CN116574976A - Flexible second phase production control method suitable for bearing steel and application thereof - Google Patents
Flexible second phase production control method suitable for bearing steel and application thereof Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 167
- 239000010959 steel Substances 0.000 title claims abstract description 167
- 238000000195 production control method Methods 0.000 title claims abstract description 21
- 238000005096 rolling process Methods 0.000 claims abstract description 104
- 238000000034 method Methods 0.000 claims abstract description 62
- 238000010438 heat treatment Methods 0.000 claims abstract description 40
- 238000009792 diffusion process Methods 0.000 claims abstract description 38
- 238000004519 manufacturing process Methods 0.000 claims abstract description 29
- 238000003723 Smelting Methods 0.000 claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 86
- 239000002893 slag Substances 0.000 claims description 78
- 239000002245 particle Substances 0.000 claims description 54
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 48
- 229910052799 carbon Inorganic materials 0.000 claims description 39
- 230000008569 process Effects 0.000 claims description 39
- 238000007670 refining Methods 0.000 claims description 35
- 230000009467 reduction Effects 0.000 claims description 34
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 29
- 238000004513 sizing Methods 0.000 claims description 27
- 239000000843 powder Substances 0.000 claims description 24
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 22
- 238000009749 continuous casting Methods 0.000 claims description 22
- 230000000149 penetrating effect Effects 0.000 claims description 22
- 238000010079 rubber tapping Methods 0.000 claims description 22
- 238000005275 alloying Methods 0.000 claims description 21
- 238000002791 soaking Methods 0.000 claims description 20
- 238000001816 cooling Methods 0.000 claims description 19
- 239000000203 mixture Substances 0.000 claims description 19
- 238000005266 casting Methods 0.000 claims description 18
- 239000012535 impurity Substances 0.000 claims description 17
- 239000000498 cooling water Substances 0.000 claims description 15
- 229910052698 phosphorus Inorganic materials 0.000 claims description 15
- 238000009987 spinning Methods 0.000 claims description 15
- 229910052717 sulfur Inorganic materials 0.000 claims description 15
- 238000009489 vacuum treatment Methods 0.000 claims description 15
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 14
- 238000007664 blowing Methods 0.000 claims description 14
- 229910052742 iron Inorganic materials 0.000 claims description 13
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 12
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 12
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 12
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 12
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 12
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 12
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 12
- 239000004571 lime Substances 0.000 claims description 12
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 9
- 239000005997 Calcium carbide Substances 0.000 claims description 6
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 6
- 229910000514 dolomite Inorganic materials 0.000 claims description 6
- 239000010459 dolomite Substances 0.000 claims description 6
- 239000010436 fluorite Substances 0.000 claims description 6
- 238000007689 inspection Methods 0.000 claims description 6
- 238000011084 recovery Methods 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 6
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 claims description 6
- 230000004907 flux Effects 0.000 claims description 5
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- 230000001681 protective effect Effects 0.000 claims 1
- 238000011946 reduction process Methods 0.000 claims 1
- 150000001247 metal acetylides Chemical class 0.000 abstract description 11
- 239000002131 composite material Substances 0.000 abstract description 7
- 238000001556 precipitation Methods 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 3
- 229910052751 metal Inorganic materials 0.000 abstract description 2
- 239000002184 metal Substances 0.000 abstract description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 25
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 24
- 239000010936 titanium Substances 0.000 description 24
- 206010016256 fatigue Diseases 0.000 description 21
- 239000011159 matrix material Substances 0.000 description 19
- 238000012360 testing method Methods 0.000 description 17
- 235000012255 calcium oxide Nutrition 0.000 description 14
- 239000000292 calcium oxide Substances 0.000 description 14
- 230000006378 damage Effects 0.000 description 13
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- 150000003568 thioethers Chemical class 0.000 description 8
- 230000005496 eutectics Effects 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 239000011575 calcium Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052596 spinel Inorganic materials 0.000 description 4
- 239000011029 spinel Substances 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 2
- -1 calcia aluminate Chemical class 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000006748 scratching Methods 0.000 description 1
- 230000002393 scratching effect Effects 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/114—Treating the molten metal by using agitating or vibrating means
- B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/36—Processes yielding slags of special composition
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/076—Use of slags or fluxes as treating agents
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/30—Parts of ball or roller bearings
- F16C33/32—Balls
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/30—Parts of ball or roller bearings
- F16C33/34—Rollers; Needles
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2220/00—Shaping
- F16C2220/40—Shaping by deformation without removing material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- General Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a flexible second phase production control method suitable for bearing steel and application thereof, and belongs to the technical field of metal product production. The control method comprises component control, smelting control, high-temperature diffusion and cogging control, hot-rolled billet heating control and wire rod rolling control. By controlling the production process parameters of the bearing steel, the invention obtains good forms, sizes and numbers of inclusions and carbides, so that the product can meet the requirements of downstream users for stably and efficiently producing the rolling bodies with high fatigue life. Obtaining proper quantity and type of inclusions through proper metallurgical technology; the property and morphology of the inclusion are changed through intermediate cogging and diffusion processes; and through the control of rolling process parameters, the composite precipitation of inclusions and carbides is inhibited, and finally, the good product quality is obtained.
Description
Technical Field
The invention relates to a flexible second phase production control method suitable for bearing steel and application thereof, belonging to the technical field of metal product production.
Background
The high-quality bearing steel is mainly used for manufacturing rolling bodies such as precision steel balls, wherein parameters such as the quantity, the shape, the size and the like of hard second phases such as inclusions, carbides and the like obviously influence the rollingFatigue life, crushing load, corrosion resistance and other performances of the moving body. A number of scholars have studied the relationship between oxide inclusions, carbide particles and rolling element fatigue life. The current bearing steel production enterprises adopt proper smelting equipment and continuous casting technology, so that the oxygen content in the bearing steel can be stably reduced to below 8ppm, the oxide inclusion quantity in the steel is greatly reduced, and the service life of the rolling bodies is greatly prolonged through proper high-temperature diffusion treatment. On the other hand, however, bearing steel produced by the electroslag remelting method, although the oxygen content reaches 18ppm, the fatigue life of the rolling element produced is still 8ppm oxygen content bearing steel L produced by continuous casting 10 1.4 times of life, L 50 1.3 times the life, which illustrates that in addition to the effect of oxygen content, the size and morphology of the hard second phase are also critical to the bearing steel fatigue life. The reduction of hard second-phase fatigue life of TiN particles, eutectic carbide particles, etc. is of great interest and research. The harm of the hard second relative steel is basically that the elastic modulus, the linear expansion coefficient and the plasticity of the hard second phase particles and the steel matrix are different, and when the hard second phase particles are stressed and deformed, the hard second phase particles and the matrix are not in coordination and synchronous, so that cracks and cavities are generated at the junction, and finally early crack source initiation and fatigue failure are caused.
Therefore, in the production process of the bearing steel, a special control means is needed to optimize the hard second phase, and the desired inclusion morphology and carbide state are obtained through a flexible control method, so that the harm of the hard second phase to the bearing steel is reduced, and the product quality is improved.
Disclosure of Invention
The invention aims to solve the problem of providing a flexible second phase production control method suitable for bearing steel, which can obtain good forms, sizes and numbers of inclusions and carbides by controlling parameters of the production process of the bearing steel, so that the product can meet the requirements of downstream users for stably and efficiently producing rolling bodies with high fatigue life. Obtaining proper quantity and type of inclusions through proper metallurgical technology; the property and morphology of the inclusion are changed through intermediate cogging and diffusion processes; and through the control of rolling process parameters, the composite precipitation of inclusions and carbides is inhibited, and finally, the good product quality is obtained.
Meanwhile, the invention provides an application of the wire rod obtained by the flexible second phase production control method suitable for bearing steel in rolling bodies.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method of controlling production of a flexible second phase suitable for use in bearing steel, comprising the steps of:
1) And (3) component control:
the steel composition of the bearing steel comprises the following components in percentage by weight: 0.95-1.05%, mn:0.25 to 0.45 percent, si:0.15 to 0.35 percent, S:0.01 to 0.025 percent, cr:1.40 to 1.65 percent, P: less than or equal to 0.025 percent, ti: less than or equal to 0.002 percent, ni: less than or equal to 0.30 percent, mo: less than or equal to 0.10 percent, cu: less than or equal to 0.25 percent, and the balance of Fe and trace impurities.
When the S content is too low, the sulfide does not form a form having oxide or nitride as a core, and only independent sulfide is formed. When the S content is too high, the grade of the formed sulfide is too high, so that the fatigue performance is deteriorated, and meanwhile, the sulfide and carbon element are subjected to eutectic reaction at the inter-dendrite position, so that large-size eutectic carbide is formed, and the fatigue performance is also deteriorated.
The excessive high sulfide grade means that the quantity of sulfide is large and the size is large, and the grade of the detected sulfide inclusion is high according to the method of measuring the content of non-metallographic inclusion in GB/T10561 steel.
