JPH05253821A - Grinding method of stainless steel strip - Google Patents

Abstract

PURPOSE:To obtain a surface characteristic with no gloss unevenness by providing plural elastic grindstone rolls in multistage in the directions crossing with and parallel to the advancing direction of a stainless steel strip, and moving the grindstones provided in the parallel direction reciprocating in the direction orthogonal to the advancing direction of the steel strip. CONSTITUTION:A former stage orthogonal elastic grindstone roll 3 and a latter stage orthogonal elastic grindstone roll 4 whose axial directions are orthogonal to the advancing direction of a stainless steel strip 1 are set, and the left side and the right side parallel elastic grindstone rolls 6 and 5 are set alternatively making their axial directions parallel to the steel strip advancing direction 2, at the left end and the right end positions in the width direction of the stainless steel strip 1, between the former and the latter orthogonal rolles 3 and 4. And the left side and the right side parallel rolls 6 and 5 are moved reciprocating continuously in the directions of the arrows in the direction orthogonal to the steel strip advancing direction and in the reverse directions between both ends in the width direction. The using abrasive grains of the rolls are made coarse in the former stage orthogonal roll 3 and minute gradually in the latter roll 4, while the abrasive grains of the left side and the right side parallel rolls 6 and 5 are made smaller than that of the former stage orthogonal roll 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding method for obtaining a stainless steel product having excellent surface properties, and more specifically, a hot rolled sheet, an annealed sheet or an annealed pickling sheet before cold rolling. The present invention relates to a method for grinding a stainless steel strip which is ground by an elastic whetstone roll to remove surface scale and flaws to obtain a smooth surface.

[0002]

2. Description of the Related Art In the process of manufacturing a stainless steel band,
By heating the slab and subsequent hot rolling or continuous casting of thin slabs, or after further annealing or annealing pickling, oxide scales or surface flaws occur on the surface, so these are removed, and for finishing the surface A process is required. Conventionally, as these methods, a method of grinding the front and back surfaces of the steel strip with a belt type grinding tool before cold rolling has been adopted, but this kind of grinding tool has time dependency of grinding performance, Since the abrasive grains are worn away with the lapse of grinding time, there has been a problem that the surface texture of the finished material after grinding varies with the grinding time. Further, since the grinding amount sharply decreases with the grinding time, the complicated work of exchanging the belt for each steel strip has been forced.

On the other hand, in order to improve the workability of a belt-type grinding tool, a cylindrical grinding device is arranged in the front stage, and a belt grinding device is arranged in the rear stage thereof to provide a continuous flaw removing facility for stainless steel strips. In Japanese Patent Laid-Open No. 1-273607, further, in Japanese Patent Laid-Open No. 1-273607, grinding rolls having different abrasive grain numbers are arranged in two stages, coarse grains are used for the front stage and fine grinding is performed for the rear stage, and an acid treatment is performed thereafter. A steel strip processing method intended to improve productivity by reducing the washing load has been proposed. However, in the former method, the workability is improved as compared with the case where all the grinding processes are carried out by the belt tool, but the belt grinding is still in the range. In the case of the latter (the same applies to the former), the grinding direction is one direction, and the deep grinding grain formed by the coarse abrasive grains in the former stage is
Transfer of a small amount of streaks to the surface of stainless steel products and no excellent surface gloss can be obtained. It is not easy to smooth out this deep grinding grain by using fine abrasive grains in the subsequent stage, and even if a subsequent pickling treatment is performed for smoothing, the amount of surface ablation will be increased. However, the problem remains that the pickling load cannot be reduced so much.

Further, Japanese Laid-Open Patent Publication No. 60-4412 proposes a method of grinding a stainless steel strip in which a grinding direction is changed by 30 ° or more every time the grain size of the grinder is changed by grinding with a multi-stage grinder. Even with this method, there is a problem that the amount of grinding per grinding machine is small and the number of times of grinding is large, and the frequency of replacement is high. In addition, when grinding at an angle intersecting the traveling direction of the steel strip, the steel strip meanders, and the shape of the steel strip And the grinding becomes uneven.

[0005]

SUMMARY OF THE INVENTION The present invention is to improve the above-mentioned conventional problems and prevent the quality of the product surface from being deteriorated. It is an object of the present invention to provide a method of grinding a stainless steel strip having a maximum surface roughness Rmax of 10 μm or less by alternately changing the surface roughness and having excellent surface properties without gloss unevenness.

