JPH0571953A - Evaluation of metal plate transferring property of roller - Google Patents

Abstract

PURPOSE:To evaluate the possibility of the generation of a slip when a metal plate is fed by a roller by calculating a transferring property index from the ratio of the cutting height level corresponding to the peak of amplitude probability density distribution and the max. height of a cross section curve. CONSTITUTION:The surface roughness signal of a steel plate 1 detected by a surface roughness sensor 2 is inputted to a surface roughness measuring operation device 3 and processing is performed by the device 3 as follows. That is, the surface property of the steel plate is measured over predetermined length Lmm to form a cross section curve A and amplitude probability density distribution B is formed from the respective height values between the max. peak part P of the cross section curve A and the min. trough part V thereof to calculate the cutting height level Hu corresponding to the peak C of the distribution B and a transferring property index Ho is calculated from the ratio of the cutting height level Hu and the max. height Rmax= Hu+Hd of the amplitude probability density distribution according to Ho-{Hu/(Hu+Hd)}X100% and the calculated index Ho is compared with a preset reference value Hs to judge whether a slip is generated. The processing result is displayed on a display device 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating roller transportability of a metal plate used for shearing, punching, pressing, etc.

[0002]

2. Description of the Related Art Metal sheets, such as cold-rolled steel sheets, have been widely used as automobile body exterior plates and home electric appliances, etc., but in recent years, particularly for automobile body exterior plates, the sharpness after painting is strong. In addition, from the viewpoint of rust prevention, the percentage of using surface-treated steel sheets such as hot-dip galvanized steel sheets is rapidly increasing, and it is an issue to balance the post-painting image clarity and press formability of surface-treated steel sheets. ing.

By the way, the surface texture of such a surface-treated steel sheet is evaluated by, for example, a method for evaluating the amplitude level of the steel sheet surface by surface roughness, surface waviness, frequency analysis, etc. (see JIS B0601), or contact ratio, load curve, Generally, the evaluation is performed by the sectional shape evaluation method of the steel sheet surface using the amplitude probability distribution curve or the like. All of these conventional evaluation methods are related to the workability and paintability of steel sheets or the finished state after painting.

[0004]

However, in the automobile factory where the above-mentioned surface-treated steel sheet is highly automated on the user side, the blank steel sheet having a length of, for example, 500 to 1000 mm is used for press working and other processes. As a rule, rollers are often used for transportation, but in the case of hot-dip galvanized steel sheets that have undergone a certain roughening treatment on the original plate, slipping often occurs and it is not possible to smoothly transport them. However, there is a problem in that the handling of the steel sheet is hindered and the productivity is impaired.

Therefore, it was inferred that the surface roughness of the steel sheet and the occurrence of slip were closely related to each other, and the relation was investigated by the above-mentioned conventional steel sheet surface property evaluation method. It turned out that an accurate response could not be taken even if applied. That is, Table 1 exemplifies the relationship between the three-dimensional surface roughness SRa and the occurrence of slip in the case of the hot-dip galvanized steel sheet whose standard is GA.
It can be seen that it is difficult to predict the occurrence of slip with dimensional surface roughness.

[0006]

[Table 1]

The present invention has been made to solve the above problems, and provides a method suitable for evaluating the possibility of slippage occurring when a metal plate is conveyed by rollers. The purpose is to

[0008]

The present invention is a method for evaluating the transportability when a metal plate is transported by rollers, in which the surface texture of the surface of the metal plate is measured over a predetermined length to obtain a sectional curve. The step of creating, and the step of creating the amplitude probability density distribution from the values of each height from the highest peak to the lowest valley bottom of this cross section curve, and the cutting height level corresponding to the peak of this amplitude probability density distribution And a step of obtaining a transportability index from the ratio of the cutting height level corresponding to this peak and the maximum height of the cross-sectional curve, the method of evaluating the roller transportability of a metal plate, comprising: is there.

[0009]

[Operation] FIG. 1 is a schematic diagram showing an example of the structure of a surface roughness measuring device used in the present invention. Reference numeral 1 is a steel plate as a material to be measured, 2 is a laser beam type surface roughness sensor, and 3 is a surface roughness sensor.
Is a surface roughness measurement calculation device, and 4 is a calculation result display device. The surface roughness signal of the steel plate 1 detected by the surface roughness sensor 2 is input to the surface roughness measuring and calculating device 3 and is processed by the surface roughness measuring and calculating device 3 in the following procedure. The calculation result is displayed on the display device 4. First, the surface texture of the steel plate surface is measured over a predetermined length L (mm), and a sectional curve A as shown in FIG. 2 (a) is created. In this cross-section curve A, when the cutting level from the highest peak P to the lowest valley bottom V is taken, the probability that the cross-section curve is equal to the cutting level is plotted in the graph as shown in Fig. 2 (b). Create as distribution curve B. The peak value C of the amplitude probability density distribution curve B and the cutting level difference Hu up to the highest peak P are obtained. From the ratio of the cutting level difference Hu and the maximum height Rmax (= Hu + Hd) of the amplitude probability density distribution, the transportability index Ho is obtained by the following equation (1).