The control of the Ti content is mainly to avoid the formation of large-sized titanium inclusions.
2) Smelting control:
tapping and alloying by proper converter (firstly, molten iron is required to be filled into the converter, the C content is 3.7-4.5%, the Si content is 0.2-0.5%, the Mn content is 0.2-0.3%, the lower the rest elements are, the better the molten iron is, after entering the converter, the molten iron is blown by an oxygen lance for 700-1000 seconds, the carbon pulling temperature is controlled at 1560-1670 ℃, and proper lime, fluorite, dolomite, iron oxide ball and the like are added in the smelting process of the converter to ensure that the converter slag components are CaO 45-55%, siO 2 :10-15%, mgO:5-8% and the balance FeO. Alloy is carried out during tappingMelting and paying attention to slag quantity lower than 3Kg/t, and adding 80-120Kg of Al blocks when the molten steel quantity in the ladle is about 4-6 t; when the steel water quantity in the ladle is about 8-12 t, adding carburant (the component of carburant is C), ferrosilicon, ferromanganese, ferrochrome and synthetic slag (the synthetic slag mainly comprises 48-50% CaO and 34-35% Al) 2 O 3 、14～15％SiO 2 And MgO in balance) to make the molten steel components conform to the following contents), and molten steel with the following components and temperature is obtained as a preliminary guarantee of LF refining treatment.
Molten steel composition: c:0.89-0.95%, si:0.10-0.15%, mn:0.27-0.32%, P:0.0087-0.0109%, S:0.005-0.01%, al:0.0086-0.0559%, ti:0.0007-0.0074%, cr:1.33-1.43%, and the balance of Fe and trace impurities.
The temperature of molten steel is as follows: 1505-1570 ℃. The LF refining procedure is carried out by a proper slag-making process (500 Kg of synthetic slag (the synthetic slag mainly comprises 48 to 50 percent of CaO and 34 to 35 percent of Al) is added at the beginning of LF refining 2 O 3 、14～15％SiO 2 And MgO) 100Kg of lime, 50Kg of calcium carbide and 100Kg of ferrosilicon powder, then fine adjustment is carried out by observing the color, the consistency and the like of slag materials on site, and finally, good white slag is obtained, namely, the final slag is obtained, and the components of the final slag are as follows: caO:40-57.2%, siO 2 ：15-25％，MgO：6-10％，Al 2 O 3 :21-25% and FeO:0.8-1.2%. The basicity R of the final slag is 3-4.5. In the LF refining process, according to the component inspection condition of molten steel, alloys such as carbon wires, ferromanganese, ferrochrome and the like are properly added for component fine adjustment, so that the use of alloys with high Ti content is avoided, and the C in molten steel obtained by LF refining is ensured: 0.89-0.95%, si:0.10-0.15%, mn:0.27-0.32%, P:0.0087-0.0109%, S:0.005-0.01%, al:0.0086-0.0559%, ti:0.0007-0.0074%, cr:1.33-1.43%, and the balance of Fe and trace impurities.
After LF refining, the molten steel enters an RH station to be refined continuously, the circulation time of RH vacuum treatment is 40-50min, the vacuum degree is 50-100Pa, and impurities and degassing in the molten steel are further removed.
The whole smelting process strictly forbids calcium treatment, namely no calcium line is added in molten steel in the LF refining process.
After the steel ladle subjected to smelting treatment and continuous casting (RH vacuum treatment enters a continuous casting machine and is produced by adopting a drawing speed of 0.65-0.8 m/min, the temperature of a tundish is controlled to 1475-1500 ℃, and casting powder is added into a crystallizer, the crystallizer adopts electromagnetic stirring, the current is set to 480-520A, the frequency is 2.35-2.45 Hz, the total water content is controlled to 100-130L/min for secondary cooling water content, and the total rolling reduction is controlled to 8.5-11mm at the tail end of the steel ladle to form a steel billet, and the second phase in the continuous casting billet has the following types: 1) Inclusions are classified into the following categories: (1) ti (C, N) inclusion, with edge angle, is orange red, and appears singly in small amount, and mostly appears with MnS; ti (C, N) is TiA, wherein A comprises C and/or N. (2) MnS-based inclusions, which mainly exist in 2 forms: bulk pure MnS, mnS with other inclusions (mostly oxides) as cores. (3) Oxide inclusions are mainly 2 types of magnesia-alumina spinel inclusions with a small amount and alumina+calcia aluminate+sulfide composite inclusions with a large amount. 2) Carbides, are classified into the following categories: (1) inter-dendrite particulate eutectic carbides. (2) Coarse, network carbide along the grain.
The mold flux is continuously consumed along with the continuous casting of the steel billet, so the mold flux is continuously added according to the actual consumption condition of the site, the molten steel is kept not to be exposed, and the general consumption is 0.2-1.0Kg/t (0.2-1.0 Kg of mold flux is consumed per ton of molten steel). The mold flux components mainly comprise: 35% SiO 2 ，22％CaO，4％Al 2 O 3 ，10％K 2 O+Na 2 O(K 2 O and Na 2 O is in any proportion), 19% c, and the balance Fe.
3) High temperature diffusion and cogging:
the continuous casting blank is subjected to slow cooling or direct hot charging to carry out high-temperature diffusion, and the temperature of each section is controlled as follows:
preheating section: the temperature is less than or equal to 900 ℃ and the time is more than or equal to 180min;
and (3) heating: the temperature is 1200-1250 ℃ and the time is 100-120min;
and (3) a soaking section: the temperature is 1250-1270 ℃ and the time is 60-90min.
The main function of high-temperature diffusion is to dissolve carbide, and enough high-temperature diffusion temperature and time are used for ensuring the dissolution of carbide second-phase particles and reducing the influence of the carbide second-phase particles on fatigue life. After high-temperature diffusion (the high-temperature diffusion is completed in a furnace, the steel billet directly enters a cogging machine through a roller way to be subjected to 6-pass large reduction after the diffusion is completed, the temperature of the steel billet is gradually reduced along with the cogging, the temperature of the steel billet is 1060-1100 ℃ after the cogging is completed) during the initial rolling, and the hot rolled billet with the section of 160 multiplied by 160mm is rolled by adopting the 6-pass large reduction. In order to ensure the rolling effect of the central area of the billet, the rolling process of each pass is as follows:
Pass 1: notch width B:320mm; groove bottom width b:285mm; height h:160mm;
pass 2: notch width B:256mm; groove bottom width b:220mm; height h:160mm;
pass 3: notch width B:226mm; groove bottom width b:190mm; height h:160mm;
pass 4: notch width B:201mm; groove bottom width b:170mm; height h:160mm;
pass 5: notch width B:175mm; groove bottom width b:155mm; height h:160mm;
pass 6: notch width B:162mm; groove bottom width b:157mm; height h:160mm.
After the high-temperature diffusion treatment and rolling into a hot rolled blank, the second phase in the steel blank is of the following types: 1) Inclusions are classified into the following categories: (1) the Ti (C, N) -based inclusions have been substantially broken up by a small number of large-sized Ti (C, N) inclusions precipitated alone, and the majority of Ti (C, N) accompanying MnS has not been deformed. (2) The MnS inclusions are all long, and part of MnS is accompanied with oxide and Ti (C, N) inclusions. (3) Oxide inclusions, mainly of the type 2 of magnesia-alumina spinel, alumina plus calcium aluminate plus sulfide composite, are mostly encapsulated by MnS inclusions. 2) Carbide: (1) the inter-dendrite particulate eutectic carbide has fully dissolved into the matrix. (2) The network carbide is precipitated at the grain boundary position, and the thickness is less than 0.5 mu m.
4) Heating a hot rolled blank:
the hot rolled blank is rolled after being heated, and the temperature of each section of the hot rolled blank is controlled as follows when the hot rolled blank is heated:
preheating section: the temperature is less than or equal to 800 ℃ and the time is 60-70min;
and (3) heating: the temperature is 1150-1210 ℃ and the time is 30-40min;
and (3) a soaking section: the temperature is 1190-1230 ℃ and the time is 30-40min.
Various second phase particles in the hot rolled blank are heated and insulated again after being cooled, and change occurs again, and the main appearance is that: (1) the quantity of small particles Ti (C, N) in the matrix is increased, and matrix cavities caused by crushing Ti (C, N) in the cogging are closed after being heated and rolled again at high temperature. Ti (C, N) associated with MnS is further wrapped by MnS, so that the hazard degree of the MnS is reduced. (2) Strip-shaped MnS in the hot rolled blank is heated and insulated, can be broken at weak points and tends to be spherical, and finally becomes individual isolated MnS particles. MnS with oxide inclusions as cores tends to become spherical shells and the Ca content of the shells is further increased, eventually becoming CaS-MnS complex inclusions. (3) After the hot rolled billet is heated and kept warm, almost all oxide inclusions appear with MnS. Most of oxide inclusions are smaller and are wrapped by MnS inclusions; the small amount of oxide inclusions are larger, and the small amount of oxide inclusions and MnS occupy part of the proportion.
