CN106555110A - A kind of hypo eutectoid air cooling hardening bearing steel and preparation method thereof - Google Patents
A kind of hypo eutectoid air cooling hardening bearing steel and preparation method thereof Download PDFInfo
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- CN106555110A CN106555110A CN201610972225.2A CN201610972225A CN106555110A CN 106555110 A CN106555110 A CN 106555110A CN 201610972225 A CN201610972225 A CN 201610972225A CN 106555110 A CN106555110 A CN 106555110A
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- 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
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- 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
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- 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
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
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- 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
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- 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
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- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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Abstract
A kind of hypo eutectoid air cooling hardening bearing steel and preparation method thereof, belongs to bearing steel material technical field.The chemical composition of the steel is：C：0.45 0.75%wt%, Mn:2.5 5.0wt%, Si：0 2.0%, Cr：0 2.0%, it is remaining for Fe and inevitable impurity.A kind of or multiple element can be separately descended on this basis：Mo:0 0.2wt%, Nb:0 0.20wt%, V：0 0.20wt% and rare earth RE：0 0.2wt%.Advantage is that the application of hypo eutectoid bearing steel not only simplify bearing mnanufacture technique, reduce bearing mnanufacture cost, can also be used to manufacture large-scale and extra large size bearing, has wider use range than traditional bearing steel GCr15.
Description
Technical field
The invention belongs to bearing steel material technical field, in particular, provides a kind of hypo eutectoid air cooling hardening bearing steel and its system
Preparation Method, can the chemical composition without net carbide bearing steel material of air cooling hardening, technology of preparing and its application technology.It is sub- common
The application of analysis bearing steel not only simplify bearing mnanufacture technique, reduce bearing mnanufacture cost, can also be used to manufacture large-scale and special
Large size bearing, has wider use range than traditional bearing steel GCr15.
Background technology
Current country's bearing output of steel is up to 4,000,000 tons, wherein the bearing Steel Bar that there are about 85% is medium and small bar, diameter
In below 70mm, and diameter is big rod more than the pole of 70mm in addition, accounts for the 15% of bearing steel total amount.With bearing rod iron
The increasing of material diameter, the net carbide control in bearing steel are further difficult, particularly bearing rod iron of the diameter more than 100mm
Material, net carbide control become the difficult problem in the world.In order to solve this problem, current countries in the world all attempt to reduce bearing steel
In carbon content, develop the bearing steel of hypo eutectoid composition solving the carbide problem in big rod bearing steel.Except big rod
Outside the problem of middle net carbide, the through hardening sex chromosome mosaicism of big wall thickness bearing bearing steel is also clearly mainly shown as bearing
Wall thickness is organized more than full through hardening cannot be obtained after 70mm, and then significantly reduces the hardness of bearing surface and center portion, causes large-scale
Wall thickness bearing quality does not pass a test, and has become a bottleneck of the development of domestic and international bearing manufacturing.
Large-scale is the high-end product in bearing with big wall thickness bearing, with of many uses and added value it is high the characteristics of.But state
Interior never to solve large-scale and ultra-large type bearing DOMESTICATION PROBLEM, main cause can be attributed to traditional high carbon bearing steel
Net carbide is serious, quenching degree is not enough and intensive quenching under the conditions of quenching distortion with cracking.Novel air cold hardening bearing steel
The characteristics of with hardening without net carbide and air cooling, steel mill's big rod not only can be solved with especially big bar net carbide
Problem, reduction big rod caused waste product because of net carbide problem, reduces the process costs in production process；And be
Bearing enterprise provides a bearing steel kind of high quality and at a reasonable price.Novel bearing steel can be solved due to its superpower through hardening ability
The certainly sex chromosome mosaicism that hardens of the big wall thickness of bearing enterprise (wall thickness is more than 70mm) bearing internal external circle and major diameter rolling element.While Novel shaft
The air cooling hardening feature for holding steel can also reduce caused quenching distortion and problem of Cracking during Bearing Quenching, will be subject to
The welcome of vast bearing enterprise.Mining machinery uses large-scale and ultra-large type bearing, the big portion of its wall thickness in a large number with engineering machinery at present
Divide more than 70mm.And effective full hardening deepness J60 of existing beating steel GCr15 effectively quenching for 7mm, GCr15SiMn and GCr18Mo
Depth J60 is 15mm thoroughly, and effective full hardening deepness J60 of GCr15SiMo is also up to 30mm, these traditional full through hardening types
Bearing steel has been unable to reach requirement of this large size bearing more than wall thickness 70mm to material, and (effective full hardening deepness J60 must be big
In 35mm).According to the applicable cases in current big rod bearing steel market, the big rod bearing steel more than 70mm accounts for 10% city
Market share, about 400,000 tons.According to the composition and process costs of novel bearing steel, new hypo eutectoid bearing steel substantially with traditional high-carbon
Chromium bearing steel is suitable, but performance is far superior to traditional high-carbon-chromium bearing steel, therefore possesses diving for the traditional high-carbon-chromium bearing steel of replacement
Power.
