KR101412838B1 - Continuous rolling apparatus and continuous rolling method of stainless steel - Google Patents

Abstract

The present invention relates to a rolling stand comprising two or more rolling stands each including a final rolling stand for rolling a stainless steel, A rolling oil supply unit for supplying rolling oil to the rolling roll at the entrance and exit of the rolling stand; And a temperature measuring unit disposed on an outgoing side of the rolling stand and measuring a temperature of an outgoing side of the rolling stand, wherein an output temperature of the rolling stand disposed before the final rolling stand has a heat stroke on the surface of the stainless steel Which is not lower than the rolling-finishing temperature.

Description

Technical Field [0001] The present invention relates to a continuous rolling apparatus and a continuous rolling method of stainless steel,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous rolling apparatus for a stainless steel and a continuous rolling method for stainless steel. More particularly, the present invention relates to a continuous rolling apparatus for a stainless steel, The present invention relates to a continuous rolling apparatus of stainless steel and a continuous rolling method of stainless steel capable of producing stainless steel satisfying both excellent surface gloss quality and high productivity by setting the rolling speed and rolling.

Typically, the deformation resistance is large stainless steel has a diameter of Zen Jimmy air mill represented using a multi-roll mills of 40mm to 120mm blind is and rolling path reciprocating rolling, 7mm ² / s to 10mm when rolling the stainless steel ² / s (@ 40 ℃) mineral oil kneading rolling oil or emulsion oil is used as the rolling oil. The rolling process using the above-mentioned small roll multi-roll mill using the other pass reciprocating rolling may be suitable for small-scale production of various kinds of products. However, in the case of small-sized small-quantity production, productivity is low.

Accordingly, various studies have been conducted to solve this problem. One of them has been developed a continuous rolling process for cold rolling a stainless steel at a high productivity. At this time, the stainless steel is rolled by disposing a small-diameter Jens miller . On the other hand, in order to pressurize the stainless steel at high speed, emulsion oil having lubricating and cooling properties is used as the rolling oil, but there is still a problem in realizing high gloss surface quality and high speed rolling simultaneously.

Further, in order to continuously perform the rolling of the stainless steel, two to six, preferably four, large-diameter Z-Hi mills having a working roll diameter of 130 mm to 150 mm in diameter are used instead of Zen- And a continuous process of rolling stainless steel using a mineral oil knife oil as a rolling oil has been developed. On the other hand, when continuously rolling a stainless steel made of paper-milled paper-high mill, the working roll diameter is larger than that of Zenjimi millet, and the surface gloss of the stainless steel is maintained due to restrictions on the number of rolling stands constituting the tandem mill The reduction rate and the rolling speed that can be applied in one pass are performed at a low level. In addition, there are restrictions on the type and size of stainless steel that can be rolled by using a tandem rolling machine of stainless steel. Especially, in the case of rolling speed, existing multi-pass reciprocating rolling mills have a degree of freedom While the tandem rolling mill determines the rolling speed of the preceding rolling stand by the continuity of the exit pressure of the final rolling stand, so that the advantages of the tandem rolling mill for high speed rolling can not be achieved. Indeed, such tandem rolling mills are used for steel grades of which the surface quality is not so strict, with a total reduction of about 60% and a maximum rolling speed of about 250 mpm.

Further, in order to supplement the lubrication and cooling performance in the continuous rolling of stainless steel using a tandem rolling mill in which a large amount of mineral oil low-viscosity rolling oil is injected, the injection flow rate of the mineral oil low viscosity rolling oil is increased, And a method of performing plate cooling. However, the effect of this is small.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a continuous rolling apparatus of stainless steel capable of continuously rolling stainless steels of various kinds and sizes.

Another object of the present invention is to provide a continuous rolling method of stainless steel capable of producing stainless steel having excellent surface quality with high productivity.

According to an aspect of the present invention for achieving the above object, the present invention provides a rolling stand comprising a rolling roll for rolling stainless steel, each of the rolling stand including a final rolling stand; A rolling oil supply unit for supplying rolling oil to the rolling roll at the entrance and exit of the rolling stand; And a temperature measuring unit disposed on the exit side of the rolling stand and measuring a temperature of the exit side of the rolling stand, wherein the temperature at the exit of the rolling stand disposed before the final rolling stand is a temperature on the surface of the stainless steel And a continuous rolling apparatus of a stainless steel which is not higher than a rolling limit temperature at which heat stroke does not occur.

