JPS5997003A - Measurement of weld penetration depth - Google Patents

Abstract

PURPOSE:To minimize the errors in the measurement of weld penetration depth by resetting a reference value of an echo level from the web bottom surface at the position separated from the welded section each time a probe performs one reciprocation of scanning to measure the weld penetration depth. CONSTITUTION:A probe 5 scans over a web 1 through a contact medium 4 and is inserted into a support 7 having a fixing rod 6 extending vertically. A reference value HBS of an echo level from the bottom surface of the web 1 is updated each time the probe 5 performs one reciprocation of scanning and the average value HBS1 thereof is used as reference value of the bottom echo level in the measurement with subsequent one reciprocation of the probe. This method can minimize errors in the measurement of weld penetration depth to accompany with the variation in the bottom echo level depending on its location.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for measuring penetration depth of bridge joints.

Square joints made by welding steel plates 1 and 2 as shown in Figure 1 are often used in bridges, but in this joint, it is necessary to check whether the penetration depth D of the welded part 3 satisfies the specified value. Confirmation by ultrasonic testing is required. In addition, steel plate 1
is hereinafter referred to as a web, and the steel plate 2 is referred to as a 7 lunge.

The penetration depth is measured by the method shown in FIG. 2. That is, as shown in FIG. 2, when a couplant 4 is applied to the surface of the web 1 to be scanned with the probe, and the probe 5 is pressed against this medium 4 and scanned in a direction perpendicular to the weld line, the welding is performed. At a position away from the part 3, a reflected wave from the bottom surface of the web 1 is obtained, whereas in the welded part 3, the ultrasonic wave passes through the welded part 3, so the echo height of the reflected wave changes as shown in the figure. As is clear from FIG. 2, when the center of the probe 5 is directly above the penetration tip of the weld 3, half of the ultrasonic waves that reach the bottom of the web 1 generate reflected waves, so at this position, The echo height at a position away from the welding part 3 is HB, ). As a result, the penetration depth can be measured by searching for this position.

By the way, when measuring the penetration depth by automatically scanning the probe using the above principle, conventionally, the reference value (H
As B8), values measured at specific points on the web were used. However, in actual product inspection, the value of HB varies depending on the location due to the influence of the surface condition of the bridge web, the distance between the probe tip and the web surface, etc.
The method of fixing B has the disadvantage of causing measurement errors.

The present invention has been made to solve the above-mentioned drawbacks.
When measuring penetration depth by automatically scanning the probe, -
By setting the reference value (H!I8) of the echo height for each round trip, and finding the average value of the echo height (HB) for the scanning length that is equal to the reference value (HBII),
The present invention aims to provide a method that can measure penetration depth with little measurement error by minimizing variations in echo height depending on location.

Next, embodiments of the present invention will be described with reference to FIGS. 3 to 5.

FIG. 3 is a schematic diagram showing one form of an apparatus used in the penetration depth measuring method of this embodiment. 5 in the figure is a probe that is scanned over the web 1 via the couplant 4. This probe 5 is inserted into a support 7 having a fixing rod 6 extending in the vertical direction. The probe 5 is connected to an ultrasonic flaw detector 8. In addition, 9 in the figure is a running trolley that runs in the Y direction along the rail 1o installed on the web 1.
The probes 5 are placed on this traveling carriage 9 by arrows x, x'
A probe traverse mechanism 11 for scanning in the lateral direction is provided as shown in FIG. This traversing mechanism 11 includes a cylinder section 12 installed on the truck 9, and an operating rod 13 that moves in the direction of the arrow X with the cylinder section 12 and whose tip is engaged with the fixing rod 6 of the support body 7. It is composed of. Furthermore, 1 in the figure
Reference numeral 4 indicates an output signal from the flaw detector 8 and a position detector 1 attached to the cylinder portion 12 of the traveling truck 9 or the traversing mechanism 11.
51.15. This is an automatic judgment device that automatically judges the penetration depth by receiving the output signal.

Next, the penetration depth measuring method of the present invention will be explained.

(1) First, a measuring device as shown in FIG. 3 is set at a predetermined location on the surface of the web 1 of the bridge, and then the couplant 4 is applied to the inspection area of the surface of the web 1.

(11) Adjust the amplification degree of the ultrasonic flaw detector 8 so that the echo height of the reflected wave from the bottom of the web 1 at a position away from the welding part 3 becomes 70% on the screen of the flaw detector 8. settings and shoot.

011) Start the probe traverse mechanism 1 and press its operating rod 13
The probe 5 supported by the υ support 7 is
Start moving in the direction (to the left). At this time, probe 5
enters the HB measurement area shown in FIG.
is the height of the bottom echo of web 1, 10 times in total at a pitch of 1 m.
n) is read 9 and its average value HBB1 is determined. The probe 5 is further moved in the X direction in FIG. 4, and when the bottom echo depth of the web 1 reaches HBllll/2, the automatic judger 14 detects the signal from the position detector 151 provided in the traversing mechanism 1. Then, the penetration depth of the welded portion 3 is calculated and displayed.

(IV) When the probe 5 reaches the leftmost end of the planned scanning pattern, the movement in the
0 in the Y direction (forward direction) at a predetermined pitch as shown in FIG.

M The traversing mechanism 11 is activated again, and the probe starts moving in the X/direction (rightward) as shown in FIG. Then,
The automatic determination device 14 performs the same processing as in the 0ψ process described above to calculate and display the penetration depth.

(vl When probe 5 reaches the rightmost end of the planned diagram,
The movement in the X' direction is stopped, and the carriage 9 moves along the rail 10 at a predetermined pitch in the Y direction (forward direction) as shown in FIG.
Move to.

Hereinafter, the same process as in steps (1) to (vti) above is performed to measure the penetration depth of the welded portion 3 over the entire lengthwise direction.

Therefore, the present invention updates the reference value HBB of the bottom echo height of the web 1 every time the probe 5 scans one reciprocation as shown in FIG. Since HB tends to decrease at the position where the monk is monked, move about 10mm from the point moved 5+mn to the left from this position.
In this method, the bottom surface echo height of the web 1 is measured in the range of , and the average value HBSI is used as the reference value for the bottom surface echo height in the next round-trip measurement of the probe. Therefore, it is possible to minimize the measurement error of the penetration depth due to the variation of the bottom echo height depending on the location, and as a result, the strength of the bridge can be determined more accurately.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing a corner joint of a bridge, Figure 2 is a schematic diagram illustrating the principle of measuring the penetration depth of a weld in a square joint of a bridge, and Figure 3 is a diagram illustrating the penetration depth of the present invention. FIG. 4 is a perspective view illustrating the scanning locus of the probe on the web, and FIG. 5 is a schematic diagram showing one form of the device used in the penetration depth measuring method of the present invention. It is a schematic diagram for explaining. 1... Web, 2... 7 lunges, 3... Welded part,
5...5 probe, 8...ultrasonic flaw detector, 9...traveling trolley, 11...probe traverse mechanism, 14...automatic determination device. Applicant's sub-agent Patent attorney Takehiko Suzue Measurement location Figure 3 L Figure 4 Figure 5 Section Tsukishi issue A/e (IL

Claims (1)

[Claims] Ultrasonic waves are incident perpendicularly from the web surface of the bridge angle joint from the probe and the reflected waves from the bottom of the web are detected, and the echo height is the same as the echo height at a position away from the welded part. In the method of measuring the penetration depth by determining the penetration depth, the reference value of the echo height of the bottom surface of the web at a position away from the weld is reset every time the probe scans back and forth. A penetration depth measuring method characterized by measuring.