WD-14-ABR-2007
(Supersedes WD-14-ABR-2000)
GOVERNMENT OF INDIA
MINISTRY OF RAILWAYS
SPECIFICATION FOR NON-ASBESTOS
‘K’ TYPE COMPOSITION
BRAKE BLOCKS FOR FREIGHT STOCK
OF INDIAN RAILWAYS
WD-14-ABR-2007
ISSUED BY
RESEARCH DESIGNS AND STANDARDS ORGANISATION
MINISTRY OF RAILWAYS
LUCKNOW
February, 2007 PRICE: RS.
SPECIFICATION FOR NONASBESTOS ‘K’ TYPE COMPOSITION BRAKE BLOCKS FOR FREIGHT STOCK OF INDIAN RAILWAYS
- SCOPE
This specification covers the technical requirements of non-asbestos ‘K’ type composition brake blocks for application on freight stock of Indian Railways. These brake blocks have a high co-efficient of friction and called ‘K’ type brake blocks.
- REQUIREMENTS
2.1GENERAL
2.1.1‘K’ type brake blockshave an average co-efficient of friction of approximately 0.25.
2.1.2The ‘K’ type composition brake blocks shall be non interchangeable with cast iron as well as low friction composition brake block (`L’Type) already in use on freight stock. The parameters for freight stock using ‘K’ type brake blocks are given in the Annexure-I.
2.1.3The composition of the material and the manufacturing process for series production of ‘K’ type composition brake blocks must always conform with that of the composition brake blocks for which approval has been given by RDSO and no change shall be made in the composition and drawing against which approval has been granted.
2.1.4The use of asbestos is prohibited.
2.1.5The use of Lead and Zinc in the metal state or in the form of compounds is not allowed. The same applies to all other components, if in the form of powder, particles or gas produced during the use of the brake blocks, which may constitute a danger to health.
2.1.6The composition of the material constituting the brake block must be chosen so as to give the best balance between:
-the braking characteristics,
-the wear and service life of blocks,
-wear on the running surface of the wheels,
-the effect on adhesion between the rail and wheel.
2.1.7The characteristics laid down in this specification must be maintained for the complete usable thickness of the braking material.
2.1.8The supplier will advise the detailed procedure for disposal of used/condemned composition brake blocks and will also associate with railways to set up facilities for disposal of used/condemned composition brake blocks.
2.2FRICTION
2.2.1As far as possible the coefficient of friction must be independent of the initial braking speed, the state of beddingin of the brake block, the specific pressure as well as the temperature and atmospheric conditions.
2.2.2The tolerance bands of the instantaneous and average coefficient of friction shall be as per AnnexureIII of this specification. The definition of the friction co-efficient is given in Annexure- II.
2.2.3During beddingin, the coefficient of friction must not vary by more than +15% from the value obtained when beddingin is complete.
2.2.4Under the influence of dampness i.e. under wet conditions, the average coefficient of friction must not vary by more than +15% in relation to the value obtained during braking when dry with other conditions remaining the same.
2.2.5After prolonged braking followed by braking to a stop, particularly high temperature occurs (maximum 375 0 C on the opposing friction surfaces). The average coefficient of friction must not vary, with the other conditions remaining the same, by more than + 15 % in relation to the value obtained during braking in the cold and dry state.
2.3GEOMETRICAL CHARACTERISTICS
2.3.1The controlling dimensions of brake blocks shall conform to the requirements given in the RDSO drawing No. WD-00006-S-01 with latest Alt. placed at Annexure-IV.
2.3.2The constructional features of the brake block must enable them to wear down to a thickness of 10mm, including the back plate, without the latter or the securing components with the brake head, coming into contact with the running surface of the wheel.
2.3.3Weight of Brake Block shall be shown in the drawing
2.4MECHANICAL, PHYSICAL AND CHEMICAL CHARACTERISTICS
2.4.1The various elements making up the brake blocks must be spread uniformly in the body of the block. There must be no pitting, flakes or other defects. The material must not attack the opposing friction surface or give rise to the formation of metallic inclusions.
2.4.2The blocks must not cause more serious heat damage to the wheels (hot spots, cracks, flaking) than would be caused by cast iron blocks used in the similar way on the similar wheels.
