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है”ह”ह

IS 9175-20 (1986): Rationalized Steels for Automobile andAncillary Industry, Mechanical and Physical Properties -Part 20 20MnCr5 Grade steel [MTD 16: Alloy Steels andForgings]

IS : 9175 ( Part 20 ) - 1986

Indian Standard RATIONALIZED STEELS FOR

THE AUTOMOBILE AND ANCILLARY INDUSTRY

PART 20 MECHANICAL AND PHYSICAL PROPERTIES OF

20MnCr5 GRADE STEEL

Co-ordinating Committee on Materials for Automobiles, SMDC 31

Chkrnan Rspresmting

SHRI C. V. TIKE~AR Tatn Engineering & Locomotive Co Ltd, Jamrhedpur

Members

SIIRJ A. K. ROY ( Allcrnatc to Shri C. V. Tikekar )

SHRI V. P. A~RAWAL Steel Authority of India Ltd ( Rourkela Steel Plant ), Rourkela

SHI~I A. K. MALHOTRA ( Alternots ) SHRI R. BR~ARI All India Automobile and Ancillary Industries

Association, Bombay SH~I S. PANIKAR ( Altarnata )

SHRI R. BHATTACHARYYA Guest Keen Williams Ltd. Calcutta SHRI A. T. BORATE Premier Automobiles Ltd, Bombay

SHRI J. M. SRAH ( Altsrnats ) SRHI R. R. CONTRACTOR Automobile Products of India Ltd, Bombay

SHRI V. A. RAJAMONEY ( Alternate ) SIIRI S. P.DEY Hindustan Motors Ltd, West Bengal SHRI V. GOPAL Lucas-TVS Ltd, Madras

SHRI K. S. SUBRA~ANIAS ( Alternate J SHRI S. C. GUPTA ’ ~~ Tata Iron and Steel Co Ltd, Jamshedpur

SHRI A. N. MITRA ( Attmatc ) SHRI D. N. GUPTA Bokaro Steel Plant ( SAIL ), Bokaro SHRI H. A. TAIEIN~HA~I Mahindra and Mahindra Ltd, Bombay

SRR~ S.-RABfAaECANuRAN( Ahmats) SHRI R. C. JEA Steel Authority of India Ltd ( ASP ), Durgapur

SARA R. C. MODI ( Alternate ) SHRI M. L. KATYAL Bajaj Auto Limited, Pune

SHRI S. R. SALCXA ( Ahrnatc ) SHR~ S. S. LAKHUNDI Bharat Forge Co Ltd, Pune

DR M. K. S. CHERUKUHN ( Altarnutr )

( Cmtinuad en page 2 )

@ Cqyrigbr 1986

INDIAN STANDARDS INSTITUTION

Thii publication is protected under the Indian Copyright Act ( XIV of 1957 ) and reproduction h whole or in part by any means except with written permission of the publisher ahall be deemed to be an infringement of copyright under the said Act.

IS ‘: 9f7!5 ( Part 28 ) - 1986

( C6ntinucdfram bug6 1 )

Mambws &f.JrUSU?ltin~

SHRI S. C. MAHINDX~U Chief Inspectorate of Heavy Vehicles, Avadi SHSI P. SOMASUNDRAM ( Altawulu )

C0L.P. M. MENON Directorate of Standardination ( DC1 ), New Delhi Da V. PLNDURAN~A Tractors and Farm Equipment Ltd, Madras

Ssm1T.K. SUBBARAYAN(A~~~~~) Saar K. PARTHASARTHY Ashok Leyland Ltd, Madras

SERI T. S. SUDARSRAN ( Altumntu ) DR P. G. PATANKAR Central Institute of Road Transport, Pune

SERI L. SHANTARAM ( A~ternutc ) DR R. V. PATEY Mahindra Ugine Steel Co Ltd, Bombay

SERI R. N. SINQH ( Aft6matc ) SHR~ G. R. PRAKASE Visvesvaraya Iron & Steel Ltd, Bhadravati

SEIRI B. HARIDASAOHAR ( Altcnzats ) SHRI R. RA~HAPAN Enfield India Ltd, Tiruvottiyur

SERI T. M. BALARAYAN ( Alturnata ) Sa~r AJAY KUMAR RAMAN Escorts Ltd, Faridabad

SERI S. D. KHANNA ( Altsrnota ) DaV. RAMASWAMY Research & Development Centre for Iron and Steel

