JPH02129547A - Flaw detecting method for whole surface of steel plate - Google Patents

Abstract

PURPOSE:To eliminate an useless process and to improve the efficiency for a flaw detection by eliminating a returning movement to an original point in the Y-direction after the scanning in the X-direction for a back end edge at the cycle just before the final scanning on the back end of a steel plate. CONSTITUTION:A starting position of the flaw detecting head 2 for the flaw detection scanning is set at a forward end side of the steel plate 1, and a remaining length of the steel plate 1 is measured while successively repeating an orthogonal quadrangle scanning for flaw detection. Based on this result, a timing of the orthogonal quadrangle scanning for flaw detection just before the final scanning is detected. At the scanning cycle n, n+1, n+2 just before the final scanning, the present position for the head is kept without returning to the original point in the Y-direction. After the steel plate 1 is forwarded by an adjacent interval l2 of contact probes 21 to the Y-direction at the final scanning cycle n+3, n+4, n+5, the head is made to move successively to the X- and Y-directions inversed from the usual direction, to return to the original point 0. Thus, the useless process is eliminated and the efficiency for the flaw detection can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an automatic ultrasonic flaw detection method, and more specifically, to a full surface flaw detection method for steel plates such as thick plates.

(B) Prior art As a typical example of a conventional full-surface flaw detection method for a steel plate, as shown in FIG.
2 and the specified flaw detection width 1. A flaw detection head 2 is used in which a predetermined scanning width is formed by differentiating a plurality of probes 21 having . The flaw detection head 2 performs orthogonal quadrilateral flaw detection scanning.

This orthogonal quadrilateral flaw detection scanning is a scanning method in which the flaw detection head 2 is alternately reciprocated in the X direction perpendicular to the Y direction and in the Y direction, and returns to the origin O by four movements ■, ■, ■, ■. be. Move in the X direction■ and ■for flaw detection scanning, and move in the Y direction■
, ■ is made equal to the above-mentioned interval j12.

This orthogonal quadrilateral flaw detection scan is repeated multiple times in the Y direction at a pitch of the scan width (L).

In such conventional flaw detection methods, at the rear end of the steel plate,
There is a wasted journey of moving in the Y direction for j2 minutes to follow the tail end, resulting in a decrease in flaw detection efficiency.

A device that performs full-surface flaw detection in a combination of the X and Y directions has been proposed (Japanese Unexamined Patent Publication No. 59-105559). This device is an automatic ultrasonic flaw detection device for steel plates that scans in the It consists of a central flaw detection mechanism that detects flaws, and an edge flaw detection mechanism that detects flaws at the leading and trailing ends of the steel plate in the longitudinal direction (Y direction). It is designed to detect flaws on the entire surface of the steel plate, including the four periphery areas.

However, this device does not disclose a specific scanning method at the rear end of the steel plate.

(C) Problem to be solved by the invention Problem C to be solved by the present invention is to eliminate wasteful steps in the final scanning cycle in a steel sheet full surface flaw detection method in which orthogonal quadrilateral flaw detection scans are repeated multiple times. The purpose is to improve flaw detection efficiency.

(d) Means for Solving the Problems The full surface flaw detection method for a steel plate according to the present invention is based on a flaw detection method in which a predetermined flaw detection width (e,
The flaw detection head, which has a predetermined scanning width (L) formed by stacking a plurality of probes having , and perform orthogonal quadrilateral flaw detection scanning in which the X direction movement is used for flaw detection scanning and the Y direction movement distance is the interval j2, and the orthogonal quadrilateral flaw detection scanning is repeated multiple times in the Y direction at a pitch of the scanning width (L). In the full-surface steel plate flaw detection method, the flaw detection scanning start position of the head is set to the tip side of the steel plate, the remaining length of the steel plate is measured while sequentially repeating the orthogonal quadrilateral edge flaw detection scan, and the timing of the orthogonal quadrilateral flaw detection scan just before the final one is determined. is detected, and in the scanning cycle, the head is held at the current position without returning to the origin in the Y direction, and in the final scanning cycle, the tail end of the steel plate is at a predetermined position in the Y direction. by a means for returning to the origin by sequentially moving in the X and Y directions in the opposite direction to the movement direction after advancing by
The above issues have been resolved.

(E) Embodiment An embodiment of the method for detecting flaws on the entire surface of a steel plate according to the present invention will be described with reference to FIG.

In the method of the present invention, the above-described orthogonal quadrilateral flaw detection scans ■, ■, ■, ■ are repeated multiple times in the conveying direction (Y) of the steel plate 1, but the last and immediately preceding scan cycles are different from those of the conventional method. The difference is as follows.

First, the flaw detection scanning start position of the flaw detection head 2 is set on the tip side of the steel plate 1, and the remaining length of the steel plate is measured while sequentially repeating the orthogonal quadrilateral flaw detection scan. Based on the results, the timing of the last orthogonal quadrilateral flaw detection scan is detected.

The current position is held without returning to the origin in the direction. After moving forward over the adjacent interval j of 21, the movement direction is sequentially moved in the opposite direction to the movement direction in the X and Y directions (([[su, (
耼 Bow Ω (Yo)) Return to the origin O.

The following methods are available for measuring the remaining length of a steel plate.

A flaw detection cycle (
4m at one time), and specify the stop length in the steel plate feed command based on the calculation result. For constant zero tail stop, stop at a fixed point using a proximity switch, etc., and decelerate immediately before that. Stopping accuracy is further improved. On the other hand, if the total length of the steel plate does not change, a tail end detector is placed on the downstream side at an interval of one cycle, and the detection detects that the next feed will be at the tail end stop. , a detector located a little apart from the stop position starts deceleration, and a fixed-point detector stops the tail end at a fixed position.

Probe spacing j! Flaw detection was performed using an actual flaw detection device with 2=20111I+ and a scanning width L=4 m. As a result, Y
There is no difference in cycle time because the direction return (movement to return to origin) is while the steel plate is moving. However, after the final end stop, it conventionally takes about 5 to 10 seconds to move in the Y direction to align the tail end. However, by scanning according to the present invention, the time required for scanning could be significantly shortened to 1 to 3 seconds.

(f) Effects According to the present invention, there is no return-to-origin movement in the Y direction after the trailing edge of the steel plate is scanned in the Since recovery is possible, wasteful processes can be eliminated and flaw detection performance can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the method for detecting flaws on the entire surface of a steel plate according to the present invention. 1: Steel plate 21: Probe flaw detection head (4 people outside)

Claims (1)

[Claims] The above Y The four orthogonal sides are made to alternately reciprocate in the X direction perpendicular to the direction and the Y direction and return to the origin after four movements, and the X direction movement is used for flaw detection scanning, and the Y direction movement distance is the interval l_2. The scanning width (
In the steel plate full surface flaw detection method that is repeated multiple times at a pitch of L), the flaw detection scan start position of the head is set on the tip side of the steel plate, and the remaining length of the steel plate is measured while sequentially repeating the orthogonal quadrilateral flaw detection scan, and the final flaw detection scan is performed. The timing of the immediately preceding orthogonal rectangular flaw detection scan is detected, and during this scan cycle, the head is held at the current position without returning to the origin in the Y direction, and in the final scan cycle, the steel plate is moved to the Y direction. 1. A full surface flaw detection method for a steel plate, characterized in that the steel sheet is moved forward in the direction until the tail end reaches a predetermined position, and then sequentially moved in the X and Y directions in the opposite direction to the direction of movement to return to the origin.