Spheroidized annealing process for shortening annealing cycle of hot rolled wire rods

An annealing cycle, spheroidizing annealing technology, applied in the field of spheroidizing annealing process, hot-rolled wire rod annealing process, can solve the problems of slow cooling or annealing, long annealing holding time, affecting production efficiency, etc., to achieve high ductility, cold The effect of low forming crack rate and high production efficiency

Inactive Publication Date: 2015-09-02
XINGTAI IRON & STEEL
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

The main disadvantages of this spheroidizing annealing process are long annealing time and high energy consumption.
[0004] At present, when producing fastener wire rods, the fastener wire rods are slowly cooled or annealed according to the existing process, and the annealing cycle is too long, which affects production efficiency; in addition, the longer annealing holding time results in greater energy consumption, resulting in rising processing costs

Method used

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  • Spheroidized annealing process for shortening annealing cycle of hot rolled wire rods

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Experimental program
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Effect test

Embodiment 1

[0027] A kind of spheroidizing annealing process that shortens the annealing period of SCM435 hot-rolled wire rod, it comprises the steps:

[0028] A. Put the fastener wire made of SCM435 in a heat treatment furnace, fill the heat treatment furnace with industrial nitrogen with a purity of 99.99%, and raise the temperature in the furnace to 630°C at a rate of 100°C / hour. The protective atmosphere will be changed to continuous nitrogen + RX gas. When the temperature in the furnace rises to 680°C, turn off the industrial nitrogen, and only fill the heat treatment furnace with RX gas. Then raise the temperature in the furnace to 770°C and keep it for 3 hours. ;

[0029] B. Cooling in the first stage: Cool the temperature in the furnace to 710°C at a rate of 30°C / hour by air cooling, and keep it warm for 6 hours;

[0030] C. The second stage of cooling: continue to cool the temperature in the furnace to 665°C at a rate of 50°C / hour through air cooling, turn off the RX gas, and fi...

Embodiment 2

[0034] A kind of spheroidizing annealing process that shortens the annealing period of SCM435 hot-rolled wire rod, it comprises the steps:

[0035] A. Put the fastener wire made of SCM435 in a heat treatment furnace, fill the heat treatment furnace with industrial nitrogen with a purity of 99.99%, and raise the temperature in the furnace to 630°C at a rate of 120°C / hour. The input protective atmosphere will be changed to continuous nitrogen + RX gas. When the temperature in the furnace rises to 680°C, turn off the industrial nitrogen, and only fill the heat treatment furnace with RX gas, then raise the temperature in the furnace to 780°C and keep it for 1.5 hours ;

[0036] B. The first stage of cooling: Cool the temperature in the furnace to 720°C at a rate of 30°C / hour by air cooling, and keep it warm for 5 hours;

[0037] C. The second stage of cooling: continue to cool the temperature in the furnace to 665°C at a rate of 50°C / hour through air cooling, turn off the RX gas,...

Embodiment 3

[0041] A kind of spheroidizing annealing process that shortens the annealing period of SCM435 hot-rolled wire rod, it comprises the following steps successively:

[0042] A. Put the fastener wire made of SCM435 in a heat treatment furnace, fill the heat treatment furnace with industrial nitrogen with a purity of 99.99%, and raise the temperature in the furnace to 630°C at a rate of 140°C / hour. The protective atmosphere will be changed to continuous nitrogen + RX gas. When the temperature in the furnace rises to 680°C, turn off the industrial nitrogen, and only fill the heat treatment furnace with RX gas. Then raise the temperature in the furnace to 790°C and keep it for 1 hour. ;

[0043] B. The first stage of cooling: Cool the temperature in the furnace to 730°C at a rate of 30°C / hour by air cooling, and keep it warm for 4 hours;

[0044] C. The second stage of cooling: continue to cool the temperature in the furnace to 665°C at a rate of 50°C / hour through air cooling, turn ...

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Abstract

The invention relates to a spheroidized annealing process for shortening the annealing cycle of hot rolled wire rods, belongs to the technical field of metal wire annealing process. The technical scheme of the spheroidized annealing process lies in that firstly, lamellar pearlites are heated to 770-790 DEG C, heat preservation is carried out for a certain time to enable the lamellar pearlite to be fused quickly, so that the undissolved carbide particles can promote the transformation of austenite into the spheroidized microscopic structure; the temperature is lowered to 710-730 DEG C, heat preservation is performed for 4-6 hours to enable the fused cementite to gather spherically, and along with the time extension of heat preservation, the rate of spheroidization of the cementite is gradually improved, and the uniformity is gradually improved. A slow three-stage cooling manner is adopted, so that the uniformity of the spheroidized structure is improved. According to the spheroidized annealing process for shortening the annealing cycle of hot rolled wire rods, the following advantages are achieved: the annealing effect is good, the technological process is simple, the annealing cycle is short, the production efficiency is high, and the cost is low. With the adoption of the spheroidized annealing process provided by the invention, the processed wire rods of fasteners are uniform in metallographic structure, high in toughness, high in malleability, low in harness, are suitable for subsequent moulding and processing forming, and the products are low in cold-forming cracking rate.

Description

technical field [0001] The invention relates to a hot-rolled wire rod annealing process, in particular to a spheroidizing annealing process capable of shortening the annealing period of an SCM435 hot-rolled wire rod, and belongs to the technical field of metal wire rod annealing processes. Background technique [0002] Spheroidizing annealing is one of the basic ways to improve the structure and performance of steel. Spheroidizing annealing can make carbides in the microstructure of steel materials spheroidize, reduce the hardness of the material, improve the shaping of the material, and reduce the deformation resistance of the material. Make the material easy to shape and shape. The spheroidizing annealing treatment often takes more than 20 hours, which is the most energy-consuming and time-consuming process in the fastener production process. Therefore, it is of great significance to shorten the annealing cycle by optimizing the annealing process. [0003] Chinese Patent...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/32
Inventor 王利军田新中张治广陈继林翟进坡王宁涛冯忠贤
Owner XINGTAI IRON & STEEL
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