SU1291237A1 - Method of producing merchant roll-formed sections - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular, to methods for the manufacture of sectional bending of rolled sections in rolls of a roll forming mill. The aim of the invention is to improve the quality of the profiles by ensuring the accuracy of their geometrical dimensions and reducing the thinning of the places of bending. Billet profile in the transition specifies the transition C-to along the bending of Astana. In subsequent transitions, fold the profile shelves against the wall. In at least one of the technological transitions, the profile flanges are compressed in the transverse direction, applying force to their ends. At the same time, the internal surfaces of the bend points are freed from the force. The magnitude of the lateral compressive force is determined from the relationship by calculation. 3 ill., 1 tab. e (L 1C; About to SO h

Description

one . one

The invention relates to the machining of sheet material using special shaped rolls and is intended for use in ferrous metallurgy, transport engineering and construction.

The purpose of the invention is to increase the profile quality by ensuring the accuracy of their geometrical dimensions and reducing the thinning of the places of bending.

Figure 1 shows a diagram of the molding of a bent channel according to the proposed method; 2 is a diagram for determining the transverse forces in FIG. 3 — an intermediate transition caliber when forming a bent channel according to the proposed method.

In the master process transition I, the preform 1 profile moves along the mill. In technological transitions II and III, in at least one of them, when bending the shelves 2 and 3 of the profile with respect to wall 4, the inner surfaces simultaneously (Nos. 5 and 6 of seats 7 and 8 of the bend are free of force and the shelves 2 and 3 of the profile compress in the transverse direction, the forces, the minimum value of which is determined from the ratio

o ..

(one)

Q,

de r. - the magnitude of the lateral compression force applied normally to the end of each shelf in the i-M technological transition;

-full pressure of the metal of the profile wall on the rolls in the i-M technological transition;

-the total angle of the hem of the profile flange in the i-M technological transition;

-the magnitude of the critical power loss of stability.

The pressure of the metal of the profile wall and the rolls during profiling can be determined by the dependence

rEhlslyllSL.

HP

 T76852xth-xJ C; 6Xfh-C. ,

(2)

where X is the distance from the top of the spot

These rolls i-ro technological transition. Full metal pressure

the curvature (origin) to 55 of the profile wall on the rolls is calculated

According to the formula

considered section.

M ".is te, (, - E, (, - | g |) i

five

0

five

where, is the specific bending moment needed to form the bend in the i-M technological transition; E-modulus of elasticity

the first kind of workpiece material;

 yield strength

workpiece material;

P (10 ... 12) - hardening modulus of the workpiece material in the second part of the graph of true stresses;

h - profile wall width;

S is the thickness of the workpiece.

oLi, - total angle

profile shelf flanges in the i-M technological transition;

- Corner of the shelf bend angle per pass in the i-M technological transition;

- the length of the lower roll section at the bend site, where there is no contact between the strip and the lower roll in the i-M technological transition;

Hz; - outer radius

bending places in i

5technological

transition;

- radius of the neutral layer of bending deformations

0in the axial plane of the rolls i-ro technological transition. Full metal pressure

0

five

0

Lo (:

 Sat-1.

.

roll profile walls

According to the formula

I p. 4

,

Q,. "Fl

From dependencies (2) and (3) have

Q.

At ES And 7; ds-. xh -h x,. LCv-l) ()

0.8426 / IT

c, improving the quality of the dimensions by eliminating the springback, and consequently, reducing the understorming of the corners, radii and deviations. In the manufacture of profiles according to the linear dimensions. Springing is eliminated by eliminating transverse tensile forces by squeezing the shelves.

but presumably} "to the first method, the total pressure force of the metal of the wall 4 of the profile on the rolls Q. in each technological transition is balanced

in the transverse direction simultaneously with the hem. Internal release

by two transverse forces, the bending points are approximated during the hem and

placed at the ends of both shelves 2 and 3:

lateral compression of the bend shelves minimizes metal thinning at the bend points, and under certain molding conditions, metal thickening at the bend points or equality of the workpiece thickness can be created.

p - 2i -lJriSi7, .b .4

 2з1пД: 1.6852 SlflTndi Cj

(five)

Based on experimental studies, it was established that the minimum amount of transverse compressive force applied normally to the end of each shelf in the axial cross section of the strip in the i-th technological transition is determined by the formula

, 4 h / bs ind :; ,

p.

(, MIC

f. (- 1). (6)

To prevent loss of stability of the flange during compression in the transverse direction, the maximum magnitude of the transverse force should not exceed the critical buckling strength. The critical plate strength can be determined by the formula

P 12% p b

(7)

where d

EP

- cylindrical

plate stiffness

35 containing a set of rolls for the manufacture of a varietal bent profile.

So, for example, the numerical values of the total hem angles of the shelves of the O fil, the minimum and maximum values of the transverse compressive force at

12 (1- /)

bending; (- Poisso coefficient f. f l / ci CHGI-P v- / Jvrn JclJUL4t rl „rlJiLJJ llf-n (for steel | h 0.3) pp sll /

 I manufacturing channel 120x1UUx4 mm Based on experimental o /

of steel, Art. hp, with a width of the wall of the study, it was established that max.

fil mm, the width of the shelf is the minimum size of the transverse compressing-G pp-g /

  mm, billet thickness mm

yield strength of material material

tovki (3. 240-a, hardening module,

Mp

billet material 2400-), 50 m

;. determined according to the proposed method are shown in the table.

force applied to the normal end of each shelf in the axial cross section of the strip in the i-th technological transition, is determined by the formula

3

R.

l, MOiKC

ES

s

(eight)

where b is the width of the flange profile.

