阅读说明：本技术 一种具有优异综合性能的超高强度热轧酸洗扩孔钢及其生产方法 (A kind of super high strength hot rolled pickling reaming steel and its production method with Good All-around Property ) 是由 郭子峰 张衍 李秋寒 郭佳 冯军 白凤霞 牛涛 武巧玲 陈斌 吕宝锋 吴科敏 于 2019-09-05 设计创作，主要内容包括：本发明公开一种具有优异综合性能的超高强度热轧酸洗扩孔钢及其生产方法,其原料化学成分质量百分比(％)为：C 0.04～0.07％；Si≤0.03％；Mn 0.9～1.3％；P≤0.015％；S≤0.003％；Cr 0.1～0.5％；Nb 0.01～0.05％；Mo 0.1～0.5％；Ti 0.03～0.09％；Al 0.1～1.0％；其余是Fe及不可避免杂质。所述具有高扩孔性能的热轧酸洗带钢的生产方法包括：铁水预处理、转炉冶炼、精炼、连铸、热轧、平整和酸洗。本发明生产出来的带钢微观金相组织为铁素体+贝氏体,其中贝氏体组织所占体积比5～15％,该带钢抗拉强度≥780MPa,扩孔率λ≥60％,延伸率A80≥14％,具备优异的带钢表面质量。(The present invention discloses a kind of super high strength hot rolled pickling reaming steel and its production method with Good All-around Property, material chemical component mass percent (%) are as follows: C 0.04~0.07%；Si≤0.03%；Mn 0.9~1.3%；P≤0.015%；S≤0.003%；Cr 0.1~0.5%；Nb 0.01~0.05%；Mo 0.1~0.5%；Ti 0.03~0.09%；Al 0.1~1.0%；Remaining is Fe and inevitable impurity.The production method of the hot rolling acid-cleaning strip with high reaming performance includes: molten iron pretreatment, converter smelting, refining, continuous casting, hot rolling, smooth and pickling.The strip microscopic metallographic structure that the present invention produces is ferrite+bainite, and wherein volume ratio 5~15% shared by bainite structure, the strip tensile strength >=780MPa, hole expansibility λ >=60%, elongation percentage A80 >=14% have excellent strip surface quality.)

1. a kind of super high strength hot rolled pickling reaming steel with Good All-around Property, it is characterised in that: the chemical component of raw material It include: C 0.04~0.07% by percentage to the quality；Si≤0.03%；Mn 0.9~1.3%；P≤0.015%；S≤ 0.003%；Nb 0.01~0.05%；Mo 0.1~0.5%；Ti 0.03~0.09%；Al0.1~1.0%；Remaining be Fe and Inevitable impurity.

2. as described in claim 1 with the super high strength hot rolled pickling reaming steel of Good All-around Property, it is characterised in that: institute The internal microstructure for stating hot rolling acid-cleaning strip is ferrite and bainite.

3. as claimed in claim 2 with the super high strength hot rolled pickling reaming steel of Good All-around Property, it is characterised in that: institute The internal microstructure for stating hot rolling acid-cleaning strip is made of volume fraction for 85-95% ferrite and 5-15% bainite.

4. as described in claim 1 with the super high strength hot rolled pickling reaming steel of Good All-around Property, it is characterised in that: institute State tensile strength >=780MPa of hot rolling acid-cleaning reaming steel, hole expansibility λ >=60%, elongation percentage A80 >=14%, surface quality FB Grade.

5. the production method of the hot rolling acid-cleaning strip described in claim 1 with high reaming performance, step include:

(1) after pre-processing molten iron, continuous casting is obtained after converter smelting, refining obtain the molten steel of ingredient described in claim 1 Slab；

(2) after being heated the slab, hot rolled plate is obtained using roughing, finish rolling；

(3) hot rolled plate is cooled down stage by stage, coils into hot rolled coil after cooling；

(4) hot rolled coil is obtained into finished product after flattened, pickling.

6. the production method of the hot rolling acid-cleaning strip with high reaming performance as claimed in claim 5, it is characterised in that: in step Suddenly in (2), the finish rolling uses constant speed rolling, and the hot rolled plate thickness specification variation range control is in 1.8~5.5mm, rolling Speed control is in 5~11m/s.

7. the production method of the hot rolling acid-cleaning strip with high reaming performance as claimed in claim 5, it is characterised in that: in step Suddenly in (2), the roughing final temperature control is 1020~1080 DEG C, and the finish rolling final temperature control is 850~910 DEG C.

8. the production method of the hot rolling acid-cleaning strip with high reaming performance as claimed in claim 5, it is characterised in that: in step Suddenly in (3), the cooling stage by stage includes that the hot rolled plate is first cooled to 640~700 DEG C, then carries out the sky of 3~8s again It is cold, water cooling is finally carried out again to 400~480 DEG C.

9. the production method of the hot rolling acid-cleaning strip with high reaming performance as claimed in claim 5, it is characterised in that: in step Suddenly in (4), first the hot rolled coil is cooled to room temperature and then carries out again smooth, smooth elongation control is 1~3%.

