CN102925806A - Y55 mark free-cutting steel plate and manufacture method thereof - Google Patents
Y55 mark free-cutting steel plate and manufacture method thereof Download PDFInfo
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Abstract
The invention discloses a Y55 mark free-cutting steel plate and a manufacture method thereof. The steel plate comprises the following chemical components by weight percent: 0.50-0.58% of C, 0.05-0.15% of Si, 0.70-1.10% of Mn, less than or equal to 0.040% of P, 0.050-0.150% of S, 0.010-0.020% of Ti, 0.0015-0.0040% of Ca, and less than or equal to 0.015% of Alt. The manufacture method comprises the following steps that: desulfuration is not performed on molten iron in a converter, wherein the oxygen content is controlled at 30-70ppm; the temperature of a tundish is 1505-1525 DEG C, and the plate blank pull speed is 0.70-1.0m/min; the total heating time is controlled according to 0.95-10.5min/mm of the thickness of a casting blank; the initial blanking temperature is 1000-1050 DEG C, and the final rolling temperature is greater than or equal to 980 DEG C; and the steel plate is slowly cooled after hot rolling, wherein the slow cooling time is more than or equal to 48h. According to the invention, the steel plate is good in cutting performance, and the manufacture method is high in production efficiency.
Description
Technical field
The present invention relates to steel plate manufacturing technology field, particularly a kind of Y55 trade mark free-cutting steel plate and manufacture method thereof.
Background technology
Along with mechanical cutting processing constantly to automatization, high speed and precise treatment future development, manufacturing concern's commute cutting steel plate has proposed to improve processing characteristics and more high-intensity requirement, adds part work-ing life with reduction cutter loss and raising machine.China produces resulfurizing series free cutting steel since the 1950's, formulates the industry standard YB 191-75 of free-cutting steel in 1975.From the seventies, begin to produce as a trial the free-cutting steel of calcium system, titanium system and leaded, selenium, tellurium or rare earth, operative norm is GB/T 8731-2008 at present, the resulfurizing series free cutting steel trade mark is named by the scope of carbon content in the Chinese phonetic alphabet first letter " Y " of " easily " word and the steel in the standard, the highest trade mark of this standard is Y45(C 0.42 ~ 0.50%), the bar steel tensile strength of hot-rolled state is 560～800MPa, elongation after fracture A 〉=12%, Brinell hardness HBW≤229, performance for the free-cutting steel plate, this standard does not propose specific requirement, is consulted by both sides of supply and demand.
At present, most domestic steel mill adopts the method for die casting or utilizes billet caster to produce free-cutting steel ingot (base), and the die casting process energy consumption is high, recovery rate of iron is low, environmental pollution is large, is not suitable with the social orientation of current energy-saving and emission-reduction and environment protection.Billet caster is produced free-cutting steel, can only rolling rod wire.Because the free-cutting steel sulphur content is high, the bad surface longitudinal crack that very easily produces of control in the sheet billet continuous casting process, impact on strand qualification rate and production cost is huge, is mainly manifested in: 1) surface crack is serious, causes strand to scrap or roll the poor waster that is judged to of rear plate surface quality; 2) the serious longitudinal crack of casting billet surface very easily causes crackle bleed-out event to occur, damage equipment, and impact is produced; 3) high-intensity free-cutting steel carbon content is high, and slab must be carried out hot delivery and hot charging, otherwise can natural fracture behind the slab cooling.Therefore, producing the report of sulphur free-cutting steel both at home and abroad there are no sheet billet continuous casting, all is rolling sulphur free-cutting steel plate after the use die casting, can't satisfy the heavy demand of mechanical processing industry commute cutting steel plate.
Summary of the invention
The method that the invention provides a kind of high-strength simple-cutting steel plate and utilize continuous casting steel billet to make is according to GB/T 8731-2008 standard resulfurizing series free cutting steel trade mark nomenclature, free-cutting steel trade mark called after Y55 of the present invention.
