Pipe expanding machine for producing variable thickness steel pipe

Abstract

The invention discloses a pipe expanding machine for producing steel pipes with variable thickness, which comprises a frame, a diameter-expanding plug with a guide section, a variable-diameter section and a fixed-diameter section, a heating device for heating steel pipes, and a heating device arranged at the top of the frame. Pushing device, a pulling device arranged at the pulling end of the frame; the frame includes a push top support plate, a pull end support plate, and a guide rod set fixedly connected to the push top support plate and the drawing end support plate at both ends , Along the direction from the pushing top support plate to the drawing end support plate, the steel pipe feeding end fixing plate and the steel pipe output end fixing plate are sequentially set on the guide rod group, and the working end of the pushing device is fixedly connected to the steel pipe feeding end. The working end of the drawing device is fixedly connected to the fixed plate at the output end of the steel pipe; the guide section of the expansion head is fixed on the support plate at the top of the pusher, and the heating device is set on the expansion joints on both sides of the connection between the guide section of the expansion head and the variable diameter section. Periphery of the head. The invention can produce large-diameter seamless steel pipes with variable diameter and wall thickness.

Description

technical field [0001] The invention relates to the technical field of production of large-diameter seamless steel pipes, in particular to a pipe expander for producing variable-thickness steel pipes. Background technique [0002] Seamless steel pipe is a commonly used fluid conveying pipeline. Compared with solid round steel, when the bending and torsional strength is the same, its manufacturing material is less, its weight is lighter, and it is easy to process and shape. It is widely used in the manufacture of structural parts and mechanical parts. The production of seamless steel pipes mainly includes the piercing process in which the tube blank is gradually formed into a hollow thick-walled capillary under the action of the roll and the plug on the piercing machine, and the capillary is rolled on the automatic rolling machine to be close to the wall thickness of the finished product. The rolling process of the waste pipe, the sizing and reducing process of the required ...

AI Technical Summary

Problems solved by technology

However, the variable diameter and variable wall rolling machine for steel pipes is only suitable for steel pipes with a diameter of less than 40 cm, and is not suitable for large diameter seamless steel pipes with a diameter greater than 400 mm.

[0009] To sum up, the diameter expansion production method of large-diameter seamless steel pipes with a diameter greater than 400mm, the use of cross-rolling mills to expand the production of large-diameter seamless steel pipes has complex diameter expansion production methods, large equipment investment, and is only suitable for large-scale large-diameter seamless steel pipes. In the production of seamless steel pipes, there are technical problems such as helical patterns inside the products and poor surface quality; large-diameter seamless steel pipes are produced by using a pull-type pipe expander to expand the diameter, and the steel pipes continue to be in a state of tension after diameter expansion deformation, which may cause The original defect of the steel pipe expands, if the control is not proper, the steel pipe may be broken, and although the wall thickness can be reduced, the wall thickness is uncontrollable, the outer diameter precision is low, and the steel pipe surface is not smooth; the hydraulic push type pipe expander is used to expand the diameter In the production of large-diameter seamless steel pipes, there are technical problems that it is difficult to greatly change the wall thickness through process optimization while expanding the diameter, the length of the produced large-diameter seamless steel pipes is relatively short, and the production speed of a single machine is slow; It can also change the thickness of the pipe wall, the thickness of the pipe wall is controllable, and the production cost is low. Large-diameter seamless steel pipe expansion production unit

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