10. the production method of the hot rolling acid-cleaning strip with high reaming performance as claimed in claim 5, it is characterised in that: In In step (4), the speed of service when hot rolled coil carries out pickling is controlled in 60~100m/min.

Technical field

The present invention relates to a kind of super high strength hot rolled pickling reaming steel and its production method with Good All-around Property belongs to In hot rolling acid-cleaning strip technical field of producing.

Background technique

In recent years, passenger car gets over the cost-effectiveness requirement of lightweight, safety and fuel oil with the development of automobile industry Come it is higher, using high strength steel and advanced high-strength steel be adapt to automobile industry development inexorable trend.800MPa rank height expands Kong Gang is widely used for manufacture passenger car as a steel grade in advanced high-strength steel with its high-intensitive, high reaming performance The kernel components such as spoke, subframe upper and lower plates, Triangular Arm.By taking Triangular Arm as an example, since part shape is complex, in addition to wanting It asks outside higher elongation percentage, has biggish reaming and flange in part key position, more demanding to ream forming, use is general Logical high-strength steel is easy to reaming cracking phenomena occur, and high reaming steel can solve the problems, such as this.

In the existing high reaming steel production technology of 800MPa hot rolling acid-cleaning, in order to obtain the intensity of superelevation, usually add higher C, Si element of content, that there are the reaming performances of strip is bad, surface quality grades are not high, hole expansibility and elongation percentage reduce asks Topic.

Summary of the invention

The present invention is intended to provide a kind of super high strength hot rolled pickling reaming steel and its producer with Good All-around Property Method.

First aspect present invention provides a kind of super high strength hot rolled pickling reaming steel with Good All-around Property, raw material Chemical component include: C 0.04~0.07% by percentage to the quality；Si≤0.03%；Mn 0.9~1.6%；P≤ 0.015%；S≤0.003%；Nb 0.01~0.05%；Mo 0.1~0.5%；Ti 0.03~0.09%；Al 0.1~ 1.0%；Remaining is Fe and inevitable impurity.

Second aspect of the present invention provides the life of the above-mentioned super high strength hot rolled pickling reaming steel with Good All-around Property Production method, step include:

(1) after pre-processing molten iron, continuous casting obtains slab after converter smelting, refining obtain the molten steel of mentioned component；

(2) after being heated the slab, hot rolled plate is obtained using roughing, finish rolling；

(3) hot rolled plate is cooled down stage by stage, coils into hot rolled coil after cooling；

(4) hot rolled coil is obtained into finished product after flattened, pickling.

Compared with prior art, the invention has the following advantages that being unfavorable for since higher C element causes carbide to increase The reaming performance of strip adds the unfavorable factor that can weaken carbide after the Si element of high level, but the fayalite generated (2FeO-SiO₂) iron scale and be difficult to remove, it is difficult to obtain the hot rolling acid-cleaning strip of higher level surface quality, and higher C, Mn element is easy to cause banded structure, reduces hole expansibility and elongation percentage.The present invention sets hot rolling acid-cleaning reaming composition of steel Meter improves product elongation percentage, forming property and reaming performance, obtained steel strip surface matter on the basis of guaranteeing higher-strength It measures outstanding.

The present invention devises matched hot rolling, cooling, smooth, acid cleaning process, gained hot rolling acid-cleaning band according to component system Steel tensile strength >=780MPa, hole expansibility λ >=60%, elongation percentage A80 >=14%, surface quality is up to FB grades, as automobile Component has higher performance when applying, and has good actual application prospect.

Specific embodiment

To facilitate the understanding of the present invention, present invention work more comprehensively, is meticulously described below in conjunction with embodiment, but this hair Bright protection scope is not limited to embodiment in detail below.

Unless otherwise defined, all technical terms used hereinafter and the normally understood meaning of those skilled in the art It is identical.Technical term used herein is intended merely to the purpose of description specific embodiment, is not intended to the limitation present invention Protection scope.For example, room temperature of the present invention refers to 10~35 DEG C of temperature.

Unless otherwise specified, various raw material, reagent, the instrument and equipment etc. used in the present invention, can pass through Market is commercially available or can be prepared by existing method.

First aspect present invention provides a kind of super high strength hot rolled pickling reaming steel with Good All-around Property, raw material Chemical component include: C 0.04~0.07% by percentage to the quality；Si≤0.03%；Mn 0.9~1.6%；P≤ 0.015%；S≤0.003%；Nb 0.01~0.05%；Mo 0.1~0.5%；Ti 0.03~0.09%；Al 0.1~ 1.0%；Remaining is Fe and inevitable impurity.

It is the effect and its restriction explanation of main component according to the present invention below:

Carbon: carbon is Ovshinsky element of volume, and it is shadow that the height of carbon content, which largely determines the tensile strength rank of steel plate, Ring the critically important index of carbon equivalent.By the control of the content of C element 0.04~0.07% in the present invention, lower C element content Guarantee steel grade compared with high-elongation and plasticity.

Manganese: manganese improves the harden ability of steel, postpones perlitic transformation and reduces bainite transformation temperature, ties the tissue Asia of steel Structure refinement.Therefore, the present invention uses 0.9~1.3% Mn content, under the premise of ensureing product tensile strength, has good Formability.

