Axle Box and Brg

8/18/2019 Axle Box and Brg

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SPECIFICATION NO. MP- 0.3600-01

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GOVERNMENT OF INDIA

(MINISTRY OF RAILWAYS)

SPECIFICATION FOR TECHNICAL SUPPLY CONDITIONS FOR

LOCOMOTIVE AXLE ROLLER BEARINGS AND AXLE –BOXES

NOVEMBER, 1981.

(REVISED)

ISSUED BY

MOTIVE POWER DIRECTORATE

RESEARCH DESIGNS & STANDARDS ORGANISATION

MANAK NAGAR, LUCKNOW-226011.


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CONTENTS

S.No. Description Page No.

1. Scope 1

2. Definitions 1

3. Applicable Documents 1

4. Contractor’s Responsibilities 3

5. Contract Drawing 4

6. Technical Requirements 4

7. Quality Assurance 9

8. Approval for Deviations 9

9. Appendix-A (Procedure for acceptance inspection of roller

bearing)

A1 to A7

10. Appendix-B (General aspects for inspection of axle-boxes). B1 to B2.


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Specification No. MP.0.3600-01

Specification for Technical Supply conditions for

locomotive axle roller bearings and axle-boxes.

1. SCOPE :

1.1 This specification covers the manufacture, supply, installation and inspection of thelocomotive axle roller bearings and axle-boxes. It specifies technical requirements, properties and tolerances and provides relevant inspection method applicable toacceptance inspection.

2. DEFINITIONS :

Throughout this specification the terms :-

2.1 “Purchaser” means the President of the Republic of India or his nominee.

2.2 “Engineer” means the Research, Designs & Standards Organisation, Ministry ofRailways, Manak Nagar, Lucknow-226011.

2.3 “Inspecting Officer” means the person (s), firm (s) or Department (s) or his deputiesnominated by the purchaser to inspect the stores on his behalf.

2.4 “Contractor” means the person, firm or company with whom the order for the supply ofthe stores has been placed.

2.5 “Sub-Contractor” means any person, firm or company from whom the Contractor may

obtain any material or fittings to be used in the supply of or manufacture of stores.

2.6 “Contract Drawings” or “Exhibited Drawings” means the drawings which are exhibitedor specified for the guidance of the contractor.

2.7 “Approval given to the drawings by the Engineers” means the approval to the generaladaptability of the design features. The Engineers shall not be responsible for theefficient performance of the design offered, the correctness of the dimensions indicatedon the drawings, the materials used or the strength and performance of the parts for all ofwhich the Contractor shall be wholly and completely responsible. The Contractor shall,when submitting proposals for the approval of the Engineers, draw specific attention to

any deviation or departure from the specifications involved in his proposals.

2.8 “Standard Specifications” means Indian Railway Standard Specifications (IRS), IndianStandard Specification (IS) and/or any other standard specifications.

3. APPLICABLE DOCUMENTS:

3.1 Relevant drawing(s) of the Engineers for the governing dimensions, axle-load, speedswheel diameter, un sprung weight, dynamic-augment, etc.

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3.2 Specifications and Standards :-

The following specifications and standards, of the issues in effect on date of invitation of bids or request for proposal, shall form part of this specification to the extent specifiedherein :

3.2.1 IS : 3823 Part 2 Methods of Evaluating Static Load Ratings of RollingBearings.

3.2.2 IS:3824 Part 2 Methods of Evaluating Dynamic Load Ratings ofRolling Bearings.

3.2.3 IS:4397 Cold Rolled Carbon Steel Strips for Ball and RollerBearing Cages.

3.2.4 IS:4398 Specification for Carbon Chromium Steel for themanufacture of balls, rollers and bearing races.

3.2.5 IS:5935 Radial Internal Clearances in Unloaded Radial RollingBearings.

3.2.6 IS:5669 General Plan of Boundary Dimensions for RadialRolling Bearings.

3.2.7 IS:5692 Tolerances for Radial Rolling Bearings.

3.2.8 IS:6453 Technical Supply Conditions for Rolling Bearings.

3.2.9 IS:7460 Tolerances for Tapered Roller Bearings.

3.2.10 IS:7461 General Plan of Boundary Dimensions for TaperedRoller Bearing.

3.2.11 IS:3073 Assessment of Surface Roughness.

3.2.12 IS:1586 Method for Rockwell Hardness Test (B & C Scales) forSteel.

3.2.13 IS:4163 Method for determination of inclusion content in steel by microscopic method.

3.2.14 ISO:R1160 International Standards Organisation RecommendationsISO Recommendation No. R 1160 on Roller Bearingsfor Railway Axle-boxes – Acceptance Inspection.