The maximum rolling speed of the final rolling stand may be controlled to be less than 250 mpm and preferably not less than 100 mpm and not more than 230 mpm so that the temperature of the stainless steel measured by the temperature measuring part is not more than the rolling limit temperature.

The rolling limit temperature may be 105 캜 or less.

The temperature measuring unit includes a temperature sensing unit for contacting or measuring the temperature of the stainless steel on the outside of the rolling stand, a temperature controller for collecting and analyzing data from the temperature sensing unit, And a temperature measurement line to connect the temperature measurement line.

The stainless steel continuous rolling apparatus may further include a return tank for collecting the used rolling oil supplied to the rolling stand, and a filtering unit for filtering the rolling oil collected in the return tank.

The rolling oil passes through the filtration part, is recovered to the rolling oil supply part, and then supplied to the inlet side and the outlet side of the rolling stand to be reused.

The rolling roll comprises a paper-hummer having a diameter of 130 mm to 150 mm, and the viscosity of the rolling oil may be 15 mm ² / s to 20 mm ² / s (40 ° C).

The rolling oil may be the only mineral oil-based rolling mill having a flash point of 200 ° C or higher and a saponification degree of 20 mg KOH / mg to 40 mg KOH / mg or higher.

According to another embodiment of the present invention, there is provided a method of cold-rolling a stainless steel with two or more rolling stands each including a rolling roll and sequentially equipped with a final rolling stand, A first continuous rolling step of passing rolling oil through the stand from a rolling oil supply portion at the entrance and exit of the rolling stand to the rolling roll and rolling the same; A second continuous rolling step of passing the stainless steel subjected to the first continuous rolling step through at least two rolling stands to supply the rolling oil and re-rolling the same; And a temperature measurement step of measuring a temperature of the exit side of the rolling stand with a temperature measurement unit having a temperature measurement device disposed on the exit side of the rolling stand, wherein the temperature of the exit side of the rolling stand, And a continuous rolling method of a stainless steel for controlling the surface of the stainless steel so as to be at or below the rolling limit temperature at which heat stroke does not occur.

In the temperature measurement step, the maximum rolling speed of the final rolling stand may be controlled to be 250 mpm or less, preferably 100 mpm or more and 230 mpm or less so that the outlet temperature of the rolling stand is below the rolling limit temperature.

The rolling limit temperature may be 105 캜 or less.

The temperature measuring unit may include a temperature sensing unit for measuring temperature by being in contact with or surrounding the stainless steel on the side of the rolling stand, a temperature control unit for collecting and analyzing data from the temperature sensing unit, And a temperature measurement line to connect the temperature measurement line.

In the step of measuring the temperature at the exit of the rolling stand, the temperature measuring unit may be placed in contact with or surrounding the stainless steel on the side of the rolling stand to measure the temperature of the stainless steel.

In the step of measuring the output temperature of the rolling stand, the temperature measuring unit may measure the temperature of the stainless steel by indirectly measuring radiant heat from the stainless steel using a laser device.

In the first continuous rolling step or the second continuous rolling step, the rolling oil supplied to the rolling stand may be collected in a return tank and then filtered through a filtering part.

The rolling oil passed through the filtration unit can be supplied to the inlet side and the outlet side of the rolling stand and reused.

The rolling roll comprises a paper-hummer having a diameter of 130 mm to 150 mm, and the viscosity of the rolling oil may be 15 mm ² / s to 20 mm ² / s (40 ° C).

The rolling oil may be the only mineral oil-based rolling mill having a flash point of 200 ° C or higher and a saponification degree of 20 mg KOH / mg to 40 mg KOH / mg or higher.

As described above, according to the present invention, in order to prevent heat streak in high-speed rolling, by setting and rolling the maximum rolling speed so that the outlet temperature of each rolling stand does not exceed the rolling limit temperature, It is possible to provide a continuous rolling apparatus of stainless steel capable of continuously rolling a stainless steel.

Further, according to the present invention, it is possible to provide a continuous rolling method of stainless steel capable of producing stainless steel excellent in surface quality with high productivity.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a continuous rolling apparatus of a stainless steel according to an embodiment of the present invention. Fig.
2 is a graph showing the relationship between the temperature at the exit of the rolling stand and the heat streak.
3 is a graph showing the relationship between the rolling speed of the rolling stand and the area ratio of oil pits.

