WO2013070133A1 - Steel ring blank or segment blank and method for manufacturing - Google Patents

Steel ring blank or segment blank and method for manufacturing Download PDF

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Publication number
WO2013070133A1
WO2013070133A1 PCT/SE2012/000176 SE2012000176W WO2013070133A1 WO 2013070133 A1 WO2013070133 A1 WO 2013070133A1 SE 2012000176 W SE2012000176 W SE 2012000176W WO 2013070133 A1 WO2013070133 A1 WO 2013070133A1
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WO
Grant status
Application
Patent type
Prior art keywords
ring
blank
steel
bearing
characterized
Prior art date
Application number
PCT/SE2012/000176
Other languages
French (fr)
Inventor
Thore Lund
Karin RYDÈN
Original Assignee
Aktiebolaget Skf
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21KMAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00Making machine elements
    • B21K1/04Making machine elements ball-races or sliding bearing races
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21JFORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J1/00Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
    • B21J1/04Shaping in the rough solely by forging or pressing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21KMAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
    • B21K1/00Making machine elements
    • B21K1/76Making machine elements elements not mentioned in one of the preceding groups
    • B21K1/761Making machine elements elements not mentioned in one of the preceding groups rings
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23POTHER WORKING OF METAL; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • B23P15/003Making specific metal objects by operations not covered by a single other subclass or a group in this subclass bearings
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30Parts of ball or roller bearings
    • F16C33/58Raceways; Race rings
    • F16C33/62Selection of substances
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30Parts of ball or roller bearings
    • F16C33/58Raceways; Race rings
    • F16C33/64Special methods of manufacture
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2204/00Metallic materials; Alloys
    • F16C2204/60Ferrous alloys, e.g. steel alloys
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2220/00Shaping
    • F16C2220/40Shaping by deformation without removing material
    • F16C2220/46Shaping by deformation without removing material by forging

Abstract

Method for manufacturing at least one steel ring blank (18) or ring segment blank, which comprises steps of forging steel into a sleeve (16), and cutting said at least one steel ring blank (18) or ring segment blank from the forged sleeve (16).

Description

STEEL RING BLANK OR SEGMENT BLANK AND METHOD FOR

MANUFACTURING

TECHNICAL FIELD

The present invention concerns a method of manufacturing at least one steel ring blank or ring segment blank, which may subsequently be cut to provide an inner or outer ring of a bearing for example. The present invention also concerns a steel ring blank or ring segment blank manufactured using such a method.

BACKGROUND OF THE INVENTION

The outer rings of bearings are usually produced from a ring blank manufactured by ring rolling, which is a specialized type of hot rolling that increases the diameter of a ring. Hot rolling is a metalworking process that occurs above the recrystallization temperature of the rolled material. After the grains deform during processing, they recrystallize, which maintains an equiaxed microstructure and prevents the metal from work hardening.

The starting material is usually a piece of metal, like a semi-finished casting product, such as a slab, bloom, or billet. If these products come from a continuous casting operation the products are usually fed directly into the rolling mills at the proper temperature. In smaller operations the starting material starts at room temperature and must be heated. As the material is worked, the temperature must be monitored to make sure it remains above the recrystallization temperature, usually 50 to 100 °C above the recrystallization temperature. If the temperature drops below this temperature the material must be re-heated before further hot rolling.

In ring rolling a workpiece is worked into the form of a thick-walled ring and is placed on an idler roll, while another roll, called the driven roll, presses the ring from the outside. As the rolling occurs the wall thickness decreases as the diameter increases. The resulting grain structure is circumferential, which gives better mechanical properties.

SUMMARY OF THE INVENTION An object of the invention is to provide an improved method for manufacturing at least one steel ring blank or ring segment blank. This object is achieved by a method comprising the steps of forging steel into a sleeve, i.e. a thick-walled ring, and cutting at least one ring blank or ring segment blank from the forged sleeve. Rings or ring segments may then be cut from the blanks. A ring formed using such a method has been found to have improved rolling contact and structural fatigue properties, increased structural strength (as measured by rotating beam testing), an increased lifetime, a lower rate of butterfly generation, a smaller average grain size, a reduced inclusion length and a better worked structure as compared to a ring manufactured from the same steel by hot rolling a ring from a steel slab, bloom or billet. Sleeve forging provides a more homogeneous matrix compared to hot rolling, which is evidenced by a more homogeneous macro-structure.

