is- 1367-part03

Indian Standard FASTENERS -THREADED t3TEEL - TECHNICAL SUPPLY CONDITIONS

PART 3 MECHANICAL PROPERTIES AND TEST METHODS FOR BOLTS, SCREWS AND STUDS WITH FULL LOADABILITY

( Third Revision )

UDC 621.882.2/.3 : 082 [ 669.14 ] : 620.1 : 006.87

0 BIS ?991

BUREAU OF INDIAN STANDARDS MANAK BHAVAN. 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

Price Group 8

IS 1367( Part3):1991 IS0 998 - 1 : 1988

Indian Standard

FASTENERS - THREADED STEEL - TECHNICAL’SUPPLY CONDITIONS

PART 3 MECHANICAL PROPERTIES AND TEST METHODS FOR BOLTS, SCREWS AND STUDS WITH FULL LOADABILITY

( Third Revision ) NATIONAL -FOREWORD

This Indian Standard ( Part 3 ) which is identical with IS0 898 - 1 : 1988 ‘Mechanical properties of fasteners - Part 1 : Bolts, scretis and studs’ issued by the lntemational~ Organization for Standardiza- tion ( IS0 ) was adopted by the Bureau of Indian Standards on the recommendation of the Bolts, Nuts and Fastener Accessories Sectional Committee ( LMD 14) and approval of the Light Mechanical Engineering Division Council.

The second version of this standard published in 1979 was based on IS0 898 _ 1 : 1978 ‘Mechanical properties of fasteners - Part 1 : Bolts, screws and studs, issued by ISO. The revision has been made by the adoption of the revised IS0 898 - 1 : 1988. The following major changes have been made in this revision:

a) The chemical compositions and tempering temperatures of steels have been revised; b) The maximum hardness values for bolts, screws and studs of property classes 3.6 to 5.8 have

been increased; c) The surface hardnesses for bolts, screws and studs of property classes 8.8 to 12.9 have been

revised;

d) The application of test programmes A and B has been revised and specified more clearly;

e) Property classes 4.8, 5.8 and 6.8 are no longer tested according to test programme A:

f) The surface integrity test has been added to test programme A, the wedge loading test fol bolts, and screws with nominal thread diameter d < 4.mm or nominal length I < 2’5 d has been deleted from test progamme 8;

g) For nominal thread diameters 10 and 12 mm, the metric fine pitch waschanged from 1.25 to 1 and 1.5 respectively, because these are the preferred pitches ( see also IS0 8676 and IS0 8765 ) : the minimum tensile loads and proofing loads were changed as a consequence; and

h) The application of the wedge loading test for bolts and screws with head b&ring diameter above 1.7 d has been specified.

In the adopted standard, certain terminology and conventions are not identical with there used in the Indian Standard, attention is. especially drawn to the following:

a) Comma ( , ) ‘has been used as a decimal marker while in Indian Standards, the current practice is to use point ( ) as the decimal marker.

b). Wherever the words ,lnternational Standard’ appear, referring to this ‘standard, they shall be read as ‘Indian Standard’.

In the adopted standard, reference appears to certain International Standards for which Indian Standards also exist. The corresponding Indian Standards which are to be substituted in their place are listed below along with their degree of equivalence for the editions indicated:

International Standard Corresponding Indian Standard Degrae of Equivalence

IS0 68 IS0 general purposescrew IS 4218 ( Part 1 ) : 1976 IS0 metric Technically threads - Basic profile screw threads: Part 1 Basic and equivalent

design profiles ( first reviamn )

1

:S 1367 (Pati3) :I991 ISO898-I:1988

IS0 83 Steel- Charpy impact (U- notch )

IS0 225 Fasteners - Bolts, screws. ..studs and nuts - Symbols and desi- gnations of dimensions

IS0 261 IS0 general purpose metric screw threads - General plan

IS0 262 IS0 general purpose metric screw threads - Selected sizes for screws, bolts and nuts

IS0 273 Fasteners’- Clearance holes ,.for bolts and screws

IS0 965 -Al IS0 general purpose metric screw threads - Tolerances - Part 1 : Principles and basic data

IS0 965- 2 IS0 general purpose metric screw threads - Tolerances - Part 2 : Limits of sizes for,general purpose bolt and nut threads - Medium quality

IS0 6157 - 1 Fasteners - Surface discontinuities - Part1 : Bolts,screws and studs for general requirements.