Through the treatment, carbide second phase particles in the hot rolled blank are almost completely dissolved, and most of inclusion second phase particles are wrapped by sulfides, so that the damage of the hard second relative fatigue life is obviously reduced. And rolling the pure brittle second phase particles and sulfide coated second phase particles into wires, and then drawing and cold heading to obtain the rolling body. It can be seen that the damage of the second phase particles to the matrix in the wire deformation process can be significantly reduced after being coated with the sulfide.
5) Rolling wire rods:
the control key points of wire rod rolling are as follows: 1) The finishing rolling temperature is 850-880 ℃, the reducing sizing temperature is 850-880 ℃, the spinning temperature is 780-810 ℃, and the water tanks of all sections reach the temperature range through proper nozzles and recovery sections. At least 2 sections of water penetrating tanks are required before finish rolling, the number of nozzles of each water penetrating tank is more than or equal to 10, and the length of the water cooling section before the whole finish rolling is more than or equal to 40m; at least 3 sections of water penetrating tanks are arranged between finish rolling and reducing sizing, the number of nozzles of each water penetrating tank is more than or equal to 10, and the length of the water cooling section before the whole finish rolling is more than or equal to 50m; at least 2 sections of water penetrating tanks are arranged between the reducing sizing machine and the wire laying machine, the number of nozzles of each water penetrating tank is more than or equal to 10, and the length of the water cooling section before the whole finish rolling is more than or equal to 20m. When the production is carried out, the cooling water temperature is required to be less than or equal to 35 ℃, the pressure of the cooling nozzle is more than or equal to 0.5MPa, and the back blowing nozzle is fully opened, and the pressure is more than or equal to 0.5MPa. The cooling nozzle controls water flow according to actual temperature, and the nozzle close to the heating furnace side is required to be opened preferentially, and the nozzle close to the wire laying machine side is required to be closed or at a small flow rate.
The main purpose of wire rod rolling is to deform the core of the rolled material at low temperature, and through proper water tank nozzle cooling and sufficient recovery section, the temperature of the core of the rolled material is always at low temperature, thus avoiding precipitation of coarse carbide second phase. And meanwhile, the lower deformation temperature enhances the strength of the steel matrix, and further reduces the harm of the second phase of the hard inclusion. At the moment, most hard inclusions are wrapped by sulfides, and the hard inclusions can be cooperatively deformed with the matrix in the deformation process, so that the harm of forming pores is drastically reduced.
In the wire rod, the ratio of the number of the oxide-sulfide associated second phase particles to the total number of the pure oxide particles and the Ti (C, N) particles is (1.52-2.09): 1.
the application of the wire rod obtained by the flexible second phase production control method suitable for bearing steel in rolling bodies is that the wire rod is manufactured into the rolling bodies through drawing and cold heading procedures.
A rolling element is made of a wire rod obtained by a flexible second phase production control method applicable to bearing steel.
Smelting control is carried out: the desired second phase type is obtained by suitable converter tapping, LF slagging, RH and continuous casting processes. High temperature diffusion and cogging: the carbide second phase is dissolved by a proper high temperature diffusion process, reducing its impact on fatigue life. After high-temperature diffusion, hot-rolled billets with 160X 160mm sections are rolled by 6 times, and expected second-phase types of inclusions are obtained. The hot rolling blank heating process comprises the following steps: through the hot rolled blank heating process, carbide second phase particles in the hot rolled blank are almost completely dissolved, most of inclusion second phase particles are wrapped by sulfides, and the harm of hard second phase fatigue life is obviously reduced. Wire rod rolling control: by controlling the deformation of the core of the rolled material in a low temperature state, the precipitation of coarse carbide second phases is avoided. And meanwhile, the lower deformation temperature enhances the strength of the steel matrix, and further reduces the harm of the second phase of the hard inclusion. At the moment, most hard inclusions are wrapped by sulfides, and can be synchronously deformed with a matrix tissue in the deformation process.
Compared with the bearing steel wire rod obtained by the conventional control method at present, the invention has the following beneficial effects: the probability of scratching the matrix by the hard second phase is reduced through flexible control, a matrix structure with low harm is obtained, rolling contact fatigue life test is carried out after the matrix structure is manufactured into a rolling body, and under the maximum contact stress of 4.5GPa load, L 10 The service life reaches 1.5 multiplied by 10 7 Cycling for a round.
Drawings
FIG. 1 is a microstructure of Ti (C, N) particles associated with MnS further encapsulated by MnS when a hot rolled slab of the present invention is heated;
FIG. 2 is a microstructure of elongated MnS in a hot rolled blank according to the present invention;
FIG. 3 is a microstructure of the elongated MnS of FIG. 2 after being heated to become CaS-MnS composite inclusion particles;
FIG. 4 is a microstructure of a sulfide coated particle of the present invention;
FIG. 5 is a microstructure view of particles of the present invention with oxide and sulfide in respective proportions;
FIG. 6 is a morphology of a cold-headed deformed second phase of wire without sulfide encapsulation;
fig. 7 is a morphology of a second phase of cold heading deformation of a wire rod coated with sulfide according to the present invention.
Detailed Description
The invention will now be described in further detail with reference to the drawings and to specific examples. The following examples are only illustrative of the present invention and are not intended to limit the scope of the invention.
Example 1
A flexible second phase production control method suitable for bearing steel,the specification comprises component control, smelting control, high-temperature diffusion and cogging control, hot rolling billet heating control and wire rod rolling control, and the production steps are as follows:
1) And (3) component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 1.0%, mn:0.35%, si:0.25%, S:0.015%, cr:1.50%, P:0.012%, ti:0.002%, ni:0.02%, mo:0.01%, cu:0.02% of Fe and the balance of trace impurities.
2) Smelting control: LF final slag component: caO:46, siO 2 ：21％，MgO：10％，Al 2 O 3 :22%, feO:1.0%. RH vacuum treatment time is 45min, and vacuum degree is 67Pa.
The molten steel with the following composition and temperature is obtained as the preliminary guarantee of LF refining treatment by proper converter tapping and alloying to lead the molten steel composition to meet the following content.
The converter tapping and alloying process comprises the following steps: molten iron is filled into a converter, the content of C is required to be 4.0%, the content of Si is required to be 0.4%, the content of Mn is required to be 0.25%, and the rest elements are not required; after molten iron enters a converter, blowing for 850 seconds by an oxygen lance, and controlling the carbon pulling temperature at 1600 ℃; in the converter smelting process, one or more of lime, fluorite, dolomite and ferric oxide balls are added to ensure the components of converter slag: caO:50%, siO 2 :12%, mgO:6% and the balance FeO; alloying during tapping, paying attention to slag quantity lower than 3Kg/t, and adding 100Kg of Al blocks when the molten steel quantity in the ladle is 5 t; when the molten steel quantity in the ladle is 10t, adding carburant, ferrosilicon, ferromanganese, ferrochromium and synthetic slag in turn, so that the molten steel components meet the requirements. The synthetic slag comprises 49% CaO and 35% Al 2 O 3 、15％SiO 2 And the balance MgO. The carburant is C.
Molten steel composition: c:0.90%, si:0.12%, mn:0.30%, P:0.0095%, S:0.008%, al:0.023%, ti:0.005%, cr:1.40% of Fe and trace impurities; the temperature of molten steel is as follows: 1550 ℃. LF refining is carried out by a slagging process (the slagging process is that when LF refining is started, 500Kg of synthetic slag, 100Kg of lime, 50Kg of calcium carbide and 100Kg of ferrosilicon powder are added, and then the slag is subjected to micro-grinding by on-site observation of the color and the consistency of the slagRegulating to obtain white slag, namely final slag), and obtaining final slag, wherein the final slag comprises the following components: caO:44, siO 2 ：20％，MgO：10％，Al 2 O 3 :25% and FeO:1%; the alkalinity R of the final slag is 3.5; in the LF refining process, according to the component inspection condition of molten steel, adding carbon wires, ferromanganese and ferrochrome for component fine adjustment, so as to ensure that the molten steel obtained by LF refining is identical to the molten steel obtained after converter tapping and alloying;
The ladle after RH vacuum treatment enters a continuous casting machine, the pulling speed of 0.7m/min is adopted for production, the temperature of a tundish is controlled at 1490 ℃, and casting powder (the consumption of the casting powder is 0.5Kg of the casting powder per ton of molten steel is consumed by each ton of molten steel) is added into a crystallizer, and the casting powder comprises 35 percent of SiO 2 ，22％CaO，4％Al 2 O 3 ，10％K 2 O+Na 2 O,19% c, and balance Fe); the crystallizer adopts electromagnetic stirring, the current is set to be 500A, and the frequency is 2.4Hz; for the secondary cooling water quantity, controlling the total water quantity to be 120L/min, adopting dynamic soft reduction at the tail end, and controlling the total reduction to be 10mm to obtain a continuous casting blank;
the second phase in the continuous casting billet is of the following types: 1) Inclusions are classified into the following categories: (1) ti (C, N) inclusion, with angular, is orange-red, appears alone in small amounts, and appears mostly with MnS. (2) MnS-based inclusions, which mainly exist in 2 forms: bulk pure MnS, mnS with other inclusions (mostly oxides) as cores. (3) Oxide inclusions are mainly 2 types of magnesia-alumina spinel inclusions with a small amount and alumina+calcia aluminate+sulfide composite inclusions with a large amount. 2) Carbides, are classified into the following categories: (1) inter-dendrite particulate eutectic carbides. (2) Coarse, network carbide along the grain.
