JPH0622754B2 - All position piping automatic welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an all-position pipe automatic welding method which is performed by using a device for automatically welding large pipes such as a power generation boiler and a chemical device with a narrow groove.

<Prior Art and its Problems> Regarding connection of large-diameter pipes, conventionally, in a factory, a welding device was fixed and positioned, and a large-diameter straight pipe was rotated to perform butt welding. However, once the pipe is bent, if the straight pipe part that is to be butt-welded is to be rotated, the bent part at the other end becomes so-called "swinging", and even if the straight pipe part is firmly held, the rotating position of the pipe The force exerted on the holding portion changes due to the unbalance due to the weight of the bent pipe portion, which causes an unfavorable situation in the control of the welding speed. On the other hand, a space for swinging the curved pipe is required, which results in waste of safety and factory space. Therefore, a curved pipe is placed on a pedestal and a skilled welding operator repeats upward and downward manual welding, which makes it impossible to perform narrow groove welding with a groove width of 10 mm and delays the work process. , Increase in processing cost and cause problems.

Further, in a large-scale boiler or a chemical device for power generation, etc., the number of large-diameter pipes is large, and the number of butt-welding points for piping is enormous. In addition, such welding must be carried out at a high place in the field and in an environment with insufficient scaffolding, and it is strongly demanded to realize automatic welding with a narrow groove for large diameter pipes in order to obtain a safe and high quality welded portion. It's a place. This is also a strong demand for the practical application of this kind of narrow groove automatic welding for large diameter pipes not only for on-site welding alone but also for the partial assembly of pipes in factories. However, such a device has never been provided in the past.

However, the inventor has developed a device that solves this problem, and previously filed a patent application under the name of all-position pipe automatic welding device and disclosed the contents. (Japanese Patent Application No. 59-243479) It is necessary to propose a welding method for complete automatic welding of piping with this equipment.

<Purpose of the present invention> The present invention is based on the above-mentioned demands, and is a control box for a welding device developed by the inventor when butt welding a large-diameter pipe by a complete narrow groove automatic welding. It is an object of the present invention to propose welding conditions to be memorized in, that is, a welding method.

In short, the present invention relates to a method of welding a butt connection of pipes by a narrow groove automatic welding device which moves along the outer peripheral surface of the pipe, and in a transverse cross section of the pipe, an arc length of about 60 degrees is defined in a counterclockwise direction. About 1/2 the thickness, followed by about 120
The bead configuration is such that the arc length is the specified bead thickness, and the subsequent 60 degree arc length is about 1/2 the specified bead thickness.
And then forming a second bead with the same bead constitution as the above-mentioned bead constitution in the clockwise direction from the beginning of the specified bead thickness in the first bead to form a first weld layer, An initial welding start point of the first welding layer and an angle offset position that does not overlap in the radial direction of the pipe are set as welding start points, and a second welding layer is formed with the same bead configuration as the first welding layer, This is an all-position piping automatic welding method characterized in that a welding layer is laminated by repeating this process to form a welding connection portion.

<Example> First, an all-posture automatic piping device used for carrying out the present invention will be described.

FIG. 5 is a perspective view of a traveling automatic welding device which is a component of this welding device. The one shown in the figure is configured to run on a thick flat steel plate, and also functions as a device for confirming the operation as a pre-stage designed for piping.
The reel mount device indicated by reference numeral 1 is a device that includes a reel of welding wire rod and that supplies compressed air as a power source of the device that forms the wire rod in a wave shape to enable narrow groove welding. A welding wire rod (hereinafter simply referred to as a wire rod) 2 sent to the traveling automatic welding device 3 forms a corrugated wire rod through a roller device 5 as shown in FIG. 4. A pneumatic type corrugating device 4 (Japanese Patent Application No. 59-167299). ) To. The wire 2 is formed in a wavy shape in relation to the reciprocating movement of the wire feed roller set 4b connected to the pneumatic cylinder 4a, the fixed roller set 4c, and the wire inlet 4e at the upper end. When it is supplied into the passage of the welding nozzle 4d and protrudes from the lower end thereof, the elasticity of the wire rod forms an arc that swings left and right as shown in the drawing to enable narrow groove welding.
Reference numeral 6 is a vertical feeding device for the welding nozzle. Reference numeral 7 is a timer device provided in the operation panel for controlling a solenoid valve (not shown) for pressurized air in the reel mount device 1.

FIG. 3 is a partial cross-sectional view of the traveling automatic welding apparatus 9 according to the present invention, showing the speed reducer 8 of the apparatus for driving the wire feed roller group 4c. Reference numeral 10 is a welding nozzle 4d
It is an up-and-down feed mechanism of the device including the. The welding nozzle adjusting device in the groove width direction is not shown. Reference numeral 11 denotes an elastic guide roller device of the traveling automatic welding device 9, which is detachably attached to the axle 12 in a state where the devices are chain-connected.

FIG. 2 shows a state in which the device according to the present invention is attached to a large diameter pipe 13 for butt and narrow groove welding of a large diameter pipe.
The tow truck 15 is located on the axis 14 of the large diameter pipe 13 at a position symmetrical to the device 9, and its weight is almost equal to that of the traveling automatic welding device 9 so as to be balanced. This traveling automatic welding device 9
When simply connecting the tow truck 15 to the tow truck 15 with the chain 16, the chain 16 comes into contact with the outer surface of the large diameter pipe, which not only damages the outer surface of the large diameter pipe but also increases the driving force of the tow truck. .

For this reason, two tension carriages 17 for applying tension to the chains so that the chains 16 do not come into contact with the outer peripheral surface of the large diameter pipe are provided so as to face each other with respect to the large diameter pipe axis, and the weights thereof are assumed to be equal to each other. The resistance of the rotational movement, that is, the driving power is made small.

