JPS63104797A - Production of welded steel pipe - Google Patents

Abstract

PURPOSE:To improve welding quality and to stabilize welding by measuring the thickness size in both edge parts of stock steel sheets, then adjusting edge prepn. positions and welding conditions in accordance with the measured thickness size, groove size, etc. CONSTITUTION:The thicknesses in both edge parts of the steel sheets S are measured by a measuring instrument A and the edge prepn. is executed by a profiling roll 7, cutter 1, etc., of a milling type end face working machine for steel sheets to the measured thickness values. The steel sheets S are pressed after the edge prepn. and are formed by an O press, then the inside and outside faces in the butt part are welded. The edge prepn. position and welding conditions are adjusted in accordance with the measurement data of the thickness size or the groove size or the data on both thereof at this time. The size of the butt part is assured and the buckling and melt down by the butt pressure are prevented. The welding quality is, therefore, improved and the welding is stabilized.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a welded steel pipe.

[Conventional technology]

In the manufacturing process of welded steel pipes (e.g., UOE pipes, spiral vss roll hend V, etc.), generally welding methods promote penetration, reduce weld bead excess, and trace weld lines (usually, seam guide rollers are used on the inner surface, and various sensors are used on the outer surface. Bevel processing is applied for such purposes as one-sided type).

Figure 5 shows the manufacturing process of UOE steel pipe.
Prior to forming, the inner and outer surfaces of the butt portions of the steel plates are beveled.

Conventionally, an edge braner has been used for the beveling of welded steel pipes, but from the viewpoint of ease of processing chips, space, equipment costs, etc., a milling-type steel plate end face processing machine as shown in Figure 6 has been adopted. Processing has begun. This processing machine is equipped with board feed rolls (2a) (2b) (input side and exit side pinch rolls) on the entry and exit sides of a pair of disc-shaped cutters (1), and a board feed roll on the entry side. (2a)
Side guide rolls (3a) and (3b) are provided at each position on the front surface of the paper and on the rear surface of the temporary feed roll (2b) on the exit side.

In beveling with such a milling-type steel plate edge processing machine, the thick plate of material is not necessarily flat, so the cutter must be fixed (as shown in Figure 7, the beveling in the longitudinal direction of the plate is uneven). This results in the following problems during butt welding.

(1) Dimensions of the butt part become smaller, causing buckling due to butt pressure and welding welding to drop. (2) Due to uneven groove dimensions, welding welding becomes uneven and bead shape. A problem occurs.

Therefore, in order to make the groove uniform in the longitudinal direction, a mechanism is usually provided for cutting along the plate surface as shown in FIG. 9. This copying mechanism is.

A holding body (4) of a cutter (1) is held by a hydraulic cylinder (5) so as to be able to be excited up and down using a pivot point (6) as a fulcrum;
A copying roll (force) is attached to the holder (4) to be in contact with the upper surface of the steel plate (S), and the copying roll (7) presses the steel plate (S) against the fixed roll (8) while opening the steel plate (S) with the cutter. The tip is processed.

FIG. 8 shows the groove shape obtained by such a tracing method.

[Problem that the invention seeks to solve]

However, even when such a tracing method is adopted, the thickness of one edge of the steel plate is
If the plate thickness differs from the designed thickness due to roll crown or the like, the same problem as in (1) above will occur. This is because when the plates are formed into a tube shape and the grooves are butted against each other, the lower surface of the plate becomes the outer surface of the tube, and this outer surface side of the tube becomes the reference surface during welding.

To solve this problem, we developed a method (see Fig. 10) in which the bottom surface of the plate, which is the reference surface during welding, is copied using a copying roller (7).
According to this method, the first
The dimensions of the abutting portion can be ensured as shown in Figures B-■ to ■. However, this method has the following mechanical problems. In other words, the copying mechanism requires the entire cutter to be pushed up by a hydraulic cylinder and the copying roll to press the steel plate against the fixed roll, but in the bottom copying method, the weight of the cutter itself cannot be used to push the steel plate with the copying roll; For cutting, a large hydraulic cylinder is required to obtain the force, and for this reason, it is necessary to increase the strength of the entire cutter, and in addition, it is necessary to adjust the fixed roll when the pass level changes due to changes in plate thickness. There are some mechanical problems in practical use, such as being complicated.