The present invention utilizes continuous casting steel billet to produce Y55 trade mark free-cutting steel plate, adopted the Composition Design of Mn-S-P-Ti-Ca system, by rational smelting continuous casting process, recrystallize is rolling and the steel plate slow cooling processes to guarantee the free cutting property of steel plate and the obdurability after the steel plate processing.
A kind of Y55 trade mark free-cutting steel plate of the present invention, its chemical ingredients by mass percent is: C 0.50 ~ 0.58%, Si 0.05 ~ 0.15%, Mn 0.70 ~ 1.10%, P≤0.040%, and S 0.050 ~ 0.150%, Ti 0.010 ~ 0.020%, Ca 0.0015 ~ 0.0040%, Alt≤0.015%, and its surplus is iron Fe and inevitable impurity.
A kind of manufacture method of Y55 trade mark free-cutting steel plate, by smelting+continuous casting+recrystallize rolling+the steel plate retarded cooling process, it is characterized in that its production technique is specific as follows:
1, converter smelting: the converter molten iron does not carry out desulfurization, and only decarburization and phosphorus are tapped sequentially to add by silicomanganese-Si-Al-Ba-Fe-iron sulphide in 1/4 o'clock and carried out weak deoxidation, and Control for Oxygen Content is at 30 ~ 70ppm;
2, LF stove refining: add refining slag, submerged arc slag, add iron sulphide control sulphur content, do not carry out white slag and process 1540 ~ 1550 ℃ of out-station temperatures;
3, continuous casting process: tundish temperature is controlled at 1505 ~ 1525 ℃, and the slab pulling rate is controlled at 0.70 ~ 1.0m/min, and secondary cooling water adopts weak cold, and the nozzle mist is cold;
4, heating cycle: with hot delivering technology of CC billets, advance process furnace and be heated to 1200 ~ 1240 ℃, slab thickness 0.95 ~ 1.05min/mm control is pressed in heating total time;
5, rolling, process for cooling: adopt the recrystallization zone rolling, 1000 ~ 1050 ℃ of start rolling temperatures, rear air cooling is rolled in finishing temperature 〉=980 ℃;
6, retarded cooling process: 720 ~ 760 ℃ of steel plates advance the insulation can slow cooling after the hot rolling, slow cooling time 〉=48 hour.
The steel plate of the inventive method preparation, take full advantage of the sulfide inclusion of manganese sulfide inclusion and oxide parcel, this type impurity can interrupt the continuity of matrix metal, when cutting, impel chip breaking to form little and short crimp radius, and be easy to get rid of, reduce machined surface roughness, reduce tool wear, improve cutter life; Simultaneously, the phosphorus solid solution can improve hardness and intensity in ferrite, reduce toughness, makes smear metal be easy to fracture and get rid of, thereby obtains good surfaceness; To be combined with aluminium, silicon and to form low-melting composite oxides (mainly be CaOAl to calcium in the steel
2O
3SiO
2), during high speed cutting, calcium is that oxide compound is attached to a cutting tool surface lubricated and antifriction function, thereby improves cutting-tool's used life.But the content of aluminium will be controlled, deoxidation products Al
2O
3Be a kind of hard particle, Cutter wear is serious, thereby has a strong impact on the use properties of free-cutting steel.Oxygen can reduce the mechanical property of steel in most of steel grade, but the control oxygen level makes sulfide be fusiform and distributes between 30 ~ 70ppm in the free-cutting steel, is conducive to improve the cutting ability of steel.Keep 0.50 ~ 0.58% carbon content in the steel, guaranteed to have high strength after the steel plate processing.Titanium in the adding steel is with deoxidation products Ti0
2Form exist, form Ti0
2-MnO – CaO-A1
20
2-Al
2O
3Be complex inclusion, the tool setting when high speed cutting of this compound has good provide protection.