The details of other embodiments are included in the detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described below, but may be embodied in various forms. In the following description, it is assumed that a part is connected to another part, But also includes a case in which other elements are electrically connected to each other in the middle thereof. In the drawings, parts not relating to the present invention are omitted for clarity of description, and like parts are denoted by the same reference numerals throughout the specification.

In the tandem cold rolling of ferritic stainless steels represented by 430 steel, low-speed rolling is inevitable in order to secure surface gloss, but in low-speed rolling, the productivity of tandem rolling is extremely lowered. That is, high-speed rolling is preferable.

However, in high-speed rolling by continuous rolling of ferritic stainless steel, fatal heat streak occurs in the cold rolling of the 400-series steel due to friction heat, thereby adversely affecting the gloss quality of the surface.

In particular, since the surface quality level has the greatest influence on the final rolling pass in the final rolling round, the rolling of the ferritic stainless steel cold-rolled steel sheet having a high gloss surface quality by the tandem rolling method has the greatest effect. It is common to carry out the final finishing rolling by lowering the roll exchanging and rolling speed. However, in the tandem rolling, since the working speed of the final stand is determined by the working speed of the entire continuous rolling mill, there is a problem in that rolling productivity is significantly lowered in the milling work.

However, in high-speed rolling of a stainless steel by a small-diameter multi-roll reciprocating mill, the oil pit increases due to an increase in the thickness of the oil film due to an increase in the flow rate introduced into the roll bite, In tandem rolling with Hi mill, we found that the fraction of oil pits with speed decreased continuously with monotonous increase with increasing rolling speed, and the heatstroke progressed with increasing plate temperature at any rolling speed.

The reduction rate is controlled so that the temperature on the outside of each stand of the cold tandem rolling mill made up of a plurality of stands is equal to or lower than a predetermined heatstreak generation threshold temperature Th by a rolling schedule determination method in a normal cold- , There is a cold rolling method for preventing the generation of heatstreaks, but it is necessary to increase the rolling speed at the set rolling reduction rate.

Generally, in the tandem cold rolling, the rolling speed becomes faster as the thickness of the final stainless steel becomes thinner. In the secondary tandem rolling, the rolling speed becomes faster as the rolling is performed from the intermediate thickness to the final finish rolling thickness . However, in tandem cold rolling of stainless steel, since it is necessary to secure not only the final thickness of the material but also the surface gloss, it is necessary to work at a lower speed even in the case of rolling. This type of operation significantly hinders the productivity of the tandem rolling system, so measures are needed to ensure surface gloss while achieving high speed without sacrificing speed.

Conventionally, in order to solve such a problem, a method of applying a lubricant-free rolling or a tungsten carbide roll to a final stand has been suggested, but a fundamental solution has not been made.

The present invention provides a method for continuously rolling a cold-rolled steel sheet which solves such a process problem and has an excellent surface gloss equal to or higher than that obtained in a conventional low-caliber Zenchimi mill with high productivity.

In cold rolling of stainless steel, it is general to aim at faithful transfer of roll roughness by reducing the thickness of the oil film between the roll and the pressurized strip by minimizing the amount of lubricant in the rolling oil flowing into the roll in terms of securing the surface gloss, Low-speed rolling in the rolling step is indispensable.

As described above, in order to ensure surface gloss, the rolling speed is lowered in spite of the decrease in productivity in the finish rolling step. When the rolling speed is increased, the oil pit fraction is increased when the film thickness sucked into the roll becomes thicker And as a result, the surface gloss significantly decreases.

This rolling zone is known to occur due to the dynamic pressure effect of the rolling oil in the mixed lubrication region. However, in the case of tandem rolling of Chongqing roll mill-Z mill (Hi-mill), since the amount of rolling per one stand is larger than that at the time of Zenji mill roll milling and the rolling mill is relatively low in speed, The fluid lubrication effect can not be expected, and consequently, it depends on the static pressure lubrication effect.

Therefore, in this region, the boundary lubrication region is further increased as the rolling speed is increased, which ultimately leads to a rise in temperature and a heat streak due to the breakage of the oil film.

