RU1811933C - Method of making helical-seam thick-wall corrugated tubes - Google Patents

Description

The corrugation heating pattern in the forming device is selected so that the bending moments of the strip sections with the corrugations are equal to the bending moments of the flat strip sections, which makes it possible to obtain a mode in which the mechanical characteristics are equalized over the entire strip width during molding. Fulfillment of these conditions will improve the geometry of the strip and, consequently, the quality of the outlet pipe.

Thus, the claimed combination of features can significantly improve the quality of the finished product (yield of pipes), since it is possible to periodically profile corrugations with heating on thick-walled strips while improving the geometry of the strip and the pipe itself .:

Figure 1 is a schematic of a production line for the production of spiral spirals. corrugated pipes that implements the proposed method, Fig. 2 shows the dependence of the yield strength of the material as, kg / mm2, from the material temperature t, ° C, for carbon steel.

The method is as follows.

Rolls from the warehouse are fed to the receiving rack of the unwinder 1, where they are unwound with the subsequent task of the strip into the rolls of the sheet straightening machine 2, which carries out the strip straightening. Then, the following operations are performed: cutting the front and rear ends of the strip and joining them to obtain a continuous tape, respectively, using guillotine shears 3 and a butt welding machine 4. After the butt welding machine 4, the strip enters the roll forming mill 5, where periodic profiling of the longitudinal corrugations is carried out therein. To perform periodic profiling, i.e. to obtain corrugated and smooth sections in a certain ratio on the strip, the rolls of the stands of the roll forming mill are spread and a smooth section of the strip is skipped, then the rolls are again rolled and corrugation is performed, etc.

In the process of periodically profiling the corrugations, the strip is heated before the second and subsequent cells using the high-frequency inductors installed in front of them. Then, on a strip with alternating corrugated and flat sections, the edges are trimmed along its width with disc scissors 6. By the feeding machine 7, the strip is then set into the forming device 8, where the corrugations are heated along the bending line of the strip by installing a heating device-high-frequency inductor in the forming device 8 itself. . In this case, the heating temperature of the corrugations in the forming device is chosen so that the bending moments of the strip sections with the corrugations are equal to the bending moments of flat strip sections.

In the forming device 8, the strip is rolled into a spiral billet, the edge joints are welded by welding machines 9, cut into smooth lengths into measured lengths by a cutting device 10. Next, the pipes enter the pipe finishing unit 11, where the flux is removed from the pipes, the ends of the pipes are cut, the chamfers are removed hydraulic tests are carried out, visual inspection and repair of defective places, acceptance of finished pipes, stamping, marking and storage.:

An example of a specific implementation.

For the manufacture of spiral seam thick-walled corrugated pipes, for example, 1220-16 mm and 12.0 m long and carbon steel 20, necessary for the construction of pipelines with temperature fluctuations of the transported product, the following is performed. Rolls from the warehouse are fed to the receiving rack of the unwinder 1, where they are unwound with the subsequent task of the strip in the rolls of the sheet straightening machine 2, performing the strip straightening.

Then the following operations are performed: cutting the front and rear ends of the strip and joining them to obtain a continuous tape, respectively, using guillotine shears 3 and a butt welding machine 4. After the butt welding machine 4, the canopies enter the profile bending mill 5, where it is periodically profiled longitudinal corrugations. To perform periodic profiling, i.e. to obtain corrugated and smooth sections in a certain ratio on the strip, the rolls of the stands of the roll forming mill are bred and a smooth section of the strip, which is 1.5-2 m, is skipped, then the rolls are again reduced and corrugation is performed. The length of the profiled section is 30 m, the corrugations are profiled at a distance of 150 mm from the edge of the strip, the height of the corrugation is 50 mm, the number is 2.

In the process of periodically profiling the corrugations, a portion of the strip for the profiled part is heated in front of the second and subsequent stands to 1800-900 ° C with the aid of high frequency inductors installed in front of them. As high-frequency inductors, for example, thyristor converters can be used

frequency selectors with a power of 800-3200 kW, When bending in the cold state, a frequency frequency of 1 kHz. After profiling carbon steel samples 20, the value

strip disc shears 6 calibrating the bending moment is equal to:

in width, cut-off near-edge sections Mp 1.2 KvW%,

Width 10-15 mm. After calibration according to-5, where Ki is the profile coefficient, for the feeding of the feeding machine 7, they are set into a coal section shape Ki 1.5;

device 8 (forming angle ".Os the yield strength of the material for

In the forming device, 8 corrugations of heating-carbon steels CTS 32 kg / mm2 (average “about the line of bending of the strip using the fixed value);

new in the forming device 810 MP 1.2 -1.5; 1540 32 Z6jl U3kgmm

heating device - high- 261 kgm.

crotHOro inductor, C 2. The moment of resistance is determined

The heating temperature and corrugations in the profile form:

The following device is chosen as follows: w jt.

so that the moments of bending of sections of the strip with gof-15 / Wz | max

were equal to the moments of bending flat; where is 1g momentation,

strip sections. ,; v; ;;, - ;;;; Umax is the most distant distance. This problem arises in connection with the tew, rb fiber db of the neutral axis.

chtb when folding the strip into corrugated-Using the calculated data, we get:

NEW TUBLISH FOR LINE FORMING 20L L bb122 D2 d2 / D - H 1

stripes in areas with rx framz occurs:; 6, (X) i686 (0 - M & MeHt, the best way to overcome Wz-- ..;;,;. ./;;: -y ----- ----- -

im K iTripf rp Nyyupdimm ugshsh, ni 2. P + Dd + d

thinly exceeding MOMewf bending D

in the straight sections of the pols5eyg drive -.: ...,.:, .-.). . / 9 "more to change the geometry of the strip and ca-; dsyub & b () - o.osh choo2 yes2 32

