High-strength hot-rolled reinforcement bar of 830 MPa level, and production technology thereof

A production process, 830mpa technology, applied in the field of steel bars and their production processes, can solve the problems of low yield strength of hot-rolled steel bars and difficulty in ensuring the yield platform, achieve good ductility, avoid excessive corrosion rate and hardness, and reduce the amount of steel bars Effect

Active Publication Date: 2015-06-24
江苏森林建筑新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The yield strength of existing hot-rolled steel bars is relatively low. It is very difficult to make the yield strength of hot-rolled steel bars reach such a high strength as 830MPa and above, and the strength is so high that it is difficult to guarantee the yield platform. Strength may be expressed as a 0.2% strain versus strength

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] The 830MPa grade high-strength hot-rolled steel bar in this embodiment has the following chemical components by weight: C: 0.38%, Cr: 0.7%, Mn: 0.6%, Mo: 0.25%, Si: 0.2%, Ni: 1.6%, S: 0.025%, P: 0.03%, N: 0.025%, and the balance is Fe.

[0035] The production process of the 830MPa grade high-strength hot-rolled steel bar of the present embodiment is carried out according to the following steps:

[0036] (1) The smelted steel bars are sent to the heating furnace to be heated to 1200 ° C, and then the steel bars are rapidly cooled to 640 ° C through the first online cooling process, and then quenched with water or quenching liquid in the quenching device for 15 seconds, and then passed through The tempering furnace is heated to 660℃ for tempering, and then cooled to normal temperature through the second cooling process;

[0037] The first cooling process: use water cooling to water-cool the steel bars to 640°C at a cooling rate of 9°C / s;

[0038] The second cooling proc...

Embodiment 2

[0045] The 830MPa grade high-strength hot-rolled steel bar in this embodiment has the following chemical components by weight: C: 0.41%, Cr: 0.8%, Mn: 0.7%, Mo: 0.15%, Si: 0.25%, Ni: 1.8%, S: 0.015%, P: 0.025%, N: 0.015%, and the balance is Fe.

[0046] The production process of the 830MPa grade high-strength hot-rolled steel bar of the present embodiment is carried out according to the following steps:

[0047] (1) The smelted steel bars are sent to the heating furnace to be heated to 1100 ° C, and then the steel bars are rapidly cooled to 650 ° C through the first online cooling process, and then quenched with water or quenching liquid in the quenching device for 16 seconds. The tempering furnace is heated to 600 ℃ for tempering, and then cooled to normal temperature through the second cooling process;

[0048] The first cooling process: use water cooling to water-cool the steel bar to 650°C at a cooling rate of 10°C / s;

[0049] The second cooling process: the combination ...

Embodiment 3

[0056] The 830MPa grade high-strength hot-rolled steel bar in this embodiment has the following chemical components by weight: C: 0.43%, Cr: 0.9%, Mn: 0.8%, Mo: 0.2%, Si: 0.3%, Ni: 2%, S: 0.013%, P: 0.015%, N: 0.012%, and the balance is Fe.

[0057] The production process of the 830MPa grade high-strength hot-rolled steel bar of the present embodiment is carried out according to the following steps:

[0058] (1) The smelted steel bars are sent to the heating furnace to be heated to 1010 ° C, and then the steel bars are rapidly cooled to 660 ° C through the first cooling process on-line, and then quenched with water or quenching liquid in the quenching device for 17 seconds. The tempering furnace is heated to 520 ℃ for tempering, and then cooled to normal temperature through the second cooling process;

[0059] The first cooling process: use water cooling to water-cool the steel bars to 660°C at a cooling rate of 11°C / s;

[0060] The second cooling process: the combination of...

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Abstract

The invention relates to a steel bar and its production process, which is a 830MPa grade high-strength hot-rolled steel bar and its production process. The chemical composition in weight percentage is: C: 0.38-0.43%, Cr: 0.7-0.9%, Mn: 0.6- 0.8%, Mo: 0.15-0.25%, Si: 0.2-0.3%, Ni: 1.6-2%, S: <0.035%, P: <0.035%, N: <0.035%, and the balance is Fe. The steel bar yield strength of the present invention can reach 830MPa, has the advantages of high strength, good ductility, strong hysteresis fracture resistance, steel saving, low relaxation, easy welding, good upsetting performance, etc., and can fully dissolve carbides and evenly diffuse, It avoids the precipitation of carbides between grains and causes excessive intergranular corrosion and pitting corrosion.

Description

technical field [0001] The invention relates to a steel bar and a production process thereof, in particular to an 830MPa grade high-strength hot-rolled steel bar and a production process thereof. Background technique [0002] Hot-rolled steel bars are finished steel bars that have been hot-rolled and naturally cooled. They are made of low-carbon steel and ordinary alloy steel at high temperatures. They are mainly used for reinforcement of reinforced concrete and prestressed concrete structures. They are used in civil engineering One of the most widely used steel varieties. Hot-rolled steel bars are graded according to the standard value of yield strength and are divided into four grades: [0003] HPB235 (Q235), the standard value of the yield strength of the steel bar is 235MPa, the diameter is 8-20mm, and the elastic modulus is 210GPa. [0004] HRB335 (20MnSi), the standard value of the yield strength of the steel bar is 335MPa, the diameter is 6-50mm, and the elastic mod...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/44C21D8/08
Inventor 姚圣法吴海洋
Owner 江苏森林建筑新材料股份有限公司
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