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GOVERNMINT OF INDIA

MINISTRY OF RAILWAYS

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SCHEDULE OF TECHNICAL REQUIREMENTS FOR

TRACTION MOTOR SUSPENSION BEARINGS USED ON

BG_DE LOCOMOTIVES

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Specification No.MP- 0.2402.01 (Revision- 02)October- 2005

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RESEARCH DESIGNS & STANDARDS ORGANISATION

MANAK NAGAR, LUCKNOW - 226011

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Technical supply requirements for Traction Motor Suspension Bearings for BG Diesel Electric locomotives

Technical supply requirements for Traction MotorSuspension Bearings for BG Diesel Electric locomotives

1.0 SCOPE

1.1 This specification covers technical supply requirements of material for finishedtraction motor suspension bearings of BHEL design (Type A) and GE design(Type B). The GE design does not have anti friction metal lining on the collar.

1.2 The existing specification is being revised to incorporate Ultrasonic test as perM&C report No. K-294 (Refer Para 6.2.2)

2.0 MATERIAL

2.1 Shell: Type A backing bearing shell castings shall conform to Grade V bronze to

IS: 1458-65 (Specification for Railway Bronze Ingots and Castings. Type Bbearing shell castings shall conform to Class IV of IS: 1458-65) amendment 2E -May, 1966.

2.2 Antifriction lining: Material used for antifriction lining shall conform to Grade 84of IS: 25-66 (Specification for antifriction bearing alloys) and cast centrifugally.

3.0 CHEMICAL COMPOSITION

3.1 The chemical composition of the bronze shell casting shall be as given in table 1.

Table 1

Constituent Type A % Type B %

Tin 4.0 - 6.0 6.0 - 8.0

Lead 4.0 - 6.0 9.0 - 11.0

Zinc 4.0 - 6.0 0.5 max.

Phosphorus (max.) 0.05 0.05

Iron (max.) 0.3 0.3

Antimony (max.) 0.3 0.4

Iron & Antimony (max.) 0.5 0.5

Aluminium (max.) 0.01 0.01Total of other elements incl.Iron & antimony (max.) 0.6 0.7

Copper plus incidental nickel Balance Balance

Note: For the purpose of utilising scrap containing a high percentage of tin, it shallbe permissible for the supplier to supply tin up to a maximum of 7.0 percent.

3.1.1 Some proportion, not exceeding 50% of reclaimed bearing metal, by judiciousselection of material and adopting good melting practice, may be used for castingthe shell but it is essential to ensure that two grades of metal should not be

melted and mixed as the bearing metal.

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3.2 The anti friction metal shall have the following chemical composition;

Grade 84

Alloy Sn Sb 10 Cu 5 Alloy elements percent:Sn 84 Min.Sb 9.0 - 11.0Pb 0.3 max.Cu 5.0 - 6.0

Impurities percent maximum:Fe 0.08 As 0.1 Al 0.005Bi 0.05Zn 0.008

Cd 0.1Total of indicated impurities,percent

0.17

3.2.1 The manufacturer shall, preferably, not cast the lining out of reclaimed metal. Byadopting suitable melting practice after proper segregation of harmfulcontaminated impurities, however, 25% max. reclaimed metal can be used.

3.2.2 Manufacture of suspension bearings using old and used shell, obtained byrunning out the white metal lining, is not permissible.

4.0 PHYSICAL PROPERTIES

The material of bronze shell shall satisfy following physical requirements:

4.1 Tensile Test

The material when tested in accordance with IS: 2654-64 shall have the tensileproperties given in table-2

TABLE-2

Sl.No.

Mode of casting oftest piece

Property and unit Type A Type B

1. Sand cast (cast on) Tensile strengthMin. kgf/ mm2

Elongation Percent Min.

19.00

8

16.00

2

2. Sand cast (separatelycast)

Tensile strengthMin.kgf/mm

2

Elongation percent Min.

21.00

12

18.00

4

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5. MANUFACTURE

5.1 The bearing shell shall be carefully cast to ensure clean castings free fromharmful casting defects such as blowholes, honeycombs, overheated structures,shrinkage etc.

5.2 The surface to be lined should be either machined, ground with coarse portablegrinder or shot blasted until the surface is bright all over. After ensuring that thesurface preparation is complete, the shells should be degreased with hot causticsoda (10 - 15%). The temperature of the alkaline solution bath should be about60 to 70 deg.C. The shells shall be thoroughly washed in running water.

5.3 Following checks shall be carried out on the bearing shell before proceeding forantifriction metal lining:

1. Check for important overall dimensions2. Check for cracks.

5.4 Freshly prepared flux is to be used before tinning. Either of the two methods oftinning i.e. by immersion of the shell in the bath of molten tin/solder and by theuse of stick of pure tin/solder can be used. During tinning, the bath temp. shouldbe kept as low as possible, 270

0C to 280

0C for pure tin, 220

0C to 230

0C for

60/40 solder and the shells should be withdrawn immediately, as the desirablefluid coating is obtained.