MY Pipes, „; .-, ;;, Gu y :; G.y ;; / 2:; No. 02 +.100 bV + bv2

To relieve stresses in areas with;. ; z zn --- tea --- corrugation offers the technique of yagrev,: these areasX directly by ... -;: -: v -: v .. :: ..;. a mold that allows you to achieve; Where is the outer diameter of the corrugation, equalizing the efforts of the bend But the whole width; i is the inner diameter of the corrugation strip. To determine the temperature, "e-;: - i The bending moment for the profile of the corrugation required to heat the sections with gechaera. / v ;; : need to decide follow. 14201 -32 818 kg-m.

1. do not bend the bending moyent; {; 3 / Mp ayraenivani bending desired bending poof corrugation:; ; cop across the entire bandwidth needed

2. determine the local heating mode; , Nonlocal heating of the plots with corrugations in order to equalize | and r plots with; corrugations of such a condition that there are no mechanical characteristics throughout: 40 the moment of bending of the sections with corrugations was the width of the strip in the molding line::; . yen to the bending moment of the strip in the cold - The calculation is made in the next HQM state; For this it is necessary to: - establish a connection between the mechanical pa- rameter 1. the moment of resistance is determined by the meter (and the material temperature t °. And bending moment for rectangular 4S For carbon steel with kg / mm2 of the strip section, concluded between this dependence has the form (according to the data on the corrugation profile: v, adjusted exerimentally).

W -klЈ-A v This relationship is represented as

in 6 graphics (figure 2),

where b is the width of the plot; / I will examine the formula for determining from h - the thickness of the strip / w to the conclusion For pipes with a size of 1220 16 mm, which is to adjust the width of the corrugation to 50 mm in width. bending moment bands necessary. rw ol ° - 2.50 le ....: -. so that the yield strength of the metal is b - 2Rr: Cos 20 - 10M mm; $ 5 in the section With corrugations would be / ha reduced in

g; so many times

106.4 -1 b2z breaking in the corrugation profile pre-W-g-- 4540 mm%. It increases the moment of chiba of the rectilinear

.-. .; strip section. : - .- ;. . . -:

Therefore, if

ML MP

818

t

05

10.2kg / mm2.

10

twenty

3,134,70

/ Those gt.

3,134

In accordance with the graph, com (Fig. 2), the heating temperature of the sections with

corrugations in the molding process should be

.55 ° C . : -.; -:: v V: - :; Y-:: - /; .. After folding the strip into a spiral billet, the edge joints are welded with welding machines 9, the rid of the smooth part is cut into measuring holes with a cutting device 10, Then the pipes arrive at 1 pipe finishing unit 11, where 15 flux is pulled out, the ends are cut off, the chamfers are cut hydraulic tests, visual inspection and repair of defective places, acceptance of finished pipes, branding, marking - and with 9ydr ova "th e; ..;:;). y- ,; ; g / - .; -.- ..

The main advantage of the claimed method of software in comparison with the prototype of Java - is the improvement of the quality of the produced ones. pipes, at the same time; ; . ;; -; - -.; ::;: -: -:.; : -: - :. :, ..

a) the quality of the ends of the ends of 25 pipes is improved when assembling on the track, since due to the periodic profiling of the longitudinal corrugations on the polis, it is possible to obtain - - smooth sections along which pipe cutting is carried out. measured lengths;

6} the quality of manufacturing of thick-walled coils of joist corrugated pipes is improved due to the fact that there is heating of the strip in front of the second and subsequent cells of the profile-flexible mill 35, which allows profiling corrugations 1 on a strip with a thickness of 8 mm, because upon heating, the plastic properties of the material increase, the zone of uniform elongation increases, and, therefore, the destruction of the strip metal is excluded:

thirty

40

0

0

fifteen

5 - -

5

0

0

c) the geometry of the strip improves due to the heating of the corrugations in the forming device along the bending line of the strip during the forming of the strip with corrugations, since the local heating of the corrugations with temperature, chosen so that the equal bending moments of the sections of the strip with corrugations and flat sections are observed, ensures equalization of mechanical characteristics over the entire width of the strip in the molding line.

Claims (2)

1. A method of manufacturing a spiral-seam thick corrugated pipe, including trimming the ends of the strip, joining them into a continuous strip, periodically profiling the strip with the formation along its length of alternating smooth and profiled sections with longitudinal corrugations that are joined along the width of the strip with Flat sections along its Edges and in the middle, molding with bending of corrugated and flat astcks of a strip along a line parallel to the axis of molding, welding of spiral seams, cutting of a welded pipe to measured lengths, from the bottom and with the fact that, in order to improve the quality of the pipes by reducing the stresses on the corrugated sections, the corrugations are profiled sequentially for several transitions and the strip is heated before each subsequent transition except the first one, and during molding, the corrugations are reheated along the line of the strip bending, while the temperature of forming the corrugations is set from the condition ensuring equal bending moments across the width of the strip in the cross-sections of the corrugations and the adjacent flat section. 2. The method according to claim 1, about t and h and y u and with the fact that strip Before the second and subsequent transitions, they are heated to a temperature that provides a decrease in the yield strength of the strip material by 1.6-6.0 times. U1 SO YU o tud goo 3; & Mo fo # 6 ° # t, Ј . - .-., .- :,:; g- :. ; ..;:. ;;: / L & -f (t) L.