JPS5927788A - Production of electric welded pipe by hot working - Google Patents

Abstract

PURPOSE:To eliminate the temp. difference between a base material and a weld zone with good efficiency, to prevent the bending, etc. of the pipe and to improve quality, by bringing cooling rolls into rolling contact with the pipe which is butted and welded of edge parts on both sides to each other in the position opposite to the weld zone of said pipe. CONSTITUTION:Roll constituting members 61b, 61c are fitted to shaft parts 61d, 61e from both end part sides thereof and are fixed in one body to the parts 61d, 61e in the form of sandwiching a cooling member 61f between both. The outside circumferential surfaces of the members 61b, 61c and the outside circumferential surface of the member 61f are made flush with each other to form one caliber. Cooling water is passed in one direction in the parts 61d, 61e, and the parts 61d, 61e are cooled by the heat exchanging with the member 61f, whereby the cooling effect of the member 61f for the weld zone is improved.

Description

[Detailed Description of the Invention] Kizashi is a hot electric wire made of heated steel + curved into a cylindrical shape so that the edges on both sides face each other, and then butt-welded the edges on both sides to form an electric resistance welded pipe. The present invention relates to a method for manufacturing a sewn tube.

Manufacturing electric power pipes under hot conditions is a disadvantage of the conventional method of manufacturing electric power pipes by locally heating and melting only the 11d side joint part of the skelp (1 joint welding) under normal cold conditions. Although this method is widely known as an effective method for eliminating residual stress, there are still problems that must be solved until it is realized, such as the hot electromagnetic loop j for heating and melting the edges g+ζ on both sides. ; jj'; (problem of improving efficiency,
There are many problems such as cutting and removing the external bead, cooling the welded part to eliminate the bend in the meat, etc., and the current situation is that it has not been put into practical use.''Of the two problems, welding Cooling from +T1 is a technique where there is a temperature difference between the welded part and the base.For example, when a tube is passed through a reteue, uneven thickness may occur due to the deformation resistance claw, or the tube may be bent. This is an essential process to prevent the increase in the amount of bee-F lino removed.For this reason, the water spray method that is conventionally used to cool the forge-welded part of forge-welded pipes cannot be applied. However, in this method, the water diffusion area is wide, and the width of the welded part is narrow, such as in the case of electric currents and hoof tubes, of several mm. However, because the water droplets are scattered onto unnecessary base metals and a good cooling effect cannot be obtained, and the cooling temperature range is narrow, the temperature difference reaches several hundred degrees as in hot electric resistance welded pipes. There were some drawbacks, such as the fact that water flow control alone could not solve the problem.

The non-explosion J was made in view of these circumstances.
The purpose of this is to reduce the efficiency of narrow IIV:i welds by rolling one or more cooling rolls equipped with heat-absorbing rollers into contact with the welds of hot electric resistance welded pipes. Hot ERW pipes are cooled well to reduce the temperature difference between the mother paulownia part and the mother paulownia part as much as possible, completely suppressing the occurrence of bending and uneven thickness of the ERW pipes, and greatly improving the quality of the pipes. We provide manufacturing methods.

The method for manufacturing a hot electric resistance welded pipe according to the present invention involves bending a heated skelp into a cylindrical shape so that the edge portions on both sides thereof face each other,
In the method of manufacturing a hot electric resistance welded pipe by mutually VC welding the edge portions on both sides while heating and melting them, a position opposite to this 1 is placed at the welded portion of the tube where the edge portions on both sides are butt welded together. 1? One or more hole-shaped cooling rolls each having a cooling member arranged on the surface are brought into contact with each other. ! Make it slight.

Hereinafter, the following description will be given in detail based on the drawings showing the state of implementation. Figure 1 shows unexploded 81. FIG. 2 is an enlarged side view of a welding part cooling device (hereinafter referred to as a seam cooler) used to carry out the method of the present invention; Third
The figure is a 1flt curved diagram that goes up the river-111 line in Figure 2,
S in the figure is a skelp, and the uncoiler shown in [7]
etc., and passed through the heating furnace 1 to heat the whole to 900 ~
Heating at 940°C []11. After that, form roll 2
The edges on both sides are bent downward to form an inverted U-shape into a cross-section of approximately 0, with the edges on both sides facing each other, and then passed through a work coil 3 where only the edges on both sides are heated to about 1400 to 1450°C. The heated and molten state is passed through a squeeze roll 4, the edge portions on both sides are welded together, and the pipe is formed into a pipe 1). The welded part 211 is connected by the heat insulating cover 5 and passed through the soaking area.
In order to eliminate the temperature difference (several hundreds of degrees +4,1-) between the weld + Il (and IJJ material), the seam cooler 6 After passing through forced cooling hino 12, straightening with reticle tensioner 7, and applying rolling pressure to 4f, (Illll-), cut to a fixed length with a rotary pot saw (not shown),
Finishing process, inspection:? ! i', the upper culm has L>K.

As shown in FIGS. 2 and 3, the seam cooler 6 is composed of a plurality of cooling rolls 61 and a port roll 62, and the cooling roll 61 is located below the moving area of the pipe P, and the cooling roll 61 is located below the moving area of the pipe I). On the other hand, the -v' boat rolls 62 are arranged so as to be alternately located with respect to the moving direction of the pipe P, respectively. The cooling roll 61 is configured as a caliber roll having a substantially semi-arc shaped hole 61a on its outer peripheral surface, and includes a pair of ceramic roll constituent parts 61b and 61c, and a shaft part 61d which also serves as a cooling water passage.