[0006]

In order to achieve the above object, the present invention has the following structures. That is, (1) the elastic grindstone roll is arranged in multiple stages in a direction in which the axial direction intersects the traveling direction of the stainless steel strip and in a parallel direction, and the abrasive grains used in the roll in the subsequent stage are finer than those in the preceding stage,
Continuously moving the elastic whetstone rolls arranged in parallel between the steel strip widths in a direction orthogonal to the steel strip advancing direction, and
(2) At least two elastic rolls arranged in the parallel direction
A method of grinding a stainless steel strip, characterized in that the reciprocating continuous movement directions are alternately different in steps.

[0007]

The present invention will be described in detail below. 1 and 2
2A and 2B are schematic plan and side views showing an example of roll arrangement for carrying out the method of the present invention, showing a traveling direction 2 of a stainless steel strip 1.
Pre-stage orthogonal elastic whetstone roll 3 whose axial direction is orthogonal to (arrow)
(Hereinafter referred to as front-stage orthogonal rolls) and rear-stage orthogonal elastic grindstone rolls 4 (hereinafter referred to as rear-stage orthogonal rolls) are installed, and between the front-stage and rear-stage orthogonal rolls 3 and 4, the left and right sides in the width direction of the stainless steel strip 1 are provided. At the end position, the right parallel elastic whetstone roll 5 so that the axial direction is parallel to the traveling direction 2 of the steel strip.
(Hereinafter, referred to as a right parallel roll) and left parallel elastic whetstone rolls 6 (hereinafter referred to as left parallel rolls) are alternately arranged. The left and right parallel rolls 5 and 6 continuously reciprocate between the widths of the steel strips at right angles to the traveling direction of the steel strips and in opposite directions as indicated by arrows. Numerals 7 and 8 are pressing rolls paired with the orthogonal rolls 3 and 4, and 9 is a pressing roll of a parallel roll.

The illustrated roll arrangement is one form of the present invention. Basically, it is sufficient to combine orthogonal rolls and parallel rolls. Therefore, a combination of one orthogonal roll and one parallel roll, and between the front and rear orthogonal rolls are used. There is a combination in which one or a plurality of parallel rolls are alternately arranged, and these combinations may be arranged in multiple stages as needed, or may be installed so that the front and back surfaces of the steel strip can be ground. is there.

The above-mentioned elastic whetstone roll is a roll (cylindrical) whetstone having a certain degree of elasticity in order to easily fit the shape of the stainless steel strip 1 (about 10 when grinding).
Elastic deformation of about 0 μm or less occurs), for example, those in which disks coated with abrasive grains are laminated and formed in a roll shape (lamination type), and those in which flap wheels are laminated and formed in a roll shape (flap type) Also, there is a roll-shaped integrally molded nylon resin containing abrasive grains (integrated type).

In the example shown in the figure, the abrasive grains of the rolls to be used are roughened by increasing the amount of grinding by roughening the orthogonal rolls in the front stage, and gradually becoming finer in the subsequent stages.
However, it is preferable that the abrasive grain count is # 240 or more in order to have a function of smoothing the grinding grain in the preceding stage. At this time, the left and right parallel rolls 5 and 6 are finer than the front orthogonal rolls, but both may have the same abrasive grain count.

In the grinding mode thus constructed, the stainless steel strip 1 having a scale or a flaw on the surface is first subjected to heavy grinding by the front-stage orthogonal roll 3 while running. Next, the heavy-ground steel strip surface is alternately ground by the parallel rolls 5 and 6 that reciprocate in the steel strip width direction. Stainless steel strip,
Since the thickness of the scale and the depth of the surface flaws generated in the hot rolling or the subsequent process annealing for manufacturing this, or the continuous casting process of the thin cast piece are at least about 5 to 10 μm,
The amount of grinding to remove the surface layer including the substrate is at least 10μ
m, preferably 20 μm or more.

Since the grinding with the parallel rolls is performed so as to intersect with the grinds that are heavily ground by the front orthogonal rolls, the heavy grindings can be efficiently removed and the surface is smoothed. Further, since the movements in the width direction of the steel strip are in opposite directions, meandering of the steel strip due to the grinding reaction force is suppressed, and effective grinding can be performed without causing uneven grinding. Therefore, it is preferable to install the parallel rolls on both right and left sides as shown in the figure. The orthogonal rolls 3 and 4 are also provided close to the parallel rolls to help prevent meandering.