IS0 6506 Metallic materials - Hard- ness test - Brine11 test

IS0 6507 - 1 Metallic materials - Hardness test - Vickers test - Part 1: HV5toHVlOO

iSO 6507 - 2 Metallic materials - Hardness test - Vickers test - Part 2 : HV 0.2 to less than HV 5

IS0 6508 Metallic materials - Hard- ness test - Rockwell test - Scales A, 8. C, D, E. F. G. H. K

IS0 6892 Metallic materials -Tensile testing

Corr&ponding~ Indian Standard

IS 1499 : 1977 Method for Charpy impact test ( U-notch ) for metals ( first revision )

IS ‘8536 : 1987 Bolts, screws, studs and nuts - Symbo!s and designation of dimensions ( first revision )

IS 4218 i Part 2 ) : 1976 ISO.metric screw threads : Part2 Diameter pitch combinations (.i’irst revision )

IS 12241 : ,I987 IS0 general purpose metric screw threads - Selected sizes for screws, bolts and nuts

IS 1821 : 1987 Dimensions forclear- ante holes for bolts and screws ( second revision )

HIS 4218 (.Part i; : j 1976 IS.0 metric screw threads : Part 4 Tolerancing system ( first revision )

IS 4218 ( Part 6 ) : 1978 IS0 metric screw threads : Part 6 Ljmits of sizes for commercial ‘bolts and nuts ( diameter range 1 to 52 mm ) ( first revision )

IS 1367 ( Part 9 ) : 1979 Technical supply conditions for threaded steel fasteners : Part 9 Su:face discontinuities on bolts, screws and studs ( second revision )

IS ‘1500: 1983 Method for Brine11 hardness test for metallic materials ( second revision )

IS 1501 ( Part 1 ) :I984 Method for Vickers hardness test for metallic materials: Part 1 HV 5 to HV 100 ( second revision )

IS 1501 ( Part 2 ) : 1984 Method for Vickers hardness test for metallic materials : Part 2 HV 0.2 to less than HV 5 ( second revision )

!S 1586 : 1988 Method for Rockwell hardness test for metallic material ( scales A, 8, C, D. E. F, G, H, K )

IS 1608 : 1972 Method for tensile testing of steel products ( first revision )

Degree of Equivalence

Technically equivalent

Identical


Identical

Identical

Technicalh, equivalent








The concerned technical committee has reviewed the provisions of IS0 1 and IS0 6157 - 3 referred in this adopted standard and has decided that they are acceptable for use in conjunction with this standard. The related Indian Standard to IS0 1 is IS 196 : 1966 ‘Afmospheric conditions for testing’.

ADDITIONAL INFORMATION The Indian Standard is a national implementation of IS0 898 _ 1 :I988 as shown only the English text has been reproduced. If the French, Bussian, German, Spanish is required, reference should be made to the original IS0 publication.

2

IS 1367 ( Part 3 ) : 1991 IS0 898 - 1: 1988

The property class symbol consists of two figures:

- the first indicates 11100 of the nominal tensile strength in newtons per square millimetre lsee R, in table 3);

- the second figure iridicstes 10 times the ratio.between lower yield stress R,, (or proof stress RpO,~) and nominal tensile strength R, lyieltl sties ratio).

The multiplication of these two figures will give 1110 of the yield stress in newtons per square millimetre.

Lotier yield stress ReL (or proof strek R& and minimum tensile strength R, arc equal to wgreater than the nominal values (see table 31.

4 Materials

Table 2 specifies steels for the different property classes bolts, screws and studs.

The minimum tempering temperatures listed in table 2 are n datory for property classes 8.8 to 12.9 in all cases.

The chemical composition limits are mandatory onlv for th fasteners which are not subject to tensile testing.

