A high-strength plastic vanadium microalloyed dual-phase steel seamless pipe and its preparation method

A seamless tube and alloying technology, which is applied in the direction of manufacturing tools, heat treatment equipment, and energy efficiency improvement, can solve the problems of inability to produce large-sized and long steel tubes, slow heating, and application limitations, and achieves further development and broad application. Prospects, the effect of reducing production costs

Active Publication Date: 2016-04-20
LAIWU IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the relatively mature materials used in the field of internal high-pressure processing are still mainly low-strength steel pipes, titanium pipes, aluminum pipes, and magnesium pipes. These materials can be used to prepare T-shaped tees, Y-shaped tees, square pipes, corrugated Parts with complex cross-sectional shapes such as pipes, but the strength of these materials is generally low
In recent years, stainless steel has been tried as a material for internal high pressure processing, and satisfactory test results have been obtained, but due to the high cost of stainless steel, its application has been limited
[0004] At present, gas heating and resistance heating are still the main heat treatment methods for steel pipes. Most of the heat treatment methods are to put the steel pipe as a whole into the heating furnace for heating. In this way, the length of the processed steel pipe is limited by the size of the furnace body and cannot be produced. Large-scale and long-length steel pipes limit the product specifications of the steel pipes; in addition, the temperature rises slowly during the heating process with this device, the oxide layer on the surface of the steel pipe is serious, and the work efficiency is not high; moreover, the furnace body The idler table cannot guarantee the uniform rotation of the steel pipe in the heating furnace, and its heating is uneven, which may lead to the bending of the steel pipe

Method used

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  • A high-strength plastic vanadium microalloyed dual-phase steel seamless pipe and its preparation method
  • A high-strength plastic vanadium microalloyed dual-phase steel seamless pipe and its preparation method
  • A high-strength plastic vanadium microalloyed dual-phase steel seamless pipe and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] The chemical composition of the steel used in this embodiment is C: 0.10%, Si: 0.42%, Mn: 1.32%, V: 0.16%, N: 0.01%, P: 0.004%, S: 0.003%, and the balance For Fe and unavoidable impurities.

[0051] The smelted ingot is forged into a bar, and the bar is turned to remove wrinkles and defects on the outer surface to form a tube billet. The tube billet is heated to 1200°C and kept for 2 hours before piercing, and then cooled to room temperature. The tube blank is cold-drawn for 5 passes to obtain a seamless cold-drawn steel tube with a wall thickness of 1.5 mm and an outer diameter of 46 mm.

[0052] The cold-drawn seamless steel pipe is heated to a two-phase region of 780-820°C at a rate of about 10°C / s by an intermediate-frequency heating induction coil, annealed for 20-40s, and then cooled naturally at a rate of about 3°C / s. Cool to 650-690°C (this temperature is referred to as the initial temperature of rapid cooling in the table); then use compressed air to cool to 2...

Embodiment 2

[0059] The chemical composition of steel selected in this embodiment is C: 0.13%, Si: 0.10%, Mn: 1.60%, V: 0.17%, N: 0.019%, P: 0.006%, S: 0.004%, and the balance For Fe and unavoidable impurities.

[0060] The smelted ingot is forged into a bar, and the bar is turned to remove wrinkles and defects on the outer surface to form a tube blank. The tube blank is heated to 1150°C and kept for 2 hours before piercing, and then cooled to room temperature. The tube blank is cold-drawn for 4 passes to obtain a seamless cold-drawn steel tube with a wall thickness of 2.0 mm and an outer diameter of 55 mm.

[0061] The cold-drawn seamless steel pipe is heated to a two-phase region of 790-820°C at a rate of about 20°C / s by a medium-frequency heating induction coil, annealed for 20-40s, and then cooled by air at a rate of about 5°C / s. Cool to 640-690°C; then use compressed air to cool at a rate of about 60°C / s to 260-280°C for isothermal treatment for 60-120s; finally air-cool to room temp...

Embodiment 3

[0067] The chemical composition of the steel used in this embodiment is C: 0.15%, Si: 0.60%, Mn: 1.10%, V: 0.17%, N: 0.021%, P: 0.004%, S: 0.005%, and the balance For Fe and unavoidable impurities.

[0068]The smelted ingot is forged into a bar, and the bar is turned to remove wrinkles and defects on the outer surface to form a tube blank. The tube blank is heated to 1250 ° C and kept for 3 hours before piercing, and then cooled to room temperature. The tube blank is cold-drawn for 4 passes to obtain a seamless cold-drawn steel tube with a wall thickness of 1.20 mm and an outer diameter of 41 mm.

[0069] The cold-drawn seamless steel pipe is heated to a two-phase region of 780-810°C at a rate of about 10°C / s by an intermediate frequency heating induction coil, and after annealing for 10-20s, it is cooled by air at a rate of about 4°C / s. Cool to 640-680°C; then use compressed air to cool at a rate of about 50°C / s to 250-270°C for isothermal treatment for 100-160s; finally coo...

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Abstract

The invention discloses a high-strength plastic vanadium microalloyed dual-phase steel seamless pipe and an on-line preparation method thereof. The seamless pipe is composed of the following chemical components in percentage by mass: 0.10-0.18% of C, 0.1-0.6% of Si, 1.1-1.6% of Mn, 0.16-0.20% of V, 0.01-0.03% of N, at most 0.006% of P, at most 0.005% of S, and the balance of Fe and other inevitable impurities. The intermediate-frequency induction heat treatment device of the thin-wall steel pipe is utilized and assisted by the vanadium microalloyed component design to produce the dual-phase steel seamless pipe with favorable comprehensive mechanical properties; the advantages of low yield-tensile ratio, high rate of work hardening, favorable strength and favorable elongation percentage of the dual-phase steel are matched and successfully applied to the field of production of steel pipes to efficiently substitute solid components with hollow components, thereby implementing light weight of the automobile; and meanwhile, the seamless pipe promotes further development of the internal high-pressure forming technique, and has wide application prospects.

Description

technical field [0001] The invention belongs to the field of steel pipe preparation, and in particular relates to a high-strength plastic vanadium microalloyed dual-phase steel seamless pipe and an online preparation method. Background technique [0002] With the increasing global environmental and energy crisis, energy saving and emission reduction have become the primary issues facing the automobile manufacturing industry. It is still the development trend of the automobile industry to realize lightweight technology under the premise of ensuring the performance of the whole vehicle. Among them, through the use of hollow parts The application of replacing solid parts is one of the most effective ways to realize the lightweight of automobiles. With the maturity of high-pressure production technology in pipes, the industrial production of high-strength hollow components has become possible, and the realization of this scheme requires high-strength and high-plastic hollow comp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/12C21D8/10C21D9/08C21D1/42
CPCY02P10/25
Inventor 侯晓英王业勤韩杰刘成宝孙会朝许荣昌
Owner LAIWU IRON & STEEL GRP
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