CN103014509A

CN103014509A - Novel low-cost Q345GJC/D steel plate for high-rise buildings and production method of steel plate

Info

Publication number: CN103014509A
Application number: CN2012105849364A
Authority: CN
Inventors: 朱书成; 许少普; 袁少威; 刘庆波; 郭艳芳; 康文举; 朱先兴
Original assignee: Nanyang Hanye Special Steel Co Ltd
Current assignee: Nanyang Hanye Special Steel Co Ltd
Priority date: 2012-12-30
Filing date: 2012-12-30
Publication date: 2013-04-03

Abstract

The invention discloses a low-cost Q345GJC/D steel plate for high-rise buildings, which consists of the following elements by weight percent: 0.13-0.16% of C, 0.20-0.40% of Si, 0.90-1.10% of Mn, not greater than 0.020% of P, not greater than 0.015% of S, 0.015-0.030% of Als, 0.020-0.030% of V, 0.10-0.20% of Cr, and the balance of Fe and inevitable impurities. The production method comprises the following steps of smelting in a converter, low-frequency (LF) fining, continuous casting, casting blank slow-cooling, heating, a thermo-mechanical control process (TMCP) and slow-cooling. Through the above original composite microalloying component design thought and the simple and effective process design, the mechanical performance, ultrasonic flaw detection and other indexes of the steel plate are guaranteed, and the saved cost of per ton of steel is 50-60 RMB/ton. theow-cost Q345GJC/D steel plate for high-rise buildings disclosed by the invention has a good promotion significance.

Description

A kind of novel low-cost Highrise buildings Q345GJC/D steel plate and production method thereof

Technical field

The present invention relates to continuous casting and produce the plate of moderate thickness field, be specifically related to a kind of novel low-cost Highrise buildings Q345GJC/D steel plate and production method thereof.

Background technology

Specification 16～80mm Q345GJC/D is a kind of steel plate for tall building commonly used, and it has higher intensity, good cold deformation ability, and plasticity and toughness are widely used in the projects such as all kinds of bridges, building, large-sized workshop, stadium preferably.Along with the continuous reduction of steel industry profit, tap the latent power and reduce ton steel cost and put on agenda in inside.

Summary of the invention

For the problems referred to above, the inventor has obtained a kind of specification 16～80mm guaranteed cost of low cost production, the Q345GJC/D steel plate for tall building of guarantor's flaw detection, thereby has finished the present invention through groping.

Therefore, the object of the present invention is to provide the Highrise buildings Q345GJC/D steel plate of a kind of low-cost specification 16～80mm guaranteed cost, guarantor's flaw detection.

Another object of the present invention is to provide the production method of this low cost steel plate.

For reaching above-mentioned first purpose, in the national standard scope, change in the little situation at process cost, utilize Cr alloying element with low cost to replace the higher Mn alloying element of a part of cost, significantly reduce ton steel cost, enlarge the product profit space.

For achieving the above object, low-cost Highrise buildings of the present invention uses the Q345GJC/D steel plate by following elementary composition: C 0.13～0.16%, Si0.20～0.40%, Mn0.90～1.10%, P≤0.020%, S≤0.015%, Als0.015～0.030%, V 0.020～0.030%, Cr0.10～0.20%, all the other are Fe and inevitable impurity.

The function analysis of above-mentioned chemical element is as follows:

C: be most basic strengthening element in the steel, improve intensity, but C affects the welding property of steel and affects toughness.Si: be the solution strengthening element, favourable to the intensity that improves steel plate.Mn: be the solution strengthening element, all favourable to intensity and the toughness that improves steel plate.P: unfavorable to welding, and have certain cold shortness, and in this steel grade, belong to harmful element, that should control is as far as possible low.S: easily form the MnS type impurity, have certain red brittleness, belong to harmful element in this steel grade, that should control is as far as possible low.Al: can play the grain refining intensificatiom effect.V: can not only improve steel intensity, reduce overheated tendency, and the low-temperature flexibility of steel is had obvious impact.Cr: chromium and iron form continuous solid solution, dwindle the austenite region, significantly improve intensity and hardening capacity, and can effectively reduce the steel plate yield tensile ratio.

For achieving the above object, the production method that the present invention takes comprises: converter smelting, LF refining, continuous casting, strand slow cooling, heating, TMCP, slow cooling.

1, in described converter smelting, tapping carbon 〉=0.05%, tapping P≤0.012%, S≤0.005%; Point blows number of times and must not greater than 2 times, avoid slag under the tapping process; The argon station adds the aluminum steel deoxidation.

2, in described LF refining, take the large quantity of slag to carry out slag making, guarantee that the white slag hold-time is controlled at more than the 15min, blew by force behind vanadium iron, the ferrochrome 3 minutes, again more than the soft blow 8min.