The content of the invention
It is an object of the invention to provide a kind of hypo eutectoid air cooling hardening bearing steel and preparation method thereof, by C, Mn, Si
It is main adding elements and the Alloying Design with the microalloy element of the strong carbide such as Mo, Nb, V and rare earth RE precipitation with Cr；
Traditional high-carbon-chromium bearing steel production technology, produces a kind of bearing steel without net carbide and air cooling hardening capacity, it is ensured that carbon
The concordance of compound distributing homogeneity and hardness along wall thickness.The bearing steel will be with through hardening bearing steel has more entirely with tradition simultaneously
Plus excellent contact fatigue property and anti-wear performance.The novel bearing steel chemical composition is：C：0.45-0.75%, Mn：2.5-
5.0%, Si：0-2.0%, and Cr：0-2.0%.The microalloy element such as Mo, Nb, V and rare earth RE can be added on this basis,
Obtain a kind of hardening of air cooling without net carbide bearing steel.Steel of the present invention can pass through conventional smelting, continuous casting, hot rolling and move back
The techniques such as fire carry out large-scale industrial production, solve the net carbide of traditional high carbon bearing steel, center portion cannot harden and
Be not suitable for the shortcoming of big wall thickness bearing mnanufacture.
The basic feature of steel of the present invention is：1st, in the chemical composition of steel, mainly by C：0.45-0.75%, Mn：
2.5-5.0%, Si：0-2.0%, and Cr：0-2.0% alloying ingredients, the component system to can ensure that and have nothing in bearing steel
The characteristics of net carbide and air cooling are hardened；Crystal grain is suppressed by the precipitation anchoring of the microalloy element such as Mo, Nb, V and rare earth RE
Grow up, it is ensured that bearing crystalline grain of steel grain refining, reduce the Hydrogen Embrittlement of bearing steel.2., in performance, steel of the present invention is with than passing
Unite the more excellent contact fatigue property of high carbon bearing steel and anti-wear performance, traditional high carbon bearing steel manufacture not only can be substituted general
Lead to middle-size and small-size bearing, and be more suitable for manufacturing the large-scale and extra large size bearing of big wall thickness.
The chemical composition of steel of the present invention is：C：0.45-0.75%wt%, Mn:2.5-5.0wt%, Si：0-2.0%,
Cr：0-2.0%, it is remaining for Fe and inevitable impurity.A kind of or multiple element can be separately descended on this basis：Mo:
0-0.2wt%, Nb:0-0.20wt%, V：0-0.20wt% and rare earth RE：0-0.2wt%.
The bearing steel material has the Mn alloyings of carbon content (0.45-0.75%) design and air cooling hardening of sub-eutectoid steel
(2.5-5.0%) design, thus not only no net carbide, also with Different Cooling Conditions such as air cooling, oil cooling and water-cooleds
The characteristics of lower acquisition center portion reaches more than 60HRC hardness with surface, the net carbide for solving traditional high carbon bearing steel is asked
The shortcoming that topic and core structure cannot harden.The novel bearing steel low-cost and easy-to is produced, can pass through conventional bearings steel smelting,
The operations such as continuous casting, hot rolling and soft annealing and technique carry out large-scale industrial production.The application of new hypo eutectoid bearing steel is not
Only simplify bearing mnanufacture technique, reduce bearing mnanufacture cost, can also be used to manufacture large-scale and extra large size bearing, than traditional axle
Hold steel GCr15 and there is wider use range.