3.2.15 IRS M2 Indian Railway Standard Specification for Steel Casting.

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4. CONTRACTOR’S RESPONSIBILITIES :

4.1 The Contractor shall be completely responsible for the execution of the Contract inaccordance with this specification and for the satisfactory and efficient performance ofthe Roller Bearings in service, notwithstanding any approval which the Engineers or theInspecting Officer may have given to :

4.1.1 the drawings prepared by the Contractors and the design features incorporated;

4.1.2 Assemblies, sub-assemblies and components during the course of manufacture atthe contractor’s/Sub-Contractor’s Works;

4.1.3 The sub-contractors for any material or fittings;

4.1.4 Other parts of the work involved in the contract;

4.1.5 The tests carried out either by the Contractor, the Engineers or the Inspecting

Officer.

4.2 The Contractor shall further, notwithstanding any exercise by the Inspecting Officer ofthe power of superintendence, be responsible for the sufficiency of packing, marking etc.,of all the parts of work to ensure their delivery without damage. The Contractor shallcomply with the instructions of the Inspecting Officer, if in his opinion further precautions than those taken by the Contractor are necessary for the proper execution andsafe delivery of all the parts of the work.

4.3 The Contractor shall at his expense replace any part of the roller bearings and axle boxesfailing or proving unsatisfactory in service and attributed to defective/faulty design,defective material or bad workmanship, within a period of 36 months or 3,60,000 kmsfrom the date of its commissioning into service. The period of warranty shall standextended by the duration for which the roller bearings remain inoperative under exerciseof this clause. Further, should any design modification be made in any part of the deviceas a result of any defect/fault/lacunae/shortcoming in the original design features, the period of 36 months would commence from the date the modified part is commissionedinto service. The sole judge in this regard will be the Engineers.

4.4 In the event of the Contractor failing to carry out any work for which he is liable underthe above clause within a reasonable time, or if in the opinion of the Engineers theurgency of the case demands it, the Purchaser, without prejudice to his other rights underthe Contract, may carry out the work himself at the expense of the Contractor.

4.5 The Contractor shall submit a list of components and equipments that is included in hisscope of supply.

4.6 The Contractor shall supply a list of materials with quantities and facilities that would beneeded from the Purchaser for installation and satisfactory operation of his equipment.

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5. CONTRACT DRAWINGS :

5.1 The Contract Drawings and any other Drawings provided by the Engineers for guidanceare not guaranteed to be free from discrepancies and may be modified to suit therequirements as subsequently directed by the Engineers. It shall be the responsibility ofthe Contractor to ensure that the working drawings prepared by him are free from suchdiscrepancies as are likely to effect the satisfactory performance/maintenance of the roller bearings.

5.2 No modifications to the Contract Drawings or any other approved Drawings shall bemade except with the prior approval of the Engineers.

6. TECHNICAL REQUIREMENTS :

6.1 Approval /Supply of drawings and Maintenance Manual :

6.1.1 The Contractor shall prepare, from the Contract Drawings and from the instructions of

the Engineers, complete working drawing in metric units giving assembly andcomponents details of roller bearings and axle-box, at his own cost, which shall besubmitted for approval to the Engineers before the work to which they relate iscommenced.

6.1.2 When submitting the drawing of a particular detail, other details depending on it shall beshown in juxtaposition and sufficient drawings of surrounding details shall be submittedto enable the design to be judged.

6.1.3 All drawings shall be fully dimensioned. The requisite tolerances shall be shown on eachdimension of the detailed drawings and the condemning sizes of wearing parts shall also

be shown against the relevant dimensions.

