Diameter 20-100mm Steel Pipe straightening Machine 7 Roller Straightener Automatic
supply Hydraulic press machine,hydraulic press, straightening machine,straightener
Introduction to Stretch Bending Straightener:
Stretch bending straightening machine, which is a kind of straightening machine, can be simply
referred to as a tension leveling machine, which achieves the purpose of straightening by repeated
bending of the sheet material, and at the same time causes yield deformation of the material.
In addition, it also improves the processing properties of the material by uniform deformation,
making it suitable for subsequent use.
Six roll or seven roll straightening principle:
In the straightening machine, the six-roll straightening machine, like the four-roll straightening
machine, is a more commonly used straightening machine. Therefore, we must also familiarize
and understand the working principle of the straightening machine. You can get a preliminary
understanding of this type of straightening machine.
In the six-roll straightener, it has six straightening rolls and is arranged in three pairs of up
and down symmetry. In addition, the six straightening rolls are all active rolls. Its frame is composed
of two parts. On the upper part of the frame, there are three sets of upper roller height adjustment
devices, as well as their balance and locking devices. Moreover, for each set of devices, there is a
separate control roll for good control.
Generally, the straightening roller in the straightening machine is a group drive, which is driven
by three motors, a reducer and a cardan shaft. Further, the adjustment gap is adjusted by a
hydraulic lock device. At the same time, it is also possible to have the straightening rollers in
the same position when working. There is a movable inlet guide on the inlet side of the straightener,
and an exit pinch roller on the outlet side.
The straightening principle used in earlier straighteners was to apply a certain tensile force at both
ends of the sheet to force the sheet to stretch longitudinally, thereby reducing the flatness. The
deformation of the sheet under tension is divided into elastic deformation and plastic deformation.
When the tensile force is removed, the elastic deformation will disappear and the plastic deformation
will remain, so only plastic deformation can provide permanent longitudinal extension of the sheet.
The straightening machine must provide a tensile tension that causes the sheet shape variable to
exceed the yield limit, so the energy consumption is large; and the excessive tensile tension causes
the sheet thickness to be significantly lowered after straightening, and the sheet is prone to breakage.
In order to reduce the tensile tension, the straightener incorporates a bending action. A steel roll is
placed in the direction of the vertical sheet surface, and the sheet is bent by pressing down the
steel roll. The sheet is convex downward by the action of the pressed steel roll, and is bent in the longitudinal direction. The bending action without stretching tension will cause the upper surface
of the sheet to shrink and the lower surface to stretch. When a suitable tensile tension is applied
to both ends of the sheet, the upper surface is offset by the contraction moment caused by the
bending and the tensile moment caused by the tensile tension, so that the upper surface is neither stretched nor shrunk. While the lower surface is simultaneously subjected to the tensile moment
and the tensile moment caused by the bending, the lower surface will be stretched. The portion
between the upper surface of the sheet and the lower surface is stretched to varying degrees.
In general, the entire sheet is stretched and the lower surface is maximally extended.
In summary, the stretch bending straightener extends the sheet by bending the sheet under tensile
tension to reduce or eliminate the unevenness of the sheet surface. The effect of the tensile tension
is that the upper and lower surfaces of the plate are in a stretched state, and are not used as the main power for the extension of the plate. The main power of the plate extension is the bending tension
provided by the bending.
Straightening machine structure:
The straightening machine consists of three parts: a tension roller set, a bending roller set and a straightening roller set. The tension roller group is composed of eight steel rollers, which are divided
into two groups (inlet tension roller group and outlet tension roller group), which provide tensile
tension through the difference between the two front and rear roller groups; the bending roller
group and the straightening roller group are usually They appear in pairs, both of which consist of a
work roll and a number of support rolls. The bending roll set and the straightening roll set provide
bending tension by pressing the sheet. The depth of the roll determines the degree of bending of
There are many process parameters for the straightener, but most of the parameters related to the mechanical design (such as the roll diameter) are fixed and not adjustable. The adjustable process parameters related to the quality of the sheet mainly include two parts: the straightening tension
provided by the tension roller set, and the bending depth of the bending roller set and the straightening roller set which determine the degree of bending of the steel plate (depression amount)
|Round pipe and tube||metal||metal||metal|
|Round pipe||∅16-∅40 mm||∅20-∅80||∅30-∅60mm|
|Round tube||∅20-60mm||∅20- ∅75||∅30-∅100mm|
|Curvature before straightening||﹤30mm/m||﹤30mm/m||﹤30mm/m|
|Size of the roller||∅150x260||∅300x260||∅220x300|
|material of the roller||9Cr2Mo||9Cr2Mo||9Cr2Mo|
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