3) High temperature diffusion and cogging: the preheating section temperature is 850 ℃, and the temperature is kept for 180 minutes; the temperature of the heating section is 1230 ℃, and the temperature is kept for 120min; the soaking section temperature is 1260 ℃, and the temperature is kept for 70min. And 6 times of cogging, and rolling into a hot rolled blank with a section of 160mm.
Directly entering a cogging machine through a roller way after high-temperature diffusion is finished to carry out 6 times of large reduction, wherein the temperature of a billet is 1200 ℃ during initial rolling; gradually reducing the temperature of the steel billet along with the cogging, rolling the steel billet into a hot rolled billet with a section of 160 multiplied by 160mm by adopting 6 times of large reduction at 1080 ℃ after the cogging is completed;
the process of each pass of reduction using 6 passes of large reduction is as follows:
pass 1: notch width B:320mm; groove bottom width b:285mm; height h:160mm;
pass 2: notch width B:256mm; groove bottom width b:220mm; height h:160mm;
pass 3: notch width B:226mm; groove bottom width b:190mm; height h:160mm;
pass 4: notch width B:201mm; groove bottom width b:170mm; height h:160mm;
pass 5: notch width B:175mm; groove bottom width b:155mm; height h:160mm;
pass 6: notch width B:162mm; groove bottom width b:157mm; height h:160mm.
After the high-temperature diffusion treatment and rolling into a hot rolled blank, the second phase in the steel blank is of the following types: 1) Inclusions are classified into the following categories: (1) the Ti (C, N) -based inclusions have been substantially broken up by a small number of large-sized Ti (C, N) inclusions precipitated alone, and the majority of Ti (C, N) accompanying MnS has not been deformed. (2) The MnS inclusions are all long, and part of MnS is accompanied with oxide and Ti (C, N) inclusions. (3) Oxide inclusions, mainly of the type 2 of magnesia-alumina spinel, alumina plus calcium aluminate plus sulfide composite, are mostly encapsulated by MnS inclusions. 2) Carbide: (1) the inter-dendrite particulate eutectic carbide has fully dissolved into the matrix. (2) The network carbide is precipitated at the grain boundary position, and the thickness is less than 0.5 mu m.
4) Heating a hot rolled blank: the temperature of the preheating section is 750 ℃, and the temperature is kept for 60 minutes; the temperature of the heating section is 1190 ℃, and the temperature is kept for 40min; soaking section temperature 1220 ℃, and preserving heat for 30min.
Various second phase particles in the hot rolled blank are heated and insulated again after being cooled, and change occurs again, and the main appearance is that: (1) the quantity of small particles Ti (C, N) in the matrix is increased, and matrix cavities caused by crushing Ti (C, N) in the cogging are closed after being heated and rolled again at high temperature. Ti (C, N) associated with MnS is further encapsulated by MnS, reducing its hazard as shown in FIG. 1. (2) Strip-shaped MnS in the hot rolled blank is heated and insulated, can be broken at weak points and tends to be spherical, and finally becomes individual isolated MnS particles. MnS with oxide inclusions as cores tends to become spherical shells and the Ca content of the shells further increases, eventually becoming CaS-MnS complex inclusions, as shown in fig. 2 to 3. (3) After the hot rolled billet is heated and kept warm, almost all oxide inclusions appear with MnS. Most of oxide inclusions are smaller and are wrapped by MnS inclusions; the small amount of oxide inclusions is large and the proportion of oxide inclusions to MnS is as shown in FIGS. 4 to 5. Oxide, mnS size and occupancy were counted using a FEI inclusion scanning analyzer as shown in table 1 below.
TABLE 1 scanning analysis results
As can be seen from Table 1, the higher the number of oxide-sulfide coated particles, the better. For the damage of fatigue life, under the condition that the total quantity of the second phases is determined, the pure sulfide second phase < oxide coated second phase particles < oxide and sulfide second phase particles < pure oxide, ti (C, N) and carbide second phase in proportion respectively. As 2335 inclusions (carbide secondary phase has been almost completely eliminated) were scanned in this test, the numbers of oxide, sulfide-associated particles were 1124, the numbers of pure oxide particles and Ti (C, N) particles were 387, 151, respectively, and the ratio of the numbers of oxide, sulfide-associated particles to the total number of pure oxide particles and Ti (C, N) particles was 1124/538=2.09. The invention reduces the quantity of hard second phases of pure oxide particles and Ti (C, N) particles, and the ratio of the quantity of oxide and sulfide associated particles to the total quantity of the pure oxide particles and the Ti (C, N) particles is more than or equal to 1.5, thus obtaining good fatigue life. In comparative example 1, most of the oxides and Ti (C, N) were not associated with sulfides, resulting in a reduction in fatigue life.
5) Rolling wire rods: the finished product is put into a finishing mill at 850 ℃, reduced sizing at 880 ℃ and spinning temperature at 790 ℃. And starting the 1 st water tank and the 2 nd water tank before finish rolling, the 1 st water tank, the 2 nd water tank and the 3 rd water tank between finish rolling and reducing sizing, and the 1 st water tank and the 2 nd water tank before reducing sizing and spinning machine. All water tanks are opened with the first 5 nozzles, the cooling water temperature is 30 ℃, the nozzle pressure is 0.6MPa, the back blowing nozzles are all opened, and the gas pressure is 0.6MPa.
In the embodiment, the water tanks of each section are controlled by the nozzles and the recovery section, so that the wire rod feeding and finishing temperature reaches 850 ℃, the feeding and reducing sizing temperature reaches 880 ℃, and the wire spinning temperature reaches 790 ℃.
Through the treatment, carbide second phase particles in the hot rolled blank are almost completely dissolved, and most of inclusion second phase particles are wrapped by sulfides, so that the damage of the hard second relative fatigue life is obviously reduced. The rolling element is prepared by rolling the pure brittle second phase particles and sulfide coated second phase particles into wires and then carrying out drawing and cold heading procedures, and the morphology of the rolling element is shown in figures 6-7. It can be seen that the damage of the second phase particles to the matrix in the wire deformation process can be significantly reduced after being coated with the sulfide.
In fig. 6, the hard oxide particles are not coated with sulfide, and in cold heading deformation and drawing deformation of the steel, the oxide particles are broken into strings and scratch the matrix to form holes, which are sources of early fatigue failure, and reduce the fatigue life of the material. In fig. 7, the hard oxide particles are encapsulated by sulfides, which protect the oxide particles from breakage during deformation of the steel, causing less damage to the steel matrix and improving fatigue life.
The wire rod is manufactured into the rolling body through the drawing and cold heading procedures.
A rolling element is made of a wire rod obtained by a flexible second phase production control method applicable to bearing steel of this embodiment.
Example 2
A flexible second phase production control method suitable for bearing steel, phi 12mm specification, comprises the following production steps of component control, smelting control, high-temperature diffusion and cogging control, hot rolled blank heating control and wire rod rolling control:
1) And (3) component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 1.01%, mn:0.34%, si:0.25%, S:0.012%, cr:1.55%, P:0.011%, ti:0.002%, ni:0.02%, mo:0.01%, cu:0.02% of Fe and the balance of trace impurities.
2) Smelting control: LF final slag component: caO:44, siO 2 ：22.9％，MgO：10％，Al 2 O 3 :22%, feO:1.1%. RH vacuum treatment time is 47min, and vacuum degree is 67Pa.
The molten steel with the following composition and temperature is obtained as the preliminary guarantee of LF refining treatment by proper converter tapping and alloying to lead the molten steel composition to meet the following content.
