073A - Head warping control method for rough rolling in production of hot-rolled steel strips - Google Patents

Abstract

Disclosed is a head warping control method for rough rolling in production of hot-rolled steel strips. Firstly, a lower-rollers electric pressing-up mechanism is adopted, and a rolling line height Delta, namely the height difference between the upper roller face of a lower operating roller of a roller mill and the upper roller faces of the roller beds of the inlet and outlet, is set as (img file = 'DDA00002978950300011.TIF' wi = '318' he = '112' /) in millimeters; h0 and h1 represent the rolled member inlet and the outlet thicknesses respectively in millimeters, and the delta is a rolling line height additional value and ranges from 2 to 10mm; meanwhile, the speed difference between an upper operating roller and the lower operating roller is adjusted, the roller mill speed increment is acquired as (img file = 'DDA00002978950300012.TIF' wi = '462' he = '172' /), d omega is a rotating speed increment in rad/s, and the DW is the diameter of rollers in millimeters. The method has the advantages that the problem of head warping for rough rolling during hot rolling production is optimized, damage to production equipment by head warping is reduced, and production stability is improved.

Description

A kind of hot-strip production roughing head warpage control method

Technical field

The invention belongs to hot-strip production technical field, particularly a kind of hot-strip production roughing head warpage control method.

Background technology

Hot-strip is important steel products, and hot continuous rolling is one of major way of hot-strip production.

In hot-strip production process, especially, in rough rolling process, often there is the head-bent phenomenon of thickness direction in rolled piece, is bent upwards and is conventionally referred to as nose, is bent downwardly as discount.As shown in Figure 1, rolled piece 10 goes out roll 20 and is bent upwards.

Hot rolling production nose and discount problem are very harmful, easily clash into and damage the equipment such as De-scaling box, roller-way when serious, affect production stability.Therefore, hot-strip manufacturer generally comparatively payes attention to nose and discount problem, is one of emphasis of paying close attention in producing.

In the operation of rolling, workpiece front end occurs upwarping or is lower curved, its basic reason is because not identical extensional has occurred the upper and lower surface metal of rolled piece, if the elongation of lower surface metal is greater than the metal elongation of upper surface, the head of rolled piece will there will be and upwarp, otherwise occur lower curved.The elongation gap of rolled piece upper and lower surface metal is larger, and the degree of crook of workpiece front end is also just more serious.

It is many-sided causing the different factor of rolled piece upper and lower surface metal elongation.As rolled piece upper and lower surface metal occurs that the roller footpath of the excessive temperature difference, upper working rolls and lower working rolls is poor, upper working rolls and lower working rolls speed difference, height of rolling line arrange improperly, and rolled piece surface coverage has in residual iron scale or the operation of rolling as roll surface has water clock grease etc., all can cause rolled piece upper and lower surface metal to produce different extensionals and workpiece front end produces bending.

For steel billet in heating furnace, the uneven head warpage issues causing with the top and bottom temperature difference of thickness direction heating, Japan Patent JP08243615A discloses a kind of control method, is to improve the top and bottom temperature difference by controlling the heating and thermal insulation time, thereby controls target nose amount.

In course of hot rolling, the phase transformation, strain inequality and the nose problem that cause due to belt steel thickness direction temperature inequality, Japan Patent JP08318303A and JP05237530A disclose a kind of control method, by adjusting the upper and lower cooling water inflow of inlet of rolling mill, the inhomogeneities of the Temperature Distribution of control thickness direction and phase transformation, strain, thus nose problem improved.

The head warpage issues causing for upper working rolls and lower working rolls roller footpath difference and roll surface state difference, Japan Patent JP2008043982A discloses a kind of control method, it is the warpage situation according to rolled piece, by controlling up-down rollers speed difference and being equipped with brush roll, control roller surface state and differential friction control rolled piece end bending.

For the improper head warpage issues causing of height of rolling line, Chinese patent CN200510110984.X discloses a kind of method, be whether to change and rolled piece supplied materials varied in thickness according to work roll diameter, determine stroke height and the height of rolling line of backing roll below hydraulic cylinder.

Above control method is generally to produce for certain corresponding control method that reason proposes, but in hot rolling production process, the reason that causes workpiece front end warpage is complicated, many-sided.Produce the head warpage issues of rough rolling process in order to improve hot rolling, consider each side influence factor herein, propose a kind of integrated control method.

Summary of the invention

Produce the head warpage issues of rough rolling process slab for hot rolling, the present invention proposes a kind of hot-strip production roughing head warpage control method, a kind of is electronic mechanism, the increase height of rolling line annex value of pressing by adopting lower roll, and regulate the integrated approach such as upper working rolls and lower working rolls roller speed is poor, to improve hot rolling production roughing head warpage issues, reduce the infringement of head warpage to production equipment, improve production stability.