2.4.3 The values of density, hardness, compression modulus, cross breaking strength, acetone extract, ash content (loss on ignition) and back plate pull off strength must be given for acceptance purposes.
2.4.4The brake block and its back plate must be designed to withstand the forces likely to occur during service. The durability of assembly can be checked with the test arrangement shown in Appendix-6 of UIC 541- 4 , back plate must not become detached from the composition material.
2.4.5The brake blocks must not reduce the adhesion between the wheel and rail to an unacceptable degree compared with that normally obtained from vehicles fitted with cast iron brake blocks.
2.5MARKING
2.5.1The marking on back plate and clamp of each brake block shall be as per Drawing No.
WD-00006-S-01 with latest Alt. placed at Annexure IV.
2.5.2These marks shall be punched in such a manner so that the block can be identified even after being fully worn in service.
2.5.3The condemning limit shall be marked in orange colour on the side of brake block, manufactured to drawing no. WD-00006-S-01, with latest Alt.
- ACCEPTANCE PROCEDURE
3.1FOR NEW SUPPLIER: -
3.1.1The tenderer seeking to supply brake blocks to Indian Railways must have a technical collaboration with an foreign manufacturer who has experience in manufacturing rail road brake blocks. The foreign collaborator must have complete manufacturing and test facilities including full scale Dynamometer for manufacturing and testing of brake blocks. The collaborator will have to give detailed information including type acceptance test data run and their verification procedure as per clause 2.2 and other details in accordance with clause no 2.4.3. The test on dynamometer will be carried out by the collaborator as per test scheme given in annexure- V.
3.1.2The condition of foreign collaboration is strictly applicable for those companies, which are not in the business of manufacturing friction composition materials for industrial use. However, the companies, which are in the business of friction composition material for industrial use and have established all the requisite manufacturing and testing facilities including full scale rail dynamometer for indigenous manufacture of the Railway brake block and are following a quality assurance plan to the satisfaction of RDSO may be exempted by RDSO from the requirement of foreign collaboration. Such firms should submit dynamometer test results after testing of samples on their own dynamometer.
3.1.3The firm cleared for regular supply of `L’ type composition brake block for freight or coaching or Loco may also manufacture the `K’ type brake block. The first lot shall be manufactured in presence of RDSO officials. Sample of brake blocks will be drawn by the RDSO representative for dynamometer testing at RDSO.
3.1.4The tenderer will have to produce adequate evidence from their collaborator in support of good performance of the collaborator and adequate experience in manufacture and supply of composition brake blocks for Rail Road application.
3.1.5The tenderer shall also submit a copy of approval certificates issued to their collaborator by any of railroads for composition brake blocks.
3.1.6The tenderer shall submit a copy of memorandum of understanding (MOU) jointly signed by the tenderer and collaborator.
3.1.7The tenderer shall submit list of past supplies made by their collaborator to different railroads along with specifications followed for manufacture and supply of brake blocks.
3.1.8The tenderer shall submit the list of plant and equipment available along with capacity, no. of such equipments, manufacturer name etc available with collaborator.
3.1.9The tenderer shall submit detailed drawing of the brake block in line with clause 2.3 for approval of RDSO.
3.1.10The tenderer will have to submit from the collaborator, the results of dynamometer test of samples carried out by the collaborator according to test scheme indicated in Annexure V. The details of friction properties as per clause 2.2 and other details of test results in accordance with clause 2.4.3 shall also be furnished.
3.1.11The information in para 3.1.1 to 3.1.10 should be presented together with a request for type acceptance test by RDSO.
3.1.12The supplier will submit six number of brake blocks for type acceptance test on RDSO’s brake dynamometer and samples will be tested as per Test Scheme given in Annexure-V The testing charges will be paid by the supplier.
3.1.13During the tests, the blocks must not reveal any sign of combustion, formation of flaking, sweating of the binding material, permanent grating or other defects.
3.1.14The wear should be uniformly distributed over the entire depth of the block, it should be as low as possible and be largely independent of the type of brake load application. The specific wear value of each brake block found by weighing should not exceed 5 cc/kw hr.