The converter tapping and alloying process comprises the following steps: molten iron is filled into a converter, the content of C is required to be 4.2%, the content of Si is required to be 0.3%, the content of Mn is required to be 0.22%, and the rest elements are not required; blowing the molten iron into a converter for 800 seconds by adopting an oxygen lance, and controlling the carbon pulling temperature at 1650 ℃; in the converter smelting process, one or more of lime, fluorite, dolomite and ferric oxide balls are added to ensure the components of converter slag: caO:55%, siO 2 :13%, mgO:7% and the balance FeO; alloying during tapping, paying attention to slag quantity lower than 3Kg/t, and adding 100Kg of Al blocks when the molten steel quantity in the ladle is 5 t; when the molten steel quantity in the ladle is 10t, adding carburant, ferrosilicon, ferromanganese, ferrochromium and synthetic slag in turn, so that the molten steel components meet the requirements. The synthetic slag comprises 49% CaO and 35% Al 2 O 3 、15％SiO 2 And the balance MgO. The carburant is C.
Molten steel composition: c:0.92%, si:0.13%, mn:0.29%, P:0.01%, S:0.006%, al:0.035%, ti:0.006%, cr:1.37% of Fe and trace impurities; the temperature of molten steel is as follows: 1530 ℃. LF refining is carried out by a slag making process (the slag making process is that when LF refining is started, 500Kg of synthetic slag, 100Kg of lime, 50Kg of calcium carbide and 100Kg of ferrosilicon powder are added, then fine adjustment is carried out by observing the color and the thickness of slag materials on site, and finally white slag is obtained, namely final slag), and the final slag is obtained, wherein the components of the final slag are as follows: caO:51, siO 2 ：18％，MgO：8％，Al 2 O 3 :22% and FeO:1%; the alkalinity R of the final slag is 4.2; in the LF refining process, carbon is added according to the component inspection condition of molten steelFine adjustment of components of the wire, ferromanganese and ferrochrome is carried out, so that the molten steel obtained by LF refining is ensured to be identical with the molten steel obtained after tapping and alloying of a converter;
The ladle after RH vacuum treatment enters a continuous casting machine, the pulling speed of 0.7m/min is adopted for production, the temperature of a tundish is controlled at 1495 ℃, and casting powder (the consumption of the casting powder is 0.6Kg of the casting powder per ton of molten steel is consumed by each ton of molten steel) is added into a crystallizer, and the casting powder comprises 35 percent of SiO 2 ，22％CaO，4％Al 2 O 3 ，10％K 2 O+Na 2 O,19% c, and balance Fe); the crystallizer adopts electromagnetic stirring, the current is set to be 500A, and the frequency is 2.4Hz; for the secondary cooling water quantity, controlling the total water quantity to be 110L/min, adopting dynamic soft reduction at the tail end, and controlling the total reduction to be 9mm to obtain a continuous casting blank; 3) High temperature diffusion and cogging: the temperature of the preheating section is 880 ℃, and the temperature is kept for 200min; the temperature of the heating section is 1220 ℃, and the temperature is kept for 110min; the soaking section temperature is 1260 ℃, and the temperature is kept for 70min. And 6 times of cogging, and rolling into a hot rolled blank with a section of 160 mm.
Directly entering a cogging machine through a roller way after high-temperature diffusion is finished to carry out 6 times of large reduction, wherein the temperature of a billet is 1200 ℃ during initial rolling; gradually reducing the temperature of the steel billet along with the cogging, rolling the steel billet into a hot rolled billet with a section of 160 multiplied by 160mm by adopting 6 times of large reduction at 1080 ℃ after the cogging is completed;
the process of each pass of reduction using 6 passes of large reduction is as follows:
pass 1: notch width B:320mm; groove bottom width b:285mm; height h:160mm;
Pass 2: notch width B:256mm; groove bottom width b:220mm; height h:160mm;
pass 3: notch width B:226mm; groove bottom width b:190mm; height h:160mm;
pass 4: notch width B:201mm; groove bottom width b:170mm; height h:160mm;
pass 5: notch width B:175mm; groove bottom width b:155mm; height h:160mm;
pass 6: notch width B:162mm; groove bottom width b:157mm; height h:160mm.
4) Heating a hot rolled blank: the temperature of the preheating section is 760 ℃, and the temperature is kept for 60 minutes; the temperature of the heating section is 1190 ℃, and the temperature is kept for 40min; soaking section temperature 1220 ℃, and preserving heat for 30min.
5) Rolling wire rods: the finished product is put into a finishing mill at 850 ℃, reduced sizing at 880 ℃ and spinning temperature at 780 ℃. And starting the 1 st water tank and the 2 nd water tank before finish rolling, the 1 st water tank, the 2 nd water tank and the 3 rd water tank between finish rolling and reducing sizing, and the 1 st water tank and the 2 nd water tank before reducing sizing and spinning machine. All water tanks are opened with the first 5 nozzles, the cooling water temperature is 30 ℃, the nozzle pressure is 0.7MPa, the back blowing nozzles are all opened, and the gas pressure is 0.7MPa.
The wire rod is manufactured into the rolling body through the drawing and cold heading procedures.
A rolling element is made of a wire rod obtained by a flexible second phase production control method applicable to bearing steel of this embodiment.
Example 3
A method of controlling production of a flexible second phase suitable for use in bearing steel, comprising the steps of:
step one, component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 0.95%, mn:0.25%, si:0.15%, S:0.01%, cr:1.40%, P:0.025%, ti:0.001%, ni:0.30%, mo:0.10%, cu:0.25% of Fe and trace impurities;
step two, smelting control: tapping and alloying by a converter to obtain molten steel with the following components and temperature, wherein the molten steel is used as a preliminary guarantee of LF refining treatment;
the converter tapping and alloying process comprises the following steps: molten iron is filled into a converter, the content of C is required to be 3.7%, the content of Si is required to be 0.2%, the content of Mn is required to be 0.2%, and the rest elements are not required; after molten iron enters a converter, blowing for 700 seconds by an oxygen lance, and controlling the carbon pulling temperature to 1560 ℃; in the converter smelting process, one or more of lime, fluorite, dolomite and ferric oxide balls are added to ensure the components of converter slag: caO:45%, siO 2 :10%, mgO:5% and the balance FeO; alloying is carried out during tapping, the slag discharging amount is less than 3Kg/t, and 80Kg of Al blocks are added when the molten steel amount in the ladle is 4 t; and when the molten steel amount in the ladle is 8t, adding carburant, ferrosilicon, ferromanganese, ferrochromium and synthetic slag in sequence to ensure that the molten steel components meet the requirements. The synthetic slag comprises 48％CaO、34％Al 2 O 3 、14％SiO 2 And the balance MgO. The carburant is C.
Molten steel composition: c:0.89%, si:0.10%, mn:0.27%, P:0.0087%, S:0.005%, al:0.0086%, ti:0.0007%, cr:1.33% of Fe and trace impurities; the temperature of molten steel is as follows: 1505 ℃. LF refining is carried out by a slag making process (the slag making process is that when LF refining is started, 500Kg of synthetic slag, 100Kg of lime, 50Kg of calcium carbide and 100Kg of ferrosilicon powder are added, then fine adjustment is carried out by observing the color and the thickness of slag materials on site, and finally white slag is obtained, namely final slag), and the final slag is obtained, wherein the components of the final slag are as follows: caO:40%, siO 2 ：25％，MgO：8.8％，Al 2 O 3 :25% and FeO:1.2%; the alkalinity R of the final slag is 3; in the LF refining process, according to the component inspection condition of molten steel, adding carbon wires, ferromanganese and ferrochrome for component fine adjustment, so as to ensure that the molten steel obtained by LF refining is identical to the molten steel obtained after converter tapping and alloying;
after LF refining, the molten steel enters an RH station to be refined continuously, the circulation time of RH vacuum treatment is 40min, and the vacuum degree is 50Pa;
the ladle after RH vacuum treatment enters a continuous casting machine, the pulling speed of 0.65m/min is adopted for production, the temperature of a tundish is controlled at 1475 ℃, and casting powder (the consumption of the casting powder is 0.2Kg of the casting powder per ton of molten steel is consumed by each ton of molten steel) is added into a crystallizer, and the casting powder comprises 35 percent of SiO 2 ，22％CaO，4％Al 2 O 3 ，10％K 2 O+Na 2 O,19% c, and balance Fe); the crystallizer adopts electromagnetic stirring, the current is set to 480A, and the frequency is 2.35Hz; for the secondary cooling water quantity, controlling the total water quantity to be 100L/min, adopting dynamic soft reduction at the tail end, and controlling the total reduction to be 8.5mm to obtain a continuous casting blank;
step three, high-temperature diffusion and cogging: the continuous casting billet is subjected to high-temperature diffusion, and the temperature of each section is controlled as follows:
preheating section: the temperature is 900 ℃ and the time is 180min;
and (3) heating: the temperature is 1200 ℃ and the time is 100min;
and (3) a soaking section: the temperature is 1250 ℃ and the time is 60min;
after the diffusion is finished, directly entering a cogging machine through a roller way to carry out 6 times of large reduction, wherein the temperature of a billet is 1180 ℃ during initial rolling; gradually reducing the temperature of the steel billet along with the cogging, rolling the steel billet into a hot rolled billet with a section of 160 multiplied by 160mm by adopting 6 times of large reduction at the temperature of 1060 ℃ after the cogging is completed;
the process of each pass of reduction using 6 passes of large reduction is as follows:
pass 1: notch width B:320mm; groove bottom width b:285mm; height h:160mm;
pass 2: notch width B:256mm; groove bottom width b:220mm; height h:160mm;
pass 3: notch width B:226mm; groove bottom width b:190mm; height h:160mm;
pass 4: notch width B:201mm; groove bottom width b:170mm; height h:160mm;
Pass 5: notch width B:175mm; groove bottom width b:155mm; height h:160mm;
pass 6: notch width B:162mm; groove bottom width b:157mm; height h:160mm.