The effect of each element of the present invention and proportioning are according to as follows：
C：Used as the main intensified element of bearing steel, the through hardening and performance of hardening to bearing steel plays a decisive role, and which contains
Amount cannot be below 0.45%.Consider that the novel bearing structure of steel without net carbide is required simultaneously, its carbon content can not be higher than
0.75%.
Mn：Mn is austenite stabilizer element and the element for improving bearing steel hardenability.In steel of the Mn higher than 2.5% more
It is easily achieved stabilization of austenite and quenching degree is improved, thus Mn contents should be higher than that 2.5%；And too high manganese content will cause steel
In there is abundant residues austenite, be unfavorable for that Bearing Steel is improved and bearing size is stable, thus manganese content be restricted to
5.0%.
Si：Si can improve the intensity of steel by solid solution, be conducive to the raising of Bearing Steel, Si contents control
In the range of 0-2.0%.
Cr:Cr can improve the stability of carbide in bearing steel, it is ensured that the carbide in annealing process middle (center) bearing steel is thin
It is little uniform；Cr has high temperature resistance surface oxidation ability simultaneously, it is ensured that bearing steel surface quality.Cr contents in steel of the present invention
Should control in 0-2.0wt%.
Mo, Nb, V and rare earth RE:Be strong carbide formed micro alloying element, can thermal deformation with it is heat treated
Inhibiting grain growth in journey, should control in the range of 0-0.2wt%.
The present invention manufacturing process and condition be：
The process for making such as the production technology of steel of the present invention is to smelt, casting, hot rolling and annealing, concrete technology are as follows：
(1) smelting of steel and solidification：Smelt suitable for converter, electric furnace and induction furnace, using continuous casting strand or molding
Production ingot casting.
(2) hot rolling of strand or ingot casting or hot continuous rolling or forging：
Hot rolled rod：Strand Jing 1100-1250 DEG C are heated, finish rolling after first roughing is cooled fast to 400-600 DEG C after rolling
In the range of carry out that stove is cold or air cooling.
(3) hot rolled rod soft annealing
Soft annealing is carried out in the range of 600-800 DEG C to process to reduce hot rolled rod hardness to hot rolled rod, with profit
In the following process of novel bearing steel.
Description of the drawings
Fig. 1 gives 1# steel according to the optics heterogeneous microstructure figure after step 2 hot rolling and air cooling, it can be seen that
No net carbide in steel after annealing.
Fig. 2 gives 5# steel and carries out the optics heterogeneous microstructure after soft annealing according to step 3, can from figure
Go out, no net carbide in steel after annealing, and fine microstructures are uniform.
Fig. 3 is the scanning electron microscope complex tissue pattern of martensite of the 3# steel Jing after 900 DEG C of dry quenchings and carbide.From figure
In as can be seen that its heterogeneous microstructure be martensitic matrix tissue be dispersed with fine uniform be distributed carbide (some carbon
Compound comes off to form pitting due to corrosion).Steel of the present invention is illustrated after austenitizing, can obtain high hard under the conditions of air cooling
The martensitic structure of degree.
Fig. 4 is martensite and carbide complex tissue pattern under scanning electron microscope high power of the 3# steel Jing after 200 DEG C of tempering.From
Can be clearly seen that in figure, through the carbide that its structure is tempered martensite matrix tissue and fine uniform distribution, explanation
Invention steel has martensite and carbide complex tissue required by traditional bearing steel.
Specific embodiment
Embodiment：
Steel of the present invention pours the billet that ingot mould is 50kg by test chamber vacuum induction furnace smelting.7 stove steel are smelted altogether, wherein
Chemical composition is shown in Table 1.