The invention has the advantages that:
1, resulfurizing series free cutting steel has adopted the Composition Design of Mn-S-P-Ti-Ca system, and the sulfide inclusion, the austenite grain boundary that take full advantage of that the manganese sulfide and the iron sulphide that are strip, spindle-type are mingled with, oxide and titanium nitride are mingled with parcel are discontinuous netted proeutectoid ferrite of separating out, perlite and discontinuous ferritic structure.The inclusion morphology that obtains, distribution have improved the cutting ability of Y55 steel;
2, continuous casting steel billet is produced Y55 trade mark free-cutting steel plate, and the surface decarburization layer is shallow, and the oxide compound segregation is light, and flaw detection qualification rate is high, and lumber recovery is high.Low, with short production cycle by this Composition Design production cost, good processability;
3, utilize slab caster to produce free-cutting steel, produce free-cutting steel with the die casting mode and compare, production efficiency is high; greatly reduce process energy consumption; increase substantially recovery rate of iron, reduced environmental pollution, adapted to the social orientation of current energy-saving and emission-reduction and environment protection.
Embodiment
It is prepared that the following example light plate is the designed chemical ingredients of the present invention, smelting continuous casting process, rolling technology and retarded cooling process.
Embodiment 1:A kind of Y55 trade mark free-cutting steel plate of present embodiment, be comprised of the component of following weight percent: C 0.58%, and Mn 1.10%, and Si 0.08%, P 0.025%, and S 0.050%, and Ca 0.0019%, Ti 0.013%, and Alt 0.008%, and its surplus is iron Fe and inevitable impurity.Slab thickness 420mm, the thickness of rolling rear steel plate are 115mm.
The smelting of present embodiment, continuous casting, heating, rolling and cooling in heap technique is as follows:
1) smelting technology: converter decarburization, dephosphorization, not desulfurization, the weak deoxidation of departures, aluminum steel is not fed at the argon station, detects oxygen level 30ppm.For improving the recovery rate of Iron sulfuret alloy, refining does not add lime, and refining slag adds 450kg, submerged arc slag add-on 500kg.This smelts the recovery rate 73.4% of Iron sulfuret alloy.1550 ℃ of out-station temperatures;
2) continuous casting process: 1515 ℃ of tundish temperatures, pulling rate 0.70m/min;
3) heating process: soaking zone: 1240 ℃.Deposit the stove time (heating total time) at 440 minutes;
4) rolling technology: adopting the rolling start rolling temperature in recrystallization zone is 1035 ℃, and finishing temperature is 1022 ℃; Adopt air cooling after the hot rolling;
5) retarded cooling process: the steel plate high temperature after rolling rolls off the production line into the insulation can slow cooling, and the inlet temperature is 735 ℃, 60 hours slow cooling time.
Embodiment 2:A kind of continuous casting steel billet of present embodiment is produced Y55 trade mark free-cutting steel plate, and be comprised of the component of following weight percent: C 0.50%, and Mn 0.9%, and Si 0.15%, P 0.045%, and S 0.08%, and Ca 0.0015%, Ti 0.010%, and Alt 0.015%, and its surplus is iron Fe and inevitable impurity.Slab thickness 300mm, the thickness of rolling rear steel plate are 85mm.
The smelting of present embodiment, continuous casting, heating, rolling and cooling in heap technique is as follows:
1) smelting technology: converter decarburization, dephosphorization, not desulfurization, the weak deoxidation of departures, aluminum steel is not fed at the argon station, detects oxygen level 58ppm.Refining does not add lime, and refining slag adds 400kg,, submerged arc slag add-on 450kg.This smelts the recovery rate 76.6% of Iron sulfuret alloy.1545 ℃ of out-station temperatures;
2) continuous casting process: 1505 ℃ of tundish temperatures, pulling rate 0.85m/min;
3) heating process: soaking zone: 1220 ℃.Deposit the stove time (heating total time) at 300 minutes;
4) rolling technology: adopting the rolling start rolling temperature in recrystallization zone is 1000 ℃, and finishing temperature is 980 ℃; Adopt air cooling after the hot rolling;
5) retarded cooling process: the steel plate high temperature after rolling rolls off the production line into the insulation can slow cooling, and the inlet temperature is 720 ℃, 48 hours slow cooling time.
