CN103952626A - Method for regulating and controlling performances of bainite non-tempered steel for fasteners - Google Patents

Method for regulating and controlling performances of bainite non-tempered steel for fasteners Download PDF

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Publication number
CN103952626A
CN103952626A CN201410199364.7A CN201410199364A CN103952626A CN 103952626 A CN103952626 A CN 103952626A CN 201410199364 A CN201410199364 A CN 201410199364A CN 103952626 A CN103952626 A CN 103952626A
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cooling
steel
bainite
rolling
speed
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曹杰
闫军
章静
沈晓辉
王会廷
潘红波
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Anhui University of Technology AHUT
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Anhui University of Technology AHUT
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Abstract

The invention discloses a method for regulating and controlling performances of bainite non-tempered steel for fasteners, belonging to the technical field of controlled rolling and controlled cooling of steel. The method is characterized by comprising the following steps: preparing the bainite non-tempered steel for fasteners by adopting high-speed wire rolling equipment, wherein the conventional rolling temperature is adopted at the crude, medium and pre-finish rolling stages of high-speed wire rolling, and the low temperature rolling technology is adopted at the finish rolling stage; controlling the austenite deformation temperature at 750-900 DEG C, wherein the deformation is not less than 40%; and controlling cooling after deformation, wherein controlled cooling is divided into single cooling and subsection cooling, the single cooling speed is 3-5 DEG C/s, rapid cooling at a speed not less than 5 DEG C/s is adopted before bainite phase transformation in subsection cooling and then slow cooling at a speed of 0.5-2 DEG C/s is adopted. The method has the beneficial effects that online regulation and control of the strength and hardness of the bainite non-tempered steel for fasteners can be achieved by regulating the parameters; good plasticity is obtained under the condition of different strengths and hardness; the cold machinability of the steel is improved.