In addition, even if the thickness of the steel plate is the same on both edges, if the overall thickness is too thick or too thin, simply beveling the top surface will result in the same problem as shown in Fig. 1A-0.

As shown in (2), all the differences are pushed to the outside surface of the tube, resulting in problems such as a lack of uniformity in welding quality and bead appearance.

The present invention was made in view of such conventional problems,
It is an object of the present invention to provide a method for manufacturing a welded steel pipe that secures the dimensions of the abutting part using the top surface scanning method, and has a welded part with good and uniform quality and bead appearance.

[Structure of the invention]

For this reason, the present invention provides a method for manufacturing a welded steel pipe that includes a beveling process of a raw steel plate, in which the thickness of the inner edge of the raw steel plate is measured, and the beveling position is adjusted based on the thickness. is its basic feature.

In addition, the present invention measures the thickness of the edge portion of the raw steel plate, adjusts the groove processing position based on the thickness, and welds based on the thickness and/or groove size of the raw steel plate. Another basic feature is adjusting conditions.

The present invention will be explained in detail below.

In the beveling process using the top surface scanning method, the present invention includes:
The thickness of the inner edge of the steel plate is measured, and the beveling position is adjusted based on this thickness. Specifically, by adjusting the relative position of the cutter and the plate using a copying roll, the groove dimensions on the inner and outer surfaces are changed to obtain the optimum groove dimension.

FIG. 1C-■ to C-■ show the state of the groove abutting portion according to the method of the present invention.

A specific processing method will be explained below with reference to this.

For example, in the case of a designed plate thickness t"14.Osm, the following method is adopted based on the measured plate thickness.

■The measured value of the plate thickness at the edge is t=14.0 on the a side.

If t = 12 and Om on the b side, adjust the copying roll on the b side and increase the outer surface groove on the b side by 2 m in Fig. 1 C-■
You will get a butt part like this.

■The measured value of the edge plate thickness is t=14.0m on the a side and t='16 on the b side. If Om, the copying roll on the b side is adjusted to reduce the outer surface groove by 21 minutes to obtain a butt portion as shown in FIG. 1C-■.

■The measured value of the edge plate thickness is 1 = 1 for both a @ * b side
In the case of 2.0 m, adjust the copying rolls on the a side and b side to obtain the optimal groove size for t = 12.0 m, and then
Obtain a butt part like ■.

■The measured value of the edge plate thickness is t=16 on both the a side and b side.
In the case of 0 m, adjust the tracing rolls on the a side and b side to get t=
The optimal groove size is set to 16.0■, and a butt part as shown in Fig. 1 C-■ is obtained.

In addition, in the case of extremely different plate thicknesses in (1) and (2) above, the difference in the dimensions of the inner and outer grooves on both sides can be reduced by adjusting the copying roll. .

Based on the data of the edge plate thickness measurement dimensions and/or groove dimensions described above, tack bonding in the subsequent process,
The welding conditions for external welding can be adjusted, thereby ensuring welding stability.

Figures 2 to 4 show the welded pipe manufacturing process applying the method of the present invention, of which Figure 2 shows the UOE'1fnK manufacturing process, Figure 3 shows the spiral pipe manufacturing process, and Figure 4 shows the roller manufacturing process. This is a bent pipe manufacturing factory.

In the UOE'ii manufacturing process shown in Figure 2, the measuring device (A)
The thickness of the steel plate edge is measured.

Based on this measured value, beveling is performed by the above-described tracing method. After this processing, the steel plate is formed by a U press and an O press, and after cleaning, the abutting portions are temporarily welded, and the inner and outer surfaces are further welded. In such a process, the measurement data of the plate thickness dimension and the measurement data of the groove dimension after beveling are supplied to the tack welding machine, internal welding machine, and external welding machine, and welding is performed according to these measurement data. Conditions are adjusted.

