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है”ह”ह

IS 12714 (1989): Bi-metallic tape for electrical contacts[MTD 10: Precious Metals]

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IS 12714: 1989

Indian Standard

BIMETALLIC TAPE FORELECTRlCAL CONTACTS - SPECIFICATION

'''«ftlf ffl;:{if)

UDe 669 - 419'4: 621'39

© BIS 1990

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

March 1990 Price Group 1

Precious Metals Sectional Committee, SMDC 13

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards on :!5 May 101:19 , after th edraft finalized by the Precious Metals Sectional Committee had been approved by the Structuraland Metals Division Council.

Bimetallic tapes are widely used in the construction of contact assemblies for telecommunicationrelays and exchange systems, domestic thermostats, automobile and domestic switches. Thematerials are selected for contact portion depending on light or medium duty. These are platinum,palladium, gold and silver, and their alloys .

Testing of solid contacts hal shown that around 50 percent of the expensive p rec ious metal isnecessary for satisfactory performances of the contact. The backing material may be of a cheaperbase metal, such as, phosphor bronze. copper-nickel alloy, etc. The backing material mostlydepends on its subsequent application. The usual backings are 70/30 brass, 80/~0 copper nickel andphosphor bronze.

The tapes are manufactured in continuous unwelded lengths integrally bonded to achieve 100percent bond between contact material and the base metal . The tapes are manufactured in avariety of shapes and sizes to closely controlled tolerances. Along the base of the tape is a continuousprojection or pattern of projection that simplifies the welding of contacts during co ntac t assembly .

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 roundedoff in accordance with IS 2 : 1960 'Rules for rounding off numerical values (revised r. Th..Humber of significant places reta ined in the rounded off value should be the same as that of th «specified value in this standard.

18 12114 , 1919

Indian Standard

BIME'IALLIC TAPE FORELECTRlCAL CONTACTS - SPECIFICATION

1 SCOPE

1.1 This ~ la ll ,j a rd covers silver -pa llad iu mbimetallic tap " used in telecommunicationindustry, fo r th e rotary dial, as a contact to bewelded on t he sp ring.

The surface is observed for cracks . Except atthe fracture, there shall be no signs of crack orflaw on the surface. Two tests shall be done.

6 DIMENSIONS AND TOLERANCES

2 REFERENCES

2.1 The followin g Indian Standards are neces-sary adjunct s 10 th is standard:

3 SUPPLY OF MATERIAL

3.1 General requirements relating to the supplyof material shall conform to IS 1387: 1967.

CONTACTMATERIAL

-ITolerances

mm

R

L

Symbol Sizemm

u 0'5 ")Hi 0'2 IH 0 '5L 1'0 ~IR 0'08 IH2 0'08 J

u

6.1 Dimensions and tolerances shall be as gi venbelow ( Set Fig. ):

Title

General req uirements for thesup ply of metallurgical mate-rials ( first revision)

. Vickers hardness test formetallic materials: Part 1 HV5 to HV 100 ( second revision )

Vickers hardnessS'test formetallic materials: Part 2 HV0'2 to less than HV 5 ( secondrevision)

Vickers .h a rdness test formetallic materials: Part 3 Lessthan HV 0'2 ( second revision )

IS 1387: 1967

is No.

IS 1501( Part I ) : E'84

IS 1 ~01( Part 2 ) : 198';'

IS 1501( Part 3 ) : 1987

4 CHEMICAL COMPOSITION

4.1 The material used for the tape shall be asgiven in Table I .

5 MECHANICAL PROPERTIES

5.1 The hardness of the precious metal sideshall be between 120 to 160 HV when tested inaccordance with IS 1501 (Parts I to 3 ).

5.2 TorsioD Test

A sample each of about 150 mm from both endsof the coil is taken. The sample is twistedunidirectionally until it breaks. Clamping isdone leaving 100 rnrn length free between grips.

6.2 Tape length shall be as per the order receiv-ed from the purchaser.

7 FREEDOM FROM DEFECTS

7.1 There shall be no crack or flaw OD the sur-face, observed after the torsion test. The surfaceshall have a bright and smooth finish.

8 PACKING

8.1 The material shall be suitably packed toprevent any transit damage and corrosion. Itmay be wound round a spool, the size of whichshall be mutually agreed to between the supplier

1

IS 12714t I'"

aRd the purchaser.

9 TEST CERTIFICATE9.1 Quality test certificate shall accompany thesupply. giving full lest results,

•10 MARKING

10.1 Description, quantity, manufacturer's nameor trade-mark and purchase order reference shallbe marked.

Matewial

Table 1 Chemical Composition( Clause 4.1 )

Alley

Percent

Impurity Limits

Percent

a) C,ntat"t Mlllmal

Silver-palladium alloy

b) Backing Material

1) Brass

2) Copper-nickel

3) Phosphor bronze

Silver: 50 ± 1Palladium: 50 ± 1

Copper: 68'5-71'5Zinc: Remainder

Copper: 1'9'0·81'0Nickel: 19'0-21'0Manganese: 0'05-0' 50

Tin: 5'5-7'5Phosphorus: 0'20-0'40Copper: Remainder

2

0"15, A'fax

Lead; 0'05, Ma.>:Iron: 0'05, MaxTotal impurities: 0'3, Max( including iron )

Lead: 0'01, MaxIron: 0·30, MaxSulphur: 002, Ma,~Carbon: O'tlS, MaxTotal impurities: 0'35, Max

Lead: 0-02, MaxZi:l1C:: O-SO, MaxTotal impmitiel!: 0'50, Max

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

StaDdard Mark

The use of the Standard Mark ill governed by the provisiens of the Bure" of IndianStandards Act, 1986 and the Rules and Regulations made thereunder. The Standard Mark onproducts covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspection,testing and quality control which is devised and supervised by BIS and operated by the pro -ducer. Standard marked products are also continuously checked by BIS for conformity to thatstandard as a further safeguard. Details of CODditioJU under which a licence for the useof the Standard Mark may be granted to manufacturers or producers may be obtained fiomthe Bureau of Indian Standards.

Bareaa of Indian Standard.

illS is a statutory institution establ ished under the Bureau if Indian Standards Act, 1986 to promoteharmonious development of the act ivities of standardization, marking' and quality certification ofgoods and attending to connected matters in the country.

Copyright

BIS has th e copyrigtu of all its publ icat ions. :-;0 part of these publications may be reproduced inany form without the prior permission in writing of BIS. This does not preclude the free use, inthe course of implementing th e standar-d, of necessary detail s, such as symbols and sizes, type Orgrade designations. Enquiries relaring to copyright be a ddressed to the Director (Publications), BIS.

Re~i.ion of Indian Standards

Indian Standards are reviewed periodically and revised, when necessary and amendments, if any,are issued from time to time . Users of Indian Standards should ascertain that they are inpossession of the latest amendments or ed ition Comments on thi~ In dian Standard may be sent

10 BIS giving the following reference:

Doc: No. SMDC 13 ( 3356 )

Amendments I..aed Since Publication

Amend No. Date of Issue

BUREAU OF INDIAN STANDARDS

Text Affected

Headquarters:

Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002Telephones: 331 01 31, 331 1375

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2 1843

41 29 16

6329295

Printed at Printograph, Delhi, India