6.1.4 Material specification for each component shall be indicated on the relevant drawings. Ifthese are other than the IS or IRS, then copies of such specifications, in English, shouldthe original be in a foreign language, shall be supplied to the Engineers in duplicate.

6.1.5 Full calculations in support of the design capacity (load rating) and life expectancy of theRoller Bearings shall be offered.

6.1.6 Tests according to the standard specification or as proposed by the Contractors to whichthe components and the assembly will be subjected to by the Contractor at his cost toestablish the quality of the product and its satisfactory working, shall be indicated in the

drawings.

6.1.7 A copy of the proposed Maintenance Manual shall be supplied incorporating thefollowing information :-

a) Description of the bearings.

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b) Procedure for initial mounting and lubrication of the bearings indicating quantityof lubricant per box.

c) Maintenance checks in service such as grease topping, bearing examination, sealchange and grease change, etc. between major examination.

d) Procedure of bearing extraction, examination and assembly, special tools, if any,for this purpose.

e) Initial and condemning limits for components.

f) The types/brands of suitable grease/lubricants (also refer to clause 6.8).

6.1.8 Particulars of laboratory and field tests carried out on the bearings offered, either by theContractor or by Railway Organisations were similar bearings have been applied, shall besupplied to the Engineer.

6.1.9 Based on the information supplied above, and any other information that may be required by the Engineers, the design shall be approved by the Engineers.

6.2 Design Requirements :

The roller bearings shall generally conform to the technical supply conditions for roller bearings as per IS: 6453*.

6.2.1 Materials :

6.2.1.1 Roller and bearing races shall be manufactured from suitable material conforming toIS:4398**. However, should the Contractor want to use any other material, sufficient

information about the alternative material shall be furnished and the same approved bythe Engineers.

6.2.1.2 Bearings shall be fitted with cages to Contractor’s standard execution. Cold rolled

carbon steel strip cages shall conform to IS:4397@

. The Contractor may use non-alloy

steel or copper alloys or any other material for the cages, with the approval of theEngineers.

6.2.1.3 The materials for the axle-box and other fittings, such as throwers, end covers etc. shallconform to relevant Engineers drawings (Refer Clause 3.1).

--------------------------------------------------------------------------------------------------------

* Technical Supply Conditions for Rolling Bearings.

** Specification for Carbon Chromium Steel for the manufacture of balls, rollers and bearing races.

@ Cold Rolled Carbon Steel Strips for Ball and Roller Bearing Cages.

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6.2.1.4 The metal employed for roller bearings shall be free from defects, such as pipes, seams,laminations, excessive inclusion of non-metallic impurities and such other internaldefects as would render the material unsuitable for the purpose for which it is intended.On microscopic examination, it shall show fine grain size and shall be free from signs ofoverheating.

6.2.2 Dimensions and Tolerances :

6.2.2.1 For Roller Bearings :

The dimensions, tolerances and internal clearances shall conform to IS:5669,IS:5692, IS:5935, IS:7460 & IS:7461 or any other published internal standards. Thespecific series or groups adopted in the design shall be shown in the Contractor’sdrawings.

6.2.2.2 For axle boxes :

These shall conform to the approved Contractor’s drawings.

6.2.3 Surface Finish :

The outer rings, the inner rings and the sides of the roller bearings shall have themaximum values of surface finish as specified in IS:6453*, when measured in

accordance with IS:3073@@

.

6.2.4 Hardness :

The rings and the rollers should have the hardness Rock Well C Hardness (HRC) of 57 ≤ HRC ≤ 66.

6.2.4.1 Rings :

The hardness values measured on one ring should not differ by more than 3 HRC units.

6.2.4.2 Rollers:

The hardness values measured on three rollers of one bearing should not differ by morethan 3 HRC units.

--------------------------------------------------------------------------------------------------------

* Technical Supply Conditions for Rolling Bearings.

@@ Assessment of Surface Roughness.

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6.2.5 Load Ratings :

6.2.5.1 The load ratings of bearings shall be computed in accordance with IS:3823$ and

IS:3824$$

.