Description

The regulate and control method of the non-modified steel for fastener performance of a kind of bainite
Technical field:
The invention belongs to the Controlled Rolling And Controlled Cooling field of steel, be specifically related to the regulate and control method of the non-modified steel for fastener performance of a kind of bainite.
Background technology:
High-intensity fasteners is generally divided into 8.8 grades, and 9.8 grades, several ranks such as 10.9 grades and 12.9 grades, generally adopt quenched and tempered steel to manufacture traditionally, and the conventional trade mark has ML35, ML45,35CrMo, 40Cr, 42CrMo etc.Adopt non-hardened and tempered steel to produce high-intensity fasteners, its production process is reduced to: hot rolling starting material → pickling → bonderizing → wire rod draw → cold-heading → thread rolling → ageing treatment.Due to annealing and the modifier treatment operation saved in high-intensity fasteners making processes, effectively utilized the work strengthening of steel, realized energy-saving and cost-reducingly, avoided the defects such as distortion in heat treatment process and decarburization, thereby come into one's own.
At present, for making the non-hardened and tempered steel kind of high-intensity fasteners, have: dual phase steel (ferrite+martensite), ferrite/perlitic steel and bainitic steel etc.Adopt dual phase steel and ferrite/perlitic steel to make the intensity rank that high-intensity fasteners can reach 8.8 grades or 9.8 grades, Bainitic Steels can reach 10.9 grades of even higher intensity ranks.While adopting non-hardened and tempered steel to produce high-intensity fasteners, metal often will bear very large deflection, so general requirement non-hardened and tempered steel should have good plasticity and cold-forming property; And it is closely related to make the mechanical property of fastening piece and the cold working characteristic of steel and machining deformation amount, so require the intensity of non-modified steel for fastener, hardness moderate, can meet the mechanical property requirements of high-intensity fasteners.Fastening piece generally adopts high speed wire rolling device fabrication with non-hardened and tempered steel.On high-speed rod-rolling mill, during the non-modified steel for fastener of production two-phase, by controlled rolling and controlled cooling, can control ferrite and martensitic transformation and proportionlity, thereby obtain suitable intensity, hardness and good plasticity.For ferrite/perlite non-hardened and tempered steel, be by thermal mechanical rolling technique, control austenite deformation temperature, deformation extent and speed of cooling, promote ferrite excess to separate out and pearlitic degeneration or nodularization, suitably reduce intensity and the hardness of steel, improve the plasticity of steel.
Chinese patent CN101619414 and CN101935806A disclose respectively a kind of making method of non-hardened and tempered steels for 10.9 grade high-strength fasteners, steel be organized as granular bainite.Two kinds of steel all adopt the Composition Design of low-carbon high-manganese and microalloying, basic alloy composition is C, Si, Mn, B, Al, P, S, Ti etc., in front a kind of steel constituent, contain trace alloying element Nb, rear a kind of steel contains Cr, V and RE, and 0.10≤V (%)+Ti (%)≤0.20, the excellent in resistance to delayed fracture of steel.Above-mentioned patent discloses bainite fastening piece and discloses the Rolling Production technique of steel by composition and the making method, particularly patent CN101619414 of non-hardened and tempered steel, but does not relate to the adjustment control method of intensity, hardness and the plasticity of steel.
Summary of the invention:
The present invention is directed to above-mentioned technical problem, the regulate and control method of the non-modified steel for fastener performance of a kind of bainite is provided, object is to improve the cold-forming property of the non-modified steel for fastener of bainite.
The regulate and control method particular content of the non-modified steel for fastener performance of a kind of bainite provided by the present invention is as follows:
Component and the weight percent of the non-modified steel for fastener of described bainite are: C0.08~0.14%, Si≤0.35%, Mn1.80~2.30%, P≤0.025%, S≤0.015%, B0.0005~0.003%, Als0.010~0.050%, Ti0.01~0.08%, Nb0.02%~0.04%, surplus is Fe and micro-tramp element; Adopt high speed wire rolling equipment to prepare the non-modified steel for fastener of described bainite, high speed wire rolling thick, neutralize the pre-finish rolling stage and adopt pair rolling temperature, described rolling temperature is 950 ℃~1050 ℃, austenite obtains refinement in the operation of rolling, the finish rolling stage adopts low temperature rolling technology, austenite deformation temperature is controlled to 750 ℃~900 ℃, deflection>=40%, after distortion, control cooling, control cooling two kinds of single cold and segmentation in cold minute, single speed of cooling is 3 ℃/s~5 ℃/s, the cooling bainitic transformation (B of segmentation s) front employing rapid cooling, fast speed of cooling>=5 ℃/s, then with 0.5 ℃/s~2 ℃/s slow cooling.
Steel grades feature of the present invention is low-carbon high-manganese boracic and microalloying, belongs to air-cooled bainitic steels, and austenite is at 3 ℃/s~5 ℃/s cooling granular bainite microstructure that obtains homogeneous continuously; Control the content of P, S, and add in right amount trace alloying element Nb, Ti to improve the plasticity and toughness energy of steel.Adjusting parameter is the speed of cooling before austenite deformation temperature and bainitic transformation, by the adjustment combination of parameter, can realize the online regulation and control of the non-modified steel for fastener intensity of bainite and hardness, under varying strength, stiffness conditions, obtain good plasticity, improve the cold-forming property of steel.