Table 1 - System of coordinates

. .- -

Minimum dongation ahe; fracture. 14 A min., %

Relationship between yield stress and tensile *length

Second figure of symb?l .6 .8 2

Lower yield stress Rep or proof stress Rpo,;’ -. 60 60 9

Nohitial tensile strength x ltw %

R,

11 Applies onQ to @lead diameter d < 16 mm.

NOTE - AtthoUgh a great number of property classes are Specified in this pa0 of ‘$0 898. this does not me& that all classes are appropriare items. Further guidance for application of the specific property classes is given in :he relevant product standard:Far non-standard items. it is adu to follow as/clqdy as p&ble the choice already made for similar standard items.

4

IS 1367( Part3):lSSl IS0 898 - 1 : 1988

P,“P”RY &SS

3.6” --

4.6” --L-

4.8”

5.6

5.8”

6.8” --

8.8*’

9.8

10.94’ --

10.95’

-- 12.95’. 61

Table 2 - Steels -

Chemical composition limits lcheck analysis) %

Material and treatment c P s

min. max. max: max. -. - 0.20 0.05 0.06

0.55 0.05 0.06

carbon *feel 0.15 0.55 0.05 0.06

0.55 0.05 0.06

Carbon steel with additives (e.g. Boron or Mn or Crl quenched and tempered

0,153’ ; 0.40 I ‘I

0,035 0,035

or I I I I

Carbon *reel quenched and tempered 0.25 0.55 0.035 0,035

Carbon *lee1 with additives kg. Boron or Mn or Cd quenched and tempered 0‘ - Carbon SW”, quenched and tempered

.-4””

Carbon steel with additives (e.g. Boron 0, Mn 0, Crl

Alloy steel quenched and tempered” 0.20 0.50 0.035 1 0.035

T*mp&g f*mpBrat”,e

oc

min.

--._...

425

--

425

---

340 - -.

425

380

1,’ Free cutting steel is allowed for lhese “,““er,y classes wid, the following maxim”m sulfur. “h”$“h”,us and lead c”n,“nts:

s”lf”ro.34 %; ph”Sph”r”S 0.11 %: lead 0.35 %.

2, For nominal diameters above 20 mm ih” steels s”ecilied for “‘““~rly class 10.9 may be necessary in order 1” achieve sufficient hardenability.

3, In case of plairi carbon boron alloyed seeI wkh a carbon conlent Wow 0.25 % (ladle analysis,. the minimum manganese come”, shall bc 0.6 % for property class 8.8 and 0.7 % for 9.8 and 10.9.

41 P,“d”c:s shall be additionally identi‘ied by underlining the ~ymhol O! the “,““e,ty class. ,see claush 91.

51 F”, the materials of these property classes, it is intended that there should be a sufficient hardenability to ““SW” a structure con~ising of approxi- mately 90 % manen~ib? in the core of the threaded sections for the tastene,~ in the “as-hardened” condition before tempering.

6, A metallog,aphically detectable white “h”s”h”r”~~ enriched layer is “of “ermitted ‘or “roperry class 12.9 on surlaces subjected to fensi,” stress.

71 Alloy steel shall contain one or more of the alloying elements thromium, nickel, molybdenum or vanadium.

5

IS 1367 ( Part 3 ) : 1991 IS0 898 - 1 : 1988

5 Mechanical properties

When tested by the methods described in clause 8, the bolts, ~crew.~ and studs shall, at r~orn temperature, have the mechanice De&S set out,in table 3.

Table 3 - Mechanical properties o+ bolts, screws and studs

Sub- c,*we

NO.

5.1 and 5.2

5:3

5.4

5.5

5.6

5.7

5.8

5.9

5.10

5.11

5.12

5.13

5.14

Property c,a**

1 lo” i _I~ Tenc.ile strength, R,,,4’, 51, N/mm2

-.-_

“icksrs hardness,,H”. F > 98 N max.

Brinkil Dz .-. min. 90, ,114 124 147 152 181 hardness, HB, F = 30 1 238 242 276 394

~max. ’ * ,238 ..304 1 318 342 361 .-

HR8 52 I 67 mtn. I 171 1.79]~2.169: -, .- - -,:

IHRC Rockwell hardness, HR

22 23 28 32 --”

HR8 99.5 - - - _,

max.. i?iz ----

32 34 37 3s ‘- -. Surface hardness, H” 0.3 max. 61

Mechanical property

---.