3.1.15The blocks tested on the dynamometer must meet the requirements given in para 2.2 of this specification.
3.1.16On successful completion of the dynamometer testing at RDSO, the brake blocks shall undergo field trials. The field trial shall be carried out in two phases. The first phase shall consist of field trials of 1500 imported brake blocks. On successful completion of the field trials of imported brake
blocks, 1500 indigenously manufactured brake blocks shall under go the field trials in second phase. The supplier has to submit the drawing as per clause 2.3 and QAP as per clause 3.2.2 for approval before undertaking manufacture of these brake blocks.
The imported/ indigenously manufactured brake blocks will be supplied for field trial only after inspection by RDSO.
3.1.17Six samples out of 1500 initial indigenously manufactured brake block shall be picked up by the RDSO to under take full-scale dynamometer test of any two samples. The supplier shall arrange this testing of blocks on his own/with collaborator. Alternatively the supplier may send the brake block for testing at RDSO at his own cost. This test will be carried out as per Test Scheme given in
Annexure-V.
3.1.18Based on the technical evaluation after field trial of 1500 Nos. of brake blocks further action will be taken for series production of composition brake blocks.
3.1.19The inspection during series production and supply will be carried out as per clause 4.
3.2FOR SUPPLIER ALREADY CLEARED FOR INDIGENOUS SUPPLY
3.2.1The supplier shall submit detailed drawing of the brake block in line with clause 2.3 for approval of RDSO.
3.2.2The supplier shall get his Quality Assurance Plan approved by RDSO before undertaking manufacture of the brake block. The Quality Assurance plan must contain the details of process of manufacture, process controls and quality records maintained. The QAP must also contain the acceptable readings of the following parameters along with the method of testing.
a) Compression modulus.
b) Cross-braking strength.
c) Acetone extract.
d) Ash content. (Loss on ignition)
e) Hardness.
f) Density.
g) Back plate pull off strength.
h) Any other tests.
3.2.3The supplier shall undertake full-scale dynamometer test (as per Annexure V) on the brake blocks under supply to Indian Railways at intervals as per QAP approved by RDSO. For this purpose requisite samples shall be picked up by RDSO and the supplier shall arrange testing of the blocks. Alternatively the supplier may send the block for testing at RDSO at his own cost. To maintain quality, RDSO at their discretion may pick up samples at any time for testing at RDSO dynamometer.
3.2.4The inspection during series production and supply will be carried out as per Clause 4.
- INSPECTION
4.1For New Supplier :-
4.1.1The inspection of the brake block shall be carried out by Director General / RDSO or his authorised representative at the premises of the supplier.
4.1.2The inspection will be carried out as per the following procedure:
i)Supplier to submit pre-inspection report for the lots offered for inspection as per the approved QAP of the firm.
ii)Supplier to ensure traceability of each block to its parent mix batch number & heat No. etc.
iii)The inspector shall inspect the quality records maintained by the supplier for the entire lot.
iv)Each lot offered for inspection shall consist of 2000 brake blocks or part thereof. The lot No. shall represent the mix, batch numbers and heat No. out of which these brake blocks have been manufactured.
v)2% of every offered lot of 2000 nos. brake blocks will be selected at random and checked for dimensional accuracy. Dimensions are to be checked as per approved drawing of manufacturer. However, it is to be ensured that blocks from different mix batches will be taken up for inspection.
vi)Two brake block selected at random from the above lot shall be tested for the following:
a)Compression modulus.
b)Cross-braking strength.
c)Acetone extract.
d)Ash contents or (loss on ignition).
e)Hardness.
f)Density.
The block shall be accepted based on acceptable readings given in the RDSO approved QAP of the supplier. The method of testing shall be as given in UIC 541-4-OR or as per the method of testing followed by manufacturer indicated in their approved QAP.
vii)Two brake block selected at random from the same lot to be tested for back plate pull off strength and accepted based on acceptance values specified in approved QAP of the firm.
viii)Two brake block selected at random will be subjected to any other test to be included in the QAP of the firm as decided by the manufacturer and RDSO.
