For the processing and forming of pressure steel pipes, in water conservancy and hydropower projects, it is rare to use a press to press tiles (or pipe joints), and usually use a steel plate rolling machine to roll them. The type of plate rolling machine usually uses a 4-roll plate rolling machine, a 3-roll horizontal downward adjustment type plate rolling machine, a 3-roll horizontal and vertical upward adjustment type (commonly known as: universal type) plate rolling machine, etc. to roll steel pipes.
Four key processes of coiling pipe joints into penstocks with plate bending machine
Tile (or pipe joint) rolling is a key process for the production of penstocks. Tile rolling includes four processes: sheet centering, pressure head (also known as plate end pre-bending), arc rolling and arc repairing.
- Process 1 – Sheet Centering: Centering is to make the sheet perpendicular to the axis of the rollers, so as not to prevent the vertical and circumferential welds of the steel pipe from being misaligned.
- Process 2 Pre-Bending: The pressure head is to roll and pre-bend the two ends of the sheet before rolling the arc, so as to ensure the arc requirements of the longitudinal weld of the steel pipe and prevent its misalignment.
- Process 3 Arc Curling: Arc curling is exactly to carry out multiple down-pressing and reciprocating rolling to make it reach the required tile radius or pipe joint diameter.
- Process 4 Arc Repairing: Arc repair means that when the curvature (radius) of the tile or the diameter of the pipe joint does not meet the required requirements, it is corrected by rolling with a plate rolling machine.
When calculating the rolling capacity of the plate rolling machine(Plate Roller), it should not be calculated according to the lower limit of the standard yield strength of the plate, but should be calculated according to the real yield strength of the plate (usually according to the yield strength on the “Sheet Warranty”) the calculation is OK.
Determination of rolling capacity of steel plate rolling machine
In order to avoid the steel pipe production process, due to the insufficient rated capacity of the steel plate rolling machine, the steel pipe will have a straight edge at the end of the sheet metal, excessive arc, and misalignment at the longitudinal seam of the tile, cracking and falling off of the universal joint of the transmission shaft of the gearbox, the newspaper is broken and even the sheet cannot be pressed when it is pre-bent. Or the steel plate rolling capacity of the steel plate rolling machine is sufficient, but due to the large diameter of the upper roller and other equipment structure, it is impossible to roll the pipe joint, especially when selecting the type of small diameter thick wall pipe, more attention should be paid to the plate rolling machine Whether the diameter of the roll and the center distance of the lower roll meet the diameter requirements of the rolled pipe joint.
If the plate rolling machine model is not selected properly, when making tiles or pipe joints, it has to be processed outside or re-select the plate rolling machine to enter the site, which will definitely affect the construction period and cost of steel pipe production. For this reason, when selecting a plate rolling machine, it is not only determined by experience, but the type of plate rolling machine should be determined by calculating from the steel pipe material, yield ratio, maximum thickness, maximum plate width, minimum curvature radius and taper.
Main technical parameters of PRT-120X3500 plate rolling machine
|1||Plate Roller Specifications||mm||120X35000|
|2||Sheet yield strength||MPa||250|
|3||Roll bending Maximum Thickness||mm||120|
|4||Roll bending Maximum Width||mm||3500|
|5||Minimum steel pipe diameter under full load||mm||4800|
|6||Pre bending Maximum Thickness||mm||95|
|7||Remaining straight edge of pre-bending||mm||1.5倍板厚|
|8||Upper roll diameter||mm||980|
|9||Lower roll diameter||mm||515|
|10||Lower roller center distance||mm||1000|
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