-_ - dower yield sires. ReL”, ~/mm? 169 300 >-.L 240 320 400 480 - -’ - -

190 zso Go. 300 ‘- 420 480’ - _ - -

Proof *tress, Rs,2. Nlrnd “Orn. 840840 720 9’33 7 -.----- -...... -.-

h”. - 840 6eQ 720

11 For 0oils uf proper:y cla.% 8.8 in diameters d < 16 mm, there is an increased risk of nut srripping in the case of inadvertent over-tightening in ing a load in excess of proofing load. Relerence to ISO 898.2 is ,ecommended.

31 Applies only to nominal fhread diameters d G 16 mm.

41 Minimum tensile properties apply to products of nominal length ! ‘z 2.5d. Minimum hardness applies twproducts of length / < 2.5d and c products which cannot be tensile+st&d (e.g. due to head configuration).

5) Fa resing of lulkire bol!s. screws and studs, the loads given in tab& 6 to 9,shall be upplied.

61 Surlacc hardness shall !?a1 be more than !I0 Vicken points above the m&wed core hardness on the product when readings of both surface core are carried out at HV 0.3. For pmpeny class 10.9, any increase in hardness at the surface which indicates that the surface hardness exq 393 WV is ““1 acccpka!c.

‘7) In CSSBS where the lower yield stress KeL cannot be determined, it is permissible to measure the proof stress R,,,,

6

IS 1367 ( Fart 3 ) : 1991 IS0 898 - 1 : 1988

6 Mechanical properties to be determined

Two test programmer., A and 6, for mechanical properties of bolts, screws and studs, using the methods described in clause6, are set out in table 5.

The application of programme 6 is always desirable, but is mandatory for products with breaking loads less than 500 kN,

Programme A is suitable for machined test pieces and for bolts with a shank area less than the stress area

Table 4 - Key to test programmes (see table 5)

Sk*

Test dtxkiw for acceptance

Bolts and screws with fhread dimmer d > 4 mm and length I > 2,5d

1) Also bolts and screws with special head or shank configurations which are weaker than the threaded lection.

IS 1397 ( Part 3 ) : 1991 IS0 898 - 1: 1999

Table 5 - Test’programmes A.and B for acceptance purpos&s (These procedures apply 10 mechanical but no, chemical properks.

Propeny class

Test method 3.6, 8.8. 9.8 4.6, IQ:9 5.6 12.9

Tensile ,e*, j . j .

6.,4 Maximum Oecarburization . dewrburhed zone 8.8

,eSt -

” R~,~pX~i”Q 5.15 Minimum tempering temperature 8.9 ,eS, .

- _-

5.16 Surface integrity 8,,. Surface integrity l l test

1) If the wedge loading ,e*, is sa,i*f*c,ory, the axial tewile te*, is not required

- Test Programme 6 --_. -

Property *,a

Test method 3.6, 4.6 8.8, 4.8, 6.6 10 j.8, 6.6 12

8.3 Hardness 1~3) l ’

--A---.. ..-_

8.5 Wedge loadir,g . . testl,

---..

---...--* 8.6

Head Sound,:.?** a.7 ,e*t

- Decarbuiiz*fi:,n

g.8 ,e*t ‘

---...-__.- __.._

8.9 Retempering ‘ test

8,,. Surface integrity e e te*t

2) Minimum hardness applies only to products of nominal length I c 2.5d and other Product* which cannot bc tensile-tested (e.g. dus to configuration).

31 Hardness may be Uckers. Brinell or Rockwell. !n ca*e of doubt. the Vickers hardness te*f is decisive for acceptance.

4) Special head bolts and *cr*w* with configurations which are weaker than the threaded section *r* excludt?d from wedge t*n*il* 18 requrements.

