New method for producing medium and large caliber alloy steel seamless pipe by utilizing radial forging technology

Abstract

The invention relates to a new method for producing medium and large caliber alloy steel seamless pipes by utilizing a radial forging technology, which comprises the following steps of: A. centrifugally casting a medium and large caliber hollow pipe blank through external refining molten steel; B. machining the internal and external surfaces of the medium and large caliber hollow pipe blank, fixedly connecting a carbon steel 'chuck material' at one end or both ends thereof and then carrying out quality inspection; C. heating and descaling the medium and large caliber hollow pipe blank; D. inserting a mandrel into the medium and large caliber hollow pipe blank and then leading into a radial forging machine for forging molding to manufacture a pipe of which the wall thickness, the diameter and the length meet requirements; and E. carrying out heat treatment, finishing and 'chuck materia' cutting for the pipe to manufacture a qualified finished product pipe. A technologic relation is established between high-quality centrifugal casting and radial forging with more ideal deforming state and tiny temperature drop by the method for the first time, thereby forming a new short-flow production process which has the advantages of energy saving, consumption reduction, high quality and economical efficiency and is used for producing alloy steel seamless pipes with large caliber, medium wall thickness and difficult deformation, and improving the product quality and the qualified rate; moreover, one end or both ends of the pipe blank is / are fixedly connected with the 'chuck material', thereby not only rapidly realizing stable deformation, but also reducing the remarkable difference of longitudinal temperature and dimensional precision of workpieces, lowering the consumption of an expensive alloy steel material and improving the yield of a finished product.

Description

technical field [0001] The invention relates to the manufacturing technology of seamless steel pipes, in particular to the manufacturing technology of alloy steel high-end seamless pipes with medium and large diameters, medium and thick walls, and difficult to process. Background technique [0002] Steel has good comprehensive performance, can bear the required load and have the required life cycle under different working conditions, and has good process performance. It is an indispensable and important basic material for national economic construction. Generally speaking, carbon-iron alloys with a carbon content of 0.02%-2% are called steel, and carbon-iron alloys with a carbon content greater than 2% are called cast iron. According to different classification standards, steel can be divided into different categories. According to the chemical composition of steel, it can be divided into carbon steel and alloy steel: [0003] In addition to iron and carbon, the components...

AI Technical Summary

Problems solved by technology

The biggest limitation mainly comes from two aspects: on the one hand, the production of medium and large-diameter alloy steel pipe billets is extremely difficult, and the quality is also difficult to be guaranteed, because the alloy steel pipe billets in the production process of the existing technology, in its central part It is very easy to form a cavity, which produces the so-called "Mannesmann effect", leaving various surface and internal defects. For example, the inner wall of the exposed cavity often forms internal folding defects, and the closed cavity is easy to produce. All kinds of delamination defects are fatal to high-end pipes; on the other hand, the production process of medium and large-diameter alloy steel pipe blanks in the prior art is very complicated, which obviously weakens the production capacity of radial forging forming technology. Technical and Economic Advantages of Alloy Seamless Pipes

Therefore, people's previous attempts are difficult to achieve the desired goal

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