SHRI S. R. MEDI~ATTA ( Alf6rnUf6 ) SAIL ( R & D-Centre ), Ranchi

SHRI C. V. K. MURTHY RAO The Association of Indian Automobile Manu-

SHRI S. P. RAO facturera, Bombay

WG Forge and Allied Industries Ltd, Thane SHRI B.K. &NANTHARAXIAH( Afturn&)

Nagarjuna Steels Ltd, Hyderabad SHRI ANANTHA REDDY SHRI J. SRINIVAS ( Alternntc )

REPRESENTATIVE REPRESENTATIVE SERI A. S. SA~ND

SHR~ B. S. SA~ND ( Alternate ) SHRI K. SHANRARANARAYANAN

Ministry of Defence ( DGI ) Automotive Research Association of India, Puns Saund Zweired Union (I) Ltd, Gwalior

Directorate General of Technical Development, New Delhi

SERI S. K. SHARMA I Ministry of Industrial Development SHRI T. R. SERQAL ( Alternate )

SHRI A. R. SONALKA~ Mahindra and Mahindra Ltd, Bombay SHRI A R. JANIKA ( Alternate )

SI~RI L. SRINIVASAYADHVAN Standard Motor Products of India Ltd. Madras SHRI K. RAN~ANATHAN ( Alternate )

SHRI M. S. GANAPATHY STJBRA- Mopeds ( India ) Ltd, Tirupathi MANIAM

SHRI A. G. NAMMALVAR ( Alternate ) SHRI S. TIWARI Directorate General Ordnance Factories, Calcutta

SHWI G. N. ROY ( Alternate ) SERI K. RA~HAVENDRAN, Director General, IS1 ( Ex-oficio Membrr )

Director ( Strut & Met )

Sccrctary

SHRI B. K. MUKHOPADEAYAY Assistant Director ( Metals ), IS1

( Continued on pag6 7 )

2

IS : 9175 ( Part 20 ) - 1986

Indian Standard RATIONALIZED STEELS FOR

THE AUTOMOBILE AND ANCILLARY INDUSTRY

PART 20 MECHANICAL AND PHYSICAL PROPERTIES OF

20MnCr5 GRADE STEEL

0. FOREWORD

0.1 This Indian Standard ( Part 20 )was adopted by the Indian Standards Institution on 27 March 1986, after the draft finalized by Co-ordinating Committee on Materials for Automobiles had been approved by Structural and Metals Division Council.

0.2 Part l* of this standard was published in 1979 which covers the chemical composition of 33 rationalized steels. The mechanical properties, hardenability and isothermal transformation characteristics of these 33 rationalized steels are being covered in different parts ofthis standard (Parts 2 to 34 ). The data concerning to these properties given in this standard is only for guidance and information purposks.

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 accord- ance with IS : 2-19607. The 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 standaad ( Part 20 ) covers the mechanical properties, harden- ability and isothermal transformation characteristics of 20MnCr5 grade of steel for use by automobile and ancillary industry.

1.2 This is a carburizing ( case hardening ) steel used for components requiring high wear resistant surface, coupled with tough cores to resist shock loads and strength to give larger service life.

*Rationalized steels for the automobile and ancillary industry: Part 1 Chemical composition.

+Rules for rounding off numerical values ( reuiscd ).

3

IS : 9175 ( P8rt 20 ) - 1986

2. CHEMICAL COMPOSITION

2d,:o’,he chemical composition of this grade of steel shall be as given

Constituents, prccnt

c Si Mn Cr S P

0.17-0’22 ‘0.15-0.35 180- 1’40 1 ‘oo- 1.30 0.035 Max 0’035 Max

3. HARDNESS

3.1 The maximum hardness for this grade of steel delivered in the as rolled or annealed or normalized condition when determined in accord- ance with IS : 1500-1983* shall be 217 HBS.

4. MECHANICAL PROPERTIES

4.1 The mechanical properties of this grade of steel in the blank carburized and hardened condition when determined in accordance with IS : 1598.19771_ and IS : 1608-l 972: shall be as given in Table 1.

