Post rolling fast cooling-production technology of high strength ribbed reinforced bar

A ribbed steel bar and production process technology, which is applied in the field of changing the physical properties of concrete steel bars, can solve the problems of unsuitable promotion of waste heat quenching technology, decline in low-temperature impact toughness, and high requirements for strength-to-yield ratio, so as to solve the problem of insufficient cooling bed area, reduce Cooling time, effect of small investment in equipment

Inactive Publication Date: 2006-01-11
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, users in our country evaluate the performance of products produced by this process: the weldability of the steel becomes poor, the ratio of tensile strength to yield point (referred to as the strength-to-yield ratio) is low, and the low-temperature impact toughness decreases. Such steel bars are obviously inferior. Poor earth

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Example 1: Rolling Φ14mm HRB335 steel bars with ordinary carbon steel

[0022] Using ordinary carbon steel with chemical composition of 0.20%C, 0.45%Si, 0.75%Mn, 0.030%P and 0.043%S as raw material, with 18 fully continuous rolling mills, including 6 rough rolling units and 6 intermediate rolling units , the finishing rolling unit uses 6 stands, each rolling mill rolling 1 pass. The billet is 150mm square billet, the rolling temperature is 1080°C, after rolling, the temperature of the rolled piece at the exit of the finish rolling is about 1050°C, and the two-cut rolling is adopted.

[0023] The rolled piece then enters the cooler for cooling. The cooler consists of 7 sections, and the number of opened sections of the cooler is adjusted to 3 sections according to the product specification. The rolling speed of the finished rolling mill is 15.0m / s, passing through the cooler in an instant of 0.5 seconds, and the temperature of the rolled piece at the outlet of the coole...

Embodiment 2

[0026] Example 2: 20MnSi steel rolling Φ25mm HRB400 steel bars

[0027] 20MnSi steel is used as raw material, and the chemical composition of the steel is 0.18-0.23% C, 0.45-0.65% Si, 1.2-1.58% Mn, and the content of P and S is less than 0.045%. A full continuous rolling mill is used, with a total of 14 stands. Among them, there are 6 rough rolling mills, 6 intermediate rolling mills and 2 finishing rolling mills, and each mill rolls 1 pass. The billet is a 150mm square billet, and the rolling temperature is 1100°C. After rolling, the temperature of the rolled piece at the exit of the finish rolling is about 10.50°C.

[0028] The rolled piece then enters the cooler for cooling. The cooler consists of 7 sections, and the number of opened sections of the cooler is adjusted to 4 sections according to the product specification. The rolling speed of the finished rolling mill is 14.5m / s, and it takes 0.8 seconds to pass through the cooler, and the temperature of the rolled piece a...

Embodiment 3

[0031] Example 3: Rolling Φ16mm HRB500 steel bar with 20MnSiV steel

[0032] The adopted chemical composition is 0.22-0.24% C, 0.50-0.80% Si, 1.3-1.58% Mn, and the content of P and S is less than 0.040%. 20MnSiV with 0.05-0.06% V is used as raw material, and a full continuous rolling mill is used, with a total of 16 stands. Among them, there are 6 rough rolling mills, 6 intermediate rolling mills and 4 finishing rolling mills, and each mill rolls 1 pass. The billet is a 170mm square billet, and the rolling temperature is 1070°C. After rolling, the temperature of the rolled piece at the exit of the finish rolling is about 1050°C.

[0033]The rolled piece then enters the cooler for cooling. The cooler consists of 7 sections, and the number of opened sections of the cooler is adjusted to 4 sections according to the product specification. The rolling speed of the finished rolling mill is 14.0m / s, and it takes 0.5 seconds to pass through the cooler, and the temperature of the rol...

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PUM

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Abstract

An ultrahigh-speed cooling technology for the rolled high-strength ribbed steel bar includes hot rolling and afterheat treating. For said afterheat treating, the rolled steel bar is quickly cooled to 480-720 deg.C within 1 second to quickly convert its austenite structure to the ferrite/ pearlite structure with the grain fineness of class 11-12. It is suitable for rolling high-quality steel bar.

Description

technical field [0001] The invention belongs to the technical field of changing the physical properties of concrete reinforcement by performing heat treatment after deformation. Background technique [0002] Hot-rolled ribbed steel bars for reinforced concrete are one of the steel products with the largest output in my country. According to the national standard of the People's Republic of China (referred to as the national standard), its grade is composed of HRB and the minimum yield point (MPa) of the grade of steel. HRB is the first letter of the English abbreviation of Hot rolled ribbed bars (Hot rolled Ribbed Bars), there are three grades of HRB335, HRB400 and HRB500. Due to the development of modern construction, the market demand for ribbed steel bars continues to grow. By 2004, its total output has reached more than 70 million tons, which is several times the output of Japan and the United States during the same period. The rapid growth of my country's steel produc...

Claims

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Application Information

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IPC IPC(8): C21D8/08
Inventor 吴迪王国栋赵宪明杜林秀刘相华
Owner NORTHEASTERN UNIV
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