Embodiment 3:A kind of continuous casting steel billet of present embodiment is produced Y55 trade mark free-cutting steel plate, component by following weight percent forms: C 0.53%, Mn 0.70%, Si 0.05%, and P 0.038%, and S 0.15%, Ca 0.0040%, Ti 0.011%, and Alt 0.003%, and its surplus is iron Fe and inevitable impurity.Slab thickness 250mm, the thickness of rolling rear steel plate are 55mm.
The smelting of present embodiment, continuous casting, heating, rolling and cooling in heap technique is as follows:
1) smelting technology: converter decarburization, dephosphorization, not desulfurization, the weak deoxidation of departures, aluminum steel is not fed at the argon station, detects oxygen level 70ppm.Refining does not add lime, and refining does not add lime, and refining slag adds 350kg,, submerged arc slag add-on 400kg.This smelts the recovery rate 81.6% of Iron sulfuret alloy.1540 ℃ of out-station temperatures;
2) continuous casting process: 1525 ℃ of tundish temperatures, pulling rate 1.0m/min;
3) heating process: 1200 ℃ of soaking zones, deposit the stove time (heating total time) at 237 minutes;
4) rolling technology: adopting the rolling start rolling temperature in recrystallization zone is 1050 ℃, and finishing temperature is 1010 ℃, adopts air cooling after the hot rolling;
5) retarded cooling process: the steel plate high temperature after rolling rolls off the production line into the insulation can slow cooling, and the inlet temperature is 760 ℃, 60 hours cooling in heap time.
To the steel plate sampling of embodiment 1-3, carry out Mechanics Performance Testing respectively, the results are shown in Table 1.
Table 1 Y55 trade mark free-cutting steel plate performance.
The invention process result as can be seen from Table 1, more than the tensile strength Rm 630MPa, elongation after fracture A＞14% vertically more than 0 ℃ of ballistic work 49 J of V-type, adopts continuous casting steel billet to produce free-cutting steel and has good mechanical property.Because the steel medium sulphide content is mingled with about 4.0 grades, inclusion is spindle-type, stub type, and inclusion particle is little and be evenly distributed, and is organized as perlite and discontinuous ferrite, and Brinell hardness HBW is easy to machining in 190 ~ 225 scopes.Comprehensive mechanical performance and cutting ability are better than hot-rolled state Y45.
Claims (2)
1. Y55 trade mark free-cutting steel plate, its chemical ingredients by mass percent is: C 0.50 ~ 0.58%, Si 0.05 ~ 0.15%, Mn 0.70 ~ 1.10%, P≤0.040%, and S 0.050 ~ 0.150%, Ti 0.010 ~ 0.020%, Ca 0.0015 ~ 0.0040%, Alt≤0.015%, and its surplus is iron Fe and inevitable impurity.