Accordingly, in the continuous rolling of stainless steel by a medium-diameter roll having a diameter of 130 mm to 150 mm, the temperature of the exit side plate of each rolling stand, particularly the temperature of the exit side plate of the second stand, seems to be correlated with generation of heatstreak. Thus, it can be seen that rolling at a rolling speed below the critical rolling speed at which the heatstreak occurs at each rolling speed condition enables rolling without heat stroke.

In the present invention, in the continuous rolling of stainless steel, the temperature of each stand plate in the set rolling pass schedule is measured, and the temperature (Th) at which the heatstreak is generated according to the rolling speed is derived, Is defined as a limit speed Vc. The rolling limit speed for each rolling condition is derived from the cold rolling temperature model for calculating frictional heat due to plastic deformation heat and friction, and rolling is performed at a speed lower than the rolling limit speed.

Particularly, in the present invention, in case of cold-rolling a stainless steel cold-rolled steel sheet in a continuous rolling mill composed of a plurality of paper-high mills having an operating roll diameter of 130 mm to 150 mm, the rolling load, the rolling roll peripheral speed, The input and output tensile strengths and thicknesses of the incoming and outgoing plates of the rolling mill are measured and calculated to obtain the frictional coefficient and the deformation resistance of the material on the basis of the data and the rolling conditions such as working roll diameter and plate width, After the maximum temperature is calculated, rolling is performed at a temperature lower than the limit value obtained from the above-described measurement and formula.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

1 is a schematic view of a continuous rolling apparatus of stainless steel according to an embodiment of the present invention.

The continuous rolling apparatus 100 according to the preferred embodiment of the present invention is provided with a rolling roll 111 for rolling stainless steel S and includes a fourth rolling stand 110d as a final rolling stand, A rolling stand 110; A rolling oil supply unit 120 for supplying rolling oil o to the rolling roll 111 at the entrance and exit of the rolling stand 110; And a temperature measuring unit (130) having a temperature measuring device (135) for measuring the temperature of the exit side of the rolling stand (110), wherein the rolling stand (110a, 110b, 110c) is 105 占 폚 or less, which is the rolling limit temperature at which no heatstreak is generated on the surface of the stainless steel (S).

In the continuous rolling apparatus 100 for the stainless steel S, the number of the rolling stands 110 may be two or more and six or less. In this embodiment, the rolling stands 110 are described as four, It is not. The rolling stand 110 may include first through fourth rolling stands 110a, 110b, 110c and 110d which are sequentially provided, and the first to fourth rolling stands 110a, 110b, 110c and 110d, Rolling rolls 111 are provided to continuously perform the continuous rolling of the stainless steel S passing through the first to fourth rolling stands 110a, 110b, 110c and 110d at a predetermined reduction rate and rolling speed. The rolling roll 111 may be provided on the upper and lower portions of the stainless steel S so as to roll the stainless steel S. For example, the rolling roll 111 may have a diameter of f130 to 150 mm, And a mill (Z-hi mill). One or more reels 10 may be provided to wind or rewind the stainless steel S with the rolling stand 110 interposed therebetween. A welder 20 and a looper 30 are provided at the front end of the first rolling stand 110 to facilitate continuous rolling of the stainless steel S. Here, the welder 30 joins the leading end of the preceding stainless steel (S) coil with the leading end of the preceding stainless steel (S) coil. The bonded stainless steel (S) coil is sent to the looper 40, which buffers or absorbs speed variations across the continuous rolling apparatus 100 to prevent flexing of the stainless steel (S) coil .

The rolling oil supply unit 120 may supply the rolling oil o to the rolling roll 111 at the entrance and exit of the rolling stand 110. The rolling oil supply unit 120 includes a rolling oil tank 121 in which the rolling oil o is stored and a rolling oil transfer line 123 connected to the rolling oil tank 121 to supply the rolling oil o to the rolling stand 110 . The rolling oil transfer line 123 is composed of four first to fourth rolling oil transfer lines 123a, 123b, 123c and 123d to be connected to the first to fourth rolling stands 110a, 110b, 110c and 110d, respectively. . The rolling oil transfer line 123 is provided with a rolling oil pump 122 to control the injection flow rate and the like of the rolling oil o. The rolling oil spraying part 124 is provided at one end of the rolling oil transferring line 123 and the rolling oil spraying part 124 is disposed inside the first to fourth rolling stands 110a, 110b, 110c and 110d The rolling oil o can be supplied to the inlet side and the outlet side of the rolling roll 111, respectively.

