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A Controlled Cooling Method for 82b Wire Rod with Small Size and High Cr After Rolling

A technology of controlled cooling and small size, which is applied in metal rolling, temperature control, metal rolling, etc., and can solve problems such as the content cannot be too high, the critical cooling rate of martensite is reduced, and the fluctuation of mechanical properties of the abnormal structure of controlled cooling is difficult. , to achieve high strength, stable mass production, and uniformity

Active Publication Date: 2016-03-30
JIANGSU YONGGANG GROUP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The content of Cr should not be too high, especially for small specifications. Compared with large specifications, due to the smaller section diameter, its hardenability will be stronger, which will cause the continuous cooling CCT curve of the wire rod after rolling to move to the right downward. Then the critical cooling rate for forming martensite is greatly reduced. If the cooling process is slightly improper, it is very easy to produce low-temperature transformation structures such as martensite and bainite. High requirements, which bring great difficulties to the control of abnormal microstructure and mechanical property fluctuations of controlled cooling after rolling

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] In summer, a method of controlled cooling after rolling of a small-scale high-Cr 82B wire rod of the present invention: the method can control the spinning temperature after rolling, the cooling rate before the phase change, the phase change temperature range, the cooling rate in the phase change zone, and the cooling rate in the phase change zone. The combined control of the speed of the Telmore roller table, the air volume of the fan and the distribution of the air volume of Jialing is as follows:

[0025] 1.1), water cooling after final rolling to avoid grain coarsening, the spinning temperature is controlled at 870°C;

[0026]1.2) Stable spinning ring shape technology of the laying machine; when the laying machine is at high speed, when the finished product speed of the finishing mill or the sizing mill is V≥90m / s, there will generally be an unstable shape of the spinning ring, such as spinning Chaotic, large and small circles, the running track of the spinning oute...

Embodiment 2

[0037] In winter, a method of controlled cooling after rolling of 82B wire rod with a small size and high Cr of the present invention, the method has a great influence on the spinning temperature after rolling, the cooling rate before the phase change, the phase change temperature range, the cooling rate in the phase change zone, and the cooling rate in the phase change zone. The combined control of the speed of the Telmore roller table, the air volume of the fan and the distribution of the air volume of Jialing is as follows:

[0038] 1.1), water cooling after final rolling to avoid grain coarsening, and the spinning temperature is controlled at 860°C;

[0039] 1.2) Stable spinning ring shape technology of the laying machine; when the laying machine is at high speed, when the finished product speed of the finishing mill or the sizing mill is V≥90m / s, there will generally be an unstable shape of the spinning ring, such as spinning There are large and small circles, the running...

Embodiment 3

[0050] In spring and autumn, a kind of method of controlling cooling after rolling of the 82B wire rod of a kind of small size high Cr of the present invention, this method is to the spinning temperature after rolling, the cooling speed before the phase change, the phase change temperature interval, the cooling rate of the phase change zone, Stelmore roller table speed, fan air volume and Carling air volume distribution are controlled in combination, as follows:

[0051] 1.1), water cooling after final rolling to avoid grain coarsening, the spinning temperature is controlled at 880°C;

[0052] 1.2) Stable spinning ring shape technology of the laying machine; when the laying machine is at high speed, when the finished product speed of the finishing mill or the sizing mill is V≥90m / s, there will generally be an unstable shape of the spinning ring, such as spinning There are large and small circles, the running track of the spinning outer circle no longer runs in a straight line,...

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Abstract

The invention relates to a post-rolling controlled cooling method for SWRH82B wire rod with high Cr (alloy content: 0.30-0.35%), which includes controlling the spinning temperature after rolling, cooling speed before spinning phase transition, phase transition temperature range and phase transition zone Combined control of cooling speed, Stelmo roller table speed, fan air volume and Jialing air volume distribution, and methods such as adjusting the production equipment to stabilize the spinning method, etc., to achieve the goal of stable production. Among them, the spinning temperature is controlled at 860-880°C, the cooling speed control range is 10.0-14.0°C / s after rolling and before the phase transformation, the phase transformation temperature range is 580-620°C, and the cooling speed control range in the phase transformation zone is 1.5- 3.0°C / s, the range of the base speed at the entrance section of the Stelmo roller table is controlled to be 0.6-1.0m / s. After the application and implementation of the technical scheme of controlling the cooling of the wire rod after rolling, it can ensure that the plasticity is not reduced while obtaining high strength On the contrary, it has been improved, avoiding the uneven cooling of the cleaning rod, resulting in the formation of low-temperature transformation structures such as martensite in local positions, and ensuring the uniformity of the cleaning rod structure and mechanical properties.

Description

technical field [0001] The invention belongs to the technical field of controlled rolling and controlled cooling of steel rolling, and in particular relates to a post-rolling controlled cooling technology of small-sized high-chromium 82B wire rod. Background technique [0002] As the main raw material of prestressed steel wire and steel strand, SWRH82B is widely used in highways, railway bridges, high-rise long-span buildings, seaport terminals and sleeper industries. In order to meet the high-strength requirements of wire rods for export without reducing the plasticity, large-scale (Φ≥8.0mm) are added with hardenable micro-alloying element Cr, but the content generally does not exceed 0.25%. ≥8mm) with low Cr content (Cr≤0.25%) has been researched and developed more and there are related reports. Whether it is domestic or foreign small size (Φ5.0-7.0mm) 82B wire rod, the tensile strength is generally ≥1180MPa when delivered by the user, and the desired target is ≥1200MPa, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21B45/02B21B37/74
Inventor 李长胜马志军王进张先轶吴锦圆余超
Owner JIANGSU YONGGANG GROUP CO LTD