6.2.5.2 The minimum B10 life rating of the roller bearing, shall be as follows :

BG Mixed Traffic loco : 4.50 x 106

kms

BG Goods loco : 2.56 x 106 kms

MG Mixed Traffic loco : 2.56 x 106 kms

MG Goods loco : 1.61 x 106 kms

Note : The Kilometers pertain to those travelled by locomotive wheels.

6.2.6 Running Noise:

The level of the running noise of the roller bearings shall be as agreed to between theContractor and the Purchaser.

6.2.7 Interchangeability:

The components of the bearings i.e., races and the rollers should normally be fullyinterchangeable.

6.3 Workmanship:

6.3.1 The rolling elements shall be free from defects of workmanship, which may affect theirserviceability.

6.3.2 The surfaces for the bore, outside diameter, sides and load carrying areas shall be smoothand shall not show any damaged areas due to corrosion.

6.4 Retouching:

No retouching shall be made without the Purchaser’s agreement. Any retouching withthe purpose of concealing a defect is not permitted.

------------------------------------------------------------------------------------------------------

$ Method of Evaluating Static Load Ratings of Rolling Bearings.

$$ Method of Evaluating Dynamic Load Ratings of Rolling Bearings.

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6.5 Marking:

Each bearing should carry on the side face of one of its rings (of both rings, if thecomponents are separable), visibly and indelibly, the following markings :

6.5.1 Contractor’s trade-mark ;

6.5.2 Complete designation of the bearing, defining type; dimensions, radial internal clearancesetc.;

6.5.3 Year of manufacture with batch number.

6.6 Protection against corrosion:

The type of protection against corrosion shall be decided by the Contractordepending on the packing material used. Under proper storage conditions, the anti-corrosive treatment shall be effective for at least 12 months in order to ensure a

satisfactory functioning of the rolling bearings.

6.7 Packing and labeling :

6.7.1 The bearings shall be suitably packed to prevent damage during transit and handling.

6.7.2 The packages should carry the following markings:

a) Contractor’s trade-mark;

b) Complete designation of the bearing, defining the type, dimensions, radial internalclearance etc;

c) Manufacturing or packaging date with batch number.

6.7.3 In case non-interchangeable components of a bearing are packaged in different boxes, thelatter should be tied together so that they cannot be separated before the bearing is used.Additionally, the boxes should carry any reference marks necessary to enable re-assembly of the bearing.

6.8 Lubrication:

6.8.1 The lubricant recommended for use shall be normally available in India.

6.8.2 The bearing shall be capable of working for a minimum period of three years without anyexamination or grease change.

6.8.3 No attention (including grease topping) shall be required between two examinations. Ifthis requirement can not be met by the Contractor, he shall submit specificrecommendations regarding minimum period for (i) grease topping, (ii) bearingexamination, (iii) seal change and (iv) grease change to the Engineers for acceptance.

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6.8.4 The Contractor shall be responsible for correct mounting, locking and initial lubricationof the roller bearings.

7. QUALITY ASSURANCE:

7.1 Acceptance Inspection:

The procedure for acceptance inspection of roller bearings is given at Appendix ‘A’.General aspects for axle box inspection are given at Appendix ‘B’ for guidance.

7.2 The whole of the material or fittings used in the construction of the work shall be subjectto inspection by the Inspecting Officer and shall be to his entire satisfaction.

7.3 The Inspecting Officer shall have the power to :

7.3.1 Adopt any means he may consider necessary to satisfy himself that all the materials orfittings specified are actually used throughout the construction;

7.3.2 Visit at any reasonable time and without previous notice, either Contractor’s Works or hisSub-Contractor’s Works to inspect the manufacture and quality of the work at any stage;

7.3.3 To reject any material or fittings that do not conform to the relevant standardspecifications or have not been manufactured in accordance with approved practices.The rejected materials or fittings shall be marked in a distinguishable manner and shall bedisposed off in such a manner as the Inspecting Officer may direct.

7.4 Tests of materials and fittings shall, as far as possible, be carried out at the Works of theMakers of the material or fittings. The Contractor shall provide, free of charge, suchmaterials or fittings as may be required for testing, or arrange for test pieces to beincorporated in forgings and castings as required by the Inspecting Officer.