The stainless steel continuous rolling apparatus 100 includes a return tank 140 for collecting the used rolling oil o supplied to the rolling stand 110 and a rolling tank 140 for filtering the rolling oil o collected in the return tank 140, And a filtering unit 150 for filtering the input signal. The rolling oil o passes through the filtration unit 150 and is recovered to the rolling oil supply unit 110 and then supplied to the inlet and the outlet of the rolling stand 110 to be reused. Here, the rolling oil o can be collected by the return tank 140, and after the contamination is removed through the filtration unit 150, the rolling oil o can be reused to reduce the process ratio. The rolling oil transfer line 123d is provided with a rolling oil valve 125 and a rolling oil pump 122 to control the injection flow rate of the rolling oil o.

A temperature measuring unit 130 may be disposed on the exit side of the rolling stand. The temperature measuring unit 130 measures the temperature of the exit side of the rolling stand 110. The temperature measuring unit 130 includes a temperature sensing unit 131 for contacting or measuring the temperature of the stainless steel S on the exit side of the rolling stand 110 and for sensing data from the temperature sensing unit 131 And a temperature measurement line 132 connecting the temperature sensing unit 131 and the temperature control unit 135. The temperature control unit 135 may be a temperature sensor, The temperature sensing unit 131 may include first to fourth temperature sensing units 131a, 131b, 131c and 131d. The temperature sensing line 132 may include first to fourth temperature sensing units 131a, 132b, 132c, and 132d so as to connect the first temperature measurement units 131a, 131b, 131c, and 131d and the temperature control unit 135, respectively.

Here, the viscosity of the rolling oil o may be 15 mm ² / s to 20 mm ² / s (40 ° C). When the viscosity of the rolling oil (o) is less than 15 mm ² / s, the rolling efficiency of the stainless steel (S) can be lowered. When the viscosity of the rolling oil (o) is more than 20 mm ² / While it is difficult to secure the surface gloss of the stainless steel (S). The rolling oil (o) is preferably a mineral oil-based rolling oil having a flash point of 200 ° C or higher and a saponification degree of 20 mgOH / mg to 40 mgOH / mg or higher. The rolling oil o may be injected between the rolling roll 111 and the stainless steel S at the inlet and outlet of each rolling stand 110 at a rolling flow rate of 1000 lpm / stand to 5000 lpm / stand.

It is preferable that the maximum rolling speed of the final rolling stand 131d is controlled to be less than 250 mpm so that the temperature of the stainless steel S measured by the temperature measuring unit 130 becomes 105 [ It is more preferable to control it to be not less than 100 mpm and not more than 230 mpm.

2 is a graph showing the relationship between the temperature at the exit of the rolling stand and the heat streak.

Since the temperature of the outgoing stainless steel S of the rolling stand 131 of the stainless steel S is highly correlated with the occurrence of heat streak, the rolling limit speed, that is, the maximum rolling speed is set do.

Referring to FIG. 2 and Tables 1 to 4, in order to control the temperature of the outgoing stainless steel S of the rolling stand 131 to 105 占 폚 or less which is the rolling limit temperature, the maximum rolling speed of the final rolling stand 131d Is preferably controlled to be less than 250 mpm, and more preferably controlled to be not less than 100 mpm and not more than 230 mpm.

In the following Tables 1 to 4, a temperature sensing unit 131 capable of measuring the temperature of the stainless steel S was installed on the exit side of the rolling stand 131 to measure the occurrence of heat stroke according to the rolling speed. As a result, when the temperature of the outgoing stainless steel S of the specific rolling stand 131 exceeded the rolling limit temperature of 105 占 폚, heat stroke occurred.

3 is a graph showing the relationship between the rolling speed of the rolling stand and the oil pit area ratio.

On the other hand, it can be seen that the boundary lubrication area becomes more severe when the surface quality of the stainless steel (S) with the increase of the rolling speed keeps the occupancy rate of the oil pit constantly low. As a result, when the rolling speed is higher than the rolling speed, it is judged that the oil film of the rolling oil (o, see FIG. 1) in the roll 124 of the rolling stand 131 is broken and heat stroke is generated on the surface of the stainless steel S . Therefore, it is preferable to reduce the maximum rolling speed to below the rolling limit temperature at which the heatstreak is generated on the surface of the stainless steel (S) to 105 DEG C, thereby rolling the stainless steel (S).

