P91 seamless steel pipe and method for manufacturing same

A technology for seamless steel pipes and steel pipes, which is applied in the direction of pipes, rigid pipes, mechanical equipment, etc., can solve the problems of high metal consumption, long production process, unstable product quality, etc., so as to achieve short production process and improve metal yield. And the effect of steel pipe yield and compact structure

Active Publication Date: 2012-07-18
HENGYANG VALIN STEEL TUBE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The present invention aims to provide a preparation method of P91 seamless steel pipe to solve the problems of long production process, high metal consumption and unstable product quality in the prior art

Method used

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  • P91 seamless steel pipe and method for manufacturing same
  • P91 seamless steel pipe and method for manufacturing same
  • P91 seamless steel pipe and method for manufacturing same

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preparation example Construction

[0023] In a typical implementation of the present invention, a kind of preparation method of P91 seamless steel pipe is provided, such as figure 1 As shown, it includes the following steps: billet smelting, the raw material is smelted and refined through the vacuum degassing continuous casting round tube billet process to obtain the billet; annealing treatment, the billet is subjected to high-temperature diffusion annealing or low-temperature isothermal annealing; Soak the processed billet, the soaking temperature is 1230-1270°C, the soaking temperature deviation is ±10°C, and keep for 1.5-3 hours; hot-rolled and pierced the billet after soaking, the temperature of hot-rolled piercing is 1100-1200°C; Then carry out periodic rolling, the temperature of periodic rolling is 950-1100°C, carry out sizing and cooling treatment; and heat treatment, the steel pipe which has undergone periodic rolling is heated to 1040-1080°C, normalized, cooled after heat preservation, and then Heatin...

Embodiment 1

[0039] Adopt the preparation method of the present invention to produce the seamless steel pipe of Φ711*63mmP91.

[0040] 1) Optimization of chemical composition of P91 steel

[0041] According to the ASME SA335 standard, the chemical composition of P91 steel is optimized. The chemical composition of the optimized P91 steel is as follows (mass fraction, %): C 0.08~0.12%, Si 0.20~0.45%, Mn 0.35~0.55%, P≤ 0.015%, S≤0.007%, Cu≤0.15%, Ni≤0.20%, Cr 8.10~9.30%, Mo 0.85~1.05%, V 0.18~0.23%, Nb 0.06~0.10%, N0.030~0.070%, Al ≤0.020%, Ti≤0.010%, Zr≤0.010%, the balance is Fe and unavoidable impurities;

[0042] 2) Smelting of blanks

[0043] Using high-quality molten iron and scrap steel as raw materials, the billet is smelted through 45-ton electric furnace smelting, 45-ton refining furnace refining, 45-ton vacuum degassing furnace and round billet arc continuous casting machine continuous casting process. During the smelting process, the quality of P91 steel is strictly controlled. ...

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Abstract

The invention provides a P91 seamless steel pipe and a method for manufacturing the P91 seamless steel pipe. The method comprises the following steps: smelting a blank: performing smelting, refining, vacuum degassing and round-blank continuous casting on raw materials to obtain the blank; annealing: performing high-temperature diffusion annealing and low-temperature isothermal annealing on the blank; rolling the blank periodically: heating the annealed blank uniformly, hot rolling, perforating, sizing and cooling; and carrying out thermal treatment: heating the blank rolled periodically to 1,040-1,080 DEG C, normalizing, preserving heat, cooling, heating to 750-800 DEG C, performing tempering, preserving heat and cooling to obtain the P91 seamless steel pipe. The content of P in the raw materials is less than or equal to 0.015%, and the content of S content is less than 0.007%. and the diameter phi of the seamless steel pipe is 325-720mm. The P91 seamless steel pipe manufactured by adopting the method is compact in internal structure and excellent in performance. The metal yielding rate and the steel pipe forming yield are improved, the production cost is reduced, and resources are saved.

Description

technical field [0001] The invention relates to the field of manufacturing seamless steel pipes, in particular to a P91 seamless steel pipe and a preparation method thereof. Background technique [0002] P91 steel is a new type of ferritic heat-resistant steel developed on the basis of 9Cr-1Mo (P9) steel by adding a small amount of Nb and V microalloying elements and controlling the content of N elements. The steel has good thermal strength, which has reached the level of austenitic heat-resistant steel's durable strength. It has excellent comprehensive mechanical properties, high thermal conductivity, low linear expansion coefficient, good hardenability and weldability, and is widely used. It is used in the manufacture of high-temperature superheaters, high-temperature reheater pipes and main steam pipes of ultra-(super)critical thermal power generating units. [0003] At present, with the development of my country's thermal power generation units in the direction of high ...

Claims

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Application Information

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IPC IPC(8): B23P15/00B21B23/00C21D8/10C22C38/26F16L9/02
Inventor 陈绍林李阳华龙功名肖鸿光闵杰张敏王勇罗家华田研冉旭范振远宋景凌
Owner HENGYANG VALIN STEEL TUBE
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