JP2895275B2 - Method for evaluating roller transportability of metal plate - Google Patents

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 the roller transportability of a metal plate subjected to shearing, punching, pressing and the like.

[0002]

2. Description of the Related Art Metal sheets such as cold-rolled steel sheets have been widely used as body panels for automobiles and household electric appliances, but recently, especially for body panels of automobiles, the sharpness after painting is strong. The use of surface-treated steel sheets, such as hot-dip galvanized steel sheets, is rapidly increasing from the point of view of rust prevention, and the balance between sharpness after painting and press formability of surface-treated steel sheets has become an issue. ing.

Incidentally, the surface properties of such a surface-treated steel sheet are evaluated, for example, by a method of evaluating the amplitude level of the steel sheet surface by surface roughness, surface waviness, frequency analysis or the like (see JIS B0601), a contact ratio, a load curve, or the like. Generally, it is evaluated by a cross-sectional shape evaluation method of the steel sheet surface using an amplitude establishment distribution curve or the like. These conventional evaluation methods are all related to the workability and paintability of the steel sheet or the finished state after painting.

[0004]

However, in a highly automated automobile factory or the like on the user side, the above-mentioned surface-treated steel sheet is subjected to press working or other processes to cut the blank steel sheet having a length of, for example, 500 to 1000 mm. Although it is often transported using rollers, in the case of a hot-dip galvanized steel sheet that has been subjected to a specific roughening treatment on the original sheet, slip often occurs and it can not be transported smoothly However, there is a problem that the handling of the steel sheet is hindered and the productivity is impaired.

[0005] Then, it was presumed that there was a close relationship between the surface roughness of the steel sheet and the occurrence of slip, and the relationship was examined by the above-described conventional steel sheet surface property evaluation method. It turned out that even if applied, an accurate response could not be taken. That is, Table 1 illustrates the relationship between the three-dimensional surface roughness SRa and the occurrence of slip in the case of a hot-dip galvanized steel sheet whose standard is GA.
It can be seen that it is difficult to predict the occurrence of slip with the dimensional surface roughness.

[0006]

[Table 1]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a method suitable for evaluating the possibility of occurrence of slip when a metal plate is transported by rollers. The purpose is to:

[0008] The present invention provides a method of assessing the transportability when conveying a metal plate with a roller, a step of creating a measured and sectional curve of the surface shape of the metal plate surface over a predetermined length, A step of creating an amplitude probability density distribution from the height of the section curve from the highest peak to the lowest valley, and a step of obtaining a level value corresponding to the peak of the amplitude probability density distribution When a step of obtaining a transport index from the ratio of the amplitude values between the lowest valley portion from highest crest level value and the cross section curve corresponding to this peak, in advance with the conveyor index
Slip occurs by comparing with the set reference value
And a step of evaluating the presence / absence of the metal plate. In addition, the above smell
A level value corresponding to the peak of the amplitude probability density distribution
The difference between the level and the highest peak is assumed to be Hu.
The level difference between the corresponding level value and the lowest valley bottom is denoted by Hd.
Then, the transportability index Ho is defined as Ho = {Hu / (Hu + Hd)} × 100% , and this Ho and a predetermined reference value set in advance
Hs was compared with that of Ho <Hs , and it was evaluated that slip occurred.
Features.

[0009]

FIG. 1 is a schematic view showing an example of the configuration of a surface roughness measuring device used in the present invention, wherein 1 is a steel plate as a material to be measured, 2 is a laser beam type surface roughness sensor, for example.
Denotes a surface roughness measurement calculation device, and 4 denotes a calculation result display device. The surface roughness signal of the steel sheet 1 detected by the surface roughness sensor 2 is input to the surface roughness measuring and calculating device 3 and processed by the surface roughness measuring and calculating device 3 in the following procedure. The result is displayed on the calculation result display device 4. First, by measuring the surface shape of the steel sheet surface over a predetermined length L (mm), to create a cross-sectional curve A, as shown in FIG. 2 (a). In this section curve A, when the cutting level from the highest peak P to the lowest valley V is taken, the probability that the section curve becomes equal to the cutting level as shown in FIG. It is created as a distribution curve B. A cutting level difference Hu between the peak value C of the amplitude probability density distribution curve B and the highest peak P is obtained. This cutting level difference Hu and the maximum height Rmax of the amplitude probability density distribution
From the ratio (= Hu + Hd), the transportability index Ho is determined by the following equation (1).

