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Bainite matrix phase-transformation induced plasticity steel seamless pipe and manufacturing method thereof

A technology for inducing plasticity and bainite, which is applied in the field of plastic steel seamless pipes induced by bainite matrix phase transformation and its preparation, can solve the problems of limited steel pipe product specifications, slow temperature rise, uneven heating, etc., to reduce production costs, Broad application prospects, stable process effect

Active Publication Date: 2014-06-18
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 heat treatment methods of steel pipes are still mainly gas heating and resistance heating. Most of them put the whole steel pipe into the heating furnace for heating. In this way, the length of the processed steel pipe is limited by the size of the heating furnace body, so it cannot produce large specifications and lengths. Larger steel pipes, thereby limiting 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 pipes is serious, and the work efficiency is not high; moreover, the roller table in the furnace body The uniform rotation of the steel pipe in the heating furnace cannot be guaranteed, and its heating is uneven, which can lead to the bending of the steel pipe

Method used

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  • Bainite matrix phase-transformation induced plasticity steel seamless pipe and manufacturing method thereof
  • Bainite matrix phase-transformation induced plasticity steel seamless pipe and manufacturing method thereof
  • Bainite matrix phase-transformation induced plasticity steel seamless pipe and manufacturing method thereof

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Effect test

Embodiment 1

[0040] The chemical composition of the steel used in this embodiment is C: 0.101%, Si: 1.80%, Mn: 1.09%, P: 0.002%, S: 0.005%, and the balance is Fe.

[0041] 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 1100°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 1.2 mm and an outer diameter of 41 mm.

[0042] The seamless cold-drawn steel pipe is heated to the austenitization temperature range of 910-950°C with an intermediate frequency heating induction coil at a heating rate of about 40°C / s, and annealed for 60-90s; then compressed air is used at a heating rate of about 50°C / s Rate cooling to different bainite temperatures (380-430° C.), isothermal treatment for 60-100 s, and then air-cooling to room temperature to obtain the b...

Embodiment 2

[0048] The chemical composition of the steel used in this embodiment is C: 0.16%, Si: 1.35%, Mn: 1.51%, P: 0.005%, S: 0.007%, and the balance is Fe.

[0049] 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 1100°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 2.1 mm and an outer diameter of 53 mm.

[0050] The seamless cold-drawn steel pipe is heated to the austenitization temperature range of 910-940°C with an intermediate frequency heating induction coil at a heating rate of about 40°C / s, and annealed for 60-90s; then compressed air is used at a heating rate of about 40°C / s Rate cooling to different bainite temperatures (400-430°C), isothermal treatment for 60-90s, and air-cooling to room temperature to obtain the bainite mat...

Embodiment 3

[0055] The chemical composition of the steel used in this embodiment is C: 0.184%, Si: 1.00%, Mn: 1.87%, P: 0.006%, S: 0.003%, and the balance is Fe.

[0056] 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 4 passes to obtain a seamless cold-drawn steel tube with a wall thickness of 1.20 mm and an outer diameter of 43 mm.

[0057] The seamless cold-drawn steel pipe is heated to the austenitization temperature range of 920-950°C with an intermediate frequency heating induction coil at a heating rate of about 40°C / s, and annealed for 60-90s; then compressed air is used at a heating rate of about 40°C / s Rate cooling to different bainite temperatures (390-420°C), isothermal treatment for 60-100s, and air-cooling to room temperature to obtain the bainit...

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Abstract

The invention discloses a bainite matrix phase-transformation induced plasticity steel seamless pipe and a manufacturing method thereof. The preparation method disclosed by the invention comprises the steps of smelting, forging a rod, turning, heating, perforating, cold drawing and thermally treating in sequence. The thermal treatment step comprises the following steps: firstly, heating a seamless cold-drawn steel pipe obtained after cold drawing to be in the austenitizing temperature range of 910-950 DEG C at the rate of 35-50 DEG C per second, and carrying out annealing treatment for 60-90 seconds; then, cooling the annealed seamless cold-drawn steel pipe to be in the bainite range of 380-430 DEG C at the ratio of 40-80 DEG C per second, and carrying out isothermal treatment for 30-100 seconds; and finally, cooling the seamless cold-drawn steel pipe subjected to isothermal treatment to room temperature. The bainite matrix phase-transformation induced plasticity steel seamless pipe having good comprehensive mechanics performance is prepared by utilizing chemical components of ordinary low-carbon steel; the cost is relatively low; the microscopic structure is composed of bainite and retained austenite, wherein the volume fraction of the retained austenite is more than or equal to 10.5%.

Description

technical field [0001] The invention belongs to the field of steel pipe preparation, and in particular relates to a plastic steel seamless pipe induced by phase transformation of a bainite matrix and a preparation method thereof. Background technique [0002] In order to cope with the increasing shortage of energy, the significant impact of carbon dioxide emissions on the human living environment, and the requirements and pressures of energy conservation and emission reduction, realizing lightweight technology under the premise of ensuring vehicle performance has become the development trend of the current automotive industry and has attracted widespread attention. , wherein the application of replacing solid parts by using hollow parts is one of the effective ways to realize the weight reduction 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 realizat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/14C22C38/12C22C38/04C21D8/10C21D1/20C21D1/26
Inventor 侯晓英王业勤许荣昌
Owner LAIWU IRON & STEEL GRP
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