CN103014522A

CN103014522A - Novel low-cost wear-resistant high-strength Q550D steel plate and production method thereof

Info

Publication number: CN103014522A
Application number: CN2012105846440A
Authority: CN
Inventors: 朱书成; 许少普; 刘庆波; 袁少威; 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 novel low-cost wear-resistant high-strength Q550D steel plate and a production method thereof. The steel plate comprises the following elements: 0.04-0.10% of C, 0.15-0.40% of Si, 1.40-1.60% of Mn, not more than 0.020% of P, not more than 0.015% of S, 0.015-0.060% of Als, 0.005-0.060% of Ti, 0.30-0.70% of Cr, 0.02-0.07% of Nb and the balance of Fe and inevitable impurities. The production method comprises the steps of smelting in a converter, LF (ladle furnace) refining, VD (vacuum degassing) treatment (optional), continuous casting, casting blank slow cooling, heating, TMCP (thermomechanical control process) rolling and slow cooling. The steel plate and the production method have the beneficial effects that through the novel composite microalloying composition design idea and concise and effective process design, the indexes of the steel plate, such as mechanical properties, ultrasonic flow detection and the like are ensured; the wear resistance of the steel plate is improved; and the steel plate has uniform properties, excellent flaw detection quality and certain wear resistance, can be widely used in engineering machinery, coal machine industry, machinery manufacturing and the like, and has good promotion significance.

Description

A kind of novel low-cost wear-resisting high-strength steel Q550D 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 wear-resisting high-strength steel Q550D steel plate and production method thereof.

Background technology

Specification 10～80mm Q550D is a kind of High Strength Structural Steel steel plate, and it has higher intensity, good cold deformation ability, and plasticity and toughness can be widely used in the projects such as all kinds of engineering machinery, bridge, building, large-sized workshop, stadium preferably.But along with the continuous progress of machine industry, the index request of mechanical means and engineering machinery is improved constantly, existing High Strength Structural Steel Q550D steel plate is difficult to meet the demands fully, and this new departure of ad hoc meter for this reason is to satisfy user's design requirement.

Summary of the invention

For the problems referred to above, the inventor has obtained a kind of specification 10～80mm guaranteed cost, has protected the novel low-cost wear-resisting high-strength steel Q550D steel plate of flaw detection, thereby finished the present invention through groping.

Therefore, the object of the present invention is to provide the high-strength steel Q550D steel plate of the low-cost guaranteed cost of a kind of specification 10～80mm, guarantor's flaw detection.

Another object of the present invention is to provide the production method of the novel low-cost wear-resisting high-strength steel Q550D steel plate with certain wear resisting property.

For reaching above-mentioned first purpose, in the national standard scope, the alloying elements such as the Mo that price in the steel is high, Ni reduce, to reduce production costs; The reduction of the alloying element content such as Mo, Ni, can cause plate property to descend, bad stability, for guaranteeing the performance of steel plate, change in the little situation at process cost, utilize the lower Cr alloying element of price to replace the alloying elements such as Mo, Ni, in the situation that reduces cost, reach the stability, uniformity of requirement performance index and performance, guarantee the overall quality index of steel plate.

Novel low-cost wear-resisting high-strength steel Q550D steel plate of the present invention is by following elementary composition: C 0.04～0.10%, Si0.15～0.40%, Mn1.40～1.60%, P≤0.020%, S≤0.015%, Als0.015～0.060%, Ti 0.005～0.060%, Cr0.30～0.70%, Nb0.02～0.07%, 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, but segregation causes detecting a flaw defective easily.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.Nb, Ti: crystal grain thinning, the intensity of raising steel plate.Cr: chromium and iron form continuous solid solution, dwindle the austenite region, significantly improve intensity and hardening capacity, and have good wear resisting property.

For achieving the above object, the production method that the present invention takes comprises: converter smelting, LF refining, VD vacuum-treat (optional), continuous casting, strand slow cooling, heating, rolling, the slow cooling of TMCP.

1, in described converter smelting, tapping carbon≤0.06%, tapping P≤0.018%, S≤0.020%; 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 ferro-niobium, ferrotianium, the ferrochrome 3-5 minute, 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 0.8-1.4min/mm, the holding temperature of soaking zone is controlled at 1200 ℃～1280 ℃.

5, in described TMCP, 1000 ℃～1100 ℃ of start rolling temperatures; The one-phase finishing temperature is at 880～980 ℃, and the two-stage start rolling temperature is at 800～900 ℃, steel thickness 〉=1.5 times of drying in the air, the two-stage take little depress rolling, finish rolling accumulative total draft＞40%, finishing temperature≤880 ℃; Red temperature＜650 ℃, cooling rate is controlled at 5～25 ℃/s.

6, in described slow cooling, enter burial pit temperature 〉=150 ℃; Cooling in heap time 〉=6 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; And improved the wear resisting property of steel plate, its plate property evenly, the flaw detection good quality, and have certain wear resisting property, can be widely used in the aspects such as engineering machinery, coal machine profession, machinofacture, be with the promotion of good sense.

Embodiment

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

Table 1 novel components (unit, wt%)

Element

C

Si

Mn

P

S

Als

Ti

Cr

Nb

National standard

≤0.18

≤0.60

≤2.00

≤0.030

≤0.025

≥0.015

≤0.20

≤0.80

≤0.11

Novel components

0.04～0.10

0.15～0.40

1.40～1.60

≤0.020

≤0.015

0.015～0.060

0.005～0.06

0.30～0.70

0.02～0.07

The production method that the present invention takes comprises: converter smelting, LF refining, VD vacuum-treat (optional), continuous casting, strand slow cooling, heating, rolling, the slow cooling of TMCP.

Claims

1. A kind ofNovel low-cost wear-resisting high-strength steel Q550D steel plate, it is by following elementary composition: C 0.04～0.10%, Si0.15～0.40%, Mn1.40～1.60%, P≤0.020%, S≤0.015%, Als0.015～0.060%, Ti 0.005～0.060%, Cr0.30～0.70%, Nb0.02～0.07%, all the other are Fe and inevitable impurity.

2. As claimed in claim 1 a kind ofThe production method of novel low-cost wear-resisting high-strength steel Q550D steel plate, it comprises: converter smelting, LF refining, VD vacuum-treat (optional), continuous casting, strand slow cooling, heating, rolling, the slow cooling of TMCP; It is characterized in that:

(1), in described converter smelting, the tapping carbon≤0.06%, the tapping P≤0.018%, S≤0.020%; 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 ferro-niobium, ferrotianium, the ferrochrome 3-5 minute, 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 0.8-1.4min/mm, the holding temperature of soaking zone is controlled at 1200 ℃～1280 ℃;

(5), in described TMCP, 1000 ℃～1100 ℃ of start rolling temperatures; The one-phase finishing temperature is at 880～980 ℃, and the two-stage start rolling temperature is at 800～900 ℃, steel thickness 〉=1.5 times of drying in the air, the two-stage take little depress rolling, finish rolling accumulative total draft＞40%, finishing temperature≤880 ℃; Red temperature＜650 ℃, cooling rate is controlled at 5～25 ℃/s;

(6), in described slow cooling, enter burial pit temperature 〉=150 ℃; Cooling in heap time 〉=6 hour.