Method provided by the invention is for the finish rolling stage of high speed wire rolling, concrete regulate and control method and parameter are adjusted direction: (1) adjusts finish rolling stage austenite deformation temperature, subsequently with the cooling acquisition granular bainite microstructure of cooling rate of 4 ℃/s, thereby adjust intensity, the hardness of steel and obtain good plasticity, adjust direction for reducing austenite deformation temperature, the intensity of steel and lower hardness, on the contrary increase; (2) before bainitic transformation, adopt rapid cooling, fast speed of cooling >=5 ℃/s, then with 1 ℃/s slow cooling, adjust fast speed of cooling slow cooling and obtain granular bainite microstructure, thereby adjust intensity, the hardness of steel and obtain good plasticity, adjust direction for increasing fast speed of cooling, the intensity of steel and lower hardness, on the contrary increase; (3) by the combination adjustment of parameter, realize intensity, the hardness adjustment of steel and obtain good plasticity.
Non-modified steel for fastener of the present invention is organized as granular bainite.By above-mentioned adjustment control method, can control the tissue morphology of granular bainite, the shape on the matrix JiM/A island of granular bainite, quantity, size and distribution be controlled, and then the intensity of steel, hardness and plasticity are regulated and controled.
The fast speed of cooling of the inventive method before to austenite deformation temperature and bainitic transformation regulates and controls, and definite its adjusted direction, can realize intensity, the hardness regulation and control online on a large scale of the non-modified steel for fastener of bainite, make steel obtain and have good plasticity under varying strength, stiffness conditions, improve the cold-forming property of steel.
Accompanying drawing explanation:
Fig. 1 is one of metallographic structure schematic diagram of the non-modified steel for fastener of bainite of the present invention;
Fig. 2 be the non-modified steel for fastener of bainite of the present invention metallographic structure schematic diagram two;
Fig. 3 be the non-modified steel for fastener of bainite of the present invention metallographic structure schematic diagram three;
Fig. 4 be the non-modified steel for fastener of bainite of the present invention metallographic structure schematic diagram four.
Wherein: the preparation condition of the non-modified steel for fastener of bainite shown in Fig. 1 is: 900 ℃ of austenite deformation temperature, 4 ℃/s of speed of cooling; The preparation condition of the non-modified steel for fastener of bainite shown in Fig. 2 is: 800 ℃ of austenite deformation temperature, 4 ℃/s of speed of cooling; The preparation condition of the non-modified steel for fastener of bainite shown in Fig. 3 is: 800 ℃ of austenite deformation temperature, 5 ℃/s rapid cooling+1 ℃/s slow cooling; The preparation condition of the non-modified steel for fastener of bainite shown in Fig. 4 is: 800 ℃ of austenite deformation temperature, 12 ℃/s rapid cooling+1 ℃/s slow cooling.
Embodiment:
In embodiment, the non-modified steel for fastener finish rolling stage austenite deformation temperature of bainite is 900 ℃ and 800 ℃, deflection is 40%, single speed of cooling is 4 ℃/s, while adopting rapid cooling+slow cooling, fast speed of cooling >=5 ℃/s, near slow cooling after being chilled to 550 ℃, slow cooling speed is 1 ℃/s, fast speed of cooling is 5 ℃/s and 12 ℃/s.Under different technology conditions, the intensity of steel, hardness and plasticity index are in Table 1.
By technique in table 11 and technique 2, can find out the impact of finish rolling stage austenite deformation temperature adjustment on rigidity energy.Technique 1 austenite deformation temperature is 900 ℃, cooling with 4 ℃/s after distortion, obtains being organized as granular bainite, and the hardness of steel (HRC) is 26.5, and tensile strength is 1083.2MPa, and relative reduction in area is 62.6%, and elongation is 28.6%.When technique 2 austenite deformation temperature are reduced to 800 ℃, the hardness of steel (HRC) reduces to 20.4, and tensile strength is reduced to 964.8MPa, and relative reduction in area is 58.7%, and elongation is 29.0%.Intensity, the hardness of steel are adjusted, and plasticity is good.
In watch 1 technique 3 and technique 4 can find out fast speed of cooling adjustment before bainitic transformation on rigidity can impact.Technique 3 austenite deformation temperature are 800 ℃, adopt segmentation cooling after distortion, and fast speed of cooling is 5 ℃/s, slow cooling is 1 ℃/s, obtains being organized as granular bainite, and the hardness of steel (HRC) is 18.3, tensile strength is 897.8MPa, and relative reduction in area is 56.0%, and elongation is 26.0%.When the fast speed of cooling of technique 4 increases to 12 ℃/s, the hardness of steel (HRC) reduces to 17.3, and tensile strength is reduced to 864.3MPa, and relative reduction in area is 58.1%, and elongation is 31.2%.Intensity, the hardness of steel are adjusted, and plasticity is good.
Fast speed of cooling adjustment before finish rolling stage austenite deformation temperature and bainitic transformation can be combined, thereby adjust intensity and the hardness of steel and obtain good plasticity.
The intensity of steel, hardness and plasticity index under table 1 different technology conditions
Above-described embodiment is only the preferred embodiment for absolutely proving that the present invention lifts, and protection scope of the present invention is not limited to this.For the non-modified steel for fastener of the close bainite of composition, every being equal to of doing on basis of the present invention, substitutes or conversion, all within protection scope of the present invention.