The chemical composition (wt.%) of 1 invention steel of table
It is as follows that steel of the present invention implements example for technological process：
Step 1：The smelting of steel
By test chamber vacuum induction furnace smelting, the billet that ingot mould is 50kg is poured.
Step 2：The forging (simulation hot rolling) of steel：
The steel ingot of 1-7# steel is heated through 1200 DEG C, is incubated 5h, is carried out hammer cogging.Start forging range 1200
DEG C, final forging temperature is 800 DEG C, is finally forged into the pole of pole that size is a diameter of 60mm and a diameter of 150mm, fast after forging
The fast protective atmosphere heating furnace into 700 DEG C carries out stove and is as cold as room temperature.
Step 3：The soft annealing of steel：
1-7# steel is first heated to into 800 DEG C of insulations, 6 hours are incubated, and then 720 DEG C of insulations 6 is dropped to 30 DEG C/min little
When, last stove be as cold as 550 DEG C after air cooling to room temperature.So not only with reduce steel hardness (not higher than 350HB and be easy to plus
Work), while realizing the nodularization of carbide in steel.
Step 4. hardness, wear-resisting and fatigue behaviour performance measurement
Quenching degree contrast test：
For science, exactly reflect steel quenching degree, according to GB " the quenching degree end quenching test method of steel "
(GB225-88) end quenching experiment is carried out, depth-hardness curve is drawn, (J60 is not less than 60HRC's for hardness to the depth value of measure J60
Full hardening deepness), the quenching degree contrast experiment for carrying out invention steel and compared steel GCr15.Under end quenching experiment condition, whole sample is equal
Hardening is realized, so J60 is set to 100mm, and the J60 of compared steel GCr15 is only 8mm.
Invention steel and compared steel are processed into the bar of a diameter of 150mm and length 200mm simultaneously, steel is heated to into 900
DEG C and be incubated 30 minutes, room temperature is cooled under the conditions of air cooling.Under the conditions of measure air cooling, the surface of invention steel and compared steel is to the heart
The uniformity of hardness in portion.It was found that after air cooling GCr15 case hardness 42HRC and center portion 28HRC, and surface and the center portion of invention steel
60HRC has been reached.
These results suggest that, invention steel not only has the quenching degree of superelevation, and can realize the spy of the uniform hardening of air cooling
Point, is particularly suitable for big-and-middle-sized and ultra-large type bearing steel manufacture.
The heterogeneous microstructure of invention steel：
As shown in figure 1, invention steel is after hot rolling and air cooling, no net carbide in steel.It is this without net carbide
Heterogeneous microstructure demonstrates the Design of Chemical Composition thinking that bearing steel hypo eutectoid composition design removes net carbide.Such as Fig. 2
It is shown after hot rolling and soft annealing, not only no net carbide in invention steel, and even tissue is tiny, is bearing steel
Hot-working and cold working established good tissue and prepared.As shown in figure 3, invention steel after austenitizing under the conditions of air cooling
The martensitic structure of high rigidity can be obtained, illustrates that invention steel has superpower quenching degree.As shown in figure 4, through quenching and returning
After fire, the heterogeneous microstructure of invention steel is the carbide of tempered martensite matrix tissue and fine uniform distribution.
Above organizational structure result shows that invention steel is with without net carbide, air cooling hardening and martensite and carbonization
The characteristics of thing complex tissue, this not only meets requirement of the traditional bearing steel to heterogeneous microstructure, while possessing bearing steel institute not
Possess the characteristics of hardening without net carbide and air cooling.
The experiment on fatigue properties of bearing steel：Step 3 is obtained into 1-6# rod irons and is processed into thrusting plate (diameter 60mm, thickness
The disk of 10mm), carry out heat treatment hardening and (apply Technology for Heating Processing：830 DEG C are incubated 30 minutes austenitizings, and then air cooling is arrived
Room temperature, finally carries out 170 DEG C and is tempered 2 hours), carry out contact fatigue property measure.Quenching of the compared steel using GCr15 bearing steels
Tempering process (830 DEG C insulation 30 minutes after oil cooling, it is last 170 DEG C tempering)；JB-T12444-2006
Contact fatigue life test is carried out according to GB JB-T10510-2005.Using the thrust similar to thrust ball bearing
The formula way of contact, test Max.contact stress are 4000MPa, and testing machine rotating speed is 1500rpm, and 4010 lubricating oil are adopted during test
1×108Fixed failure number test.Experimental result is as shown in table 2.