Ho = {Hu / (Hu + Hd)} × 100 (%) (1) The slip index is compared by comparing the transportability index Ho with a preset reference value Hs. The presence or absence of occurrence is determined. Here, supplementing the transportability index Ho described above,
First, the fact that the transportability index Ho is small means that FIG. 3 (a)
Since the cutting level of the peak value C of the amplitude probability density distribution curve B is high as shown in FIG. 3, a deep valley and a plateau-like topography are shown as shown in FIG. Is easily worn away, the surface in contact with the roller becomes a smooth flat surface, and slip tends to occur. This tendency is remarkable especially on a soft surface such as a hot-dip galvanized steel sheet.

On the other hand, when the transportability index Ho is large, the cutting level of the peak value C is low as shown in FIG. 4A, and therefore, the steepness as shown in FIG. Represents a terrain with a high mountain, high peak N in this mountain
Does not disappear easily even when it comes into contact with the rollers, and maintains a frictional force, so that it has good transportability. However, increasing the transportability index Ho generally increases the surface roughening cost and adversely affects the finish quality of the painted surface. Therefore, the necessary Ho is added in accordance with the roller transport conditions. It is better to do so.

[0012]

Embodiments of the present invention will be described below.
As the material to be measured, standard; GA material thickness; 1.6 mm x width;
Table 10 shows the results of calculating the transportability index Ho by using the method of the present invention for 10 coils of hot-dip galvanized steel sheet, which are 1219 mm coils, and whether or not slippage occurs when the coil is subsequently transported as a blanking material by rollers. 2 is shown. Here, ○ indicates “no occurrence of slip”, Δ indicates “occurrence of slip”, and x indicates “occurrence of slip”. 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 in Table 2 are shown in FIGS. 5 and 6 in correspondence with the transportability index. Here, the slip occurrence index “0” means no slip occurrence, “1” means slip portion occurrence, and “2” means slip occurrence. As can be seen from comparison of these figures, it is difficult to determine the conventional three-dimensional surface roughness (SRa) in correspondence with the transportability index, but the transportability index Ho of the present invention is 2.
If it is less than 24% between 4 and 26%, slip occurs and 26%
It is clear that there is no occurrence of slip in the case of exceeding. Therefore, in the case of the above steel sheet, the reference value Hs of the transportability index is
If it is set in the range of 24 to 26%, it is possible to reliably determine whether or not a slip has occurred.

[0015]

As described above, according to the present invention, the level value corresponding to the peak of the amplitude probability density distribution is obtained,
Highest peaks of the level value and a sectional curve corresponding to this peak
From the minimum valley bottom to determine the transportability index from the ratio of the amplitude value between the lowest valley bottom, it is possible to make a highly accurate determination of the transportability of the roller, to ensure the presence or absence of slip
It is possible to predict and contribute to the improvement of the productivity of the press processing line.

[Brief description of the drawings]

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

FIGS. 2A and 2B are characteristic diagrams of (a) a sectional curve and (b) an amplitude probability density distribution curve.

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

FIG. 4 is an explanatory diagram of (a) an amplitude probability density distribution curve and (b) a cross-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 occurrence index.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel plate 2 Surface roughness sensor 3 Surface roughness measurement calculation device 4 Calculation result display device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-129545 (JP, A) JP-A-3-165210 (JP, A) JP-A-3-291511 (JP, A) 129810 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01B 21/30 102 B65G 13/00

Claims (2)

(57) [Claims] 1. A method of evaluating the transfer properties when transporting a metal plate with a roller, comprising the steps of creating a profile curve by measuring the surface shape of the metal plate surface over a predetermined length, the cross-section A step of creating an amplitude probability density distribution from a value of each height between the highest peak and the lowest valley of the curve, a step of obtaining a level value corresponding to a peak of the amplitude probability density distribution, Level value and the cross-sectional curve
Calculating the transportability index from the ratio of the amplitude value between the highest peak and the lowest valley , and setting the transportability index in advance.
Evaluate the occurrence of slip by comparing with the specified reference value
A method of evaluating roller transportability of a metal plate, comprising: 2. The roller transportability of the metal plate according to claim 1.
Evaluation method, the peak of the amplitude probability density distribution
Hu is the level difference between the corresponding level value and the highest peak.
And the level value corresponding to this peak and the lowest valley bottom
Assuming that the level difference is Hd, the transportability index Ho is Ho = {Hu / (Hu + Hd)} × 100% Defined by This Ho is compared with a predetermined reference value Hs set in advance.
In comparison, Ho <Hs Was evaluated as having a slip when
Characteristic evaluation method of roller transportability of metal plate.