The rear orthogonal roll 4 has a large abrasive grain count,
That is, using fine abrasive grains of abrasive grain count # 240 or more,
Since the grinding is performed in the traveling direction of the steel strip, that is, the grinding is performed by crossing the grinding by the parallel rolls, the deep grinding is eliminated and the surface is smoothed including the removal of these grinding.

As described above, according to the present invention, even if deep grinding occurs in the preceding grinding with a coarse grindstone, the direction of the grinding is alternately changed and the smoothing is facilitated.
It is possible to obtain a stainless steel strip having an excellent surface property with a maximum surface roughness Rmax of 10 μm or less.

The present invention carries out the surface grinding treatment as described above, but in the case of continuously treating a stainless steel strip,
The steel strip is unwound from the pay-off reel, welded to the preceding material by a welding machine through a leader, and after a flaw or a crack on the edge part is removed by a trimmer or an edge grinder, if necessary, a dry or wet shot. When blasting is performed, the collision force of the steel balls projected onto the surface promotes cracking and peeling of the oxide scale, and then passing through a tension leveler further promotes the cracking and peeling, as well as uniform grinding. The shape may not be corrected for ease, and a pretreatment such as addition of heat treatment for scale modification may be appropriately selected and carried out as necessary. Further, a pickling treatment may be carried out after the grinding step, which further smoothes the ground lines and improves the surface gloss.

[0016]

EXAMPLES Hot rolled steel strips or thin cast strip steel strips of SUS304 and 430 were used as test materials, and two pairs of front-stage orthogonal rolls (first stage) and subsequent left and right parallel rolls were arranged in front and rear, a total of two pairs. Then, the plate was passed through a grinding machine provided with a post-stage orthogonal roll (third stage). The passing speed is 20 m / min, and the average reciprocating speed of the parallel rolls in the width direction of the steel strip is 60.
m / min. Table 1 shows the abrasive grain counts of the rolls used in each stage. The amount of steel strip surface grinding with these rolls was set to 50 μm so that scales and flaws could be removed. For comparison, grinding was carried out by an apparatus, which is a conventional method, in which a plurality of elastic grindstone rolls having axes at right angles to the steel strip passing direction are arranged, and the abrasive grain numbers are shown in Table 2. The sheet passing speed and the grinding amount were the same as those in Table 1.

In order to obtain surface properties such as excellent gloss and surface roughness, it is important to obtain a ground surface with a small maximum surface roughness without deep grinding residue generated by preceding grinding with a coarse abrasive grain count. However, the maximum surface roughness Rmax needs to be 10 μm or less. Therefore, based on the maximum surface roughness Rmax of 10 μm of the ground surface of the steel strip, 10 μm or less is ◯, 1
Evaluation was made with x exceeding 0 μm, and the results are shown in Tables 1 and 2. Rmax was measured in the width direction of the steel strip with a surface roughness meter. As is clear from Tables 1 and 2, the invention examples (Table 1) achieved all the values below the standard in a small number of steps, and there were no troubles such as meandering in the grinding process. On the other hand, in the conventional example (Table 2), the target value is finally reached by the six-stage roll processing.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

As is apparent from the above, according to the present invention, since the grinding is carried out while alternately changing the grain direction of the steel strip, the grinding load can be reduced and the steel can be ground with a smaller number of grindings than the conventional one. A grinding amount for descaling and flaw removal of the strip surface can be obtained, and a stainless steel strip having a surface maximum roughness of 10 μm or less and excellent surface properties can be obtained by such an efficient grinding method.

[Brief description of drawings]

FIG. 1 is an explanatory plan view showing an embodiment of the present invention.

FIG. 2 is an explanatory side view showing an embodiment of the present invention.

Claims (2)

[Claims] 1. A plurality of elastic grindstone rolls are arranged in multiple stages with their axial directions intersecting and parallel to the traveling direction of the stainless steel strip, and the abrasive grains of the rolls of the latter stage are finer than those of the former stage, A method for grinding a stainless steel strip, characterized in that the elastic whetstone rolls arranged in the parallel direction are continuously moved back and forth between the widths of the steel strip in a direction orthogonal to the traveling direction of the steel strip. 2. The method for grinding a stainless steel strip according to claim 1, wherein the elastic rolls arranged in the parallel direction have at least two stages, and the directions of the reciprocal continuous movement are alternately different.