TABLE 1 MECHANICAL PROPERTIES IN BLANK CARBURIZED HARDENED CONDITION

LIMITING

BUILDING SECTION mm

30

TENSILE STRENGTH

MPa

1 000-l 300

YIELD ELONGATION IZODIMPACTVALUE, STRESS GL 5’65s’h Min, JOULES AT Roox Min Min TEMPERATURE MPa Percent

700 8 40

5. HOT WORKING AND HEAT-TREATMENT TEMPERATURES

5.1 The recommended hot working and heat-treatment temperatures are given below:

Forging/rolling 1 250°C

Annealing/normalizing 860-910%

Carburising temperature 850.930°C

Refining temperature 850-880%

Hardening temperature 8 lo-84O’C

Tempering temperature 230°C Max

*Method for Brine11 hardness test for metallic materials ( second reaision ). *Method for Izod impact test of metals ( jirst rsoision ). $Method for tensile testing of steel products ( jrst recision ).

4

IS t 9175 ( Part 26 ) - 1986

6. TRANSFORMATION CHARACTERISTICS

6.1 The isothermal transformation diagram for this grade of steel is gken in Fig. I.

AUSTENITISiNG TEMPERATURE 870% 10 Min. 1000

900

800

700

o, 600

o-1 1 10 102 103 104 105 sec. I 1 I I )

TIME - 1 10 100 1000 min

FIG. 1 ISOTHERMAL TRANSFORMATION DIAQR~ OF 20MnCr5 GRADE STEEL

5

IS x 9175 ( Part 26 ) - 1966

7. HARDENABILITY

7.1 The end quench hardenability curve is given in Fig. 2.

AUSTENITISING TEMPERATURE 87OrtS’C 55

50

15

0 5 10 15 20 25 30 35 10 45 50 OISTANCE FROM THE QUENCHED’ EN0

FACE IN mm -_

Digtance 1 2345678 9 10 15 20 25 30 35 40 mn

Min(Rc) 41 40 39 37 36 34 33 31 31 29 25 23 21 - - -

Mux(Rc) 49 49 49 4a 48 47 46 45 44 43 40 37 35 34 33 31

FIG. 2 END QUENCH HARDENABILITY TEST DATA FOR 20MnCr5 GRADE STEEL

I8 : 9175 ( Part 29 ) - 1986

( Continued from popr 2 )

Panel to Collect Data on Steel for Automobile Purposes, SMDC 3l/P12

Conwean R+esmting

DR R. V. PATH9 Mahindra Ugine Steel Co Ltd, Khopoli

Members SHRI B. K. ANANTHARAYAIH WG Forge and Allied Industries Ltd, Thane

SHRI 0. B. DIN ( Altsrnatc ) PROF R. C. CFIATURVEDI Indian Institute of Technology, Bombay SHRI B. HARIDASACHAR Visvesvaraya Iron and Steel Ltd, Bhadravati

SHRI D. P. VERNEKAR ( Allcmats) SHRI H. A. JAISINOHANI Mahindra & Mahindra Ltd, Bombay SHRX M. G. LAWATE Tata Engineerin & Locomotive Co Ltd, Pune DR V. RAMABWAMY Research and 8 evelopment Centre for Iron and

Steel SAIL ( R & D Centre ), Ranchi SHRI S. R. MEDIRATTA ( Altcrnafe)

REPRESENTATIVE Automobile Products of India Ltd, Bombay DR K. R. SATYANARAYANAN College of Engineering, Pune

DR R. D. CHAUDRARI ( Alternate )

7

INTERNATIONAL SYSTEM OF UNITS ( SI UNITS )

Bmmc ullitm

QUANTITY

L-l@ Maas

Time

Electric current

Thermodynamic temperature

Luminous intensity

Amount of fiubstance

Supplementmy Uoltm

QUANTITY

Plane angle

Solid angle

Derived Unita

QUANTITY

Force

Energy

Power

Flux

Flux density

Frequency

Electric conductance

Electromotive force

Preasurc, rtress

UNIT

mctre

kilogram

second

ampere

kelvin

candela

mole

UNIT

radian

steradian

UNIT

newton

joule

watt

weber

teala

hertz

aiemens

volt

paacal

SYNBOL

m

kg !4

A

K

cd

mol

SYMBOL

rad

sr

SYMBOL

N

J w Wtl T

HZ

S

V

Pa

DE~~ITI~N

1 N = 1 kg.m/r’

1 J=lNm

1 W = 1 J/s

1 Wb = 1 V.s

1 T = 1 Wb/m*

1 Hz = 1 c/s (s-l)

1 S = I A/V

I V = 1 W/A

1 Pa = 1 N/m8