JPH02160105A - Method and device for hot highly lubricated rolling - Google Patents

Abstract

PURPOSE:To reduce an electric power consumption unit by applying a degreasing agent on a work roll for specific seconds between a time immediately after runout of a rolled stock and a succeeding biting time in a time for which application of a lubricant on the work roll is interrupted. CONSTITUTION:A lubricant applying device 6 and a dewatering wiper 8 are installed in the vicinity of the bite inlet side of a work roll 3a of a hot rolling mill. A degreasing agent applying device 7 and a dewatering wiper 9 are installed in the vicinity of the outlet side. The mill is used; application of a lubricant to the surface of the roll 3a which remaining water is wiped off is started at immediately after bite of a rolled stock 1. After that, application of the lubricant is interrupted immediately before runout of the stock 1. Additionally, a degreasing agent is applied to the roll 3a to prepare a succeeding biting for 5-30sec between the time immediately after the runout and the succeeding biting time in a time for which application of lubricant is interrupted. Hence, an electric power consumption unit is reduced.

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention is directed to hot highly lubricated rolling (rolled material and work roll) for stably manufacturing hot rolled products of excellent quality with low energy consumption. The present invention relates to a hot rolling method in which the average coefficient of friction between the two is 0.2 or less, and hot rolling equipment with high lubrication used therein.

<Prior art and its problems> -a, for hot rolling of steel plates, a hot rolling facility with a rough rolling mill of 1 to 6 stands and a finishing mill of 6 to 7 stands is used. Thickness is 200-270
Dragon slabs are rolled to a finished thickness of about 1.2 to 1.2 loam.

Here, the finishing mill that rolls the material to be rolled to a thickness of 1.2 to 10 mm, which has been rolled to a rough bar of about 25 to 40 mm in the rough rolling mill, is used for the general purpose as described above. ~Although it is said to be a continuous equipment configuration with 7 stands, when the finished thickness is relatively thick, such as 4 mm or more, it is not necessarily necessary to use a large number of 6 to 7 stands, and in some cases, 1 to 2 stands at the final position are required. For this purpose, so-called "dummy rolling 1" is sometimes performed in which the roll gap is left open and no rolling is performed.For this reason, it was considered to reduce the number of stands and make the equipment more compact.
When rolling a material with a finished thickness of less than 3 fins, it is necessary to use 6 to 6 fins due to constraints on rolling torque and rolling load per 1 stand.
This required seven rolling stands, which was difficult to achieve.

By the way, the technology of applying a lubricant to reduce the rolling load and rolling torque during hot rolling has been researched and put into practical use for quite some time.

For example, pages 125 to 12B of the collection of lecture papers from the ``26th Plastic Working Union Lecture'' introduces a method for directly injecting cylinder oil and rapeseed oil at the inlet side of the work roll using a premix method. . However, according to this report, the average coefficient of friction (μ) between the rolled material and the work roll was 0.4 μm when no rolling oil was used, but was reduced to 25 μm by using rolling oil. However, it is said that the reduction rate of rolling load and rolling power (rolling torque) in this case is only about 10 to 20% at most.

As described above, the effect of reducing rolling load and rolling torque in conventional hot lubrication rolling has been relatively small, and therefore lubrication rolling has often been adopted for the purpose of reducing roll wear.

However, theoretically, as the coefficient of friction between the material to be rolled and the work roll decreases, the rolling load and rolling torque should decrease accordingly.

For example, Figure 3 shows the "26th Plastic Working Union Lecture"
As introduced in the collection of lecture papers, page 127,
"This is a graph that calculates the relationship between μ (average coefficient of friction between the material to be rolled and the work roll) and rolling load using a theoretical formula from data obtained from experimental mills, etc."
When μ is reduced to a value of μ≦0.2, especially the rolling reduction (
It is clearly seen that in the region where the value obtained by dividing the plate thickness reduction amount by the entrance plate thickness is large, the reduction in rolling load is significant.

Therefore, here, the lubrication level where μ≦0.2 is distinguished from normal lubrication rolling and is referred to as "highly lubrication rolling."

