JPS6221009A - Root gap measurement for single-side welding - Google Patents

Abstract

PURPOSE:To enable a better single side welding, by measuring the position of the groove bottom in a single-side welding to determine the root gap value, on which a proper welding condition is selected. CONSTITUTION:A backing material 31 coated with an SiO2 based black paint is abutted on the back of a groove of an object 5 to be welded. A light receiver of a height measuring device 1 using a laser light scans at a fixed speed above the object facing the groove face to receive the reflected laser light made to irradiate from the unit 1. In the measurement at the position 1a, the reflected lights 101 and 102 are made incident into the light receiver via the points P1 and Q1. In this case, the height is obtained as the position determined by the averaging of the intensity of lights at both the points. In the measurement at the point 1b, though the points P2 and Q2 are very close, the coating of the paint 100 prevent the effect of the secondary reflection on the reflection intensity at the point Q2 allowing the measurement of the height of the groove face at the groove bottom. From a measuring point train in the surface of the object 5 being welded obtained by said method, the position of the groove bottom in a single-side welding is calculated to determine the root gap value. On the basis of a proper welding condition is selected thereby assuring a better backing bead.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a method for measuring a root gap for single-sided welding.

[Prior art and its problems]

Conventionally, distance meters that use laser light to detect the groove shape have begun to be used, and a method has been adopted in which the distance meter is oscillated across the weld line and distance data is taken intermittently. When welding a steel plate on one side, the backing material used is a stack of glass tape, or a thin cellophane or plastic sheet covering the tape. When such a material receives the laser beam reflected from the groove, it reflects with a high reflectance, which may affect the signal system on the laser beam receiving side. This tendency is caused by the fact that when measuring a position near the groove root surface close to the backing material side, the secondary reflection intensity is high and the indicated value at the measurement point differs from the actual value. This makes it impossible to measure the root gap. Therefore, by feeding back the route gap,
The method of automatically setting single-sided welding conditions cannot be adopted. Welding conditions are related to penetration and the amount of welding, so it is necessary to adopt values that correspond to the root cap, but it is extremely difficult to maintain a constant root gap in curved plates, on-site construction, etc. Therefore, finding the root cap above is the M arrow when welding automatically and without supervision.
The welding conditions to be fed back during automatic welding can be determined in advance by changing the size of the root gap, the plate thickness, etc. in real numbers, and setting the results in a table.

[Failure to solve the problem]

In the present invention, a bracing material whose surface is coated with a black paint mainly composed of S10° is attached to the back side of the groove of a welded object, and the material is placed above the groove and facing the groove surface. A light receiver of a height measuring device using a laser beam is scanned at a predetermined speed, the reflected light of the laser beam irradiated from the measuring device to the groove is received by the light receiver, and a predetermined calculation process is performed. This is a method for measuring the root gap for single-sided welding, which is characterized in that the black paint is applied with a brush, air spray, etc.
It is desirable to apply the coating to a thickness of about 80 μm.

If the coating thickness is less than 20μ7n, use glass tape as the entire backing material. Low reflectance of cellophane sheets, etc. Furthermore, if the thickness of the coating exceeds 80 μm, an increase in gas components and an unnecessary increase in StZ occur, making it impossible to perform good measurements.

[Action of the invention]

According to the root gap measurement method for single-sided welding according to the present invention, the bottom of the groove is measured using a laser beam.The backing material reflects the light reflected from the groove surface to the backing material side again. ,
The height of the groove surface at the bottom of the groove can be clearly measured without affecting the light receiving element of the light receiver. Since the groove surface at the bottom of the groove can be clearly measured in this way, the root gap of the groove can be reliably measured. Furthermore, since the root gap can be measured, good single-sided welding can be achieved by selecting welding conditions according to each root gap determined in advance by a test.

[Embodiments of the invention]

Hereinafter, the real k column of the present invention will be explained with reference to the drawings. FIG. 1 is an explanatory diagram showing an embodiment of the present invention. In the figure, 1 is a height measuring device consisting of a distance measuring device using a laser beam. The installation position of the height measuring device 1 is
This is above the groove surface 3 formed by gas cutting on a 2 tll steel plate 5. The height measuring device 1 is provided with an oscillator 2 that is driven by a motor over a constant width.