7.5 The Contractor shall provide, free of charge, labour and appliances required by theInspecting Officer for inspecting and testing of the whole of the work under the Contract,whether inspected at his own or his Sub-Contractor’s premises, and shall make provisionsin his orders to his sub-contractor’s for the inspection and testing of materials or fittingsat their works, unless permission is given by the Inspecting Officer for the same to beinspected after delivery at the Contractor’s Works.

7.6 All materials and fittings required for tests and analysis shall be selected by theInspecting Officer, and these tests shall be carried out in his presence. No test piece shall

be cut from any material or fittings until it has been stamped with such identifying marksas the Inspecting Officer may require.

8. APPROVAL FOR DEVIATIONS :

Specific approval of the Engineers shall be obtained for any deviations from thisspecification.

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APPENDIX A

Specification No. MP.0.3600.01

PROCEDURE FOR ACCEPTANCE INSPECTION OF ROLLER BEARINGS

A.1 SAMPLING:

A1.1 Presentation of the delivery

On completion of manufacture, the bearings are presented for inspection ready foruse. According to previous agreement between Purchaser and contractor, bearings may

be presented lubricated or unlubricated, packaged or unpackaged.

Bearings with the same designation, belonging to the same manufacturing batch

and presented at the same time, constitute a lot.

A1.2 Sampling procedure

Each bearing is checked for :

A1.2.1 Dimensions and appearance,

A1.2.2 Functioning –

The Purchaser then selects at random from each lot presented, the bearingsintended for the sampling inspection described in clause A2 and marks them indelibly.

The number of sample bearings is indicated in the table below.

The bearings selected for sampling inspection should be degreased, if necessary.

Table – Number of samples

No. of bearings in the lot No. of bearings to be selected for tests

Upto 100 2 *

From 101 to 250 3

Over 250 4

* The number of bearings to be selected from a lot equal to or less than 50 bearings issubject to agreement between Purchaser and Contractor.

The dimensions and tolerances of the bearings should be as stated on the drawingsfurnished by the contractor (refer clause 6.2.2).

Appearance : All essential portions of the roller bearings should be clean and free fromdefects such as porosity, burrs, hardening cracks, grinding marks, indentations, rust

marks etc.

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Surfaces other than –

Those portions of the roller faces which are not in contact with the ring ribs,

The roller chamfers, and

The reliefs at the ends of the outer and inner ring raceways should be smooth.

A2. SAMPLING INSPECTION:

A2.1 Place of inspection :- Inspection of the bearings is carried out at the contractor’s premises, except for the examination of inclusions and chemical analysis, which, unless

otherwise specified, are carried out in the Purchaser’s Laboratory.

A2.2 Inspection of raw material :- The material should be antifriction bearing steel

conforming to SAE 52100 or IS.4398-1972, type two grade 103 Cr. 2. Test report to be

furnished by the manufacturers.

Microstructure and inclusion content of the material should conform to thestipulation laid down in IS:4398.

A2.3 Inspection of appearance :- The examination is carried out visually (without

magnification).

A2.4 Inspection of dimensions, radial runout and radial internal clearance

A2.4.1 General

Temperature : Measurements are carried out at the ambient temperature. The gauges

and measuring instruments and the parts to be inspected should be stabilised at thistemperature before any test is carried out.

Gauges : The gauges operating by contact (dial gauge) should be provided with a

plunger contact of spherical form, having a minimum curvatures radius of 2.5 mm.

The force exerted by the dial gauge on the bearing should not exceed 3.3 N

(approximately 340 gf).

Reference side :- The following are considered as reference sides :-

- on symmetrical rings, the side opposite the bearing designation marking,

- on asymmetrical rings, the side intended as the thrust side.

If these criteria are not sufficient to identify the reference side, the Contractor shoulddesignate the reference side on the bearing drawing.

A2.4.2 Bore diameter d (cylindrical bore) and outside diameter D

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For these measurements the bearing should preferably be placed on a substantially

horizontal plane surface (see fig. 1 and 2).