The tension trolley 17 is provided with a device utilizing a spring force or the like so as to absorb a slight change in the outer diameter of the pipe and to smoothly rotate the device to obtain a good welded portion.

The amount of the inert gas supplied before and after the arc for shaping the bead shape and improving the penetration is controlled, so that the bead formation during the upward and downward welding is suitable. (Japanese Patent Application No. 53-49220) Welding speed, supply voltage to welding equipment,
The feed rate of the wire rod and the amount of supply of the inert gas before and after the arc are adjusted by the welding device, that is, the position of the arc on the outer circumference of the pipe to be welded, and whether the welding is the up welding or the down welding. It is necessary to make adjustments, and these are running automatic welding equipment (arc) for the pipe to be welded.
The position and the traveling direction of the are determined as signals.
These control factors are inserted into a storage device in a control box (not shown), and a command signal from the storage device causes the control mechanism to instruct the numerical values of the above-mentioned various conditions.

Next, a method for welding pipes using the above automatic pipe welding apparatus will be described.

FIG. 1 shows the welding sequence from the first layer. In the first layer welding, it is necessary to consider means for preventing the occurrence of defects at the welding start portion. For this reason, first, the condition of the welding position is taken into consideration according to the time division when the cross section of the illustrated pipe is viewed on the watch face, and the control box is inserted. As an example, first, at a position of 7 o'clock, the welding condition is 1/2 of the weld bead wall thickness of 1 pass, and welding is performed until 5 o'clock in the counterclockwise direction. Then, while forming a weld bead with a prescribed weld bead wall thickness, that is, twice the wall thickness between 7 o'clock and 5 o'clock, weld up to the point at 1 o'clock, and then again under the condition that the weld bead has a thickness of 1/2. Welding is performed between 1 o'clock and 11 o'clock to form a welded portion 1R (first bead, FIG. 6 (A)).

Then, while forming the weld bead wall thickness corresponding to the wall thickness from 5 o'clock to 7 o'clock, welding proceeds in the clockwise direction from 5 o'clock to 7 o'clock, with the specified bead wall thickness from 7 o'clock to 11 o'clock, and From 11:00 to 1:00, welding was performed to form a wall thickness that is 1/2 of the specified bead thickness, and the first layer 1L [second bead on the left half of the drawing]. FIG. 6 (B)] is formed. The 1L and 1R form a first welding layer.

For the second layer, remove the position at 7 o'clock, for example, from the position at 7:30, weld a half wall thickness at a section of arc length of 60 degrees, and then weld a specified bead wall thickness from 1:30 to 11 By the time of 30 minutes, the welding of 1/2 thickness is made and the second layer welding 2R of about half circumference is formed.

Similarly, from 5:30 pm, weld 1/2 thickness weld clockwise at 7:30 pm
Perform up to 0 minutes and then weld to the specified thickness until 11:30, 1
By the time 30 minutes, the welding of 1/2 thickness is made and the second layer welding 2L is formed to complete the welding of the second layer. A second welding layer is formed by 2R and 2L.

This welding is repeated to sequentially weld the third and fourth layers to complete the weld connection of the pipes.

In the control box, the feeding speed at 1 o'clock, 2 o'clock, ... 12 o'clock,
Automatic welding is performed by inserting the supply amount of the gas before and after the arc of the inert gas and the conditions of the welding up and down.

<Effect> Staggering the welding start point at 5 o'clock and 5:30 pm, 7 o'clock and 7:30 pm prevents the occurrence and continuation of welding defects, and the welding of the specified bead layer thickness is the half bead. This has an effect of melting and removing a defective portion generated at a thick welding start point.

In addition, welding with a narrow groove such as 10 mm not only saves welding time and material, but also has a great effect on forming a good weld with less drooping of beads when moving up and down.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a welding connection portion schematically showing a welding sequence according to an embodiment of the present invention, and FIG. 2 is a front view showing an arrangement of constituent members of an automatic welding apparatus used for carrying out the present invention. FIG. 3 is a partial cross-sectional side view of the automatic traveling welding apparatus, FIG. 4 is a front view showing an example of a pneumatic wave corrugating apparatus, and FIG. 5 is a traveling automatic welding apparatus and reel mount used for welding thick steel plates. A perspective view of the apparatus, FIG. 6 (A) shows beads 1R, (B) shows 1
L, (C) are 2R, (D) is a drawing which shows the cross section of a 2L welding bead, respectively. 1 …… Reel mount device 16 …… Chain 2 …… Welding wire rod 3,9 …… Running automatic welding device 11 …… Elastic guide roller device 13 …… Large diameter pipe 17 …… Tension truck 15 …… Travel truck 1R… … Nearly right half of the first layer 1L …… Bob left half of the first layer 2L, 2R …… Second layer bead

Claims (1)

[Claims] Claim: What is claimed is: 1. In a method of welding a butt joint of pipes by a narrow groove automatic welding device that moves along the outer peripheral surface of the pipe, a welding bead defining an arc length of about 60 degrees in a counterclockwise direction with respect to a transverse section of the pipe. A first bead having a bead configuration of about ½ thickness, then about 120 ° arc length with a specified bead thickness, and further about 60 ° arc length with about ½ of the specified bead thickness. And then forming a second bead with the same bead structure as the bead structure in the clockwise direction from the point where the specified bead thickness of the first bead starts, and then forming the first welding layer. The first welding start point of the welding layer and the position where there is no angular overlap in the radial direction of the pipe are set as the welding start point, and the second welding layer is formed with the same bead configuration as the first welding layer, and this repetition is repeated. To form a welded connection by stacking welded layers. All Position pipe automatic welding method comprising.