Step four, heating a hot rolled blank: the hot rolled blank is rolled after being heated, and the temperature of each section of the hot rolled blank is controlled as follows when the hot rolled blank is heated:
preheating section: the temperature is 800 ℃ and the time is 60min;
and (3) heating: the temperature is 1150 ℃ and the time is 30min;
and (3) a soaking section: the temperature is 1190 ℃ and the time is 30min;
step five, rolling the wire rod:
the control key points of wire rod rolling are as follows: the finishing rolling temperature is 850 ℃, the reducing sizing temperature is 850 ℃, the spinning temperature is 780 ℃, and the water tanks in each section pass through the nozzle and the recovery section to reach the temperature so as to obtain the wire rod. 2 sections of penetrating water tanks are required before finish rolling, the number of nozzles of each water tank is 10, and the length of the water cooling section before finish rolling is 40m; 3 sections of water penetrating tanks are arranged between finish rolling and reducing sizing, the number of nozzles of each water penetrating tank is 10, and the length of the water cooling section before the whole finish rolling is 50m; 2 sections of water penetrating tanks are arranged between the reducing sizing machine and the wire laying machine, the number of nozzles of each water penetrating tank is 10, and the length of the water cooling section before the whole finish rolling is 20m; during production, the cooling water temperature is required to be 35 ℃, the cooling nozzle pressure is required to be 0.5MPa, and the back blowing nozzles are all opened and the pressure is required to be 0.5MPa.
The wire rod is manufactured into the rolling body through the drawing and cold heading procedures.
A rolling element is made of a wire rod obtained by a flexible second phase production control method applicable to bearing steel of this embodiment.
Example 4
A method of controlling production of a flexible second phase suitable for use in bearing steel, comprising the steps of:
step one, component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 1.05%, mn:0.45%, si:0.35%, S:0.025%, cr:1.65%, P:0.01%, ti:0.001%, ni:0.20%, mo:0.03%, cu:0.10% of Fe and trace impurities;
step two, smelting control: tapping and alloying by a converter to obtain molten steel with the following components and temperature, wherein the molten steel is used as a preliminary guarantee of LF refining treatment;
the converter tapping and alloying process comprises the following steps: molten iron is filled into a converter, the content of C is required to be 4.5%, the content of Si is required to be 0.5%, the content of Mn is required to be 0.3%, and the rest elements are not required; after molten iron enters a converter, blowing for 1000 seconds by an oxygen lance, and controlling the carbon pulling temperature at 1670 ℃; in the converter smelting process, one or more of lime, fluorite, dolomite and ferric oxide balls are added to ensure the components of converter slag: caO:55%, siO 2 :15%, mgO:8% and the balance FeO; alloying is carried out during tapping, the slag discharging amount is less than 3Kg/t, and 120Kg of Al blocks are added when the steel ladle is filled with 6t of molten steel; when the molten steel amount in the ladle is 12t, adding carburant, ferrosilicon, ferromanganese, ferrochromium and synthetic slag in turn, so that the molten steel components meet the requirements. The synthetic slag comprises 50% CaO and 35% Al 2 O 3 、14％SiO 2 And the balance MgO. The carburant is C.
Molten steel composition: c:0.95%, si:0.15%, mn:0.32%, P:0.0109%, S:0.01%, al:0.0559%, ti:0.0074%, cr:1.43% of Fe and trace impurities; the temperature of molten steel is as follows: 1570 ℃. LF refining is performed by a slag-making process (the slag-making process is that LF refining starts)Adding 500Kg of synthetic slag, 100Kg of lime, 50Kg of calcium carbide and 100Kg of ferrosilicon powder, and then finely adjusting the color and the consistency of slag materials through on-site observation to finally obtain white slag, namely final slag, wherein the final slag comprises the following components: caO:57.2%, siO 2 ：15％，MgO：6％，Al 2 O 3 :21% and FeO:0.8%; the alkalinity R of the final slag is 4.5; in the LF refining process, according to the component inspection condition of molten steel, adding carbon wires, ferromanganese and ferrochrome for component fine adjustment, so as to ensure that the molten steel obtained by LF refining is identical to the molten steel obtained after converter tapping and alloying;
After LF refining, the molten steel enters an RH station to be refined continuously, the circulation time of RH vacuum treatment is 50min, and the vacuum degree is 100Pa;
the ladle after RH vacuum treatment enters a continuous casting machine, the pulling speed of 0.8m/min is adopted for production, the temperature of a tundish is controlled at 1500 ℃, and casting powder (the consumption of the casting powder is 1.0Kg of the casting powder consumed by each ton of molten steel and the components of the casting powder comprise 35 percent of SiO) is added into a crystallizer 2 ，22％CaO，4％Al 2 O 3 ，10％K 2 O+Na 2 O,19% c, and balance Fe); the crystallizer adopts electromagnetic stirring, the current is set to be 520A, and the frequency is 2.45Hz; for the secondary cooling water quantity, controlling the total water quantity to be 130L/min, adopting dynamic soft reduction at the tail end, and controlling the total reduction to be 11mm to obtain a continuous casting blank;
step three, high-temperature diffusion and cogging: the continuous casting billet is subjected to high-temperature diffusion, and the temperature of each section is controlled as follows:
preheating section: the temperature is 850 ℃ and the time is 200min;
and (3) heating: the temperature is 1250 ℃ and the time is 120min;
and (3) a soaking section: the temperature is 1270 ℃ and the time is 90min;
directly entering a cogging machine through a roller way after finishing diffusion to carry out 6 times of large reduction, wherein the temperature of a billet is 1230 ℃ during initial rolling; the temperature of the billet is gradually reduced along with the cogging, the temperature of the billet is 1100 ℃ after the cogging is completed, and the billet is rolled into a hot rolled billet with the section of 160 multiplied by 160mm by adopting 6 times of large reduction;
The process of each pass of reduction using 6 passes of large reduction is as follows:
pass 1: notch width B:320mm; groove bottom width b:285mm; height h:160mm;
pass 2: notch width B:256mm; groove bottom width b:220mm; height h:160mm;
pass 3: notch width B:226mm; groove bottom width b:190mm; height h:160mm;
pass 4: notch width B:201mm; groove bottom width b:170mm; height h:160mm;
pass 5: notch width B:175mm; groove bottom width b:155mm; height h:160mm;
pass 6: notch width B:162mm; groove bottom width b:157mm; height h:160mm.
Step four, heating a hot rolled blank: the hot rolled blank is rolled after being heated, and the temperature of each section of the hot rolled blank is controlled as follows when the hot rolled blank is heated:
preheating section: the temperature is 750 ℃ and the time is 70min;
and (3) heating: the temperature is 1210 ℃ and the time is 40min;
and (3) a soaking section: the temperature is 1230 ℃ and the time is 40min;
step five, rolling the wire rod:
the control key points of wire rod rolling are as follows: feeding the wire rod into a finishing mill at a temperature of 880 ℃, feeding a reducing sizing temperature of 880 ℃, and a spinning temperature of 810 ℃, wherein each section of water tank passes through a nozzle and a recovery section to reach the temperature, so as to obtain the wire rod. 3 sections of water penetrating tanks are required before finish rolling, the number of nozzles of each water penetrating tank is 12, and the length of the water cooling section before finish rolling is 50m; 4 sections of water penetrating tanks are arranged between finish rolling and reducing sizing, the number of nozzles of each water penetrating tank is 15, and the length of the water cooling section before the whole finish rolling is 70m; 3 sections of water penetrating tanks are arranged between the reducing sizing machine and the wire laying machine, the number of nozzles of each water penetrating tank is 15, and the length of the water cooling section before the whole finish rolling is 30m; during production, the cooling water temperature is required to be 30 ℃, the cooling nozzle pressure is 0.6MPa, and the back blowing nozzles are all opened with the pressure of 0.6MPa.
The wire rod is manufactured into the rolling body through the drawing and cold heading procedures.
A rolling element is made of a wire rod obtained by a flexible second phase production control method applicable to bearing steel of this embodiment.