The maximum interface temperature Tdmax (占 폚) of the stainless steel S in the rolling stand 131 roll 124 is obtained as follows.

The maximum interface temperature (Tdmax (占 폚)) increased by the strain heat is expressed by the following equation (1).

Where, r _{p is the} density of the stainless steel, C _{p is} the specific heat of the stainless steel, l _p , l _r is the thermal conductivity of the stainless steel and roll, a _p , a _r is the thermal diffusivity of the stainless steel and roll, and L is the contact length.

The maximum interface temperature Tdmax (占 폚) increased by the frictional heat is expressed by the following equations 2 and 3.

Here, q _{fm is an} average frictional heat, and Dv is an average relative sliding speed.

Where Pm is the average rolling pressure.

The maximum temperature (T) at the interface of the stainless steel (S) in the roll 124 of the rolling stand 131 is given by Equation 4 below.

However, since it is difficult to actually measure the temperature rise in the roll 124 of the rolling stand 131, the temperature of the stainless steel S on the exit side of the roll 124 of the rolling stand 131 is measured, The temperature inside the heat exchanger 124 is inversely calculated as shown in Equation 5 below.

Here, T _EX: panchul side temperature, T _EN: plate inlet temperature, T _C: rolling oil temperature, Tx: distance from the rolling stand, the roll exit side (x = 0 is a rolling stand roll exit side), r: density of the strip, S: The specific heat of the strip, s _c : the compressive yield strength of the strip, and J: the heat equivalent.

Next, a continuous rolling method of a stainless steel according to another aspect of the present invention is a method of cold rolling a stainless steel with two or more rolling stands, each of which is equipped with a rolling roll, sequentially provided and including a final rolling stand, A first continuous rolling step of passing a steel through the rolling stand and supplying rolling oil from the rolling oil supply part on the side and the outside of the rolling stand to the rolling roll for rolling; A second continuous rolling step of passing the stainless steel subjected to the first continuous rolling step through at least two rolling stands to supply the rolling oil and re-rolling the same; And a temperature measurement step of measuring a temperature of the exit side of the rolling stand with a temperature measurement unit having a temperature measurement device disposed on the exit side of the rolling stand, wherein the temperature of the exit side of the rolling stand, The surface temperature of the stainless steel is controlled so as to be 105 deg. C or lower, which is the rolling limit temperature at which heat stroke does not occur.

2 to 6 of the rolling stands may be sequentially arranged. Hereinafter, the rolling stand will be described as four rolling stands for convenience of explanation, but the present invention is not limited thereto.

On the exit side of the rolling stand, a temperature measuring part can be arranged. The temperature measuring unit measures the temperature of the exit side of the rolling stand. The temperature measuring unit includes a temperature sensing unit for contacting or measuring the temperature of the stainless steel on the exit side of the rolling stand, a temperature control unit for collecting and analyzing temperature data from the temperature sensing unit, And a temperature measurement line connecting the temperature measurement lines. Here, the temperature sensing part may be a device using a laser, but the temperature sensing part is not limited to the laser. Temperature data can be collected by sensing radiant heat from a stainless steel surface using a laser. When temperature data is collected by contacting the temperature sensing part with the temperature sensing part, the temperature of the stainless steel surface may be deteriorated. Place the temperature sensing part around the stainless steel to indirectly measure the temperature. Next, the temperature inside the roll 124 of the rolling stand 131 is inversely calculated by the above Equations 1 to 5.

As described above, according to the present invention, in order to prevent heat streak in high-speed rolling, by setting and rolling the maximum rolling speed so that the outlet temperature of each rolling stand does not exceed the rolling limit temperature, It is possible to provide a continuous rolling apparatus of stainless steel capable of continuously rolling a stainless steel.

Further, according to the present invention, it is possible to provide a continuous rolling method of stainless steel capable of producing stainless steel excellent in surface quality with high productivity.

Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are only a preferred embodiment of the present invention, and the scope of the present invention is not limited by the following examples.

And the first to fourth rolling stands are sequentially arranged, and the first to fourth rolling stands are each provided with a tandem rolling type continuous rolling mill having a diameter of 130 to 150 mm, The stainless steel was rolled under the conditions described in " Tables 1 to 4 show Comparative Examples 1 to 4 respectively, and Tables 5 to 8 show Examples 1 to 4, respectively. The stainless steels of the comparative examples of Tables 1 to 4 and the examples of Tables 5 to 8 were hot-rolled annealed pickling coils of STS430 having a size of 3.0 tx 1100 mm and were supplied with rolling oil at the entrance and exit of the rolling stand And the stainless steel was cold-rolled.