The measurements are made in two planes parallel to the sides and at a distance of

2r from the adjacent side (r = nominal ring chamfer dimension).

For both dimensions d and D, the smallest single diameter (dmin and Dmin.) and

the largest single diameter (dmax and Dmax) found in either of the two planes are

determined, using a measuring instrument with two points of contact. The mean

diameter (dm

and Dm

) of a ring is the arithmetical mean value of the smallest and the

largest single diameter.

2

maxmin d d dm

+=

2

maxmin D D Dm

+=

A2.4.3 Inner ring width and outer ring width : (Except for tapered roller bearings where the

bearing width is measured).

For both the rings, the distance between the side faces is checked using a

measuring instrument with two points of contact. At every point the distance should be within the stipulated limits.

A2.4.4 Inner ring width variation:- The variation is placed on three equal-distance supports

which are in contact only with the inner rings (see fig. 3)

A dial gauge is applied to the middle of the inner ring side face directly above one

of the supports. A guide centres the bearing.

The width variation is equal to the total variation of the dial gauge reading during

one revolution of the inner ring.

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A2.4.5 Radial run-out of inner and outer rings in the assembled bearing.

Cylindrical roller and self aligningroller bearings

Tapered roller bearings.

The bearing is mounted without

clearance or deformation on a tapered *mandrel set horizontally between

centres (see fig. 4)

The bearing is mounted without clearnace

or deformation on a tapered* mandrel setvertically between centres (see fig. 5).

* Taper of about 0.03 mm on diameter per 100 mm length. If the bore is slightly

tapered, its taper should be positioned in the same direction as that of the mandrel.

Beforehand, the radial runout of the mandrel should be measured and located, and thereadings of the dial gauge corrected, if necessary.

A dial gauge is placed in contact with the outer ring outside surface in the plane

containing the middle of the raceway.

On cylindrical roller bearings without ribs, tapered roller bearings and self-aligning roller bearings, the outer ring should be guided laterally.

(a) Radial runout of inner ring (all bearing types). The radial runout is equal to the

differences between the maximum and the minimum reading of the dial gauge in contactwith the outer ring, when rotating the mandrel and the inner ring through one revolution,

the outer ring being stationary.

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(b) Radial runout of the outer ring (all bearing types). The radial run out is equal to the

difference between the maximum and the minimum reading of the dial gauge in contactwith the outer ring, when rotating this ring through one revolution the inner ring being

stationary.

For tapered roller bearings other equivalent methods may be used for this inspection.

A2.4.6 Radial runout of inner and outer ring raceways :

The ring is placed on an inclined plane surface and is guided in its bore at two

points situated in a plane parallel to the supporting surface and containing the middle of

the roller raceway. A dial gauge is applied to the outside surface of the ring in line with

one of the internal guides (see fig. 6).

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The radial runout is equal to the difference between the maximum and the

minimum reading of the dial gauge when rotating the ring through one revolution.

A2.4.7 Radial internal clearance :- (except for tapered roller bearings).

With the bearing standing on a reasonably horizontal plane surface, the clearance

in the upper part of the bearing, between the two rollers adjacent to the vertical planeand either the outer ring or the inner ring as applicable, should be measured with feeler

gauges of known thickness (see fig. 7).

Three measurements should be carried out, the outer ring being rotated through

1200 between measurements while the inner ring is kept stationary.

The bearing clearance is the arithmetical mean value of the clearances measrued.

For double row roller bearings, these measurements are made on both rows.

A2.4.8 Interchangeability of inner ring of cylindrical roller bearings :-

In a given complete bearing the inner ring is changed and the radial internalclearance measured according to clause A2.3.7.

A2.5 Magnetic particle testing :- The test is made on both rings and three rollers of each bearing. It should be made according to a method agreed upon by the Purchaser andthe Contractor.

The rings and rollers should not show any signs of cracks or harmful defects.

A2.6 Hardness testing :- The test is carried out according to the Rockwell hardness test

(B&C scales) for steel (IS:1586*).

A2.6.1 Rings : The test is made on both rings of each bearing. The Rockwell hardness ismeasured on one of the side faces of the ring at both ends of two diameters pendicular

to each other. In each of the four checked areas two measurements, giving compatible

results, should be made.