For achieving the above object, technical scheme of the present invention is:

A kind of hot-strip production roughing head warpage control method, first, adopting lower roll is the electronic mechanism that presses, and sets a height of rolling line Δ, and height of rolling line Δ refers to the upper roll surface and the difference in height that enters, exports roller-way top roll face of milling train bottom working roll, and it is:

$\mathrm{\Δ}=\frac{h_0-h_1}{2}+\mathrm{\δ}---\left(1\right)$

In formula, Δ is height of rolling line, mm; h ₀and h ₁represent respectively rolled piece entrance and exit thickness, mm, δ is height of rolling line added value, mm; δ value is 2～10mm;

Simultaneously, speed between adjustment upper working rolls and lower working rolls is poor, the rotating speed that passes through to improve the rotating speed of a rolled piece elongation working roll less than normal or reduce a rolled piece elongation working roll bigger than normal, make rolled piece upper and lower surface obtain identical or close elongation, thereby reach the object of the bending that prevents workpiece front end; Rotating speed raising amount is relevant with height of rolling line added value and the roller diameter of increase, and milling train rotating speed raising amount is as follows:

$\mathrm{d\ω}=\frac{4v_0\mathrm{\δ}}{D_W(\frac{h_0-h_1}{2}-\mathrm{\δ})}---\left(2\right)$

In formula, d ω is rotating speed raising amount, unit: rad/s, D _wfor roller diameter, unit: mm.

In hot-strip production roughing head warpage integrated control method of the present invention:

(1) adopting lower roll is the electronic mechanism that presses, and increases a height of rolling line annex value, and height of rolling line Δ refers to the upper roll surface and the difference in height that enters, exports roller-way top roll face of milling train bottom working roll.

The conventional method that regulates height of rolling line is adjust lower support roll backing plate and join roller, and this method can only be similar to and ensure that height of rolling line is in certain zone of reasonableness, but can not ensure the generation of head warpage.For this reason, it is the electronic mechanism that presses that the present invention adopts lower roll, and this mechanism can arrange the desired height of rolling line of each passage easily, while also having avoided roll change, will ensure the trouble that rolling height brings by the backing plate group of the various respective thickness of each roller footpath size configure.

In the operation of rolling, just can ensure that rolled piece upper and lower surface obtains equal or close deflection as long as height of rolling line equals the half that rolled piece enters, exit thickness is poor, thereby avoid due to the unreasonable generation workpiece front end of height of rolling line warpage.

But in actual production, due to Action of Gravity Field and vibration, one section of slab of not nipped easily swings, and breast roll is produced and impacted.Therefore, in order to prevent in the operation of rolling, the swing of one section of slab of not nipped produces excessive impact to breast roll, the present invention is except meeting above-mentioned condition, a height of rolling line added value δ of extra increase, δ value can determine according to process conditions such as slab material, thickness, deflections, generally rule of thumb be taken as 2～10mm.

(2) by adjusting the poor control head of the speed warpage between upper working rolls and lower working rolls

Height of rolling line increases an added value can cause the lower curved of workpiece front end trace, and this method that can slightly improve bottom working roll rotating speed makes up.In addition, can make up by the speed difference between suitable adjustment upper working rolls and lower working rolls the head warpage that other various factors bring, the rotating speed that passes through to improve the rotating speed of a rolled piece elongation working roll less than normal or reduce a rolled piece elongation working roll bigger than normal, make rolled piece upper and lower surface obtain identical or close elongation, thereby reach the object of the bending that prevents workpiece front end.This is a kind of effective measures.

Beneficial effect of the present invention:

In steel hot-strip is produced, especially, in rough rolling process, the often head warpage issues with steel, brings adverse effect to device security and production stability, must be controlled.Consider each side influence factor herein, propose a kind of integrated control method, for improving Curling at Front End of Hot Rolled Steel Strip problem, in practical application, received good result, significantly reduced the generation of head warpage.

Brief description of the drawings

Fig. 1 is hot rolling nose schematic diagram in hot-strip production process.

Fig. 2 is height of rolling line schematic diagram of the present invention.

Detailed description of the invention

Referring to Fig. 2, rolled piece 10 enters upper and lower working roll 1,2 by inlet roller way 3, is exported by outlet roller-way 4, and upper and lower working roll 1,2 is upper lower support roll 5,6 up and down.