In the spiral tube manufacturing process shown in Fig. 3, (9) is an uncoiler, C1G is a strip leveler, υ is an end strip welder, and 0 is a leveler.

C3 is the end face processing machine, α is the main drive roll, al
is a preforming roll, (16) is a forming machine, qη
1 is an automatic welding machine for internal and external surfaces, and 1 is an old ultrasonic flaw detector.

(1G is a traveling cutting machine. After the thickness of the edge portion of the strip steel plate (S) is measured with the measuring device (A), beveling is performed using the above-mentioned tracing method based on this measurement value. After this processing, the steel plate (S) is formed into a spiral shape by forming rolls, and the inner and outer surfaces of the seam are sequentially welded by an automatic inner and outer welding machine aη. Also, the groove dimension data after groove processing is supplied, and the welding conditions are adjusted accordingly.

In the roller bending tube manufacturing process shown in FIG.

After the thickness of the edge portion of the steel plate is measured by the measuring device (A), beveling is performed using the above-mentioned tracing method based on this measured value. After this processing, the ends of the steel plate (S) are rounded.

Next, it is formed into a perfect cylinder using bending rolls, and the mating portions of the raw tubes are welded. The welding machine is supplied with the measurement data of the plate thickness dimension and the measurement data of the groove dimension after groove processing, and the welding conditions are adjusted according to these measurement data.

〔Effect of the invention〕

According to the present invention described above, in the top surface copying method, it is possible to ensure the dimensions of the abutting part, and to prevent buckling due to the abutting pressure and welding from welding.
Uniform welding quality and bead appearance can be maintained regardless of plate thickness accuracy. In addition to these effects, stable welding can be performed because welding conditions are adjusted based on data on plate thickness and groove dimensions.

[Brief explanation of the drawing]

FIG. 1 shows the state in which edge portions of steel plates butted together are beveled by the conventional top surface copying method, bottom surface copying method, and the method of the present invention. FIGS. 2 to 4 are explanatory diagrams showing the welded steel pipe manufacturing flow applying the method of the present invention,
Figure 2 shows the UOE pipe manufacturing flow, Figure 3 shows the spiral pipe manufacturing flow, and Figure 4 shows the roller bending pipe manufacturing flow.
Fig. 5 is an explanatory diagram showing a normal troEyg manufacturing flow; Fig. 6 is a plan view showing a processing situation using a milling type steel plate end face processing machine. Figures 7 and 8 show the conventional beveling shape.
FIG. 7 is an explanatory view showing each beveling shape without profiling, and FIG. 8 is an explanatory diagram showing each beveling shape with profiling. FIG. 9 is an explanatory diagram showing a top surface scanning type copying mechanism in a milling type steel plate end face processing machine. Figure 10 is an explanatory diagram showing the copying situation by the roller in the case of the bottom copying method. Patent applicant: Nippon Kokan Co., Ltd. Inventor: Toru Suga Masaru Rodo
Shun Terunuma Mimai
Yoshi Fujioka Daido
Toshiki Takizawa, Patent Attorney
Masatoshi Tomabechi, Masatoshi Yoshihara, Sando

Claims (2)

[Claims] (1) A method for manufacturing a welded steel pipe that includes a beveling process of a raw steel plate, characterized by measuring the thickness of both edges of the raw steel plate, and adjusting the beveling position based on the thickness dimension. A method for manufacturing welded steel pipes. (2) In a method for manufacturing a welded steel pipe that includes a beveling process for a raw steel plate, the plate thickness of both edges of the raw steel plate is measured, the beveling position is adjusted based on the thickness dimension, and the beveling position is adjusted based on the plate thickness dimension. A method for producing a welded steel pipe, the method comprising adjusting welding conditions based on plate thickness and/or groove dimensions.