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IS 11095 (1984): Bi-metallic strips and bars with preciousmetal on phosphor bronze base for electrical contacts [MTD10: Precious Metals]

IS : 11095 - 1984

Indian Standard SPECIFICATION FOR

BI-METALLIC STRIP AND BAR WITH PRECIOUS METAL ON PHOSPHOR BRONZE BASE FOR

ELECTRICAL CONTACTS

UDC 669-419.4 [ 669.35' 779 ] : 621.3.066.6

© Copyright 1985

I N D I A N STANDARDS I N S T I T U T I O N MANAK BHAVAN. 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002

Gr 2

February 1985

IS : 11095 -1984

Indian Standard SPECIFICATION FOR

BI-METALLIC STRIP AND BAR WITH PRECIOUS METAL ON PHOSPHOR BRONZE BASE FOR

ELECTRICAL, CONTACTS

Precious Metals Sectional Committee, SMDG 1.3

Chairman Representing SHBI A. W. CHAWATHE Ministry of Finance, New Delhi

Members SHBI B. G. K. BAUGA Bharat Gold Mines Ltd, Colar Gold Field SHBI D. K. BANDYOPADHYAY Hindustan Copper Ltd, Calcutta SHBI J. NAGESH BHATT - Indian Telephone Industries Ltd, Bangalore

SHBI A. DWABAKANATU ( Alternate } SHBI RAMANLAL P. CHOKSI Bharat Bullion Co-op Refinery Society Ltd,

Ahmadabad SHRI CHINTXBHAI D. SBETH ( Alternate )

SHBI RAVJKDKA S. CBOKSI Choksi Contacts Pvt Ltd, Udaipur SHBI PRAKASH S. CHOKSI ( Alternate)

SHBI SHASHIKANT S. CHOKSI Hindustan Platinum Pvt Ltd, Bombay SHBI CHAWDBAKANT S. CHOKSI ( Alternate)

DBV.M. DESAI Government Dental College and Hospital, Bombay SHBI M. P. DKIBEY National Test House, Calcutta SHBI N. GCRPAIIAN Regional Office of the Gold Control Administrator,

Bombay SHBI M. P. REGE .( Alternate)

DB C. S. P. IYER Bhabha Atomic Research Centre, Bombay DB T. P. RADHAKBISHNAK1 ( Alternate )

SHRI J. N. KANSARA Gujarat Bullion Refinery, Ahmadabad SHBI B. S. KAJTSABA ( Alternate)

SHBI DBABAMVEEB KAPOOB All India Sarafa Association, Delhi SHBI PREM NATH KHAKNA( Alternate)

SHBI S. C. MAHANTI The Hutti Gold Mines Co Ltd, Hulti SHBI J. S. GUBTJRAJ NAJK ( Alternate)

SHBIMATI PTTSHPA MOT W AMI Consumer Guidance Society of India, Bombay . SHBIMATI SHARI>A JOSHI ( Alternate)

SHU i R. C. PAIHAN Export Inspection Council of India, New Delhi SHBI J. P. MAJKHARI ( Alternate )

SHBI K. S. RANGABAJAN Directorate General of Technical Development, New Delhi

SHSI M. K. BANERJEE ( Alternate) { Continued on page 2 )

© Copyright 1985 INDIAN STANDARDS INSTITUTION

This publication is protected under the Indian Copyright Act (XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the

publisher shall be deemed to be an infringement of copyright under the said Act.

IS : 11095 - 1984

( Continued from page I )

Members Representing REPRESENTATIVE Development Commissioner for Handicrafts,

New Delhi SHRI P. K. SEN Ministry of Defence ( DGI) SHBI G. K. SHAH National Refinery Pvt Ltd, Bombay

SHBI S. P. SON AW ALA ( Alternate ) SHBI AMREPLAL G. SON AW ALL A The Bombay Bullion Association Ltd, Bombay

SHBI SHASPTILAL NARANDAS ( Alternate ) SHBI V. V AND AGONAL Tamil Nadu Jewellers' Federation, Madras SHBI NATWAB T. ZAVEBI The Gem & Jewellery Export Promotion Council,

Bombay SHBI NIRMAL KUMAR RAKYAN ( Alternate ) SHBI K. RAGHAVBNDBAN, Director General, IS I ( Ex-qffieio Member )

Director ( Struc & Met) Secretary

SHBI A. B. TEWARI Deputy Director ( Metals ), 1ST

Precious Metals Electrical Contacts Material Subcommittee, SMDG 13 :6

Convener SHBI A. W. CHAW AT HE India Government Mint, Ministry of Finance

Members SHBI J. NAGESH BHATT Indian Telephone Industries Ltd, Bangalore SHBI RAVINDRA S. CHOKSI Choksi Contacts Pvt Ltd, Udaipur SHBI SHASHIKANT S. CHOKSI Hindustan Platinum Pvt Ltd, Bombay

SHBI CHANDRAE: ANT S. CHOKSI ( Alternate ) DB C. S. P. IYER Bhabha Atomic Research Centre, Bombay REPRESENTATIVE Bharat Heavy Electricals Ltd, Hyderabad SHRI ISMAIL SAIT Amalgamated Components Pvt Ltd, New. Delhi

SHBI ANIL LAL ( Alternate ) SHRI C. K, SHAH National Refinery Pvt Ltd, Bombay

SHBI P. SONAWALA ( Alternate )

2

IS : 11095 - 1984

Indian Standard SPECIFICATION FOR

BI-METALLIC STRIP AND BAR WITH PRECIOUS METAL ON PHOSPHOR BRONZE BASE FOR

ELECTRICAL CONTACTS

0. F O R E W O R D

0.1 This Indian Standard was adopted by the Indian Standards Institution on 31 May 1984, after the draft finalized by the Precious Metals Sectional Committee had been approved by the Structural and Metals Division Council.