2. the manufacture method of a Y55 trade mark free-cutting steel plate, by smelting+continuous casting+recrystallize rolling+the steel plate retarded cooling process, it is characterized in that its production technique is specific as follows:
1) converter smelting: the converter molten iron does not carry out desulfurization, and only decarburization and phosphorus are tapped sequentially to add by silicomanganese-Si-Al-Ba-Fe-iron sulphide in 1/4 o'clock and carried out weak deoxidation, and Control for Oxygen Content is at 30 ~ 70ppm;
2) LF stove refining: add refining slag, submerged arc slag, add iron sulphide control sulphur content, do not carry out white slag and process 1540 ~ 1550 ℃ of out-station temperatures;
3) continuous casting process: tundish temperature is controlled at 1505 ~ 1525 ℃, and the slab pulling rate is controlled at 0.70 ~ 1.0m/min, and secondary cooling water adopts weak cold, and the nozzle mist is cold;
4) heating cycle: with hot delivering technology of CC billets, advance process furnace and be heated to 1200 ~ 1240 ℃, slab thickness 0.95 ~ 1.05min/mm control is pressed in heating total time;
5) rolling, process for cooling: adopt the recrystallization zone rolling, 1000 ~ 1050 ℃ of start rolling temperatures, rear air cooling is rolled in finishing temperature 〉=980 ℃;
6) retarded cooling process: 720 ~ 760 ℃ of steel plates advance the insulation can slow cooling after the hot rolling, slow cooling time 〉=48 hour.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104294161A (en) * | 2014-10-31 | 2015-01-21 | 武汉钢铁(集团)公司 | High-temperature-resistant free-cutting high-strength steel |
| CN106756503A (en) * | 2016-12-27 | 2017-05-31 | 北京首钢吉泰安新材料有限公司 | Free cutting alloy, B alloy wire, its preparation method, nib, pen core and pen |
| CN109252086A (en) * | 2017-07-13 | 2019-01-22 | 鞍钢股份有限公司 | A kind of production method of high-sulfur steel |
| CN111549287A (en) * | 2020-06-28 | 2020-08-18 | 宝钢特钢韶关有限公司 | Medium carbon steel and production process thereof |
| CN111876689A (en) * | 2020-09-08 | 2020-11-03 | 鞍钢股份有限公司 | Low-carbon selenium-containing free-cutting steel for instruments and manufacturing method thereof |
| CN112080700A (en) * | 2020-09-14 | 2020-12-15 | 新余钢铁股份有限公司 | High-sulfur low-aluminum free-cutting steel continuous casting slab and production method thereof |
| CN113604745A (en) * | 2021-08-12 | 2021-11-05 | 山东钢铁股份有限公司 | High-sulfur free-cutting tool steel bar and preparation method thereof |
| CN114107820A (en) * | 2021-11-26 | 2022-03-01 | 宝武集团鄂城钢铁有限公司 | Steel plate with elongation rate more than 30% and good cutting performance and production method thereof |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104294161A (en) * | 2014-10-31 | 2015-01-21 | 武汉钢铁(集团)公司 | High-temperature-resistant free-cutting high-strength steel |
| CN106756503A (en) * | 2016-12-27 | 2017-05-31 | 北京首钢吉泰安新材料有限公司 | Free cutting alloy, B alloy wire, its preparation method, nib, pen core and pen |
| CN109252086A (en) * | 2017-07-13 | 2019-01-22 | 鞍钢股份有限公司 | A kind of production method of high-sulfur steel |
| CN111549287A (en) * | 2020-06-28 | 2020-08-18 | 宝钢特钢韶关有限公司 | Medium carbon steel and production process thereof |
| CN111876689A (en) * | 2020-09-08 | 2020-11-03 | 鞍钢股份有限公司 | Low-carbon selenium-containing free-cutting steel for instruments and manufacturing method thereof |
| CN111876689B (en) * | 2020-09-08 | 2022-05-13 | 鞍钢股份有限公司 | Low-carbon selenium-containing free-cutting steel for instruments and manufacturing method thereof |
| CN112080700A (en) * | 2020-09-14 | 2020-12-15 | 新余钢铁股份有限公司 | High-sulfur low-aluminum free-cutting steel continuous casting slab and production method thereof |
| CN112080700B (en) * | 2020-09-14 | 2022-02-01 | 新余钢铁股份有限公司 | High-sulfur low-aluminum free-cutting steel continuous casting slab and production method thereof |
| CN113604745A (en) * | 2021-08-12 | 2021-11-05 | 山东钢铁股份有限公司 | High-sulfur free-cutting tool steel bar and preparation method thereof |
| CN114107820A (en) * | 2021-11-26 | 2022-03-01 | 宝武集团鄂城钢铁有限公司 | Steel plate with elongation rate more than 30% and good cutting performance and production method thereof |
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