3, in described casting process, adopt the whole process protection cast, the cast superheating temperature is controlled at 5～20 ℃, and permanent pulling rate cast entered the burial pit slow cooling 24 hours after the continuously cast bloom cutting.

4, pine in described adding, heat-up time 0.9min/mm, the holding temperature of soaking zone is controlled at 1220 ℃～1240 ℃.

5, in described TMCP, 1040 ℃～1100 ℃ of start rolling temperatures; The one-phase finishing temperature is at 940～980 ℃, and the two-stage start rolling temperature is at 830～850 ℃, 1.5～2 times of the steel thickness of drying in the air, the two-stage take little depress rolling, finish rolling accumulative total draft＞50%, finishing temperature≤810 ℃; Red temperature＜750 ℃, cooling rate is controlled at 3～6 ℃/s.

6, in described slow cooling, enter burial pit temperature 〉=450 ℃; Cooling in heap time 〉=24 hour.

By combined microalloying Composition Design thinking and the brief effective process design of above novelty, guaranteed the index such as mechanical property, UT (Ultrasonic Testing) of steel plate; The ton steel is saved cost at 50～60 yuan/tons, is with the promotion of good sense.

Description of drawings

Below in conjunction with accompanying drawing, the present invention is further elaborated.

Fig. 1 is process flow sheet of the present invention.

Fig. 2 is the typical gold phase constitution figure (100X) of TMCP of the present invention after rolling.

Fig. 3 is the typical gold phase constitution figure (100X) of TMCP of the present invention after rolling.

Embodiment

Low-cost Highrise buildings of the present invention uses the Q345GJC/D steel plate by following elementary composition: C 0.13～0.16%, Si0.20～0.40%, Mn0.90～1.10%, P≤0.020%, S≤0.015%, Als0.015～0.030%, V 0.020～0.030%, Cr0.10～0.20%, all the other are Fe and inevitable impurity.

The Composition Design scheme that the present invention takes such as following table 1:

The traditional composition of table 1 and novel components contrast (unit, wt%)

Element

C

Si

Mn

P

S

Als

V

Cr

National standard

≤0.18

≤0.55

≤1.60

≤0.020

≤0.015

≥0.015

≤0.060

≤0.30

The tradition composition

0.13～0.16

0.20～0.40

1.40～1.50

≤0.018

≤0.015

0.015～0.030

0.020～0.030

0.04～0.05

Novel components

0.13～0.16

0.20～0.40

0.90～1.10

≤0.018

≤0.015

0.015～0.030

0.020～0.030

0.10～0.20

The production method that the present invention takes comprises: converter smelting, LF refining, continuous casting, strand slow cooling, heating, TMCP, slow cooling.

Claims

1. low-cost Highrise buildings Q345GJC/D steel plate, it is by following elementary composition: C 0.13～0.16%, Si0.20～0.40%, Mn0.90～1.10%, P≤0.020%, S≤0.015%, Als0.015～0.030%, V 0.020～0.030%, Cr0.10～0.20%, all the other are Fe and inevitable impurity.

One kind low-cost Highrise buildings is with production methods such as Q345GJC/D steel plates as claimed in claim 1, this production method comprises: converter smelting, LF refining, continuous casting, strand slow cooling, heating, TMCP, slow cooling; It is characterized in that:

(1), in described converter smelting, the tapping carbon 〉=0.05%, the tapping P≤0.012%, S≤0.005%; Point blows number of times and must not greater than 2 times, avoid slag under the tapping process; The argon station adds the aluminum steel deoxidation;

(2), in described LF refining, take the large quantity of slag to carry out slag making, guarantee that the white slag hold-time is controlled at more than the 15min, blew by force behind vanadium iron, the ferrochrome 3 minutes, again more than the soft blow 8min;

(3), in described casting process, adopt the whole process protection cast, the cast superheating temperature is controlled at 5～20 ℃, permanent pulling rate cast entered the burial pit slow cooling 24 hours after the continuously cast bloom cutting;

(4), pine in described adding, heat-up time 0.9min/mm, the holding temperature of soaking zone is controlled at 1220 ℃～1240 ℃;

(5), in described TMCP, 1040 ℃～1100 ℃ of start rolling temperatures; The one-phase finishing temperature is at 940～980 ℃, and the two-stage start rolling temperature is at 830～850 ℃, 1.5～2 times of the steel thickness of drying in the air, the two-stage take little depress rolling, finish rolling accumulative total draft＞50%, finishing temperature≤810 ℃; Red temperature＜750 ℃, cooling rate is controlled at 3～6 ℃/s;

(6), in described slow cooling, enter burial pit temperature 〉=450 ℃; Cooling in heap time 〉=24 hour.