Niobium: the present invention promotes the refined crystalline strengthening of ferrite crystal grain using microalloy element niobium, helps to reduce bainite/iron Intensity difference between ferritic matrix, so as to improve the stretch flangeability of steel.The content control of Nb element is existed in the present invention 0.01~0.05%.

Aluminium: aluminium does not dissolve in cementite, and it is strong prevent in austenite and during bainitic transformation cementite precipitation, it is right There is remarkable effect in promoting hole expansibility and surface quality.Al content is limited to 0.1~1.0% by the present invention.

Silicon: silicon has certain invigoration effect but deteriorates pickling rear surface quality, and Si content is limited to by the present invention≤ 0.03%.

Phosphorus: phosphorus is generally solid-solubilized in ferrite in steel, there is very strong solution strengthening effect, for improving the intensity of steel, drop The toughness of low steel, but the P of too high amount is unfavorable to welding performance, is harmful element, therefore phosphorus content should be reduced to the greatest extent, in the present invention Content≤0.015% of P.

Sulphur: sulfur content and the form of sulfide are to influence the principal element of formability, and the quantity of sulfide is more, and size is got over Greatly, more unfavorable to reaming performance performance, therefore the practical controlled level of product S content is not limited strictly in the present invention, this hair Bright middle S content≤0.003%.

Preferably, the internal microstructure of the hot rolling acid-cleaning strip is ferrite+bainite.

It is more preferred, the internal microstructure of the hot rolling acid-cleaning strip by volume fraction be 85~95% ferrites and 5-15% bainite composition.

Preferably, the organization type of aforementioned proportion can guarantee the hot rolling acid-cleaning strip tensile strength >=780MPa, reaming Rate λ >=60%, elongation percentage A80 >=14%, strip surface quality is up to FB grades.

Second aspect of the present invention provides the life of the above-mentioned super high strength hot rolled pickling reaming steel with Good All-around Property Production method, step include:

(1) after pre-processing molten iron, continuous casting obtains slab after converter smelting, refining obtain the molten steel of mentioned component；

(2) after being heated the slab, hot rolled plate is obtained using roughing, finish rolling；

(3) hot rolled plate is cooled down stage by stage, coils into hot rolled coil after cooling；

(4) hot rolled coil is obtained into finished product after flattened, pickling.

The production method of the hot rolling acid-cleaning strip according to the present invention uses constant speed in the finish rolling in step (2) Rolling, hot rolled plate thickness specification variation range control in 1.8~5.5mm, mill speed because of thickness change, control 5~ 11m/s.The variation of mill speed mainly guarantees to guarantee that strip passes through milling train, by finish rolling entrance under target temperature point It is fixed that the difference of temperature and finishing temperature is come.

The production method of the hot rolling acid-cleaning strip according to the present invention, in step (2), the roughing final temperature control It is 1020~1080 DEG C, the finish rolling final temperature control is 850~910 DEG C.Temperature is excessively high to be easily formed acicular ferrite, modeling Property is poor；And the ferrite crystal grain or entrance γ+α two-phase section of the too low elongation then easy to form of temperature.By roughing final temperature control For system at 1020~1080 DEG C, the finish rolling final temperature control is 850~910 DEG C., which is that can guarantee that steel plate has Good intensity, hole expansibility and elongation percentage matching.

The production method of the hot rolling acid-cleaning strip according to the present invention, in step (3), the cooling stage by stage includes will The hot rolled plate is first quickly cooled to 640~700 DEG C, then carries out the air-cooled of 3~8s again, finally carry out again water cooling to 400~ 480℃.640~700 DEG C of quick forming core areas for ferrite (α) phase are quickly cooled to the shape that the temperature spot is conducive to ferritic phase Core, and the air cooling time of 3~8s guarantees that ferritic phase has the enough time of growing up, 400~480 DEG C of cooling temperatures are for shape At bainite structure, temperature is excessively high to be easily formed pearlite, and the too low martensite etc. that is easily formed is organized.

The hot rolled coil is first cooled to by the production method of the hot rolling acid-cleaning strip according to the present invention in step (4) Then room temperature carries out smooth again, smooth elongation control is 1~3%.

The production method of the hot rolling acid-cleaning strip according to the present invention, the hot rolling in step (4), after smooth Speed of service when volume carries out pickling is controlled in 60~100m/min.Pickling speed is too low to easily cause overpickling, excessive velocities Deficient pickling is easily caused, is not able to satisfy FB grades of surface quality requirements of belt steel surface.

Hot rolling acid-cleaning strip and its production method provided by the invention with high reaming performance, by chemical component Control and rolling, the control of acid cleaning process parameter, so that the strip microscopic metallographic structure produced is ferrite+bainite, Wherein volume ratio 5-15% shared by bainite structure, the strip tensile strength >=780MPa, hole expansibility λ >=60%, elongation percentage A80 >=14%, have excellent strip surface quality.

Below in conjunction with specific embodiment to provided by the present application a kind of with the super high strength hot rolled of Good All-around Property Pickling reaming steel and its production method are described in detail.