Method for production of high-strength threaded steel bar through on-line quenching and tempering, and heating blackening coating processes

A threaded steel bar and coating process technology, applied in heat treatment furnaces, manufacturing tools, heat treatment equipment, etc., can solve problems such as inability to complete coating anti-corrosion treatment, insufficient quenching and heat preservation time, high rolling heating temperature, etc., to achieve mechanical properties and The effect of anti-corrosion requirements, stable product quality, and high toughness level index

Active Publication Date: 2012-12-12
LIUZHOU OVM MASCH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The existing technology has the following disadvantages: these two quenching and tempering processes are basically used on the fine-rolled threaded steel bars with small diameters (diameter below 50mm), and cannot complete online blackening and coating anti-corrosion treatment
Using the waste heat of rolling heating for quenching and tempering treatment will easily cause insufficient quenching and holding time, high rolling heating temperature, prone to coarse grains, and low rolling temperature will affect rolling performance, thereby affecting mechanical properties
In addition, due to the problem of transmission speed, it is easy to cause insufficient quenching and tempering, and the mechanical properties will decrease

Method used

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  • Method for production of high-strength threaded steel bar through on-line quenching and tempering, and heating blackening coating processes
  • Method for production of high-strength threaded steel bar through on-line quenching and tempering, and heating blackening coating processes
  • Method for production of high-strength threaded steel bar through on-line quenching and tempering, and heating blackening coating processes

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Experimental program
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Effect test

Embodiment 1

[0032] The weight percentages used are: C: 0.37%, Si: 0.3%, Mn: 0.8%, Cr: 0.8%, Mo: 0.25%, P: 0.035%, S: 0.002%, and the balance is a steel rod of Fe.

[0033] The threaded steel bar formed after the steel bar is peeled and rolled is subjected to 3-stage induction quenching heating, that is, 3 induction heaters are used, the first 2 induction heaters are used for preheating heating, and the last induction heater is used for heat preservation heating. Control the temperature of the threaded steel bars in the quenching preheating zone to 700~750°C, and control the temperature of the threaded steel bars in the latter one of the two preheating induction heaters to be 50°C higher than that in the previous one (that is, the first and second sets The temperatures of the rebars in the preheated induction heaters were 700°C and 750°C, respectively). The temperature of the threaded steel bar in the quenching and heat preservation zone is 820~850°C, the time for the threaded steel bar to...

Embodiment 2

[0035] The weight percentages used are: C: 0.39%, Si: 0.35%, Mn: 0.65%, Cr: 1.08%, Mo: 0.25%, P: 0.025%, S: 0.035%, and the balance is a steel rod of Fe.

[0036] The threaded steel bar formed after the steel bar is peeled and rolled is subjected to 5-stage induction quenching heating, that is, 5 induction heaters are used, the first 4 induction heaters are used for preheating heating, and the last induction heater is used for heat preservation heating. Control the temperature of the threaded steel bars in the quenching preheating zone to 700~850°C, and control the temperature of the threaded steel bars in the latter set of 4 preheating induction heaters to be 50°C higher than that in the previous set (that is, the first set and the second set , 3rd and 4th preheating induction heaters, the temperatures of the rebars are 700°C, 750°C, 800°C and 850°C, respectively). The temperature of the threaded steel bars in the quenching and heat preservation zone is 850-870 °C, and the ti...

Embodiment 3

[0038] The weight percentages used are: C: 0.45%, Si: 0.17%, Mn: 0.69%, Cr: 1.17%, Mo: 0.22%, P: 0.014%, S: 0.014%, and the balance is a steel rod of Fe.

[0039] The threaded steel bars formed by peeling and rolling the steel bars are subjected to 6-level induction quenching heating, that is, 6 induction heaters are used, the first 4 induction heaters are used for preheating, and the last 2 induction heaters are used for heat preservation. Control the temperature in the quenching preheating zone to 800-850°C, the temperature in the quenching and holding zone to 850-910°C, and the time for the threaded steel bars to pass through the quenching and holding zone is 12 minutes. The speed of quenching and heating is 0.2m / min, and the threaded steel bar enters the graded spray ring for cooling within 25s after coming out of the quenching and heat preservation zone, and performs quenching treatment, cooling at a cooling rate of 70°C / s, and the temperature of the spray ring cooling dev...

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Abstract

The invention relates to a method for production of high-strength threaded steel bar through on-line quenching and tempering, and heating blackening coating processes. The method includes the following steps of: subjecting a thread steel bar to multistage induction quenching heating, controlling the temperature of a quenching preheating zone at 700-850DEG C and the temperature of a quenching heat preservation zone at 820-950DEG C, and keeping the speed of quenching heating at 0.2-0.5m / min, then carrying out a quenching treatment, performing cooling at a cooling speed of 50-100DEG C / s, controlling the temperature of the thread steel bar released out of a spray ring cooling device at 60-100DEG C, then performing multistage induction tempering heating at a proceeding speed of 0.2-0.5m / min, controlling the tempering temperature at 500-650DEG C, delivering the tempered threaded steel bar to a surface coating zone to conduct heating blackening antiseptic treatment, implementing online packaging, and finally conducting offline storage. The technological method realizes on-line quenching and tempering, and heating blackening production of high-strength threaded steel bars, and has the characteristics of small deformation of workpieces, high production efficiency, energy saving, environmental protection, and less pollution, etc.

Description

technical field [0001] The invention relates to heat treatment and coating anti-corrosion production of long rod (pipe) materials, in particular to a method for producing high-strength threaded steel bars by on-line quenching and tempering and heating blackening coating technology. Background technique [0002] High-strength threaded steel bar is a new type of steel for prestressed concrete structures. This material has high strength and can be screwed, which solves the problem that high-strength steel bars are not easy to be welded and lengthened. It also has the advantages of easy connection and anchoring, strong adhesion, and safe anchorage Reliable, convenient construction and other advantages. It is used in the construction of continuous beams and large frame structures in large-scale water conservancy projects, industrial and civil buildings, construction and rock mass anchorage of long-span bridges in highways and railways, nuclear power plants and ground anchors. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F17/00C21D8/08C21D1/25C21D9/56
Inventor 阳余莲曾杰赖祥智杨瑞朱万旭黄永诚龙跃邓学奇张升华熊武梁黎霞
Owner LIUZHOU OVM MASCH CO LTD
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