Controlled rolling method in hot rolling process of seamless pipe

A technology for controlling the rolling and hot rolling process, applied in rolling mill control devices, metal rolling, metal rolling, etc., can solve the problems of uneven structure, difficult to meet the performance standards, difficult to form, etc., to improve the structure and improve the comprehensive performance effect

Active Publication Date: 2017-08-25
TIANJIN PIPE GROUP CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Using the conventional seamless pipe hot rolling process, many steel types have problems such as difficulty in forming, uneven structure, difficulty in meeting performance standards, and cumbersome heat treatment processes in the process of being processed into seamless pipes.

Method used

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  • Controlled rolling method in hot rolling process of seamless pipe
  • Controlled rolling method in hot rolling process of seamless pipe
  • Controlled rolling method in hot rolling process of seamless pipe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The chemical composition of the 23Mn2SiCrV steel used in the experiment is shown in Table 1.

[0028] Table 1 Chemical composition of steel grade 23Mn2SiCrV

[0029] Component Content (wt.%) C 0.20~0.25 Si 1.20~1.40 Mn 2.00~2.20 Cr 0.50~0.70 V 0.02~0.05 P≤0.025 S≤0.015

[0030] The 23Mn2SiCrV steel grade used in the test is a high-strength steel with a B / M composite phase structure, which can be widely used in mechanical parts and engineering construction. The excellent strength and toughness of this material mainly relies on the two-phase combination of bainite and martensite, which cuts off the martensite matrix with bainite and prevents crack propagation, so as to have a stable retained austenite film and a carbon-free ultra-fine structure It is realized by replacing conventional bainite with bainite. The laboratory preparation process is billet forging at 1200℃, homogenization at 700℃ for 2h, and furnace cooling. After proper heat treatment, a composite structure...

Embodiment 2

[0054] The chemical composition of the 9Ni steel used in the experiment is shown in Table 1.

[0055] Table 6 Chemical composition of 9Ni steel

[0056] Component Content (wt.%) C≤0.13 Si 0.13~0.32 Mn≤0.90 Ni 8.40~9.60 P≤0.025 S≤0.025

[0057] The 9Ni steel used in the test is a low-temperature steel, which is widely used in the storage and transportation of liquefied petroleum gas (LNG). The normal use temperature is -162°C. The main feature is that it still has good impact toughness at -196°C. ASTM A33 stipulates that the lateral expansion of the alloy seamless pipe -195℃ Charpy impact test is above 0.38mm as qualified. The literature shows that the rough rolling opening temperature of 9Ni steel plate is between 1150~1100℃, the rough rolling final rolling temperature is above 975℃, the finishing rolling opening temperature is 850℃, and the finishing rolling temperature is above 730℃.

[0058] The Assel unit production line used in this experiment plan produces φ152×16mm se...

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Abstract

The invention provides a controlled rolling method in a seamless pipe hot rolling process. According to the method, the following data are used for design: a perfect recrystallization temperature lower limit, a non-recrystallization temperature upper limit, temperatures of an inlet and an outlet of a perforator for rolling seameless pipe of the target specification by the conventional process on a production line planned to use, an inlet and an outlet of a pipe rolling machine and an inlet and an outlet of a tension reduction / sizing machine as well as rolling hole patterns for perforation, pipe rolling and tension reduction / sizing. A controlled rolling process is designed according to acquired data. The controlled rolling method comprises the following steps: performing rolling deformation adjustment and rolling temperature design by taking the two steps of perforation and pipe rolling as rough rolling and the step of tension reduction / sizing as fine rolling, and controlling the finish rolling temperature of rough rolling and open rolling temperature of fine rolling by a certain method to finally realize the controlled rolling process. The controlled rolling method has the beneficial effects that the microscopic tissue of the hot-rolled seamless pipe is improved, and the comprehensive mechanical property, particularly the impact strength, of a finished product pipe subjected to thermal treatment is improved. The properties of both 23Mn2SiCrV high-strength steel and ultralow-temperature 9Ni steel can be obviously improved by the use of the controlled rolling process.

Description

Technical field [0001] The invention belongs to the technical field of production of hot-rolled seamless steel pipes, and in particular relates to a controlled rolling method during the hot-rolling process of seamless pipes. Through controlled rolling, the rolling structure of the seamless pipe is improved and the final mechanics of the seamless pipe after heat treatment is improved. performance. Background technique [0002] The controlled rolling process is an important production process in the production of modern steel materials, which is mainly divided into three steps: heating, rough rolling and finishing rolling. The rough rolling step is mainly carried out in the completely recrystallized zone to obtain fine original austenite grains; the finishing rolling is generally carried out in the non-recrystallized zone to improve the internal defects of the original austenite grains and increase the ferrite / Bainite nucleation position. Through controlled rolling, the grains c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21B37/78
CPCB21B37/78
Inventor 王琳宁丁炜张国柱梁海泉张传友朱人君肖雁孙宇
Owner TIANJIN PIPE GROUP CORP
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