0.2 The Bi-metallic precious contact strips and bars (on a base of phosphor bronze ) are used as electrical contacts in telecommunication and other similar low current applications. The precious metallic portion makes the contact while the base metal acts as a backing material.

0.3 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS : 2-1960*. Thr number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. SCOPE

1.1 This standard prescribes the requirements of bi-metallic strips and bars with precious metal layer of two types, with silver-copper and silver-palladium alloys, both on a backing of phosphor bronze material.

2. SUPPLY OF MATERIAL

2.1 General requirements relating to the supply of material shall conform to IS : 1387-1967 †

♦Rules for rounding off numerical values ( revised ). t General requirements for supply of metallurgical materials (first revision ).

3

IS : 11095 - 1984

3. TERMINOLOGY

3.0 For the purpose of this standard, the following definitions shall apply.

3.1 Strip — The material from 0 05 to 10 mm thick with width of less than 300 mm is termed as strip.

3.2 Bar — According to dimensions given in 7.1.

4. MANUFACTURE

4.1 The surface of the backing material shall be smooth and bright and free from scratches, pits, burrs or any other defects.

5. REQUIREMENTS

5.1 The chemical composition of the backing material shall be according to Grade 1 of IS : 7814-1975*.

5.2 The chemical composition of the precious metal shall conform to the following:

Silver-Copper Alloy Silver-Palladium Alloy Percent Percent

Silver 89.5 to 90.5 69.5 to 70.5 Copper 95 to 10.5 — Palladium — 29.5 to 30.5

5.3 Hardness —The hardness of the backing material shall be 120 HV, Min,

5.4 Freedom from Defects — The precious metal shall have a smooth glossy surface free from scratches, pits and black stains.

6. BONDING TEST OF PRECIOUS METAL

6.1 The bonding of the precious metal to the backing metal shall be tested according to Fig. 1. There shall be no separation of precious metal from the backing metal after the test which is conducted according to 6.2.

6.2 The material shall be bent through an angle of 90° around a radius equal to half the thickness with the precious metal on outside. It is then returned to the original flat position.

•Specification for phosphor bronze sheet, strip and foil.

4

IS : 11095 - 1984

FIG. 1 ADHERENCE OF PRECIOUS METAL TO BACKING

7. DIMENSIONS

7.1 The total thickness of double metal bars shall be 0.80 mm on its whole surface and the thickness of the precious metal shall be 0.100 mm. The width and length of the bars shall be as indicated in Fig. 2. The cladding thickness is microscopically checked on metallographic cross section at 100 times magnification. The precious metal layer shall not show any inclusions of the backing material.

7.2 If any other sizes are required, it shall be as specified in contract or order.

7.3 Twist — The material shall be free from kinks and warps. The admissible limit shall be ±5° twsit 125 mm length.

7.4 Straightness — straightness.

The bars shall conform to Fig. 3 regarding

8. SPECIAL IDENTIFICATION MARK

8.1 To identify between silver-copper alloy (see 5.2 ) and silver-palladium alloy ( see 5.2 ) the strips and the bars at the rear portion of the backing material shall have the insertion of white metal approximately 0.01 mm thick, as in Fig. 2 for silver-copper alloy bi-metallic strips/bars.

5

IS: 11095 - 1984

where

A = Length B = Width C = Length of projection

D = Depth of insert of white metal E = Total thickness F = Thickness of precious metal

FIG. 2 BI-METALLIC STRIPS/BARS SHOWING WHITE METAL

9. CONDITION OF DELIVERY

9.1 The condition of delivery shall be as agreed to between the purchaser and the manufacturer.

10. SAMPLING

10.1 Lot—In a consignment not more than 100 coils of bi-metallic precious contact strips and bars of the same composition and dimensions

6

IS : 11095 - 1984

NOTE — All values based on material lying flat under its own weight.

FIG. 3 STRAIGHTNESS

shall constitute a lot. From each lot, samples shall be drawn and tested for various requirements for ascertaining the conformity of the lot.

10.2 Visual and Dimensional Requirements — From each lot, the number of coils to be sampled for the purpose of examining backing material ( see 4.1) and dimensions (see 7) shall be as given below. The sample coil shall be selected at random ( see IS : 4905-1968* ):

Lot Size

Up to 25

26 “ 50

51 “ 100

Sample Size

5

8

13

All the samples coils shall meet the respective requirements given in 5.2, 7,8 and 9.

*Methods for random sampling.

7

IS : 11095 - 1984

10.3 Chemical, Mechanical and Bonding Tests — One test shall be conducted for chemical, composition ( see 5.1 and 5.2 ), hardness ( see 5.3 ) and bonding test (see 6.1). The test results shall comply with the respective requirements if the lot is to be accepted under this clause.

11. PACKING

11.1 The material shall be securely and suitably packed as agreed to between the purchaser and the supplier.

12. MARKING

12.1 Each package shall be marked with description of the material; name of the manufacturer and trade-mark if any, month and year of manufacture; and number of strips/bars in the bundle.

12.1.1 The material may also be marked with the ISI Certification Mark. NOTE — The use of the ISI Certification Mark is governed by the provisions of the Indian

Standards Institution ( Certification Marks ) Act and the Rules and Regulations made thereunder. The ISI Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well-defined system of inspection, testing and quality control which is devised and supervised by ISI arid operated by the producer. ISI marked products are also continuously checked by ISI for conformity to' that standard as a further safeguard. Details of conditions, under which a licence for the use of the ISI Certification Mark may be granted to manufacturers or processors, may be obtained from the Indian Standards Institution.

8

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