Comparative example 1: ( This comparative example differs from example 1 only in that: s content is too low )
A flexible second phase production control method suitable for bearing steel, phi 12mm specification, comprises the following production steps of component control, smelting control, high-temperature diffusion and cogging control, hot rolled blank heating control and wire rod rolling control:
1) And (3) component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 1.0%, mn:0.34%, si:0.22%, S:0.002%, cr:1.50%, P:0.015%, ti:0.003%, ni:0.02%, mo:0.01%, cu:0.02% of Fe and the balance of trace impurities.
2) Smelting control: LF final slag component: caO:45%, siO 2 ：22％，MgO：10％，Al 2 O 3 :22%, feO:1.0%. RH vacuum treatment time is 47min, and vacuum degree is 67Pa.
3) High temperature diffusion and cogging: the preheating section temperature is 850 ℃, and the temperature is kept for 180 minutes; heating the temperature of 1228 ℃ in a heating section, and preserving heat for 120min; the soaking section temperature is 1250 ℃, and the temperature is kept for 70min. And 6 times of cogging, and rolling into a hot rolled blank with a section of 160 mm.
4) Heating a hot rolled blank: the temperature of the preheating section is 750 ℃, and the temperature is kept for 60 minutes; the temperature of the heating section is 1195 ℃, and the temperature is kept for 40min; the soaking section temperature is 1222 ℃ and the temperature is kept for 30min.
5) Rolling wire rods: feeding into finishing mill 850 deg.C, reducing diameter 878 deg.C and spinning temp. 800 deg.C. And starting the 1 st water tank and the 2 nd water tank before finish rolling, the 1 st water tank, the 2 nd water tank and the 3 rd water tank between finish rolling and reducing sizing, and the 1 st water tank and the 2 nd water tank before reducing sizing and spinning machine. All water tanks are opened with the first 5 nozzles, the cooling water temperature is 30 ℃, the nozzle pressure is 0.6MPa, the back blowing nozzles are all opened, and the gas pressure is 0.6MPa.
Comparative example 2: ( This comparative example differs from example 1 only in that: in high-temperature diffusion and cogging, the temperature of the heating section and the soaking section are too low )
A flexible second phase production control method suitable for bearing steel, phi 10mm specification, comprises the following production steps of component control, smelting control, high-temperature diffusion and cogging control, hot rolled blank heating control and wire rod rolling control:
1) And (3) component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 1.0%, mn:0.35%, si:0.25%, S:0.015%, cr:1.50%, P:0.012%, ti:0.002%, ni:0.02%, mo:0.01%, cu:0.02% of Fe and the balance of trace impurities.
2) Smelting control: LF final slag component: caO:46, siO 2 ：21％，MgO：10％，Al 2 O 3 :22%, feO:1.0%. RH vacuum treatment time is 45min, and vacuum degree is 67Pa.
3) High temperature diffusion and cogging: the preheating section temperature is 850 ℃, and the temperature is kept for 150min; the temperature of the heating section is 1100 ℃, and the temperature is kept for 100min; the soaking section temperature is 1100 ℃, and the temperature is kept for 50min. And 6 times of cogging, and rolling into a hot rolled blank with a section of 160 mm.
4) Heating a hot rolled blank: the temperature of the preheating section is 750 ℃, and the temperature is kept for 60 minutes; the temperature of the heating section is 1180 ℃, and the temperature is kept for 36min; the soaking section temperature is 1190 ℃, and the temperature is kept for 30min.
5) Rolling wire rods: the finished product is put into a finishing mill at 850 ℃, reduced sizing at 880 ℃ and spinning temperature at 790 ℃. And starting the 1 st water tank and the 2 nd water tank before finish rolling, the 1 st water tank, the 2 nd water tank and the 3 rd water tank between finish rolling and reducing sizing, and the 1 st water tank and the 2 nd water tank before reducing sizing and spinning machine. All water tanks are opened with the first 5 nozzles, the cooling water temperature is 30 ℃, the nozzle pressure is 0.6MPa, the back blowing nozzles are all opened, and the gas pressure is 0.6MPa.
Comparative example 3: ( This comparative example differs from example 1 only in that: in the heating of the hot rolled blank, the temperature of the heating section and the soaking section are too low, and the temperature of the finishing mill and the wire-laying temperature are too high )
A flexible second phase production control method suitable for bearing steel, phi 14mm specification, comprises the following production steps of component control, smelting control, high-temperature diffusion and cogging control, hot rolled blank heating control and wire rod rolling control:
1) And (3) component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 1.0%, mn:0.33%, si:0.23%, S:0.018%, cr:1.50%, P:0.012%, ti:0.002%, ni:0.02%, mo:0.01%, cu:0.02% of Fe and the balance of trace impurities.
2) Smelting control: LF final slag component: caO:40%, siO 2 ：25.1％，MgO：8％，Al 2 O 3 :26%, feO:0.9%. RH vacuum treatment time is 50min, and vacuum degree is 70Pa.
3) High temperature diffusion and cogging: the preheating section temperature is 850 ℃, and the temperature is kept for 150min; the temperature of the heating section is 1230 ℃, and the temperature is kept for 120min; the soaking section temperature is 1260 ℃, and the temperature is kept for 70min. And 6 times of cogging, and rolling into a hot rolled blank with a section of 160 mm.
4) Heating a hot rolled blank: the temperature of the preheating section is 750 ℃, and the temperature is kept for 60 minutes; the temperature of the heating section is 1100 ℃, and the temperature is kept for 40min; soaking section temperature 1120 ℃, and preserving heat for 30min.
5) Rolling wire rods: 900 ℃ is fed into a finishing mill, 880 ℃ is fed into a reducing sizing mill, and the spinning temperature is 900 ℃. And opening a 1 st section water tank before finish rolling, 1, 2 and 3 sections water tanks between finish rolling and reducing sizing, and 1 section water tank before reducing sizing and a spinning machine. All water tanks are opened with the first 5 nozzles, the cooling water temperature is 30 ℃, the nozzle pressure is 0.6MPa, the back blowing nozzles are all opened, and the gas pressure is 0.6MPa.
The results of comparison of the effects of examples 1 to 4 and comparative examples 1 to 3 are shown in Table 2 below.
Table 2: effect contrast
As can be seen from Table 2, in comparative example 3, the presence of the network carbon carbide reduced L 10 Lifetime, but less detrimental than other secondary phases.
L 10 The life test steps are as follows:
1) And the test steel ball is arranged in the test piece clamp, the test piece clamp is clamped on the test shaft and rotates along with the test shaft, and the accompanying test steel ball is arranged in the supporting circular table hole. When the hand wheel is rotated clockwise to enable the screw rod to ascend, and when the accompanying test steel ball is contacted with the test steel ball, the hand wheel is rotated clockwise again to enable the test piece to be slightly stressed, and then the test can be carried out. The temperature and vibration sensors are arranged on the test tool and can respectively detect the temperature and vibration of the test piece.
In the test, lubricating oil provides lubrication and cooling for the sample, and return oil is pumped back to the oil tank through the oil pipe.
2) The test load was set to 15KN (instrument maximum load: 19.6 kN);
3) Setting the rotating speed of a transmission shaft to 2500r/min (the highest rotating speed of an instrument is 3000 r/min);
4) The instrument starts to transport and relevant measurement parameters (load, speed, temperature, current, vibration, etc.) are recorded in a computer;
5) When the parameters of load, current, vibration and the like reach the set alarm values, the steel ball is considered to be in fatigue failure, and the life value of the steel ball at the moment is recorded.
It should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be construed as reflecting the intention that: i.e., the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of the above description, will appreciate that other embodiments are contemplated within the scope of the invention as described herein. Furthermore, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is defined by the appended claims.
The foregoing is only a preferred embodiment of the invention, it being noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.