The rolling oil is a mineral oil-based rolling oil having a viscosity of 15 mm ² / s to 20 mm ² / s (40 ° C), a saponification value of 20 mg KOH / g to 40 mg KOH / g and a flash point of 200 ° C or more. In each table, one pass means that stainless steel passes through the first rolling stand, and 2 to 4 pass means pass through the second rolling stand to the fourth rolling stand, respectively.

Comparative Example 1 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 5.0 3.8 24.0 24.0 133 - 2 3.8 3.0 21.0 40.0 171 132 3 3.0 2.4 20.0 52.0 211 133 4 2.4 2.0 16.7 60.0 250 133 Occur

Comparative Example 2 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 4.0 3.0 25.0 25.0 108 - 2 3.0 2.2 26.7 45.0 147 125 3 2.2 1.6 27.2 60.0 203 126 4 1.6 1.3 18.7 67.5 250 126 Occur

Comparative Example 3 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 3.5 2.8 20.0 20.0 125 2 2.8 2.2 21.4 37.1 159 112 3 2.2 1.8 18.2 48.5 194 113 4 1.8 1.4 16.7 57.1 250 112 Occur

Comparative Example 4 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 3.0 2.45 20.0 20.0 133 2 2.8 1.85 21.4 37.1 171 108 3 2.2 1.4 18.2 48.5 211 109 4 1.8 1.2 16.7 57.1 250 109 Occur

Example 1 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 5.0 3.8 24.0 24.0 52 2 3.8 3.0 21.0 40.0 66 105 3 3.0 2.4 20.0 52.0 83 104 4 2.4 2.0 16.7 60.0 100 103 Not occurring

Example 2 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 4.0 3.0 25.0 25.0 52 2 3.0 2.2 26.7 45.0 66 105 3 2.2 1.6 27.2 60.0 83 105 4 1.6 1.3 18.7 67.5 100 104 Not occurring

Example 3 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 3.5 2.8 20.0 20.0 85 2 2.8 2.2 21.4 37.1 109 105 3 2.2 1.8 18.2 48.5 133 105 4 1.8 1.4 16.7 57.1 160 104 Not occurring

Example 4 pass Thickness
(Mm) Output Thickness
(Mm) Reduction rate (%) Total Reduction (%) Rolling speed
(mpm) Output temperature
(° C) Hitstreak
Occurrence One 3.0 2.45 20.0 20.0 122 2 2.8 1.85 21.4 37.1 157 105 3 2.2 1.4 18.2 48.5 194 105 4 1.8 1.2 16.7 57.1 230 104 Not occurring

Examination of Tables 1 to 4 reveals that heat strokes occur in all of Comparative Examples 1 to 4 of Tables 1 to 4, and no heat scrick occurs in Examples 1 to 4 of Tables 5 to 8 . Accordingly, it can be confirmed that, in Examples 1 to 4, the surface quality of the stainless steel after rolling was excellent.

Further, in Comparative Examples 1 to 4 of Tables 1 to 4, the outlet surface temperature of stainless steel after 4 passes exceeded 105 DEG C, whereas in Examples 1 to 4 of Tables 5 to 8, the outlet surface temperature of stainless steel was The temperature can be controlled to 105 ° C or lower.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalents thereof are included in the scope of the present invention Should be interpreted.

100: Stainless steel continuous rolling mill 110: Rolling stand
120: Rolling oil supply part 130: Temperature measurement part
131: Temperature sensing part 132: Temperature measuring line
135: temperature control unit 140: return tank
150:

Claims (20)

