JP2003266101A - Method for cold-rolling stainless steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cold-rolling method of a stainless steel sheet having little uneven gloss. <P>SOLUTION: Ester is supplied to places corresponding to generating places of the uneven gloss of the sheet. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cold rolling of a stainless steel sheet, and more particularly to a method of cold rolling a stainless steel sheet having less gloss unevenness. 2. Description of the Related Art Conventionally, a stainless steel strip (including a steel sheet, which has been subjected to an intermediate annealing after hot rolling and then to a descaling treatment such as a shot blasting treatment or a pickling treatment, etc. Therefore, including the case of a steel strip, it is simply referred to as a “sheet”, and a hot-rolled sheet as a cold-rolled material is also referred to as a “base sheet”.) The surface roughness was reduced to an average roughness of 0.2 to 0.7 μm Ra (Ra: J) in the former stand (or first half pass) in the subsequent cold rolling.
Cold rolling is performed using a work roll having an arithmetic average roughness specified in IS B 0601) and a work roll having a surface roughness of 0.1 to 0.25 μm Ra in the final stand (or final pass). This is a general method for producing a cold-rolled stainless steel sheet. In some cases, plate surface grinding may be performed prior to cold rolling. It is in sequence with the lubrication-free rolling described above,
There are both cases. However, the above-described method of cold rolling with a work roll having a surface roughness has almost no effect on the difference in surface properties (irregularity) generated in the width direction of the steel strip. It is known that the gloss unevenness corresponds to the unevenness of the roll coating (the phenomenon that the roll surface is colored by the oxide film of the rolled material) generated on the work roll. [0004] As a measure against coating unevenness of a work roll, the inventors have previously disclosed in Japanese Patent Application No. 2001-38038 (not disclosed at the time of filing of the present application) a method of reducing the roughness of a base plate in a steel sheet surface grinding line. A method was proposed that reduced the stripping action of the coating due to However, as shown in FIG. 3, this method is based on the results of a subsequent study, and as shown in FIG. 3, a relatively large depression such as a grinding (grinder) mark 12 or a shot residue left when the surface of the rolled plate (stainless steel plate) 10 is ground. It has been found that, due to free deformation within the cutting tool of the work roll 20 and the formation of the streak-like oil pits 14, it is rather easy to cause gloss unevenness. [0005] As another means, measures have been taken to reduce the rolling speed (100 mpm or less) so as to make the oil film thinner, thereby facilitating the generation of roll coating, and to make the coating as uniform as possible in the width direction. [0006] There are problems to be solved in order to prevent the coating unevenness of the work roll. Measures to Reduce the Roughness of the Base Plate at the Steel Plate Surface Grinding Line When the surface of the plate surface is ground, unevenness in grinding (grinding marks) in the width direction due to the grinding belt may occur, resulting in uneven gloss. is there. On the other hand, if annealing is added after surface grinding, gloss unevenness due to grinding unevenness can be reduced, but on the contrary, there is a problem that glossiness is reduced. [0008] There is a problem in that the rolling speed is reduced (100 mpm or less) to reduce the thickness of the oil film. To solve these problems, the inventors of the present invention have made intensive studies and have arrived at the present invention. [0010] In order to solve the above-mentioned problems, the present invention provides, in cold rolling of a stainless steel sheet, supplying an ester to a roll bite at a place corresponding to a spot where gloss unevenness occurs on the sheet. A cold rolling method for a stainless steel sheet. Thereby, it is possible to prevent the occurrence of gloss unevenness in the width direction without lowering the productivity. An embodiment of the present invention will be described below with reference to the drawings. As a result of the investigation, gloss unevenness generated during cold rolling of a stainless steel plate as shown in FIG.
It was found that the defects were caused by defects in the mother plate (grinding marks due to the steel sheet surface grinding line and marks of shots for removing scale in the line for annealing and pickling the sheet after hot rolling) in the mode shown in FIG. On the other hand, it has been confirmed that when annealing is performed again after the plate surface grinding is performed, it is effective in suppressing the annealing. However, by additionally performing annealing, as shown in FIG. 4, in the case of SUS304,
The glossiness of the plate that has been subjected to surface grinding → annealing → cold rolling has an average of only about 650 points as indicated by ■, and compared to the plate subjected to surface grinding → cold rolling indicated by ●. Since the glossiness of the surface was reduced, it could not be implemented as an effective measure. Therefore, conventionally, low-speed rolling (100 m
