Manufacturing method of large-aperture thin-walled seamless steel tube for nuclear power plant

Abstract

The invention provides a manufacturing method of a large-aperture thin-walled seamless steel tube for a nuclear power plant. The manufacturing method includes the steps of heating continuously-cast round billet; using a cone piercing mill to pierce the continuously-cast round billet to form tubular billet; using an MPM (multi-stand pipe mill) set of Phi 340mm to roll the tubular billet into tube billet, and ensuring the wall thickness tolerance of the tube billet to meet S+ / -7%, wherein the difference between the maximum value and the minimum value of any cross section of the tube billet should be smaller than 80% of the wall thickness tolerance; heating the tube billet to 950-1050 DEG C, and then expanding the tube billet by a drawing tube expander set; performing grinding to the inner surface and the outer surface of the expanded tube billet, wherein the grinding quantity is controlled to be 0.8-1.6mm; and using a precise hydraulic drawing machine to draw the tube billet subjected to integral grinding to manufacture a large-aperture thin-walled seamless steel tube for a nuclear power plant. The manufacturing method of the large-aperture thin-walled seamless steel tube for the nuclear power plant has the advantages that production cost is low, production efficiency is high, the steel tube is high in precision of the geometric size and high in surface quality, and the like.

Description

Technical field [0001] The present invention relates to the technical field of manufacturing large-caliber seamless steel pipes, and more specifically, to a method for manufacturing large-caliber thin-walled seamless steel pipes for nuclear power plants. Background technique [0002] In the prior art, the production of large-diameter thin-walled seamless steel pipes mainly includes the following production processes: [0003] The first type is the billet supply of the tube rolling unit + cross-rolling expansion machine; the second type is the billet supply of the tube rolling unit + the integral heating drawing hot expansion machine; the third type is the billet supply of the tube rolling unit + the segmented heating jacking Type expanding machine, the fourth type, the tube rolling unit for billet + internal boring and external drawing machining + integral heating drawing type thermal expansion machine. [0004] Among them, the first process is a production process in which the cont...

AI Technical Summary

Problems solved by technology

[0006] The second and third processes have the characteristics of simple production process and low cost. However, the geometric dimension accuracy and internal and external surface quality of steel pipes produced by this process are poor.

[0007] The fourth process is suitable for the production of ultra-thin-walled tubes that have certain requirements for geometric accuracy. However, it has the disadvantages of complex production process, low efficiency, large metal loss, low yield, and high cost.

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