61e and a cooling member 61f'4-.

Roll $i! l112. The subassemblies 61b and 61c are formed into a core-like shape divided into two by a plane perpendicular to the axial direction at approximately the center in the axial direction, that is, the most concave part of the hole mold 61a, and the axial parts 61d and 61e are The shaft ends 1n1 are concentrically opposed to each other at a required interval, and the outer peripheral surface of each shaft end is made of copper support rings 61g, 61g that protrude in opposite directions.
A cooling portion U'61f shaped like a circle Uτχ is disposed therebetween. The cooling material 61f is made of copper and has an annular shape, and its outer diameter is approximately equal to the diameter at the most concave part of the hole mold 61a. , 61e] The outer peripheral edges of six rings 61g and 61e are fixed by welding.Thus, the cooling member 61f is fixed concentrically with the shaft portions 61cl and 61e. Roll configuration part 4:, A61b, 61
c It axis part 61d.

61e from each end side (fitted and cooled 1) 1ζ
(ll'llll with the A61f sandwiched between them)
t'SB 61 (+, 61 e and integrally fixed, outside each roll component 4/161b, 61c +i!f
The first surface and the outer circumferential surface of the cooling member 61f form an upper surface to form a typical hole shape. i'llll t
TIs (i 1 d.

Inside 61e, water for cooling is allowed to flow in one direction as shown by the arrow .
Heat exchange with e:l cooling 81S4361f] 1. 2 of the cooling member 611 to the junction W
1) Reject effect II'! 1 mel J:')IcL"?-Al. Cooling effect f';1.' 1llllll tel((i
1 d, (i le 'fr, 11L The temperature of the water flowing, the water fitv kyo-C) is to be appropriately controlled during chartering.In addition, instead of water, a refrigerant such as oil, for example, is used.
Of course, liquid nitrogen or the like may also be used. Also, the number of cooling rolls to be used can be arbitrarily set to control the cooling effect.

Next, an example of the above-mentioned final method 1-s
h, l, l++. Made of low carbon steel with a thickness of 3. '5
tnm Skelp was heated to about 900°C in a heating furnace \1. After that, it is formed into a cylindrical shape so that both edge portions are facing each other, and then passed through a gesoak coil so that only the edge portions on both sides are shaped into a cylinder with a width of 2 mm.
The tube was butt welded while heating and melting to a depth of about 1400 DEG C. to form a tube with a diameter of 80 mm. This tube was finished by passing it through a seam cooler and a redu-°'/'r. The above-mentioned method of the present invention and '+Q' are the same as O1? Regarding the reference method in which the pipe was stretched and rolled using a strain reducer without being scraped, the estimation of the welded part width of the pipe and the illumination temperature was completely detected. The graph in FIG. 4 shows this result. The graph shows time Q'J)'a:, t on the 4j''ff axis, and welding temperature on the vertical axis. Base material 1 by method
'B +7ii1 degree, and the solid line connecting the plotted points with white circles represents the temperature of the welded part of the pipe P manufactured by one method, and the dashed line represents the total temperature of the welded part of the pipe manufactured by the reference method. Showing 7.

Jin's graph karari 1 raka agency like this book 1, 1 month Is the welding method applied compared to the reference method? SIS tent
The +brightness has been luxuriously reduced, and the 111R degree difference with the mother paulownia part is 4
You can see that it is smaller at IIIζ. In addition, the obese skin rate e'' book, childbirth method υku! ! It is 4.5 yen in the left tube, and 10% in the case of Jlaltγ, and fata (liii meat) t4 is also significantly improved, Rukoshichi confirmed.

ij: 'I't's 7' method
Water-cooled structure cooling (11ζ month) (11ζ month (liii) or multiple hole type cooling roll full rotation 4
Only the welded part is cooled r!
It is efficiently cooled by R14 and σ) and 1γ, and moreover, it is welded 7 in 1 (D because 100 grafts are not attached to it) 4#
'r'S+< IIJ (= 4 capitals are inevitably cooled down by water splashing < ,), lJ destruction i11. It is possible to prevent the song v'4- of Q'(, and the similar quality person 1
The end result 1 does not give excellent results, such as 11rf direction.

[Brief explanation of drawings]

Figure 1 shows the implementation of the method/, lj, I〉1-1
Figure 2 is an enlarged side view showing the complete construction of the seam cooler, Figure 3 is a half-mounted view of the cooling roll in the seam cooler, and Figure 4 is the finished product manufactured by the 11 method. It is a graph showing the change in temperature between the main welded part of the pipe and the welded part.

Claims (1)

[Claims] 1. A method of manufacturing a hot electrical resistance welded pipe by curving a heated skelp into a cylindrical shape so that its edge portions on both sides face each other, and welding the edge portions against each other while heating and melting them,
A thermostatic electric resistance welded pipe characterized in that one or more hole-shaped cooling rolls having a cooling member disposed at opposing positions are brought into contact with the welded part of the pipe whose edge parts on both sides are butt-welded. manufacturing method.