Claims (10)
1. A method of controlling the production of a flexible second phase suitable for use in bearing steel, comprising the steps of:
Step one, component control: the steel composition of the bearing steel comprises the following components in percentage by weight: 0.95-1.05%, mn: 0.25-0.45%, si: 0.15-0.35%, S: 0.01-0.025%, cr: 1.40-1.65%, P: less than or equal to 0.025 percent, ti: less than or equal to 0.002 percent, ni: less than or equal to 0.30 percent, mo: less than or equal to 0.10 percent, cu: less than or equal to 0.25 percent, and the balance of Fe and trace impurities;
step two, smelting control: tapping and alloying by a converter to obtain molten steel with the following components and temperature, wherein the molten steel is used as a preliminary guarantee of LF refining treatment;
molten steel composition: c: 0.89-0.95%, si: 0.10-0.15%, mn: 0.27-0.32%, P: 0.0087-0.0109%, S: 0.005-0.01%, al: 0.0086-0.0559%, ti:0.0007 to 0.0074%, cr: 1.33-1.43%, and the balance of Fe and trace impurities; the temperature of molten steel is as follows: 1505-1570 ℃; LF refining is carried out by a slag forming process to obtain final slag, wherein the final slag comprises the following components: caO: 40-57.2%, siO 2 ：15~25%，MgO：6~10%，Al 2 O 3 : 21-25% and FeO: 0.8-1.2%; the alkalinity R of the final slag is 3-4.5; in the LF refining process, according to the component inspection condition of molten steel, adding carbon wires, ferromanganese and ferrochrome for component fine adjustment, so as to ensure that the molten steel obtained by LF refining is identical to the molten steel obtained after converter tapping and alloying;
after LF refining, the molten steel enters an RH station to be refined continuously, the circulation time of RH vacuum treatment is 40-50 min, and the vacuum degree is 50-100 Pa;
The ladle subjected to RH vacuum treatment enters a continuous casting machine, is produced by adopting a pulling speed of 0.65-0.8 m/min, the temperature of a tundish is controlled to be 1475-1500 ℃, and casting powder is added into a crystallizer; the crystallizer adopts electromagnetic stirring, the current is set to be 480-520A, and the frequency is 2.35-2.45 Hz; controlling the total water quantity to be 100-130L/min for the secondary cooling water quantity, and adopting dynamic soft reduction at the tail end, and controlling the total reduction to be 8.5-11 mm to obtain a continuous casting blank;
step three, high-temperature diffusion and cogging: the continuous casting billet is subjected to high-temperature diffusion, and the temperature of each section is controlled as follows:
preheating section: the temperature is less than or equal to 900 ℃ and the time is more than or equal to 180min;
and (3) heating: the temperature is 1200-1250 ℃ and the time is 100-120 min;
and (3) a soaking section: the temperature is 1250-1270 ℃ and the time is 60-90 min;
after the diffusion is finished, directly entering a cogging machine through a roller way to carry out 6 times of large reduction, wherein the temperature of a billet is 1180-1230 ℃ during initial rolling; gradually reducing the temperature of the steel billet along with the cogging, rolling the steel billet into a hot rolled billet with a section of 160 multiplied by 160mm by adopting 6 times of large reduction, wherein the temperature of the steel billet is 1060-1100 ℃ after the cogging is completed;
step four, heating a hot rolled blank: the hot rolled blank is rolled after being heated, and the temperature of each section of the hot rolled blank is controlled as follows when the hot rolled blank is heated:
preheating section: the temperature is less than or equal to 800 ℃ and the time is 60-70min;
And (3) heating: the temperature is 1150-1210 ℃ and the time is 30-40min;
and (3) a soaking section: the temperature is 1190-1230 ℃ and the time is 30-40min;
step five, rolling the wire rod:
the control key points of wire rod rolling are as follows: the finishing rolling temperature is 850-880 ℃, the reducing sizing temperature is 850-880 ℃, the spinning temperature is 780-810 ℃, and the water tanks of each section reach the temperature range through the nozzles and the recovery sections to obtain the wire rod.
2. The method for controlling the production of a flexible second phase suitable for bearing steel according to claim 1, wherein the converter tapping and alloying process is as follows: molten iron is filled into a converter, wherein the content of C is required to be 3.7-4.5%, the content of Si is required to be 0.2-0.5%, and the content of Mn is required to be 0.2-0.3%; after molten iron enters a converter, blowing for 700-1000 seconds by an oxygen lance, and controlling the carbon pulling temperature to 1560-1670 ℃; in the converter smelting process, one or more of lime, fluorite, dolomite and ferric oxide balls are added to ensure the components of converter slag: caO: 45-55%, siO 2 : 10-15%, mgO: 5-8% of FeO and the balance;alloying during tapping, paying attention to slag quantity lower than 3Kg/t, and adding 80-120 Kg of Al blocks when the molten steel quantity in the ladle is 4-6 t; and when the molten steel amount in the ladle is 8-12 t, adding carburant, ferrosilicon, ferromanganese, ferrochromium and synthetic slag in sequence to ensure that the molten steel components meet the requirements.
3. The method for controlling production of flexible second phase suitable for bearing steel according to claim 2, wherein the synthetic slag comprises 48-50% CaO, 34-35% Al 2 O 3 、14~15%SiO 2 And the balance MgO.
4. A method of controlling the production of a flexible second phase suitable for use in bearing steel according to claim 3, wherein the slag formation process is: when LF refining is started, adding 500Kg of synthetic slag, 100Kg of lime, 50Kg of calcium carbide and 100Kg of ferrosilicon powder, and then carrying out fine adjustment by observing the color and the consistency of slag materials on site to finally obtain white slag, namely final slag.
5. The flexible second phase production control method for bearing steel according to claim 1, wherein the mold flux consumption is: 0.2-1.0 Kg of protective slag is consumed per ton of molten steel; the covering slag comprises the following components: 35% SiO 2 ，22%CaO，4%Al 2 O 3 ，10%K 2 O+Na 2 O,19% c, and balance Fe.
6. A method of controlling the production of a flexible second phase suitable for use in bearing steels according to claim 1, wherein each pass of reduction process using 6 passes of high reduction is as follows:
pass 1: notch width B:320mm; groove bottom width b:285mm; height h:160mm;
pass 2: notch width B:256mm; groove bottom width b:220mm; height h:160mm;
Pass 3: notch width B:226mm; groove bottom width b:190mm; height h:160mm;
pass 4: notch width B:201mm; groove bottom width b:170mm; height h:160mm;
pass 5: notch width B:175mm; groove bottom width b:155mm; height h:160mm;
pass 6: notch width B:162mm; groove bottom width b:157mm; height h:160mm.
7. The flexible second phase production control method for bearing steel according to claim 1, wherein in the fifth step, at least 2 sections of penetrating water tanks are required before finish rolling, the number of nozzles of each water tank is more than or equal to 10, and the length of the water cooling section before the whole finish rolling is more than or equal to 40m; at least 3 sections of water penetrating tanks are arranged between finish rolling and reducing sizing, the number of nozzles of each water penetrating tank is more than or equal to 10, and the length of the water cooling section before the whole finish rolling is more than or equal to 50m; at least 2 sections of water penetrating tanks are arranged between the reducing sizing machine and the wire laying machine, the number of nozzles of each water penetrating tank is more than or equal to 10, and the length of the water cooling section before the whole finish rolling is more than or equal to 20m; when the production is carried out, the cooling water temperature is required to be less than or equal to 35 ℃, the pressure of the cooling nozzle is more than or equal to 0.5MPa, and the back blowing nozzle is fully opened, and the pressure is more than or equal to 0.5MPa.
8. The method for controlling production of a flexible second phase suitable for bearing steel according to claim 1, wherein the ratio of the number of oxide-sulfide associated second phase particles to the total number of pure oxide particles and TiA particles in the wire is (1.52-2.09): 1, a step of; in TiA, A includes C and/or N.
9. The application of the wire rod obtained by the flexible second phase production control method suitable for bearing steel according to any one of claims 1-8 in rolling bodies, wherein the wire rod is manufactured into the rolling bodies through drawing and cold heading procedures.
10. A rolling element characterized by being made of a wire rod obtained by the flexible second phase production control method for bearing steel according to any one of claims 1 to 8.
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| EP2770077B1 (en) * | 2011-10-20 | 2019-07-10 | Nippon Steel Corporation | Bearing steel and method for producing same |
| JP5820326B2 (en) * | 2012-03-30 | 2015-11-24 | 株式会社神戸製鋼所 | Steel for bearings with excellent rolling fatigue characteristics and method for producing the same |
| US9896749B2 (en) * | 2012-10-19 | 2018-02-20 | Nippon Steel & Sumitomo Metal Corporation | Steel for induction hardening with excellent fatigue properties |
| CN107904492B (en) * | 2017-11-25 | 2020-05-15 | 江阴兴澄特种钢铁有限公司 | Low-silicon high-carbon chromium bearing steel and hot rolling production method thereof |
| CN110257717B (en) * | 2019-07-25 | 2020-12-18 | 建龙北满特殊钢有限责任公司 | High-end bearing steel material for machine tool bearing ring and manufacturing method thereof |
| CN110527909A (en) * | 2019-09-11 | 2019-12-03 | 本钢板材股份有限公司 | A kind of preparation method of the beating steel GCr15 of ultralow titanium containing Cu-J |
| CN112662934A (en) * | 2020-11-30 | 2021-04-16 | 南京钢铁股份有限公司 | Method for reducing bearing steel 100Cr6 carbide banded structure |
| CN113083936B (en) * | 2021-02-25 | 2022-07-05 | 江阴兴澄合金材料有限公司 | High-carbon chromium bearing steel wire rod with diameter less than or equal to 10mm and capable of meeting large-area-reduction-rate hot rolling straight pulling and production method thereof |
| CN114669724B (en) * | 2022-03-31 | 2024-01-23 | 中天钢铁集团有限公司 | Control method for producing large-size wind power bearing steel carbide by continuous casting and rolling process |
| CN115323255B (en) * | 2022-08-19 | 2023-04-25 | 建龙北满特殊钢有限责任公司 | Preparation method of 200-square continuous casting blank for high-quality and high-homogeneity bearing steel wire rod |
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