Hot-rolling seamless steel pipe applicable to high temperature of 580-620 DEG C and high pressure of 24-30MPa and production method thereof

A seamless steel pipe, 30mpa technology, applied in heat treatment furnaces, temperature control, heat treatment equipment and other directions, can solve problems such as high price, inability to guarantee rolling ratio, and restricting the development of the power industry

Active Publication Date: 2010-03-03
TIANJIN PIPE GROUP CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, the high-temperature and high-pressure P91 required by domestic boiler manufacturers is mainly supplied from abroad, but foreign manufacturers often use periodic rolling tubes and other methods, which not only has low production efficiency, but also cannot guarantee that the rolling ratio is greater than 3, which has a great impact on product quality. At the same time, the supply period is long and the price is expensive, which seriously restricts the development of my country's electric power industry, thus affecting the speed of

Method used

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  • Hot-rolling seamless steel pipe applicable to high temperature of 580-620 DEG C and high pressure of 24-30MPa and production method thereof
  • Hot-rolling seamless steel pipe applicable to high temperature of 580-620 DEG C and high pressure of 24-30MPa and production method thereof
  • Hot-rolling seamless steel pipe applicable to high temperature of 580-620 DEG C and high pressure of 24-30MPa and production method thereof

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Experimental program
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Effect test

Embodiment 1

[0034]The chemical composition of the hot-rolled seamless steel pipe used at a high temperature of 580-620 °C and a high pressure of 24-30 MPa is (wt%) C: 0.10%, Si: 0.33%, Mn: 0.45%, P: 0.009%, S: 0.003 %, Ni: 0.08%, Cr: 8.28%, Mo: 0.91%, Cu: 0.08%, Al: 0.011%, V: 0.20, Nb: 0.08%, Ti: <0.010%, N: 0.0471%, and the balance is Fe.

Embodiment 2

[0036] Ratio of electric furnace ingredients: molten iron: 45t; pipe head: 45t; bottom ash: 2 tons. Electric furnace tapping requires C≤0.06%, P≤0.005%. Before tapping, add 2 bags of S removal agent, use 0.5 tons of silicon-calcium-barium deoxidizer for deoxidation, add 1 ton of molybdenum ferromolybdenum, and 0.1 tons of lime. The tapping temperature is guaranteed to be 1680-1690°C.

[0037] Ladle refining: add micro-carbon Cr iron in batches, adjust Mo, V, Nb, Si and other alloying elements to pass after reaching the target value.

[0038] VD: VD high vacuum time must be guaranteed to be ≥ 10 minutes, then feed Ca-Si wire and CrN cored wire, and then change to blow N 2 About 20min.

[0039] Die Casting: Cast the molten steel after VD, protect the ingot mold by argon blowing before casting, and heat the ingot mold at the same time, and strictly control the casting temperature to ensure the quality of the mold casting billet. When the mold temperature drops to 500℃, the mol...

Embodiment 3

[0041] The steel pipe is rolled by a three-roll high-precision pipe rolling unit PQF. After the tube billet is cut to length, it enters the ring furnace and is heated to 1150°C. If the temperature is too high or too low, the plasticity of the tube billet will deteriorate, which will easily cause surface quality defects of the steel pipe. In the deformation process such as sizing, according to the characteristics of high alloy content such as Cr and Mo, through experimental research, the initial rolling temperature is controlled to be less than 1300 °C, and the final rolling temperature is greater than 800 °C. The final outer diameter deviation is controlled at about +0.91%, and the wall thickness deviation is controlled at about +10%.

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Abstract

The invention provides a hot-rolling seamless steel pipe applicable to high temperature of 580-620 DEG C and high pressure of 24-30MPa and a production method thereof. The steel pipe comprises the components by weight percentage of 0.08-0.12% of C, 0.20-0.50% of Si, 0.30-0.60% of Mn, 0-0.020% of P, 0-0.010% of S, 0-0.40% of Ni, 8.00-9.50% of Cr, 0.85-1.05% of Mo, 0-0.20% of Cu, 0-0.015% of Al, 0.18-0.25% of V, 0.06-0.10% of Nb, 0.030-0.070% of N and the balance of Fe. Simultaneously, the invention also provides the production method for producing the hot-rolling seamless steel pipe. The steelpipe and the production method have the effects that the performance of the steel pipe completely meets the requirement of ASME SA-335M standard on the tension and hardness and meets the requirement of GB5310 on impacting and duration strength, the steel pipe has excellent high-temperature performance, is applicable to the high-temperature bearing parts such as a steam pipeline, a connecting box and the like, which are used for high-temperature and high-pressure corrosive environment; and the duration strength under the temperature of 590 DEG C is 112MPa and the duration strength under the temperature of 620 DEG C is 81.4MPa.

Description

technical field [0001] The invention relates to heat-resistant, corrosion-resistant, high-pressure resistant P91 steel pipes and production methods for steam pipes, headers, etc. used in boilers, chemical industry, energy and other equipment, especially for high temperatures of 580-620 ° C, 24-30 MPa A high-pressure hot-rolled seamless steel pipe and a production method thereof. Background technique [0002] As the rapid development of science and technology has brought negative impacts such as environmental pollution, people have gradually realized this serious problem and began to invest a lot of energy and financial resources in environmental improvement. [0003] As an indispensable energy source for people's daily life, electricity is also the blood of industrial development, so the demand is quite large. At present, the world's power generation mainly depends on coal, and the combustion of coal will produce a large amount of CO 2 and SO 2 and other harmful gases, se...

Claims

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Application Information

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IPC IPC(8): C22C38/48C22C38/26C21C5/52C21C7/06C21C7/10C21C7/072B22D37/00B22D27/04C21D1/26C21D1/18C21D1/28C21D8/10C21D9/08B21B37/74
CPCY02P10/20
Inventor 张宝惠肖功业姚家华何彪王国亮陈洪琪刘永利尹溪泉吴国强赵庆权张俊萍
Owner TIANJIN PIPE GROUP CORP
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