Method for making printed angle rectangle section steel pipe

Abstract

The method for manufacturing rectangular pipe with sharp corner is characterized by that it uses rolling central line as a diagonal line of formed pipe to make multiple-pass cold-bending symmetrical deformation so that two side ends of steel strip which are made into oblique end face are finally closed on the rolling central line so as to form included angle with 90 deg. of said rectangular pipe. Said method is easy to regulate and operate, small in formed error, weld seam and two side are in symmetrical state, so that its welding effect is good, and its energy consumption also can be reduced.

Description

technical field [0001] The invention relates to a method for manufacturing rectangular steel pipes by cold bending, in particular to a method for manufacturing rectangular steel pipes with sharp corners. Background technique [0002] The upper side beam of the China Railway Freight Open Car is a rectangular steel pipe with a bending angle of R≤7 in cross section, usually called a sharp-angled rectangular steel pipe. In the past, it was made of butt-welded hot-rolled channel steel. Due to various quality deficiencies, the current industry standard has changed it to use cold-formed steel products. The production plant that has now is 93104319.0 by Chinese patent number, " a kind of method for manufacturing pointed square tube " produces this product. However, this method has the following disadvantages: First, the method adopts eccentric cold-bending forming, and the deformation moment is unbalanced. The strip steel is always in a metastable state and the twisting moment is ...

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Problems solved by technology

However, this method has the following disadvantages: First, the method adopts eccentric cold-bending forming, and the deformation moment is unbalanced. The strip steel is always in a metastable state and the twisting moment is large, which makes the adjustment operation difficult, and the deformation accumulation error is large, and the final geometric accuracy of the forming The guarantee is poor, and it needs a lot of power to complete the finishing and straightening process, and the energy loss is large; the second is that the interface of the formed steel pipe is parallel to the inner surface of the other side, that is, The interface is in a T-shaped vertical state, and the weld seam is asymmetrical to both sides, and the induced current is unevenly distributed on the entire weld seam. Therefore, the welding energy consumption is large and the welding quality is not good.

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