DE102004039599B3 - Process to produce sheet metal of varying thickness for subsequent use as pipe rolling material or profiled components - Google Patents

Abstract

In a process to roll metal pipes or profiles from sheet metal followed by seam welding, the pre-rolled sheet metal (21) is produced with thin and thick zones. The sheet metal thickness is formed into transverse thick and thin zones that are subsequently brought to uniform thickness in the pipe rolling process.

Description

The The invention relates to a method for the production of shaped sheet metal parts, in the blanks or pipes or profiles of flexible rolled Strip material produced in the rolling direction variable sheet thickness be transformed in a forming process under material stretching spatially become. The said tubes or profiles are in this case from the flexible rolled strip material in a follow-up process in particular produced in a roll forming plant.

From the DE 100 41 281 C2 a method of the type mentioned above and a device suitable for this purpose is known, according to which a board made of flexibly rolled sheet is formed by deep drawing into a U-profile. Here, the device is designed so that the first after the flexible rolling symmetrically to a median plane of the strip material or the board representing variation of the sheet thickness after deep drawing is reflected exclusively on the inside of the U-profile or exclusively on the outside of the U-profile ,

At the Deep drawing occurs in areas of the sheet metal part that after the Deep drawing mainly in the direction of relative tool movement extend to a material stretch, while areas of the sheet metal part, the predominantly perpendicular to the relative direction of movement of the tools lie substantially retain their original sheet thickness. The transitions between These two extremes are fluid.

The Starting material for the forming under material stretching is used must be chosen so that too in the areas of least wall thickness after forming the allowable material stretch not exceeded becomes. This can lead to significant oversizing the areas of larger sheet thickness after forming lead.

Of the The present invention is based on the object, a method of the type mentioned above, with the weight savings possible on the finished sheet metal part are.

The solution therefor consists in a process for the production of sheet metal parts, at the boards or profiles or pipes made of flexibly rolled strip material with variable in rolling direction sheet thickness be prepared and in a forming process under material stretching spatial be transformed, in which when forming the largest material extension exposed areas previously rolled to relatively larger sheet thickness be considered as at least a part of the transformation or exclusively predominantly bending deformed areas or none Deformed areas. The mentioned profiles or pipes are while flexible rolled strip material in a downstream Forming process, in particular roll forming method produced and optionally by welding closed along a longitudinal seam. This is the flexible rolling used in making the Board or the profile or pipe used so that the variation the sheet thickness of the subsequent forming process under material stretching adapted is that areas largest material stretch with a relatively larger initial thickness be trained and thus with greater certainty a damage-free Material stretching can be suspended. Hereby can be the extent of Increase material stretch In the material stretching not subject areas a weight reduction bring about by minimizing sheet thickness.

decisive Here is the sheet thickness profile in the rolling direction. At a subsequent spatial Forming transverse to the rolling direction is the aforementioned optimization not to the same extent possible.

It is thus provided that the when forming a maximum material stretching underlying areas before forming a relatively larger sheet thickness exhibit. It is intended that the when forming a maximum Material stretching underlying areas after forming a have sufficient sheet thickness, in particular are not weaker, as the areas that have undergone a lower material stretch are..

To the Others suggest that the Forming exclusively or predominantly bending deformed areas or none Deformed areas before and after forming a optimized adapted to the stress sheet thickness.

To an idealized method is provided that when rolling according to the flexible rolling the sheet thickness is varied so that after forming under material stretching the sheet thickness variation is minimized, d. H. that both the maximum stretched Areas as well as the predominantly or exclusively curved areas as also the undeformed areas essentially the same Have material thickness. As mentioned earlier, this definition applies on sections of the sheet metal part, which extend in the rolling direction.

One preferred embodiment the procedure is in the drawings in comparison with a method according to the State of the art shown.

• a) eine Platine nach dem üblichen Walzen a1) in Draufsicht; a2) in Seitenansicht;
• b) ein aus dieser hergestelltes Blechumformteil nach einem Tiefziehen

1 shows with respect to a method according to the prior art

• a) a board after the usual rolling a1) in plan view; a2) in side view;
• b) a formed from this sheet metal part after deep drawing

• a) eine Platine nach dem flexiblen Walzen a1) in Draufsicht a2) in Seitenansicht;
• b) ein aus dieser hergestelltes Blechumformteil nach einem Tiefziehen.

2 shows with respect to a method according to the invention

• a) a circuit board after the flexible rollers a1) in plan view a2) in side view;
• b) a formed from this sheet metal part after deep drawing.

• a) ein Rohr, hergestellt aus nach einem üblichen Walzen hergestellten Bandmaterial
• b) ein aus diesem hergestelltes Blechumformteil nach einem Innendruckumformen;

3 shows with respect to a method according to the prior art

• a) a tube made of strip material produced by a conventional rolling
• b) a formed from this sheet metal part after an internal pressure forming;

• a) ein Rohr, hergestellt aus gemäß dem flexiblen Walzen hergestellten Bandmaterial
• b) ein aus diesem hergestelltes Blechumformteil nach einem Innendruckumformen.