A rolling stand having a rolling roll each for rolling stainless steel and comprising at least two including a final rolling stand;
A rolling oil supply unit for supplying rolling oil to the rolling roll at the entrance and exit of the rolling stand; And
And a temperature measuring unit disposed on the exit side of the rolling stand and having a temperature measuring device for measuring the temperature of the exit side of the rolling stand,
The exit temperature of the rolling stand disposed before the final rolling stand is below the rolling limit temperature at which no heat stroke occurs on the surface of the stainless steel,
Wherein the rolling roll comprises a paper-hi-mill having a diameter of from 130 mm to 150 mm, and the viscosity of the rolling oil is from 15 mm ² / s to 20 mm ² / s (@ 40 ° C). The method according to claim 1,
Wherein the maximum rolling speed of the final rolling stand is controlled to be less than 250 mpm so that the temperature of the stainless steel measured by the temperature measuring unit becomes lower than the rolling limit temperature. 3. The method of claim 2,
Wherein the maximum rolling speed of the final rolling stand is controlled to be not less than 100 mpm and not more than 230 mpm. 3. The method of claim 2,
Wherein the rolling limit temperature is 105 占 폚 or less. The method according to claim 1,
The temperature measuring unit includes a temperature sensing unit for contacting or measuring the temperature of the stainless steel on the outside of the rolling stand, a temperature controller for collecting and analyzing data from the temperature sensing unit, And a temperature measuring line for connecting the temperature measuring lines. The method according to claim 1,
Wherein the stainless steel continuous rolling apparatus further comprises a return tank for collecting the used rolling oil supplied to the rolling stand and a filtering unit for filtering the rolling oil collected in the return tank. The method according to claim 6,
Wherein the rolling oil passes through the filtration part, is recovered to the rolling oil supply part, and then supplied to the inlet side and the outlet side of the rolling stand to be reused. delete The method according to claim 1,
Wherein the rolling oil is a mineral oil-based rolling oil having a flash point of 200 ° C or higher and a saponification degree of 20 mg KOH / mg to 40 mg KOH / mg or higher. A method of cold-rolling a stainless steel with two or more rolling stands, each of which is equipped with a rolling roll, which is sequentially provided and includes a final rolling stand,
A first continuous rolling step of passing the stainless steel through the rolling stand, wherein rolling oil is supplied to the rolling roll from a rolling oil supply part at the entrance and exit sides of the rolling stand and rolled;
A second continuous rolling step of passing the stainless steel subjected to the first continuous rolling step through at least two rolling stands to supply the rolling oil and re-rolling the same; And
And a temperature measurement step of measuring a temperature of the exit side of the rolling stand with a temperature measurement part having a temperature measurement device disposed on the exit side of the rolling stand,
Wherein the temperature of the outlet of the rolling stand disposed before the final rolling stand is controlled so as not to exceed a rolling limit temperature at which no heat stroke occurs on the surface of the stainless steel,
Wherein the rolling roll comprises a paper-hummer having a diameter of from 130 mm to 150 mm and the viscosity of the rolling oil is from 15 mm ² / s to 20 mm ² / s (40 ° C). 11. The method of claim 10,
In the temperature measurement step,
Wherein the maximum rolling speed of the final rolling stand is controlled to be 250 mpm or less such that the temperature at the exit of the rolling stand is below the rolling limit temperature. 11. The method of claim 10,
In the first continuous rolling step or the second continuous rolling step,
Wherein the maximum rolling speed of the final rolling stand is controlled to be not less than 100 mpm and not more than 230 mpm. 11. The method of claim 10,
In the first continuous rolling step or the second continuous rolling step,
Wherein the rolling limit temperature is 105 占 폚 or less. 11. The method of claim 10,
The temperature measuring unit may include a temperature sensing unit for measuring temperature by being in contact with or surrounding the stainless steel on the side of the rolling stand, a temperature control unit for collecting and analyzing data from the temperature sensing unit, And a temperature measuring line to which the stainless steel is connected. 15. The method of claim 14,
In the step of measuring the output temperature of the rolling stand,
Wherein the temperature measuring unit is disposed in the vicinity of or in contact with the stainless steel on the outside of the rolling stand to measure the temperature of the stainless steel. 15. The method of claim 14,
In the step of measuring the output temperature of the rolling stand,
Wherein the temperature measuring unit indirectly measures radiant heat from the stainless steel using a laser device to measure the temperature of the stainless steel. 11. The method of claim 10,
In the first continuous rolling step or the second continuous rolling step,
Wherein the rolling oil supplied to the rolling stand is collected in a return tank and then filtered through a filtration unit. 18. The method of claim 17,
Wherein the rolling oil passed through the filtration unit is supplied to the inlet side and the outlet side of the rolling stand to be reused. delete 11. The method of claim 10,
Wherein the rolling oil is a mineral oil-based rolling oil having a flash point of 200 ° C or higher and a saponification degree of 20 mg KOH / mg to 40 mg KOH / mg or higher.

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