51 Only for bolts. *cr*w* and studs with thread diameter* d > 16 mm and only if required by the ,,urch**~r.

61 Only properry class 6.6.

71 Only for bolts and *crew* with thread diameler* d < 16 mm and lengths 100 Short 10 permit wedge load testing,

IS 7367 C Part 3 ) : 1991 IS0 898 - 1 : 1988

7 Minimum ultimate tensile loads and proofing loads

see isbleo 6, 7, 8 and 9

Table 6 - Minimum ultimate tensile loads - IS0 metric coarse pitch thread

-- 4 530 6 100 7900

12 800 18 100 26 ooo 32 900 52 200 75 900

104 003 14,003

_.

-

- -

-. 5230 7050

~9130 14 ml 20 900 30 100

38 10s 60 303 87 703

120 00.3 163 eon %(ww3 255 000 315 ocn 387 ooo 477 m 583cw 772 cc0 !

85occo ! 020 co9 .L -.-.

.__.._ 3 020 4 070 5 270 8 520

-2 ml vi 3cm

22 000 3: *ccl 50 8%

nom 0,; ooo

::‘iooo ii.‘/ 0-m 182lXXl 212 ox 275 cc0 337 &xl 418 Cc0 490 m 588cca

4 020 5 420 7 020

11 350 16 100 23‘100

79200 48 400 87 4002 92 0032

125 003’ 159 cm 203 CXJ 252 Ooo 293 Ooo 381 OKJ 488 om 576 000 878 Cal *lOCOO

T

! I i

1 / I

_L

/ I

i93m 230 003 23G”W 28000; 292rm 347003

Table 7 - Proofing; loads - IS0 metric coarse pitch thread

T - SfreSS area

~r.nom 2 mm

5.03 6.78 8.78

14.2 20.1 28.9 36.6 58 84.3

115 157 192

245 303 353 459 581 694 817 978

Thread”

M3 M3.5 M4 M5 &I6 M7 M8

MiO NllZ i1014 M1G Ml8

M20 M22 M24 M27 M30 M33

M38 M39

910 1220 1580 2560 3 820 5203 8 590

1” 400 15 203

20 703 28 3M 34 lx0 44 loo 5t!ml 63 !m 82 693

101 cc0 125wO 147 m 178wJ

3 270 4 410 6 710

9 230 13 100 18 SW 23 800 37 700 54800

74 SRI 102Oml

. .

1560 j ,410 1910 2100 19w i 2580 2 720 2450 j 3 340 4402 3980 : 5400 8 230 5 630 8 969 8 (MO

303 CO3 ! 273 Ooo ; 371 Ooo /--I-,A

2 210 2980 3860 ‘3250 8 840

:? 700 >8 100

25 500 37 100 50 803 89 1w e-4 503

108 Ox) 133 ooo 155m 202 cm 247 Ooo 305 m 359 co3 429cal

1 130 1 !m 1980 3 ml 4 !i2O 6 ii00 8 240

13 oco !9Oco 25 9w 35 :ml 432w 55 Too 68200 79 4100

103 ml 126!xM 156ma

154col 22OwO

2 97.0 3940 5 100 8 230

11 SCQ 18800 21 200 33 7ca 48 ‘Jo0

68 700 91 cm

115col 147 OCQ 182 oco 212Om 275 000 337cNJ 416 wo 4wcm 5ssocQ

IS 1367CPart3):1991 IS0 898 - 1 : 1988

Table 8 - Minimum ultimate tensile loads - IS0 metric fine pitch thread

Thread

39.2 12 WI 157co 64.5 21 300 25 803 88.1 29 ml 35200

125 41 *co 5occo 167 55 lco 66800 216 713co 86403 272 898W 109cco 333 llOw0 133 cc0 384 127 CO3 I54GOO 496 184cco 194 oco 621 205ooO 248cco 761 251 cc0 3Mml 865 285 000 346coo

1030 34OCOO 412 ooo

Table 9 - Proofing loads -. IS0 mefric fine pitch thread

39.: M.! Ea.