This highly lubricated rolling with μ≦0.2 cannot be achieved with lubricants used in normal rolling, but for example, if a well-known graphite-based lubricant with a large μ reduction effect is applied to the roll surface, μ can be reduced to 0.15. It becomes possible to reduce it to about 0.20.

However, when such a lubricant with a large μ reduction effect is used, it becomes impossible to secure the friction coefficient necessary to make the tip of the rolled material bite into the roll, causing slip troubles, resulting in stable rolling. There was a problem in that the work could not be carried out.

In other words, if such a tip slipping problem occurs at a stand midway through a row of continuous hot finishing mills, the rolled material will accumulate between the stands, causing a major rolling accident, and the roll surface will be significantly damaged, resulting in serious damage. This leads to damage.

For this reason, in order to put "highly lubricated rolling" into practical use and ensure sufficient rolling load and rolling torque reduction effects, it was necessary to establish reliable countermeasures against jamming at the tip of the rolled material.

Therefore, the purpose of the present invention is to set lubrication conditions such that μ is μ≦0.2 during normal rolling in hot rolling,
When biting the rolled material, the μ required for tip biting (for example, μ
≧0.3), and by this means can produce hot-rolled products of excellent quality using compact equipment, with minimum energy consumption, and without causing defects in the biting of the rolled material. This is to provide a way to obtain.

The present invention has been made in order to achieve the above-mentioned object. Using a hot rolling mill equipped with a degreaser applicator and a drain wiper near the exit side of the roll bite, we start applying lubricant to the work roll surface that has been wiped with cooling water immediately after the rolled material is bitten. After that, the application of lubricant is stopped immediately before the butt removal of the rolled material, and the biting of the rolled material during this lubricant application interruption period is continued for 5 to 30 seconds from immediately before the next biting of the rolled material. By applying a degreasing agent to the work roll surface over a period of time and performing hot rolling in preparation for biting, hot rolling with high lubrication (rolling with μ≦0.2) can be carried out stably. '', and furthermore, ``a hot rolling facility for carrying out the above hot highly lubricated rolling is equipped with a lubricant applicator and a drain wiper near the entry side of the work roll bite of the hot rolling mill. It is also characterized by the fact that a degreaser applicator and a draining wiper are installed near the exit side of the work roll bite.

Hereinafter, the present invention will be explained based on the drawings.

<Operation> FIG. 1 shows an example of the equipment arrangement near the roll bite entry and exit sides of the hot high lubrication rolling equipment according to the present invention, and reference numeral 1 indicates the rolled material at the entry side position; 1' is the rolled material being rolled; 2a and 2b are upper and lower backup rolls; 3a and 3b are upper and lower work rolls; 4.
5 is a stripper guide on the entrance side and the exit side, 6 is a lubricant application (injection) device, 7 is a degreasing agent application (injection) device,
8.9 shows the drain wipers on the inlet and outlet sides, respectively.

In addition, in FIG. 1, illustration of the lower stripper guide, lubricant applicator, etc. (corresponding to symbols 4 to 9 on the upper side) is omitted.

Now, when hot highly lubricated rolling is carried out using the equipment shown in Fig. 1, the material to be rolled 1 is first bit into the rolls, and then
As shown in FIG. 2, the work roll surface is continuously coated with lubricant using the lubricant applicator 6 until just before the bottom of the rolled material 1' is removed, and high lubrication rolling with μ≦0.2 is performed. The application of the lubricant is stopped immediately before removal. Next, the bottom removal is carried out for a certain period of time (for example, t = 5 in Fig.
The degreaser is then applied to the surface of the work roll by the degreaser applicator 7 for 10 seconds), and the μ at the time of biting of the next rolled material is increased to, for example, about 0.3 μm. Here, the role of the entry side drain wiper 8 is to provide roll cooling water (not shown).
The purpose of this is to remove the lubricant from the surfaces of the work rolls 3a and 3b to improve the spread of the lubricant onto the work roll surfaces.On the other hand, the role of the outlet wiper 9 is to remove the degreaser to be applied using roll cooling water. To remove roll cooling water from the surfaces of the work rolls 3a and 3b so that they can function effectively without being diluted, and to wipe off degreased oil and fat bones from the surfaces of the work rolls 3a and 3b.