It should be noted that the expression "cutting" as used in this document is intended to mean any process wherein material is brought to a specified geometry by removing excess material from a forged sleeve to leave at least one ring blank or ring segment blank that meets specifications or wherein material is brought to a specified geometry by removing excess material from a ring blank or ring segment blank to leave at least one ring or ring segment that meets specifications. Cutting processes may include one, or any combination of the following: manual technologies such as sawing or chiselling, machine technologies such as turning, milling drilling, filing, grinding or sawing, welding/burning technologies such as burning by laser, oxy-fuel burning and plasma and/or erosion technologies such as water jet or electric discharge.

According to an embodiment of the invention, the forged sleeve is cut into at least one ring or ring segment blank when the forged sleeve is cold, i.e. when the forged sleeve has cooled down to room temperature for example.

According to an embodiment of the invention the method comprises the step of forging the sleeve from a slab, bloom, or billet, which is forged from an ingot weighing over 4 ton, over 10 ton, over 15 ton, over 20 ton or more. A billet is a length of metal that has a round or square cross-section, with an area less than 230 cm2. A billet may be created directly via continuous casting or extrusion. A bloom is similar to a billet except its cross-sectional area is greater than 230 cm2. A slab is a length of metal that is rectangular in cross- section. It may be created directly from continuous casting. According to another embodiment of the invention the at least one ring or ring segment blank constitutes an outer or inner bearing ring blank or ring segment blank.

According to a further embodiment of the invention at least one ring or ring segment blank is cut from a position located as close to the centre of the forged sleeve as possible.

According to an embodiment of the invention the steel has the following composition in weight-%: C 0.6-1.5

Si 0- 2.0

Mn 0-2.0

Cr 0.01-2.0

Mo 0.01-1.0

Ni 0.01-2.0

V and/or Nb 0.01-1.0 of V or 0.01-1.0 of Nb, or 0.01-1.0 of both elements

S 0- 0.002

P 0- 0.015

Cu 0-0.5

Al 0.010-1.0

balance Fe and normally occurring impurities.

Such steel, which has very few inclusions, is particularly suitable for the manufacture of components intended for an application with high demands on fatigue and toughness properties.

According to another embodiment of the invention the forged sleeve is forged to a final reduction (reduction after the final re-heating operation) ratio of 2-4. One major difference between single ring blank forging and sleeve forging is that the reduction given to the steel after the final re-heating operation is significantly enhanced.

According to a further embodiment of the invention the forging takes place at a temperature of max. 50-100°C above the recrystallization temperature of the steel, i.e. the steel is hot forged, preferably at a temperature just above its recrystallization temperature; the lower the temperature, the better. As the steel is deformed work hardening effects are negated by the recrystallization process. The present invention also concerns a steel ring blank or ring segment blank manufactured using a method according to any of the embodiments of the invention. A ring or ring segment cut from such a steel ring blank has been found to have improved rolling contact and structural fatigue properties, an increased lifetime, a lower rate of butterfly generation, a smaller average grain size, reduced inclusion length and/or a better worked structure as compared to a ring blank made from the same steel but manufactured by hot rolling. Tests have shown that a ring blank manufactured using a method according to the present invention has a rate of butterfly generation that is 35-70 lower than a corresponding ring manufactured by hot rolling. The average wing size developed in a ring blank manufactured using a method according to the present invention is up to five times smaller than a corresponding ring manufactured by hot rolling and its estimated L10 life is up to 7.5 times as long as for a corresponding ring manufactured by hot rolling.

According to an embodiment of the invention the steel ring blank or ring segment blank is arranged to be cut to provide at least part of one of the following: a ball bearing, a roller bearing, a needle bearing, a tapered roller bearing, a spherical roller bearing, a toroidal roller bearing, a ball thrust bearing, a roller thrust bearing, a tapered roller thrust bearing, a wheel bearing, a hub bearing unit, a slewing bearing, a ball screw, or a component for an application in which it is subjected to alternating Hertzian stresses, such as rolling contact or combined rolling and sliding and/or an application that requires high wear resistance and/or increased fatigue and tensile strength. The present invention also concerns the use of a method according to any of the embodiments of the invention to manufacture a steel ring blank or ring segment blank having at least one of the following: improved rolling contact, structural fatigue properties, increased structural strength (as measured by rotating beam testing), an increased lifetime, a lower rate of butterfly generation, a smaller average grain size, a reduced inclusion length and/or better worked structure as compared to a corresponding steel ring blank manufactured by hot rolling.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be further explained by means of non-limiting examples with reference to the appended figures where; Figure 1 shows the steps of a method according to the prior art,

Figure 2 show steps of a method according to an embodiment of the invention,

Figure 3 shows a step of a method according to an embodiment of the invention, and

Figure 4 shows a component comprising at least one steel ring cut from at least one steel blank manufactured using a method according to an embodiment of the invention.