125 167 216 272 333 384 496 621 761 865

1030 -

706a 11 603 15 9co 22m 30 x0 33900 49 lx0 599m 69 1w 693ca

112cco 137 coo 156cco 185 WO

M8 Y 1 Ml0 Y 1 Ml2 Y 1.5 Ml4 x 1.5 Ml6 x 1.5 MlE x 1.6 Mm x 1.5 PA22 x 1.6 MS?‘4 x 2 MT7 x 2 M30 Y * M33 x 2

MI% x 3 M33 x 3 --

P rot -- 11 oco y-

18 ice 287W 35x0

/

46 ml 605c-o 76 200 93 200

108 co3 :39CW, 17nva 213(10 242 000 28arxn

!

I

I i.

25500 41900 57 3ca 81 200

109 ooo

-..-

afin9 IOJd ,/I$ is So’, N ---

14900 17200 ; 22703 id 5cxl i 28r.00 j 37400 33500 i 38803 51 100 47500 I 55000 72 500 63500 : 735co 96900 82 100 95000 130000

I I

I I I

I I I

, I I

I

!03OOi~ : 12oooo 163ooO 200 000 23owM

17.6000 i 146 COO 146000 169000 188000 i ;11* XXI 236OOO / 273ooo 289 000 i 335000 3zswJ / 381000 391000 j 453 oco

10

IS 1367 ( Part 3 ) : 1991 ISO’ 898 - 1 : 1988

8 Test methods

.$.l Tensile test for machined test pieces

The following properties shall be checked on machined test pieces by tensile tests in accordance with IS0 6892..

a) ten#e strength, R,,

b) lower yield stress, R,, or proof streee of non- proportional elongation 0.2 %, R,,,,

c) percentage elongation after fracture:

L” - Lo A=-y-- x loo LO

The test piece shown in figure 1 shall be used for the tensile .?st.

When machining the feet piece, the reduction of the shank diameter of the heat-treated bolts and scwws with d > 16 mm shall not exceed 25 % of the original diameter labout 44 % of the initial cross-sectional areal of the test piece.

Products in property classes 4.8, 5.8 and 6.8 Icold-forged product) shall be t’ensile-tested full-size (see 8.2).

8.2 Tensiie test for full-size bolts, screws and studs

~The tensile test shall be carried out’on full-size bolts in confor- mity with the tensile test on machined test pieces (see 8.1). It is carried cut for the purpose of determining the tensile strength. The calculation of the tensile.strength, R,. .is based on the stress area A,:

where

4 * is the basic pitch diameter of the thread;

d3 is the minor diameter of the thread

d3= d, - ;

in which

* dt . is the basic minor diameter,

H is the height‘of the fundamental t:iangle of the Ihread.

For testing of full-size bolts, screws and studs the loads given ‘I” tables 6 to 9 shall be applied.

When carrying out the test, a free threaded length equal to one diameter (IdI shall be subjected to the tensile load. To meet~the requirements of this test, the ~fracture shall occur in the shank or the thread of the bolt and not et the junction of the head and the shank. The test ring, shall be designed accordingly.

The,speed of testing, as determined with a free-running cross- head, shall not,exceed 25 mmlmin:The grips of the testing machine shoilld !x self-aligning to avoid side thrust on the specimen.

8.3 Hardn,css test

For routine, irppection. hardnesy of bolts, .scr?ws and studs may be determined on the head, end or shank after removal of any plating o: other coating and after suitable preparation of the specimen.

d = “ominal thread diameter Lc = length of straight portion (L, + do)

do = diameter of test piece (dh < minor diameter L, = fotel IenQth of test piece IL, + 2 r .+ bl of thread) L” = length after fracture,

b = length of thread lb > dl SO = crosw.ectio”al area

LO = 5 do or (5.65 61 r = fillet radius (r > a’mm)

Figure 1 - Test piece for tensile test

* See IS0 965-l. II

IS 1367 C ,Part 3 ) : 1991 IS0 898 - 1 : 1988

For rwqmty classes 4.8, 5.8 and 6.8, the hardness shall be determined only on the end of the bolt or screw.

8.4 Proofing load test for full-size bolrs

If the maximum hardness is exceeded, a retest shall be con- The proofing load test consists of two main operation

ducted at the inid-radius position, one diameter back from the follows:

end, at which position the maximum hardness specified shall not be exceeded. In case of doubt. the Vickers hardness test is al application of a specified tensile proofing load decisive for.acceptance. figure 2). and

Hardness readings for the surf.& hardness shall be taken on the ends or h,exagon flats, which shail be orepared by minimal grinding or polishing to ensure repraiucible reading and main- tain the original surface of the materis;. The Vickers test hV 0.3 shall be the referee test for surface herdress testing.