Therefore, when rolling the material to be rolled, a highly lubricated rolling condition of μ≦0.2 can be maintained, and on the other hand, when the material to be rolled is bitten, a relatively high μ, which is necessary for tip biting, can be ensured.
The rolling load and rolling torque during rolling can be significantly reduced, making it possible to reduce the number of stands in a hot finishing mill, and also reliably preventing jamming of the rolled material. Therefore, it is possible to stably manufacture hot-rolled products of excellent quality with minimal energy consumption using compact equipment.

Note that the graphite-based lubricant mentioned above is suitable as the lubricant to be applied, and a solvent with degreasing properties such as trichlorethylene is suitable as the degreaser.

In addition, one of the features of the present invention is that the degreaser applicator 7 is installed on the exit side rather than the roll bite inlet side, and the lubricant applicator 6 etc. are arranged, which reduces the installation space. By avoiding the unfavorable roll bite entry side, the degreasing agent coating device 7 can be optimally arranged, and it is extremely convenient from the point of view of equipment balance. The arrangement of the degreaser applicator 7 is such that the degreaser is sprayed at a timing when the rolled material 1 or 1' is passing through the roll bit as described above. This is based on the results that support the idea that, as long as the placement position is near the exit roll bite, the effect is no different from that of the entry side placement.

By the way, regarding the degreaser application (spraying) time, t<
At 5 seconds, a sufficient degreasing effect cannot be obtained; on the other hand, at >30 seconds, the degreaser continues to be sprayed until the next rolled material is bitten in the case of normal rolling work. The time was set at 5 to 30 seconds.

(Summary of Effects) As explained above, according to the present invention, the number of required stands can be reduced by 2 to 3 stands compared to conventional hot finishing rolling mills (3 to 5 stands is sufficient). This allows for a significant reduction in equipment costs, and a significant reduction in motor power consumption due to a significant reduction in rolling torque.Furthermore, it ensures excellent surface quality while reliably preventing biting defects during rolling operations. Industrially, extremely useful effects are brought about, such as the ability to stably produce hot-rolled steel sheets.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the equipment arrangement near the roll bite entry side and exit side of the hot high lubrication rolling equipment according to the present invention. FIG. 2 is a drawing showing an example of the application (injection) timing of lubricant and degreaser in the hot high lubrication rolling method of the present invention. FIG. 3 is a graph showing the relationship between μ (average coefficient of friction between the material to be rolled and the work roll) and rolling load. In the drawings, l: Rolled material at entry side position. 1': Rolled material during rolling. 2a...Upper backup roll. 2b...lower back up roll. 3a...Upper work roll. 3b...lower work roll. 4...Entrance side stripper guide. 5...Outside strimp guide. 6...Lubricant application device. 7...Degreasing agent application device. 8...Inlet drain wiper 9...Outlet drain wiper

Claims (2)

[Claims] (1) A hot rolling machine is used that is equipped with a lubricant applicator and drain wiper near the inlet side of the work roll bite, and a degreaser applicator and drain wiper near the exit side of the work roll bite. Immediately after the material to be rolled is bitten, the application of lubricant to the surface of the work roll wiped with cooling water is started, and then the application of lubricant is stopped immediately before the material to be rolled falls off, and the lubricant application is interrupted during this period. 5 to 30 minutes between the end of the rolled material and the next rolled material.
A hot rolling method with high lubrication, characterized in that hot rolling is performed while preparing for biting by applying a degreasing agent to the surface of a work roll for seconds. (2) A lubricant applicator and a drain wiper are installed near the work roll bite inlet side of the hot rolling mill, and a degreaser applicator and a drain wiper are installed near the work roll bite exit side. Highly lubricated hot rolling equipment.