Hot-strip production roughing head warpage control method of the present invention, first, adopting lower roll is the electronic mechanism that presses, and sets a height of rolling line Δ, height of rolling line Δ refers to the upper roll surface and the difference in height that enters, exports roll surface on roller-way 3,4 of milling train bottom working roll 2, and it is:

$\mathrm{\Δ}=\frac{h_0-h_1}{2}+\mathrm{\δ}---\left(1\right)$

In formula, Δ is height of rolling line, mm; h ₀and h ₁represent respectively rolled piece entrance and exit thickness, mm, δ is height of rolling line added value, mm; δ value is 2～10mm;

Simultaneously, speed between adjustment upper working rolls and lower working rolls 1,2 is poor, the rotating speed that passes through to improve the rotating speed of a rolled piece elongation working roll less than normal or reduce a rolled piece elongation working roll bigger than normal, make rolled piece upper and lower surface obtain identical or close elongation, thereby reach the object of the bending that prevents workpiece front end; Rotating speed raising amount is relevant with height of rolling line added value and the roller diameter of increase, and milling train rotating speed raising amount is as follows:

$\mathrm{d\ω}=\frac{4v_0\mathrm{\δ}}{D_W(\frac{h_0-h_1}{2}-\mathrm{\δ})}---\left(2\right)$

In formula, d ω is rotating speed raising amount, unit: rad/s, D _wfor roller diameter, unit: mm.

Embodiment mono-

To certain passage rough rolling process, inlet thickness 87.4mm, exit thickness 59.2mm, roller diameter 1015.0mm, mill speed 2.1m/s.

According to said method, getting height of rolling line added value is 3.0mm, can calculate height of rolling line:

$\mathrm{\Δ}=\frac{h_0-h_1}{2}+\mathrm{\δ}=\frac{87.4-59.2}{2}+3.0=17.1\left(\mathrm{mm}\right)$

Rotating speed raising amount:

$\mathrm{d\ω}=\frac{4v_0\mathrm{\δ}}{D_W(\frac{h_0-h_1}{2}-\mathrm{\δ})}$

$=\frac{4\×2.1\×3.0}{1015.0\×(\frac{87.4-59.2}{2}-3.0)}=0.002237(\mathrm{rad}/s)$

Embodiment bis-

To certain passage rough rolling process, inlet thickness 57.3mm, exit thickness 40.0mm, roller diameter 1015.0mm, mill speed 2.4m/s.

According to said method, getting height of rolling line added value is 2mm, can calculate height of rolling line:

$\mathrm{\Δ}=\frac{h_0-h_1}{2}+\mathrm{\δ}=10.65\left(\mathrm{mm}\right)$

Rotating speed raising amount:

$\mathrm{d\ω}=\frac{4v_0\mathrm{\δ}}{D_W(\frac{h_0-h_1}{2}-\mathrm{\δ})}=0.002608(\mathrm{rad}/s).$

Embodiment tri-

To certain passage rough rolling process, inlet thickness 160.7mm, exit thickness 119.4mm, roller diameter 1015.0mm, mill speed 1.8m/s.

According to said method, getting height of rolling line added value is 4.0mm, can calculate height of rolling line:

$\mathrm{\Δ}=\frac{h_0-h_1}{2}+\mathrm{\δ}=24.65\left(\mathrm{mm}\right)$

Rotating speed raising amount:

$\mathrm{d\ω}=\frac{4v_0\mathrm{\δ}}{D_W(\frac{h_0-h_1}{2}-\mathrm{\δ})}=0.001704(\mathrm{rad}/s).$

Claims (1)

1. a hot-strip production roughing head warpage control method, first, adopting lower roll is the electronic mechanism that presses, and sets a height of rolling line Δ, and height of rolling line Δ refers to the upper roll surface and the difference in height that enters, exports roller-way top roll face of milling train bottom working roll, and it is:

$\mathrm{\Δ}=\frac{h_0-h_1}{2}+\mathrm{\δ}---\left(1\right)$

In formula, Δ is height of rolling line, unit: mm; h ₀and h ₁represent respectively rolled piece entrance and exit thickness, unit: mm, δ is height of rolling line added value, unit: mm; δ value is 2～10mm;

Simultaneously, speed between adjustment upper working rolls and lower working rolls is poor, the rotating speed that passes through to improve the rotating speed of a rolled piece elongation working roll less than normal or reduce a rolled piece elongation working roll bigger than normal, make rolled piece upper and lower surface obtain identical or close elongation, thereby reach the object of the bending that prevents workpiece front end; Rotating speed raising amount is relevant with height of rolling line added value and the roller diameter of increase, and milling train rotating speed raising amount is as follows:

$\mathrm{d\ω}=\frac{4v_0\mathrm{\δ}}{D_W(\frac{h_0-h_1}{2}-\mathrm{\δ})}---\left(2\right)$

In formula, d ω is rotating speed raising amount, unit: rad/s, D _wfor roller diameter, unit: mm.