4.1.2.1The brake blocks shall conform to the requirements mentioned in the QAP of the firm and approved by RDSO. If any of the samples selected as per para 4.1.2 fail to meet the requirements of any of the requirements, double the quantity of samples stipulated in clause 4.1.2 shall be selected for tests. If during retesting any of the brake blocks fail to meet the requirements of any of the tests the entire lot of brake blocks offered for inspection shall be rejected and brake blocks shall be rendered unserviceable.
4.1.2.2The rejected lot shall be destroyed.
4.2For supplier already cleared for indigenous supply :-
4.2.1The inspection of the brake block shall be carried out by Director General / RDSO or his authorised representative at the premises of the supplier.
4.2.2The inspection will be carried out as per the following procedure:
i)Supplier to submit pre-inspection report for the lots offered for inspection as per the approved QAP of the firm.
ii)Supplier to ensure traceability of each block to its parent mix batch number & heat No. etc.
iii)The inspector shall inspect the quality records maintained by the supplier for the entire lot.
iv)Each lot offered for inspection shall consist of 2000 brake blocks or part thereof. The lot No. shall represent the mix, batch numbers and heat No. out of which these brake blocks have been manufactured.
v)1% of every offered lot of 2000 nos. brake blocks will be selected at random and checked for dimensional accuracy. Dimensions are to be checked as per approved drawing of manufacturer. However it is to be ensured that blocks from different mix batches will be taken up for inspection.
vi)One brake blocks selected at random from the above lot shall be tested for the following:
a)Compression modulus.
b)Cross-braking strength.
c)Acetone extract.
d)Ash contents or (loss on ignition).
e)Hardness.
f)Density.
The block shall be accepted based on acceptable readings given in the RDSO approved QAP of the supplier. The method of testing shall be as given in UIC 541-4-OR or as per the method of testing followed by manufacturer indicated in their approved QAP.
vii)One brake blocks selected at random from the same lot to be tested for back plate pull off strength and accepted based on acceptance values specified in approved QAP of the firm.
viii)Two brake blocks selected at random will be subjected to any other test to be included in the QAP of the firm as decided by the manufacturer and RDSO.
4.2.2.1The brake blocks shall conform to the requirements mentioned in the QAP of the firm and approved by RDSO. If any of the samples selected as per para 4.2.2 fail to meet the requirements of any of the requirements, double the quantity of samples stipulated in clause 4.2.2 shall be selected for tests. If during retesting any of the brake blocks fail to meet the requirements of any of the tests the entire lot of brake blocks offered for inspection shall be rejected and brake blocks shall be rendered unserviceable.
4.2.2.2 The rejected lot shall be destroyed.
- TESTING FACILITIES
i)Suppliers shall have complete facilities/gauges for checking of brake blocks according to dimensional tolerances shown on the drawing.
ii)Suppliers shall have adequate facilities for determining the characteristics as laid down in para 4.1.2 (vi) / 4.2.2 (vi).The equipment used for testing shall be able to give output in print out form of these parameters for maintenance of record.
iii) The supplier shall have in house full-scale dynamometer facilities to test the brake block as per test scheme laid down in Annexure-V. The frequency of testing samples on Dynamometer should be as laid down in the QAP approved by RDSO. The supplier shall submit test results to RDSO.
- PACKING
6.1The brake blocks shall be securely packed in cardboard boxes so that there is no damage to brake blocks during transit. This shall be got approved from RDSO along with drawing.
6.2Firm having collaborator, Packing should be in accordance with the recommendations of the collaborator. This shall be too got approved from RDSO along with drawing.
- WARRANTY
The warranty on account of manufacturing defect shall be 24 months from the month of supply or duly life cycle i.e.time taken in reaching the wear limit of the brake block, whichever is earlier.
ANNEXURE-I
PARAMETERS FOR FREIGHT STOCK
S. No. / Particulars / DATA1. / Maximum axle load (Tonne) / 25
2. /
No. of wheels per wagon
/ 083. / Wheel dia (mm)
New
Condemning / 1000 mm
906 mm
4. / No. of brake block per wheel / 01
5. / Brake block force ( Kg ) / block / 2370
6. / Max. speed (kmph) / 100
7. / Type of brake system / Air Brake
ANNEXURE-II