pm or less), there was no other way than to take measures against uneven gloss, but this significantly impaired productivity. [0015] Therefore, the present invention is to supply the ester at the entry side of the roll bite, to be able to change the supply amount in the plate width direction, to change the state of the oil film at the pinpoint, and as a result, to generate in the plate width direction This is to eliminate roll coating unevenness. With this mechanism, it is possible to prevent the occurrence of unevenness in gloss in the width direction of the sheet without lowering the productivity. An embodiment to which the present invention is applied will be described with reference to FIGS. FIG. 5 is a side view, and FIG. 6 is a front view. In the figure, 10 is a stainless steel plate (rolled material), 20 is a work roll of a multi-high rolling mill, 22 is an intermediate roll, and 24 is a backup roll. Reference numeral 30 denotes a rolling oil supply tank, 32 denotes a rolling oil supply pipe, 40 denotes an ester supply tank, 42 denotes an ester supply pipe, 50 denotes a return pan, and 52 denotes a recovery tank. What is characteristic in this embodiment is that the portions corresponding to the various widths of the stainless steel plate 10 being rolled by the multi-high rolling mill 20 and corresponding to the portions where the gloss unevenness occurs in the width direction of the stainless steel plate are as follows. As shown by a solid line in FIG. 6, the ester supply pipe 42 is branched so that the ester can be ejected. Each of the nozzles is located at an intermediate position in the downstream pipe after branching until reaching the ester injection nozzle 46. That is, a valve 44 capable of injecting and stopping the ester every time is provided. For example, when the operator observes the surface of the stainless steel plate 10 being rolled and notices that gloss unevenness has begun to occur, if the operator notices that the gloss unevenness has begun to occur, the work roll 20 of the work roll 20 corresponding to the gloss unevenness generated portion of the stainless steel plate 10 is observed. Ester injection valve 44 for injecting ester toward the axial position
Is operated by the operator so as to open the other, and to close the other ester injection valves 44. It is sufficient that the ester is eventually supplied to the roll bite (where the plate is actually rolled by the work roll 20). It may be injected on the roll 20 side or on both sides. As shown in FIG. 5, the rolling oil and the ester can be partially sprayed in the width direction of the plate by another system. As esters, monoesters and diesters are suitable for use, and as monoesters, butyl stearate,
Glyceride oleate, octanol laurate and the like are preferable, and diesters such as dioctyl sebacate and dioctyl adipate are preferable. By the way, the supply of the rolling oil is called a so-called width division, and the rolling oil supply pipe 32 shown by a broken line in FIG.
As in the above, if a supply system that can be injected and stopped so as to be symmetrical with respect to the center in the width direction of the stainless steel sheet, when rolling a narrow stainless steel sheet, the rolling oil that does not contribute to the rolling with respect to the outer part thereof It is more preferable because the supply can be stopped and the rolling oil consumption rate can be improved. In the figure, 34 is a rolling oil injection valve, and 36 is a rolling oil injection nozzle. Examples of rolling a stainless steel strip using a rolling mill having this mechanism are shown in Tables 1 to 3. Table 1 shows that the material thickness is 4 mm and the product thickness is 0.8 m.
Table 2 shows an example in which Mo, Cu, and Ti are added in the same size with SUS430 having a width of 1000 mm and a width of 1000 mm.
The example applied to US430 and Table 3 are examples applied to SUS304 with a material thickness of 4 mm, a product thickness of 1.0 mm, and a board width of 1000 mm. The example is one in which the rolling oil is supplied and the ester is partially supplied. [Table 1] [Table 2] [Table 3] From these results, it can be seen that uneven supply of gloss can be prevented by partially supplying the ester in the width direction of the rolled sheet. In the present invention, the ester is partially supplied. However, this apparatus is also diverted to a rolling oil supply system and locally supplied to prevent gloss unevenness in the direction of reducing the overall gloss. It is also possible. According to the present invention, in cold rolling of a stainless steel sheet, it is possible to prevent the occurrence of gloss unevenness in the sheet width direction without lowering the productivity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of gloss unevenness generated during cold rolling of a stainless steel plate. FIG. 2 is a plan view showing the results of a plate surface inspection after finish annealing, pickling, and temper rolling. 3) Side view showing the hypothesis of the cause of gloss unevenness [Fig. 4] Diagram showing the effect of additional annealing after surface grinding on the plate surface after finish annealing, pickling and temper rolling [Fig. 5] For supply of rolling oil Side view of a rolling mill showing a piping system [FIG. 6] Front view [Description of reference numerals] 10 ... Rolled material (stainless steel plate) 20 ... Work roll 22 ... Intermediate roll 24 ... Backup roll 30 ... Rolling oil supply tank 32 ... Rolling oil supply pipe 34 ... Rolling oil injection valve 36 ... Rolling oil injection nozzle 40 ... Ester supply tank 42 ... Ester supply pipe 44 ... Ester injection valve 46 ... Ester injection nozzle 50 ... Return receiving pan 52 ... Collection Link

Continuation of front page    (72) Inventor Junichi Tateno             1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba             Inside the Iron Corporation Chiba Works F term (reference) 4E002 AD05 BC08 BC10 CB03

Claims (1)

Claims: 1. A cold rolling method for a stainless steel sheet, comprising supplying the ester to a roll bite at a location corresponding to a spot where gloss unevenness occurs on the stainless steel sheet.