Method for producing high-strength finishing rolling threaded steel bar by online hardening and tempering technology

A fine-rolled thread and high-strength technology, which is applied in the direction of process efficiency improvement, temperature control, and energy efficiency improvement, can solve the problems of long off-line induction quenching and tempering treatment cycle, low steel strength, and unstable toughness, etc., to save off-line Effects of quenching and tempering treatment, reduction of production cost, and improvement of strength and toughness index

Active Publication Date: 2009-08-26
YINGKOU JIULONG FINE SCREW
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problems of low strength and unstable toughness of hot-rolled steel bars with water waste heat treatment; long production cycle and high cost of off-line induction quenching and tempering treatment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] The weight percentage is: C: 0.45%, Si: 1.60%, Mn: 1.0%, Al: 0.022%, P: 0.022%, S: 0.010%, and the balance is Fe.

[0018] Heating the steel billet to 1150-1200°C, rolling it, and rolling it into the shape of the required finish-rolled threaded steel bar, controlling the final rolling temperature to 880°C, and the rolling exit speed to 30 m / min, so that the steel bar exits the rolling mill quickly enter the cooling device within 2 seconds, perform quenching treatment, and cool at a cooling rate of 200°C / s to control the surface temperature of the steel bar after the cooling device to 80°C; pass the quenched steel bar through the transfer roller table and the horizontal The moving platform is transported to the tempering line for tempering treatment. The tempering line adopts two conveying roller tables arranged in parallel. The roller shaft is perpendicular to the traveling direction of the steel bars. Two induction heaters are installed in the middle of each conveying r...

Embodiment 2

[0020] By weight percentage: C: 0.42%, Si: 1.5%, Mn: 0.9%, Als: 0.010%, P 0.021%, S 0.011%, and the balance is Fe.

[0021] Heating the steel billet to 1150-1200°C, rolling it, and rolling it into the shape of the required finish-rolled threaded steel bar, controlling the final rolling temperature to 1045°C, and the rolling exit speed to 26 m / min, so that the steel bar exits the rolling mill Quickly enter the cooling device, perform quenching treatment, and cool at a cooling rate of 390 ° C / s, control the surface temperature of the steel bar after cooling out of the cooling device to 54 ° C; the quenched steel bar is transported through the transfer roller table and the traversing platform to the tempering line for tempering treatment. The tempering line adopts two conveying roller tables arranged in parallel. The roller axis is perpendicular to the direction of steel bar travel. Three induction heaters are installed in the middle of each conveying roller table, and the steel...

Embodiment 3

[0023] By weight percentage: C: 0.48%, Si: 1.7%, Mn: 1.1%, Als: 0.05%, P 0.018%, S 0.020%, and the balance is Fe.

[0024] Heating the steel billet to 1150-1200°C, rolling it, and rolling it into the shape of the required finish-rolled threaded steel bar, controlling the final rolling temperature to 960°C, and the rolling exit speed to 23 m / min, so that the steel bar exits the rolling mill quickly enter the cooling device within 2 seconds, perform quenching treatment, cool at a cooling rate of 300°C / s, and control the surface temperature of the steel bar after the cooling device to 55°C; pass the quenched steel bar through the transfer roller and horizontal The moving platform is transported to the tempering line for tempering treatment. The tempering line adopts two parallel conveying roller tables. The roller axis is perpendicular to the direction of steel bar travel. Three induction heaters are installed in the middle of each conveying roller table, and the steel bars are co...

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PUM

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Abstract

The invention relates to a method for producing high-strength finishing rolling threaded steel bar by an online hardening and tempering technology. The used technical proposal comprises the steps that: a steel blank is heated to 1150-1200 DEG C, the blank is rolled to the shape of the required finishing rolling threaded steel bar, the temperature of final rolling is controlled in a range from 880 to 1050 DEG C, rolling exit velocity is controlled in 20-30 meter/minute, the steel bar enters into a cooling device in 5 seconds from the exit of a rolling machine so as to be quenched and then be cooled at 200-400 DEG C/second, the steel bar has the surface temperature of 50-80 DEG C after getting out of the cooling device, the quenched steel bar is conveyed to an annealing line via a transferring roller channel and a shifting platform for the annealing, the steel bar passes through an induction heater at the speed of 10-15 meter/minute, the annealing temperature is controlled in a range from 520-680 DEG C, and then blanking and cutting are implemented. In the invention, direct quenching is carried out after hot rolling, so that the steel bar can be completely quenched into a martensitic structure and is then directly annealed online to remarkably lower the production cost and dramatically improve toughness index of the steel bar.

Description

technical field [0001] The invention relates to an on-line production method of high-strength finish-rolled threaded steel bar. Background technique [0002] Finished threaded steel bar is a new type of steel for prestressed concrete structures. This material has high strength and a revolvable appearance, which solves the problem that high-strength steel bars are not easy to be welded and lengthened. It also has tension anchorage and prefabricated beam splicing. And other unique advantages, suitable for long-span bridges, plant construction and rock mass anchorage. [0003] At present, the production of finished-rolled threaded steel bars mainly adopts two processes: one is to produce high-strength finished-rolled threaded steel bars by self-tempering after hot-rolling and water penetration. The second is to use the steel bars that are hot-rolled into the shape of finished-rolled threaded steel bars to go off the assembly line, and then produce high-strength finished-rolled...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/06C21D1/25C21D1/42B21B37/74
CPCY02P10/25
Inventor 郝佩良丁凡
Owner YINGKOU JIULONG FINE SCREW
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