It should be noted that the drawings have not been drawn to scale and that the dimensions of certain features have been exaggerated for the sake of clarity.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 shows the steps of a method of manufacturing a steel ring blank 14 according to the prior art. A steel ingot 10 is used to produce a steel billet 12 by continuous casting for example. The ingot 10 may for example weigh 4.2 tons and be used to forge a 350 mm diameter billet round 12. The billet round 12 may for example be sectioned, re-heated, upset forged, pierced, re-heated and then fed into rolling mills and hot rolled into a ring blank 14. Figure 2 shows the steps of a method according to an embodiment of the invention. The method comprises the step of producing a steel billet 12 from a steel ingot and forging the steel round 12 into a sleeve 16. The forged sleeve 16 may have a final reduction ratio of 2-4. The ingot 10 may for example weigh 25 tons and be used to produce a 775 mm diameter billet round 12, which is then forged into a sleeve 16 at a temperature of 1160°C. Figure 3 shows that a plurality of steel ring blanks 18 may then be cut from the forged sleeve 16. The steel ring blanks 18 may be cut to provide outer and/or inner bearing rings. The plurality of steel ring blanks 18 are preferably cut from a position located as close to the centre 20 of the forged sleeve 16 as possible. The thickness T of the forged sleeve 16 is preferably selected to allow a plurality of steel ring blanks 18 of thickness f to be cut therefrom. The length L of the forged sleeve 16 is preferably selected to allow a plurality of steel ring blanks 18 of length / to be cut therefrom.

Steel rings cut from such a forged sleeve 16 have been found to have an increased lifetime, a lower rate of butterfly generation, a smaller average grain size, a reduced inclusion length (25 μιη at Reduced Variate 3.0) and/or a better worked structure as compared to corresponding steel rings manufactured from the same steel by hot rolling, even as compared to extremely well hot rolling reduced steel rings. Figure 4 schematically shows an example of a bearing component 22, namely a rolling element bearing that may range in size from 10 mm in diameter to a few metres in diameter and have a load-carrying capacity from a few tens of grams to many thousands of tonnes. The bearing component 22 may namely be of any size and have any load- carrying capacity. The bearing component 22 has an inner ring 24, an outer ring 26 and a set of rolling elements 28. The inner ring 24 and/or the outer ring 26 of the bearing component are cut from at least one ring blank 18 that is manufactured using a method according to the present invention.

According to an embodiment of the invention the inner ring 24 and/or the outer ring 18 are manufactured from steel that comprises in weight-%: 0.6-1.5 C, 0-2.0 Si, 0-2.0 Mn, 0.01- 2.0 Cr, 0.01-1.0 Mo, 0.01-2.0 Ni, 0.01-V or 0.01-1.0 of Nb, or 0.01-1.0 of both V and Nb, 0-0.002 S, 0-0.015 P, 0-0.5 Cu, 0.010-1.0 Al, the remainder being Fe and normally occurring impurities. For example, the steel may comprise 1.0 % C, 0.2 Si, 0.7 Mn, 1.8 Cr, 0.5 Mo, 0.1 Ni, 0.15 V, 0.001 S, 0.008 P, 0.15 Cu, 0.035 Al, the remainder being Fe and normally occurring impurities. Such a steel will have a Dl of over 400 mm.

Further modifications of the invention within the scope of the claims will be apparent to a skilled person.