Ho = {Hu / (Hu + Hd)} × 100 (%) ───────── (1) The transportability index Ho is compared with a predetermined reference value Hs that has been preset. Determine whether it has occurred. Here, supplementing the above-mentioned transportability index Ho,
First, the fact that the transportability index Ho is small means that Fig. 3 (a)
As shown in Fig. 3, since the cutting level of the peak value C of the amplitude probability density distribution curve B is high, it represents a deep valley and plateau-like topography as shown in Fig. 3 (b), and a small peak M in this plateau. Is easily worn away, and the surface in contact with the roller becomes a smooth flat surface, so that slip easily occurs. This tendency is remarkable especially on a soft surface such as a hot-dip galvanized steel sheet.

On the other hand, the fact that the transportability index Ho is large means that the cutting level of the peak value C is low as shown in FIG. 4 (a), so that it is steep as shown in FIG. 4 (b). Represents a terrain with a high mountain shape, high peak N in this mountain
Does not easily disappear even when it comes into contact with the roller, and maintains the frictional force, so it has good transportability. However, increasing the transportability index Ho generally increases the roughening processing cost and adversely affects the finish quality of the coated surface. Therefore, the required Ho is added according to the roller transport conditions. It is better to do so.

[0012]

EXAMPLES Examples of the present invention will be described below.
As the material to be measured, standard; GA material, plate thickness; 1.6 mm × plate width;
Table 10 shows the results of calculation of the transportability index Ho using the method of the present invention for 10 coils of 1219 mm hot-dip galvanized steel sheet, and the presence or absence of slippage when transported by rollers as blanking materials thereafter. Shown in 2. Here, ◯ indicates “no slip occurrence”, Δ indicates “slip portion occurrence”, and X indicates “slip occurrence”. For comparison, the conventional three-dimensional surface roughness SRa was measured, and the measured values are also shown in the same table.

[0013]

[Table 2]

The results of Table 2 are shown in FIGS. 5 and 6 in correspondence with the transportability index. Here, the slip generation index “0” means that no slip has occurred, “1” means that a slip portion has occurred, and “2” means that slip has occurred. As can be seen by comparing these figures, in the case of the conventional three-dimensional surface roughness (SRa), it is difficult to make a determination in correspondence with the transportability index, but the transportability index Ho of the present invention is 2
Slip occurs at less than 24% at the boundary of 4 to 26%, 26%
It is obvious that no slip occurs when the value exceeds. Therefore, in the case of the above steel sheet, the reference value Hs of the transportability index is
If it is set within the range of 24 to 26%, it is possible to reliably determine the occurrence of slip.

[0015]

As described above, according to the present invention, the cutting height level corresponding to the peak of the amplitude probability density distribution is obtained, and the cutting height level corresponding to this peak and the maximum height of the sectional curve are calculated. Since the transportability index is obtained from the ratio, the transportability of the roller can be determined with high accuracy, which contributes to the improvement of the productivity of the press working line.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of the configuration of a surface roughness measuring device used in the present invention.

FIG. 2 is a characteristic diagram of (a) cross-section curve and (b) amplitude probability density distribution curve.

FIG. 3 is an explanatory diagram of (a) amplitude probability density distribution curve and (b) sectional curve when the transportability index Ho is small.

FIG. 4 is an explanatory diagram of (a) amplitude probability density distribution curve and (b) sectional curve when the transportability index Ho is large.

FIG. 5 is a characteristic diagram showing a relationship between a transportability index Ho and a slip occurrence index.

FIG. 6 is a characteristic diagram showing a relationship between a three-dimensional surface roughness SRa and a slip generation index.

[Explanation of symbols]

 1 Steel Plate 2 Surface Roughness Sensor 3 Surface Roughness Measurement Calculation Device 4 Calculation Result Display Device

Claims (1)

[Claims] 1. A method for evaluating transportability when a metal plate is transported by rollers, the method comprising: measuring a surface texture of a surface of the metal plate over a predetermined length to create a sectional curve.
A step of creating an amplitude probability density distribution from each height value between the highest peak and the lowest valley bottom of this sectional curve, and a step of obtaining a cutting height level corresponding to the peak of this amplitude probability density distribution, And a step of obtaining a transportability index from a ratio of a cutting height level corresponding to this peak and a maximum height of the cross-section curve.