Surface hardness readings taken at t?V 0.3 shall be compared with a similar core hardness reading at HV 0.3 in order to make a realistic comparison and determine ihe relative increase up to 34 Vickers points.~An increase of mwe than 30 Vickers points indicates carburization.

bl measurement of permanent extension, if any, ca by the proofing load.

The proofing load. as given in tables 7 ar~l 9, shall be a~ axially to the bolt in a normal tensile testil~.g r.achine. Th proofing load shall be held.for 15 s. The length of free tt subject to the load shall be 6 &tc:hes of We thread (6Pl.

For screws threaded to the head, the length ot free thread jetted to the load shall be as close as practice: to 6 pitch the thread.

For measurement of permanent extension, the bolt shi axially centre-drilled W’ cone) at each epd. lilefore and the application of the proofing load, the bolt shall be place, bench:mounted measuring ‘in’strument’ fitted with sph anvils. Gloves or tongs shall be’&d ,to minimize mea&w error.

For property clauses 8.8 to 12.9 the difference between core hardness and surface hardness is decisive for the judgement of the carburization condition in the stirface layer of the bolt, screw or stud.

There may nbt be a direct relationship between hardness and theoretical tensile strength. Maximum hardness values have been selected for reasons other than theoretical maximuin strength considerations (e.g. to avoio embrittlement).

NOTE - Careful differentiation nwt be made between an increase in hardness caused by carburhatiun and thbt diw to heat-treatment or cold working of the surface.

8.3.1 Vickers hardness test

The Vicken hardness test shall be carried out in accordance with IS0 6507.

8.3.2 Brineil hardness.test

The Brinell hardness test shall be carried out in accordance with IS0 8506.

8.3.3 Rockwell hardness test

The Rockwell hardness t&t shall be carried out in accordance with IS0 65%.

TO meet the requirements of the proofing :oad test, the I< of the bolt, wew or stud after loading shall. DB the\san before loading within a tolerance of f 12.5 ii? allowe “eaS”re”e”t error.

The speed of testing, as determined with a free-running c head, shall not exceed 3 mmlmin. The grips of tt,e te machine should be self-aligning to avoid side thrust or specimen.

Some variables, such as straightness and thread align (plus meawrement error), may result in apparent elongati, the fasteners when the proofing load is initially applied. In cases, the fasteners may be retested using a 3 ?/o greater and may be considered satisfactory if the length after loading is the same as before this @ding (within the 12,, t3leranCe for meaS”rement error1.

12

6 1367 ( Part 3 ) : 1391 ISO 898 - 1 : ‘7988

I

11 d,, according 10 IS0 273. medium series isee fable 101.

Figure 2 - Application of proofing load to full-size bolts

13

!S 1367(P&t3).:1991 ISo898-?:1988

8.5 Test for strength under wedge loading of full-size bolts and screws (not studs)

The test for strength under wedge loading shall be carried out ps illustrated in figure 3:

The minimum distance from the thread wn-out of the bolt to the contact surface of the nut of the fastening device sliall bed. A hardened.wedge in accordance with .ables ,lO and 11 shall be placed u,nder the head of the bolt. A tensile test shall be continued until fracture occurs.

To meet the iequirements of this test, the fractureshall occur in the shank or the thread of the bolt, and not between the head and the shank. The bolt shall meet the requirements foi minimum tensile strength, either during wedge tensile testing or in a supplementary tensile test without a wedge, according

to the values given for the relevant property class before ture 0CC”rs.

Screws threaded to the head shall pass the requirement o test if a fracture which causes failure originates in the length of thread, even if it has extended or spread into the area or the head before separation.

For product grade C, a radius rl should be usr?d ac.xrdir the formula

r, = ,max. + 0.2

where r max. = da max. - d, min.