4 shows with respect to a method according to the invention

• a) a tube made of strip material produced according to the flexible rolling
• b) a formed from this sheet metal part after an internal pressure forming.

In 1 is a section or a board in representation a 11 of strip material of constant thickness S0, produced by a conventional rolling process. In illustration b is the board 11 after deep drawing to a trough-like profile 12 reshaped. Here are the profile bottom 13 and the flange areas 14 . 15 essentially the material thickness S0 of the originally rolled-out board 11 while two flank areas 16 . 17 have a reduced thickness S2. It is understood that the initial thickness S0 of the entire board is designed so that the thickness S2, which is reduced by material stretching during deep drawing, can be produced without damage.

In 2 is a tape section or a board in representation a 21 made of flexibly rolled material having variable thickness along the rolling direction. On the board are longitudinal sections 28 . 29 . 30 smaller sheet thickness S0 and two intermediate sections 31 . 32 larger sheet thickness S1 recognizable. In illustration b, the circuit board ( 21 ) after deep drawing to a trough-like profile 22 reshaped. From the thickness structure of the starting material it follows that a profile bottom 23 and two flange areas 24 . 25 essentially have the unchanged lower initial thickness S0, two flank areas 26 . 27 however, have a reduced thickness compared to the larger starting thickness S1, which has also been set to S0. According to the invention, a profile has been created which after deep drawing has approximately uniform thickness S0 and thus uniform strength over the entire cross section.

In 3 in illustration a is a straight tube 41 shown, which in particular can be bent around and longitudinally welded from the usual rolled strip material of constant thickness S0. In illustration b, the tube is shown after a high-pressure forming in a die by means of hydraulic internal pressure. The result is an enlarged diameter spindle-shaped hollow body 42 with maximum inner and outer diameter in half 46 the axial length and the constant change in diameter from one end of the pipe to the other. Here are only the diameter of the tube ends unchanged 44 . 45 essentially the wall thickness S0 of the original pipe 41 while the entire intermediate area has a reduced wall thickness, being halfway 46 the length at the largest diameter of the hollow body 42 the lowest wall thickness S2 is present. It is understood that the wall thickness S0 of the original tube 41 is designed so that the reduced thicknesses, in particular the minimum wall thickness S2, which are caused by material stretching, can be produced without damage.

In 4 in illustration a is a straight tube 51 shown, which has been bent and closed from flexibly rolled strip material along the rolling direction. On the pipe are pipe ends 54 . 55 lowest wall thickness S0 and in half 56 the length of a central cross section of greatest wall thickness S1 recognizable, wherein the changes in thickness over the tube length are continuous. In the representation b is one in the same way as after 3 by high-pressure forming in a die by means of hydraulic internal pressure converted in diameter enlarged spindle-shaped hollow body 52 shown. Due to the variable wall thickness of the outlet tube over the length, the wall thickness over the entire tube length has been set to the value S0. Apart from the influence of shape, the hollow body according to the invention thus has 52 over the length substantially the same strength. In any case, the material stretching that took place during high-pressure forming has not led to any weak zones of lesser wall thickness.

11

circuit board

12

profile

12 '

bowl

13

ground

14

flange

15

flange

16

flank

17

flank

21

circuit board

22

profile

23

ground

24

flange

25

flange

26

flank

27

flank

28

section small sheet thickness

29

section small sheet thickness

30

section small sheet thickness

31

section larger sheet thickness

32

section larger sheet thickness

41

pipe

42

hollow body

44

pipe end

45

pipe end

46

pipe center

51

pipe

52

hollow body

54

pipe end

55

pipe end

56

pipe center

Claims (7)

A process for the production of sheet metal parts, in which blanks or tubes or profiles of flexibly rolled strip material are produced with variable in the rolling direction sheet thickness and are formed in a forming process under material stretching spatially, characterized in that when forming the largest material stretch exposed areas previously on relatively larger Sheet metal thickness are rolled as at least a portion of the exclusively or predominantly bending deformations exposed during forming or the areas exposed to any deformation. Method according to claim 2, characterized in that that at Forming exclusively or mostly Bending deformation exposed areas or no deformation exposed areas are previously rolled to minimum sheet thickness. Method according to one of claims 1 or 2, characterized that at flexible rolls, the sheet thickness is varied so that after the spatial Forming the sheet thickness variation is minimized. Method according to one of claims 1 to 3, characterized that to Forming a hydraulic hydroforming process is used. Method according to one of claims 1 to 3, characterized that to Forming a mechanical deep drawing process is used. Method according to one of claims 1 to 3, characterized that to Forming a mechanical stretch-drawing method is used. Method according to one of claims 1 to 6, characterized that at least such areas previously rolled to relatively larger sheet thickness where thinning exceeds 30% during forming.