The hardness of 2 steel of table and contact fatigue property test result
Claims (2)
1. a kind of hypo eutectoid air cooling hardens bearing steel, it is characterised in that chemical component weight percent is：C：0.45-
0.75wt%, Mn:2.5-5.0wt%, Si：0-2.0%, Cr：0-2.0%, it is remaining for Fe and inevitable impurity；In this base
A kind of or multiple element is descended on plinth separately：Mo:0-0.2wt%, Nb:0-0.20wt%, V：0-0.20wt% and rare earth RE：0-
0.2wt%.
2. a kind of hypo eutectoid air cooling described in claim 1 hardens the preparation method of bearing steel, including smelt, casting, hot rolling and
Soft annealing whole process；The technical parameter for controlling in process is：
(1) smelting of steel and solidification：Smelt suitable for converter, electric furnace and induction furnace, using continuous casting strand or molding production
Ingot casting；
(2) hot rolling of strand or ingot casting or hot continuous rolling or forging：
Hot rolled rod：Strand Jing 1100-1250 DEG C are heated, finish rolling after first roughing is cooled fast to 400-600 DEG C of scope after rolling
Inside carry out that stove is cold or air cooling；
(3) hot rolled rod soft annealing
Soft annealing is carried out in the range of 600-800 DEG C to process to reduce hot rolled rod hardness to hot rolled rod, is beneficial to axle
Hold the following process of steel.
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Citations (6)
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| JPH06264186A (en) * | 1993-03-12 | 1994-09-20 | Kawasaki Steel Corp | Bearing steel excellent in delay characteristic of change in microstructure caused by repeated stress load |
| JP2905242B2 (en) * | 1990-03-03 | 1999-06-14 | 川崎製鉄株式会社 | Method for producing low Cr bearing steel material with excellent rolling fatigue life |
| CN1668773A (en) * | 2002-07-11 | 2005-09-14 | 三和钢棒株式会社 | Quenched and tempered steel wire with superior cold forging characteristics |
| CN1888116A (en) * | 2006-08-04 | 2007-01-03 | 钢铁研究总院 | High hardness and high wear resistance no-magnetism bearing steel |
| JP5598016B2 (en) * | 2010-02-23 | 2014-10-01 | 日本精工株式会社 | Manufacturing method of thrust trace of needle thrust bearing |
| CN104662192A (en) * | 2012-09-26 | 2015-05-27 | Skf公司 | Hypoeutectoid bearing steel |
-
2016
- 2016-10-31 CN CN201610972225.2A patent/CN106555110A/en active Pending
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|---|---|---|---|---|
| JP2905242B2 (en) * | 1990-03-03 | 1999-06-14 | 川崎製鉄株式会社 | Method for producing low Cr bearing steel material with excellent rolling fatigue life |
| JPH06264186A (en) * | 1993-03-12 | 1994-09-20 | Kawasaki Steel Corp | Bearing steel excellent in delay characteristic of change in microstructure caused by repeated stress load |
| CN1668773A (en) * | 2002-07-11 | 2005-09-14 | 三和钢棒株式会社 | Quenched and tempered steel wire with superior cold forging characteristics |
| CN1888116A (en) * | 2006-08-04 | 2007-01-03 | 钢铁研究总院 | High hardness and high wear resistance no-magnetism bearing steel |
| JP5598016B2 (en) * | 2010-02-23 | 2014-10-01 | 日本精工株式会社 | Manufacturing method of thrust trace of needle thrust bearing |
| CN104662192A (en) * | 2012-09-26 | 2015-05-27 | Skf公司 | Hypoeutectoid bearing steel |
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| 何人葵: "《工程材料与热处理》", 31 July 2015 * |
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Application publication date: 20170405 |