Claims (3)

1. a regulate and control method for the non-modified steel for fastener performance of bainite, is characterized in that the method particular content is as follows:
Component and the weight percent of the non-modified steel for fastener of described bainite are: C0.08~0.14%, Si≤0.35%, Mn1.80~2.30%, P≤0.025%, S≤0.015%, B0.0005~0.003%, Als0.010~0.050%, Ti0.01~0.08%, Nb0.02%~0.04%, surplus is Fe and micro-tramp element; Adopt high speed wire rolling equipment to prepare the non-modified steel for fastener of described bainite, high speed wire rolling thick, neutralize the pre-finish rolling stage and adopt pair rolling temperature, described rolling temperature is 950 ℃~1050 ℃, the finish rolling stage adopts low temperature rolling technology, austenite deformation temperature is controlled to 750 ℃~900 ℃, deflection >=40%, after distortion, control cooling, control cooling two kinds of single cold and segmentation in cold minute, single speed of cooling is 3 ℃/s~5 ℃/s, adopt rapid cooling before the cooling bainitic transformation of segmentation, fast speed of cooling >=5 ℃/s, then with 0.5 ℃/s~2 ℃/s slow cooling.
2. the regulate and control method of the non-modified steel for fastener performance of a kind of bainite according to claim 1, is characterized in that described single speed of cooling is 4 ℃/s.
3. the regulate and control method of the non-modified steel for fastener performance of a kind of bainite according to claim 1, is characterized in that described slow cooling speed is 1 ℃/s.
CN201410199364.7A 2014-05-12 2014-05-12 Method for regulating and controlling performances of bainite non-tempered steel for fasteners Pending CN103952626A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104532125A (en) * 2014-12-22 2015-04-22 武汉科技大学 High-strength steel for engineering machines and preparation method of high-strength steel
CN111041362A (en) * 2019-12-16 2020-04-21 首钢集团有限公司 Method for improving steel ladle simmer effect of non-quenched and tempered bolt
CN113373376A (en) * 2021-05-27 2021-09-10 本钢板材股份有限公司 Bainite non-quenched and tempered high-strength steel with tensile strength of more than or equal to 960MPa and manufacturing method thereof
CN113430460A (en) * 2021-06-19 2021-09-24 宝钢湛江钢铁有限公司 Low-cost high-strength non-quenched and tempered steel plate with yield strength of 690MPa and manufacturing method thereof
CN114317918A (en) * 2021-12-28 2022-04-12 内蒙古科技大学 High-toughness tissue quantitative control Baima complex phase heavy rail steel and preparation method thereof
CN114733916A (en) * 2022-03-04 2022-07-12 贵州捷盛钻具股份有限公司 Hollow steel hot rolling method for drill rod, hollow steel, heat insulation box and hot rolling mill
CN115418590A (en) * 2022-08-31 2022-12-02 马鞍山钢铁股份有限公司 Non-quenched and tempered steel with good corrosion resistance and high strength and toughness for wind power bolt and production method thereof
TWI800397B (en) * 2022-06-02 2023-04-21 中國鋼鐵股份有限公司 Steel wire material with high strength and high toughness, manufacturing method and use thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101619414A (en) * 2009-07-29 2010-01-06 马鞍山钢铁股份有限公司 10.9-grade niobium-containing non-quenched and tempered cold-heading steel and rolling method of hot finished rod thereof
CN101935806A (en) * 2010-09-10 2011-01-05 钢铁研究总院 Low-carbon bainitic cold-work-strengthened non-quenched and tempered steel with excellent delayed fracture resistance

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101619414A (en) * 2009-07-29 2010-01-06 马鞍山钢铁股份有限公司 10.9-grade niobium-containing non-quenched and tempered cold-heading steel and rolling method of hot finished rod thereof
CN101935806A (en) * 2010-09-10 2011-01-05 钢铁研究总院 Low-carbon bainitic cold-work-strengthened non-quenched and tempered steel with excellent delayed fracture resistance

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104532125A (en) * 2014-12-22 2015-04-22 武汉科技大学 High-strength steel for engineering machines and preparation method of high-strength steel
CN104532125B (en) * 2014-12-22 2016-06-08 武汉科技大学 A kind of high-strength engineering machinery steel and preparation method thereof
CN111041362A (en) * 2019-12-16 2020-04-21 首钢集团有限公司 Method for improving steel ladle simmer effect of non-quenched and tempered bolt
CN111041362B (en) * 2019-12-16 2021-05-25 首钢集团有限公司 Method for improving steel ladle simmer effect of non-quenched and tempered bolt
CN113373376A (en) * 2021-05-27 2021-09-10 本钢板材股份有限公司 Bainite non-quenched and tempered high-strength steel with tensile strength of more than or equal to 960MPa and manufacturing method thereof
CN113430460A (en) * 2021-06-19 2021-09-24 宝钢湛江钢铁有限公司 Low-cost high-strength non-quenched and tempered steel plate with yield strength of 690MPa and manufacturing method thereof
CN114317918A (en) * 2021-12-28 2022-04-12 内蒙古科技大学 High-toughness tissue quantitative control Baima complex phase heavy rail steel and preparation method thereof
CN114317918B (en) * 2021-12-28 2023-09-22 内蒙古科技大学 Beehive composite phase-change heavy rail steel with high strength and toughness tissue quantitatively controlled and preparation method thereof
CN114733916A (en) * 2022-03-04 2022-07-12 贵州捷盛钻具股份有限公司 Hollow steel hot rolling method for drill rod, hollow steel, heat insulation box and hot rolling mill
TWI800397B (en) * 2022-06-02 2023-04-21 中國鋼鐵股份有限公司 Steel wire material with high strength and high toughness, manufacturing method and use thereof
CN115418590A (en) * 2022-08-31 2022-12-02 马鞍山钢铁股份有限公司 Non-quenched and tempered steel with good corrosion resistance and high strength and toughness for wind power bolt and production method thereof
CN115418590B (en) * 2022-08-31 2023-08-29 马鞍山钢铁股份有限公司 High-strength and high-toughness non-quenched and tempered steel with good corrosion resistance for wind power bolts and production method thereof

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Application publication date: 20140730