5.5 The anti friction metal lining shall be provided by centrifugal casting methodFollowing safeguards shall be built into the system to obtain clean, densematerial free from porosities, oxides shrinkage cavities etc. with highest degree ofbond strength-

(i) Quick chilling and rapid rotation shall be ensured so that fine crystals areproduced in the white metal.

(ii) The process and QC procedures should be such as to reduce the problem ofsegregation due to centrifugal action.

5.6 After completing the lining, the bearing shall be accurately machined to thedimensions and tolerances specified in the drawing.

6.0 INSPECTION

6.1 Each finished bearing shall be subjected to the following checks apart from tests

stipulated in IS:1458-65 and IS:25-66.

6.1.1 Dimensional check - All important dimensions shall be checked with the drawingto ensure that these are within permissible limits. Bearings not conforming to thedimensions shown in the drawing shall be rejected.

6.1.2 The manufacturer shall install a suitable fixture in which a finished suspensionbearing complete can be fitted and tightened to the stipulated torque on thetraction motor. The dimensions and the ovality of the bearing bore shall be withinthe specified limit when the same is checked on this fixture. This test should bedone on sampling basis as per the sampling plan given in clause 6.2.3.

6.2 Following tests shall be conducted to check the quality of bond between the whitemetal lining and bronze shell.

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6.2.1 Ringing test - The bearing shall be suitably suspended and tapped with ahammer. The sound emitted shall have a ringing tone. The bearing giving adull sound as obtained in grey cast iron or castings having internal defects shalbe rejected.

6.2.2 Ultrasonic test - The quality of bond between the anti friction lining and thebearing shell, shall be tested ultrasonically according to 'Metallurgical andchemical report no. K-294' for Standardisation of ultrasonic testing technique ofsuspension bearings of traction motor type 165 of WDM2 locomotive (Copyenclosed).

6.2.3 In addition to the ultrasonic test on 100% basis, liquid penetrant test on edgesand corners, shall be done as a sample check. Sampling shall be done byrandom selection of at least two bearings for a lot of 100 bearings or less and twobearings per 100 bearings for a lot of 101 bearings or more.

7.0 TEST CERTIFICATE AND MARKING

7.1 Manufacturer/supplier shall provide test certificate giving test results coveringchemical composition and mechanical properties of material.

7.2 Each bearing shall be legibly marked with the following particulars as specified inthe drawing furnished by the purchaser:

(i) Manufacturer’s/Supplier's identification/trade mark

(ii) Serial number of the suspension bearing.

(iii) "UT" stamp against the serial number, on each bearing to indicate that thebearing has passed the ultrasonic test.

8.0 PACKING

Each set of bearing shall be packed in an individual wooden box. A woodenpartition shall be kept between the two halves in order to avoid any chance ofone hitting the other piece. The wooden piece and the two halves shall besecured tightly by packing strips. Further each half shall be packed in bubble airpacking.

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UDC 620. 179. 16: 625. 2.01 For official use only

GOVERNMENT OF INDIAMINISTRY OF RAILWAYS

RESEARCH DESIGNS AND STANDARDS ORGANISATIONLUCKNOW

STANDARDISATION OF ULTRASONIC TESTINGTECHNIQUE OF SUSPENSION BEARINGS OF

TRACTION MOTOR TYPE 165 OF

WDM-2 LOCOMOTIVES

METALLURGICAL AND CHEMICAL REPORT NO. K-294

Printed MAY 1984

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This report is based on ultrasonic tests conducted by the Metallurgical and ChemicalDirectorate of RDSO. Every care has been taken in recording data accurately and in

analyzing it objectively. The views expressed in this report are subject to modification from

time in the light of fresh data. Further, they do not necessarily represent the views of theMinistry of Railways (Railway Board), Government of India.

This report is the property of the RDSO and is meant essentially for official use. It

may not be loaned, reproduced in part or in full, or quoted as an authority without the permission of Director General, RDSO, Lucknow.

K. N. Gupta

Director (M & C)

B. B. AjmaniAdditional Director (Met.)

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C O N T E N T S

S. No. Description Page

1. Scope . . . . . . . . . 1

2. Equipment required . . . . . . . 1

3. Surface finish . . . . . . . . 1

4. Testing procedure . . . . . . . . 1

5. Limit of acceptance . . . . . . . . 2

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STANDARDISATION OF ULTRASONIC TESTING TECHNIQUE OF SUSPENSIONBEARINGS OF TRACTION MOTORS TYPE 165 OF WDM-2 LOCOMOTIVES.