---------------------------------------------------------------------------------------------------* Method of Rockwell hardness tests (B & C scale) for steel.

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A2.6.2 Rollers : The test is made on three rollers of each bearing. The Rockwell Hardness is

measured at one point on the surface of one end of the roller.

In each checked area two measurements, giving compatible results, should be made.

The rings and rollers should have Rockwell C hardness of 57 ≤ HRC ≤ 66.

A2.7 Expansion testing of inner rings:- The test involves the expansion of the bore of the ring

by means of a tapered mandrel. The expansion should be such that the bore diameterincrease is 0.0015 times the bore diameter. The expansion should be rapid. The use of

an eccentric press is considered suitable and it is recommended that necessary

precautions be taken during the test, since ejected frangments, if fracture occurs may be

dangerous. An equivalent method may be used.

After the completion of the test, the ring should show no signs of failure.

A2.8 Examination of structure and carburisation :- The examination is made on both rings

and three rollers of each bearing. The ring or the roller is fractured by a method chosen by the contractor and accepted by the Engineers during the qualifying procedure to

show the structure of a brittle fracture. A reagent may be used to permit accurate

measurement of the thickness of the carburised layer.

The fractured sections should not show any discontinuity, laminations, flaws,shrinkage cavities or other material defects. When case-hardening is one of the

manufacturing operations, the thickness of the carburised layer should be in accordance

with the specifications.

The structure is examined visually (without magnification).

A2.9 Chemical analysis :- The chemical analysis is made on both rings and one roller from

each bearing. A piece of one of the fragments, having a minimum mass of 50g. isanalysed in accordance with the national standards of the Purchaser.

Analysis results should correspond to the chemical compositions stipulated in theapproved drawings.

A2.10 Surface finish :- This shall conform to clause 6.2.3 of the specification.

A3. CRITERIA FOR ACCEPTANCE :

Any deviation from the stipulations found by inspection of a sample bearing mayresult in the rejection of the corresponding lot.

Where the Purchaser is agreeable to repeat his tests, the number of bearings to be

submitted for these further tests should be determined by special agreement betweenPurchaser and Contractor.

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APPENDIX B

Specn. No. MP-0.3600.01.

GENERAL ASPECTS FOR INSPECTION OF AXLE BOXES

(FOR GUIDANCE OF INSPECTORS)B1. Material :

The material shall conform to clause 6.2.1.3 of this specification. The casting

shall be free from defects like spon iness, blow and pin holes and sand inclusions, etc.

B2. Dimensional and Squareness Checks, etc. of axle-boxes :

2.1 The dimensions of the axle box shall conform to relevant approved drawings.

2.2 The following main aspects of the axle box needs maticulous cheking:-

a) Wall thickness – At a number of locations.

b) Bore – Size, taper, ovality and surface finish of bore.

c) Bearing Seating Face – Distance from end face for ensuring central location of the bearing to journal i.e. main bore depth is checked.

d) Spring Seat – Size, depth, centrality of springs seat to the journal centre and alsoto the horn faces and height of spring seat from the journal centre line.

e) Horn Face – Horn distance, parallelism of the faces and squareness of the faces to

the spring seat.

f) Horn Check Faces – Lateral location (distance from the box front face to the

check face), squareness of check faces to horn faces.

g) Thrower End Bore – Sizes for adequate clearance from thrower after assembly.

B3. Dimensional checks for loose components :

Thrower, end cover, locking plates, etc. shall conform to dimensions of relevant

approved drawings.

B4. Assembled Boxes :

a) Diametrical clearance at the journal portion - The clearance should be within permissiblelimits and also be uniform all round.

b) Clearance between the thrower and thrower end cover of the box should be adequate.

c) Centrality and parallelism of the horn faces to the axle of the journal.

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d) Free rotation of the individual rollers and also of the box on the journal.

e) Proper greasing of roller bearings and the boxes.

f) Painting of the assembled boxes after end cover fitting.

g) Proper protection and storage to prevent any rusting of the boxes or bearings.

Axle Box and Brg

Documents

Transcript of Axle Box and Brg