The release of the internal surfaces of the places of bending from the impact of forces during the forming by bending flat elements with compression of the shelves in the transverse direction provides

in the transverse direction simultaneously with the hem. Internal release

 Renniza bend when bending and

15

20

25

lateral compression of the bend shelves minimizes metal thinning at the bend points, and under certain molding conditions, metal thickening at the bend points or equality of the workpiece thickness can be created.

Due to the fact that during normal profiling the most intensive wear of the rolls occurs at the places of their contact with the inner surfaces of the bending of the strip, which requires repair of the rolls, when these surfaces are freed using the proposed method, the resistance of the rolls increases.

The presence of mathematical dependences to determine the efforts and their maximum permissible values allows one to quite accurately calculate the molding parameters of each specific profile.

The proposed method can be implemented using a device

35 containing a set of rolls for the manufacture of a varietal bent profile.

So, for example, the numerical values of the total hem angles of the shelves of the O fil, the minimum and maximum values of the transverse compressive force at

thirty

  l / ci ChGI-P v- / Jvrn JclJUL4t rl „rlJiLJJ llf-) pp shl /

(eight)

The profile is molded in a continuous manner on a roll forming mill 1-4x50-300 from a rolled billet. In master process transition 1 (I), workpiece 1 is guided along the mill.

In technological transitions 2–10 (II and III), the inner surfaces 5 and 6 of places 7 and 8 of the profile bend are simultaneously free from forces, and shelves 2 and 3 of the profile are compressed in the transverse direction by forces P. The total angles of the flange of the shelves are determined by the method of expert assessments (and they are used equal to the angles of the flex in the manufacture of the profile according to a known method). The minimum values of the transverse compressors are min. determined by the formula (1), and the maximum values of R. - according to

1, Mac I

Formula (2), Valid Values

The transverse compressive force is determined experimentally.

To obtain the finished profile of the proposed method (as well as by the known method), ten technological transitions were required. The thinning of the metal of the curvature of the finished profile is 5-6%, and the deviation in the width of the flange is + 1.2-1.5 mm, which is within the limits of the requirements (permissible maximum deviation in the width of the flange with continuous profiling for shelves from 50 up to 100 mm is 2 mm, for category I, 5 mm).

. According to the experimental test on a roll forming mill 1-4x50-300, the proposed manufacturing method allows, in comparison with a known method, to improve the quality of high-quality curved profiles by improving the accuracy of their geometrical dimensions and reducing the thinning of the bend sites (for example, when making the channel 120x 100x4 by the proposed method, thinning the curvature of the finished profile is 5-6%, and in the manufacture according to a known method 10-11%, the deviation in the width of the flange in the manufacture of the proposed method is 2-1.5 mm; phenomena by a known method (3.0 mm); to raise

durability and reduce the mass of work rolls; to improve the quality of the inner surface of the places of bending of varietal curved profiles.

The proposed method does not adversely affect the state of the environment.

The economic effect is obtained by increasing the quality of varietal curved profiles, increasing durability and reducing the weight of the work rolls.

F o rm ula invention

A method of making varietal curved rolled profiles, mainly channel-type by multi-transition bending of profile elements in the rolls, in which at least in one of the technological transitions the profile shelves squeeze in the transverse direction by applying forces to their ends with simultaneous release of the inner surface of the bend points from the effect of characterized in that, in order to improve the quality of the profiles by ensuring the accuracy of their geometrical dimensions and reducing the thinning of the places of bending, The lateral compression force is determined from the ratio

0.9R. R. . ,

 kr1Sinoti

f R.

Q, - o (.: - cr

amount of lateral compressive force B i-M technological transition

full force of pressure of the profile wall to the rolls in the i-th technological transition; the total angle of the hem of each shelf of the profile in the 1st technological transition; - the value of the critical force of loss of stability of the flange profile.

Fa2.g

Claims (1)

Claims A method of manufacturing high-quality bent sections of rolled products, mainly of the channel type, by multi-junction bending of profile elements in rolls, in which at least in one of the technological transitions the profile shelves are compressed in the transverse direction by applying forces to their ends with simultaneous release of the bent surface of the bending places from the action of forces, characterized in that, in order to improve the quality of the profiles by ensuring the accuracy of their geometric dimensions and reduce the thinning of the places of bending of pepper efforts from the ratio, the amount of compression is determined 0.9 R cr where R. Qi of the transverse force of the ith technological value of compression in the lump; the full pressure force of the profile wall on the rolls in the i-th technological transition; the total bending angle of each profile shelf in the i-th technological transition; the magnitude of the critical strength of the loss of stability of the profile shelf. one one 1291237 8 Total Minimum Maximum Action- angle new significant new significant body Transition ί bending singing singing value lok pro river river transverse Filia d- " compressive compressive compressive hail ’ forces R., kN ’, Ning’ force '·, ^kN forces R; , KN one 0 0 128 0 2 8 27,2 128 34.0 3 eighteen 32.8 128 46.0 four ^thirty 44.3 128 58.0 5 44 56.8 128 66.0 6 58 60.0 128 68.0 7 70 50,4 128 56.0 8 80 40.1 128 42.0 9 88 26.3 128 32,0 10 90 12,4 128 14.0