This code of procedure describes the details of ultrasonic testing technique to evaluate

the quality of the bond between white metal and bronze shell of suspension bearing of

traction motor type 165 of WDM-2 locomotives.

1. SCOPE: The code describes the testing technique to evaluate the quality of the bond between “White Metal” and “Bronze Shell” of suspension bearing of traction motors type

165 WDM-2 locomotive.

2. EQUIPMENT REQUIRED

2.1 ULTRASONIC FLAW DETECTOR: Model UFD-67 of ECIL or FD-201A of vibronicsor any other having similar characteristics may be used.

2.2 PROVE: 2 MHz, 20mm diameter, double crystal lead zirconate-titanate as supplied by

ECIL or any other equipment having similar characteristics.

2.3 CALIBRATION BLOCK: International Institute of Welding Block or 25 mm thick

block of class 4 steel to IS: 1875- 1971, forged normalized and rough machined. Both end-

faces shall be parallel.

2.4 ACOUSTIC COUPLANT: Lubricant grease conforming to grade 2 or 3 of IS: 507-1967.

3. SURFACE FINISH: The testing of the bearings should be conducted preferably beforemachining the white metal. This will eliminate unnecessary marching of defective bearings.The surface should be smooth to ensure good coupling.

4. TESTING PROCEDURE

4.1 Calibration: Calibrate the time scale to 10 mm per main scale division.

4.2 Calibration in terms of bronze/white metal: The following velocities should be taken

into consideration:

(i) Velocity of ultrasonic waves in steel = 5.9 x 106 mm/sec.

(ii) Velocity of ultrasonic waves in bronze = 3.83 x 106 mm/sec.

(iii) Velocity of ultrasonic waves in white metal = 2.16 x 106 mm/sec.

(iv) Velocity of ultrasonic waves in perspex = 2.73 x 106 mm/sec.

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(a) Ratio of the velocity of ultrasonic waves, steel to bronze =6

6

1083.3

109.5

x

x

= 1.5

(b) Ratio of the velocity of ultrasonic waves, steel to white metal =6

6

1016.2

105.59

x

x

= 2.7

(c) Ratio of the velocity of ultrasonic waves, steel to perspex =6

6

1073.2

109.5

x

x

= 2.2

The ultrasonic waves have to traverse through the Perspex of 10 mm thickness (in the case of

ECIL probe used), white metal of 1.5-1.6 mm thickness and bronze of 17.22 to 17.31 mm

thickness. The thickness in terms of steel is as below:

(a) Thickness of perspex in terms of steel = 10 x 2.2= 22 mm

(b) Thickness of white metal in terms of steel = 1.5 x 2.7= 4.05 mm

(c) Thickness of bronze in terms of steel = 17.3 x 1.5= 26.0 mm

The total path travelled by ultrasonic waves in terms of steel is 22.0 plus 4.0 plus 26.0= 52mm (approximately). The thickness in terms of steel for flange portion having 27.5 mm thick

bronze base and 35 mm thick white metal lining works out to 72.0 mm approximately.

4.3 SENSITIVITY: The sensitivity of the equipment should be adjusted so as to give fourfull screen height back echoes from 25 mm thick portion of IIW block.

4.4 SCANNING: Clean the white metal surface and apply to couplant. Place the prove overthe white metal surface and scan the complete area. While scanning, the prove should be kept

2-3 mm away from the edge of the bearing to avoid stray signals.

4.5 TRACE PATTERNS: The trace patterns as obtained from sound bond are given in Fig.1 and 2. Fig. 3 shows the pattern obtained from a bad bond. A defective bronze shell will be

give an abnormal pattern on the lines shows in Fig. 3A.

5. LIMIT OF ACCPTANCE

5.1 MAIN BEARING (SHELL PORTION): The sum total of the poor bond areas shall notexceed 10% of the total bearing area, provided the largest individual defect is not more than

625 sq. mm and the defects are separated from each other by at least 50 mm and situated atleast 10 mm away from the edge. The standard test plate for comparison purposes is shown

in Fig. 4.

5.2 FLANGE: In the dovetail portion of the flange upto 25%, poor bond is allowed, providedthere is no poor bond within 15 mm circumferential length near the horizontal joint and such

areas are distributed and the largest individual poor bond area does not exceed 26 mm in

length.In remaining area of the flange leaving the dovetail portions, maximum of 20% poor bond is

allowed provided there is no poor bond within the 25 mm circumferential length near the

horizontal joint and the largest individual poor bond does not exceed 25 mm in length.

GIPN-S5-477 RDSO Luck/83-1.6.84-350

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This report is based on the work carried out by:

O. P. Srivastava, Ex- Assistant Director (NDT)

C. L. Piplani, Ex-Chief Research Assistant (NDT)

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