The height measuring device 1 is connected to a 16-bit microcomputer or lateral control device 4 via a control cable 41. The control device 4 is connected to a welding power source 61 via a control cable 41. The welding power source 61 includes
One welding nozzle is connected via a cabtire cable 62. A welding control drum 5 is connected to the control device 4 via a control cable 41. A wire feeding motor 10 is connected to the welding control vane 51 via a control cable 41. The control device 4 includes
Control cable 41. Wheels 53 for running the welding machine are provided by sequentially controlling the motor 52 for moving the welding machine. The welding nozzle 11 is connected to the welding nozzle 11 through a wire feed motor 10.
An i-Mn wire 13 is supplied. On the back side of the groove, a backing material 31 is provided in which a glass tape 34 is layered on a refractory material 32 with a solid flux 33 interposed therebetween and the entire surface is covered with a thin film 35. Backing material 31
On the thin film 35, a 5iO1 black paint 100 is applied with a brush to a thickness of about 30 μm. In addition, 1 in the same figure
2 is a sto, -MnO-CaO system 7 racket filled in the groove, and 6
3 is a cabtyre cable connected to a welding power source 6.

Welding is performed by the submerged arc welding method using the welding mechanism configured as described above, and the root gap for single-sided welding is measured as shown in FIG. That is, the height measuring device 1 is
The groove portion 3 is crossed and the position is changed as shown by 1a and Ib in the figure. At position 1a, the reflection 10 of the laser beam
1°102 enters the light receiver at position 1a directly from 28 points or via 91 points. In this case, the height is 2
It is determined as the average position of the light intensities at 3 points and 91 points. If the distance from point 21 to point 97 is long, the intensity of light from point 98 will be extremely weak, so point 21 is marked as the measurement point.

Further, at the position 1b, the reflected lights 103 and 104 enter the light receiver at the position 1b from 21 points or via the Fiqz point. In this case, although points 26 and Q1 are close, the reflection intensity at point 92 is not affected by secondary reflection because the StO, point color paint 100% is applied, and the groove surface at the bottom of the groove is clearly visible. The height of the can be measured. In actual application, the height measuring device 1 was oscillated at a speed of 301/cm and measurement points were obtained at a frequency of 256 Hz.According to these conditions, the points indicated by the black circles in Fig. 3 were measured. The indicated point is 0
．． It can be determined as measurement points at 12” intervals.

Still, the measurement point array on the surface of the steel plate 50 is 6111 in total on the groove surface 3.
Set up a straight line equation for the points that change into a series of points and solve it, A(”
a m'/a) e C("6 * 3' (
: ) was sought. Then, '/B '/B * ”/
(H-ytl is the point B(t
, *yb)*Point D(x6*3'di) The plate thickness was determined by calculating the depth direction using the slope of the surface of steel a5 as a reference plane.

The distance between xb and xd causes a maximum tolerance of 0.241111, but it is not a size that is harmful to the setting of welding conditions.

The root gap was found by calculating the F device b-"d)"86557 0 Welding conditions were selected from the root gap found in this way and the appropriate welding conditions shown in the table below, which was determined in advance from another experiment. Then, a control signal was sent to the welding machine to set the welding current. Welding was carried out by giving the welding voltage as a reference value and the welding speed as a seven-taper rotation speed. In this way, a submerged arc weld bead with a good back bead shape could be obtained.

Table [Effects of the Invention] According to the method for measuring the root gap for single-sided welding according to the present invention, the root gap value is determined by measuring the position of the bottom of the single-sided welding groove, and appropriate welding conditions are selected based on this. , it is possible to obtain a good underwave bead.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the principle of height measurement, and FIG. 3 is an explanatory diagram showing the procedure for measuring the root gap. 1... Distance measuring device using laser light, incorporating a light emitting device and a light receiver, 2... Oscillator of the distance measuring device,
3... Gas cut groove surface, 4... Control device, 5...
... Steel plate to be welded, 3I ... Backing material, 32 ... Fireproofing agent, 33 ... Solid flux, 34 ... Glass tape, 35 ... Thin film, 100 ... Sing-based black paint, DESCRIPTION OF SYMBOLS 12... Flux for submerged arc welding, 13... Wire for welding, 10... Sear pongee motor, 11... Welding nozzle, 41... Control cable, 51... Governor for welding control , 52... Welding machine feeding motor, 53...
- Welding machine running wheels, 61... Welding power source, 62,
(i 3... Gear tire cave knob.

Claims (1)

[Claims] A backing material whose surface was coated with a black paint containing SiO_2 as a main component was brought into contact with the back side of the groove of the object to be welded, and a laser beam was applied above the groove and facing the groove surface. A light receiver of a height measuring device is scanned at a predetermined speed, and a reflected light of a laser beam irradiated from the measuring device to the groove portion is received by the light receiver, and a predetermined arithmetic processing is performed. Root gap measurement method for single-sided welding.