Claims

1. Method for manufacturing at least one steel ring blank (18) or ring segment blank, characterized in that it comprises the steps of forging steel into a sleeve (16), and cutting said at least one steel ring blank (18) or ring segment blank from the forged sleeve (16).
2. Method according to claim 1, characterized in that it comprises the step of forging said sleeve (16) from a slab, bloom, or billet (12).
3. Method according to claim 1 or 2, characterized in that said at least one ring (18) or ring segment blank is cut to provide an outer (26) and/or inner bearing ring (24) or ring segment blank.
4. Method according to any of the preceding claims, characterized in that said at least one ring (18) or ring segment blank is cut from a position located as close to the centre (20) of the said forged sleeve (16) as possible.
5. Method according to any of the preceding claims, characterized in that said steel has the following composition in weight-%:
C 0.6-1.5
Si 0- 2.0
Mn 0-2.0
Cr 0.01-2.0
Mo 0.01-1.0
Ni 0.01-2.0
V and/or Nb 0.01-1.0 of V or 0.01-1.0 of Nb, or 0.01-1.0 of both elements
S 0- 0.002
P 0- 0.015
Cu 0-0.5
Al 0.010-1.0
6. Method according to any of the preceding claims, characterized in that said forged sleeve (16) is forged to have a final reduction ratio of 2-4.
7. Method according to any of the preceding claims, characterized in that said forging takes place at a temperature of max. 50-100°C above the recrystallization temperature of said steel.
8. Steel ring blank (18) or ring segment blank, characterized in that it is manufactured using a method according to any of the preceding claims.
9. Steel ring blank (18) or ring segment blank according to claim 8, characterized in that it is arranged to be cut to provide at least part of one of the following: a ball bearing (22), a roller bearing, a needle bearing, a tapered roller bearing, a spherical roller bearing, a toroidal roller bearing, a ball thrust bearing, a roller thrust bearing, a tapered roller thrust bearing, a wheel bearing, a hub bearing unit, a slewing bearing, a ball screw, or a component for an application in which it is subjected to alternating Hertzian stresses, such as rolling contact or combined rolling and sliding and/or an application that requires high wear resistance and/or increased fatigue and tensile strength.
10. Use of a method according to any of claims 1-7 to manufacture a steel ring blank (18) having at least one of the following: improved rolling contact properties, structural fatigue properties, increased structural strength, an increased lifetime, a lower rate of butterfly generation, a smaller average grain size, a reduced inclusion length and/or a better worked structure, as compared to a steel ring blank (14) manufactured by hot rolling.
PCT/SE2012/000176 2011-11-11 2012-11-05 Steel ring blank or segment blank and method for manufacturing WO2013070133A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
SE1100841-4 2011-11-11
SE1100841 2011-11-11

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20120846906 EP2776186A4 (en) 2011-11-11 2012-11-05 Steel ring blank or segment blank and method for manufacturing

Publications (1)

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WO2013070133A1 true true WO2013070133A1 (en) 2013-05-16

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WO (1) WO2013070133A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4393563A (en) * 1981-05-26 1983-07-19 Smith David T Cold forced sintered powder metal annular bearing ring blanks
JPS60135520A (en) * 1983-12-23 1985-07-18 Honda Motor Co Ltd Production of blank material for cold forging
US6065322A (en) * 1998-03-04 2000-05-23 Ntn Corporation Method and device for forming blanks for bearing rings
JP2007130673A (en) * 2005-11-11 2007-05-31 Sanyo Special Steel Co Ltd Manufacturing method of outer and inner ring of bearing race using in bearing steel pipe
US20090257700A1 (en) * 2006-10-03 2009-10-15 Hironobu Itoh Blank for a ring member of a bearing, manufacturing method for the same,manufacturing method for a ring member of a mearing, and bearing

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4860567A (en) * 1987-12-21 1989-08-29 United Technologies Corporation Ring forging process
FR2873940B1 (en) * 2004-08-03 2008-01-04 Snecma Moteurs Sa Process for manufacture of component parts of a hollow blade by rolling

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4393563A (en) * 1981-05-26 1983-07-19 Smith David T Cold forced sintered powder metal annular bearing ring blanks
JPS60135520A (en) * 1983-12-23 1985-07-18 Honda Motor Co Ltd Production of blank material for cold forging
US6065322A (en) * 1998-03-04 2000-05-23 Ntn Corporation Method and device for forming blanks for bearing rings
JP2007130673A (en) * 2005-11-11 2007-05-31 Sanyo Special Steel Co Ltd Manufacturing method of outer and inner ring of bearing race using in bearing steel pipe
US20090257700A1 (en) * 2006-10-03 2009-10-15 Hironobu Itoh Blank for a ring member of a bearing, manufacturing method for the same,manufacturing method for a ring member of a mearing, and bearing

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2776186A4 *

Also Published As

Publication number Publication date Type
EP2776186A1 (en) 2014-09-17 application
EP2776186A4 (en) 2015-12-02 application

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