.-. 2

NOTE - Symbols r, d, and ds are defined in IS0 225

Hardnes$46 HRC min.

k\\\‘t\. Radius or \ I

/ - chamfer of W

II dh according to IS0 273, medium series.

Figure 3 - Wedge loading of full-size bolts

Table 10 - Hole diameters for wedge loading test

Nominal thread diameter. d 3 3.5 , 4

‘4 3.4 3.9 4.5

, rl 0.7 0.7 0.7

Dimensions in millirr

Nominal thread diameter, d 16 18 20 22 24 / 27 30 33 36. 3 4 17.5 20 22 24 26 1 30 33 36 39 42 --_-- - .--. +_-_-_ ‘I 1.3 1.3 1.3 1.6 1.6 1.6 1.6 1.6 1.6 1

14

IS 1367 ( Part 3 ) : 1681 ISO888-I:1888

Nominal diameter of bolt and screw

d

Table 11 - Wedge dimensions

PropenV Class for:

bolts and screws with plain shank length 1. > 2 d

3.6, 4.6, 4.8, 5.6, 5.8.8.8..9.8. 10.9 I 6.8. 12.9

bolts and screw3 threaded to.!& head or with plain shank len9th (, < 2 d

3.6, 4.6, 4.8, 5.6, 5.8. 8.8. 9.8. 10.9 I 1 12.9 6.8,

For products with head bearing diameters above 1,7dwhich fail 8.7 Head soundness test for’full size bolts with the wedge tensile test, the head may be machined to 1.7d and d < 16 mm and with lengths too short to permit re-tested on the wedge angle specified in table 11. wedge load testing

Moreover for products with head bearing diameters above 1.9d. the loo wedge angle may be reduced to 6O

The head soundness test shall be carried out as illustrated in figure 4.

8.6 Impact test for machbied test pieces

The impact test shall be carried out in accordance with IS0 83. The test piece shall be taken lengthwise, located as close to the surface of the bolt or screw as possible. The non-notchi?d side of the te.st piece shall be located “ear the surfize of the bolt. Only bolts of thread diameters d > 16 mm can be tested.

When struck several blows with a hammer, the head of the belt or screw shall bend to awangle of !3Y -fi without showing soy sign of crackirig at thd shank head fillet, when viewed at a magnification of not less than X8 nor more than X10.

Where screws are threaded up to the head, the requiremerxs may be considered met even if a crack should,appaar in the first thread, provided that the head does not snap off.

NOTES 1 Ford,, and r2 lwhere ,* = r,), see table 10. 2 The thicknz% of the ios! plate should beover 2 d.

Figuie 4 - Head soundness test

Table~lZ - Values of angle fl

I 3.6 4.6 5.5 4.8 5.8

600 15

IS 1367 i Part 3 ) : 7991

IS0 898 _ 1 : 1988

8.8 Decarburization test

Using the appropriate measuring method (8.8.2.1 or 8.8.2.2 es apdicablel, the longitudinal section of the thread shell be examined to determine that the height of the zone of base metal El and the depth of the zone with complete decatburiza- lion ICI are within specified limits lsee figure 51.

The maximum vaii~ for G and the formulae for the minimum value for E are specified in table 3.

8.9.1 Definitions

8.8.1:1 base metal hardness: Hardness closest to the SM. face (wher; rraversing from core to outside diemeter) just before en increase or decrease occurs denoting cerburization or dacarburization.

8.8.1.6 carburization: A process of increasing swface car. bon to a content above that of the b&e me,eI.

8.8.2 Measurement methods

8.8.2.1 Microscopic method

8.11.1.2 decarbukation: Generally. loss 01 carbon a! the surface of commercial ferrous materials kteelsl.

Aftar rqoun!ing. grind end polish the wrface in accordance wit:1 gwd merallographic practice.

8.5.1.3 partial decarburization: Decarburization with loss of carbon sufficient to cause a lighter shade of tempered mxtensite and significantly lower hardness than that of the adjecenf ba?.e mefal.

8.8.1.4 complete decarburization: Decarburization with sU;: icient carbon Ic,ss to show only clearly defined ferrite grains under metallographic examination.

Unless otherwise agreed between the interested pa&s. Xl00 megnifi::etion she:, be used for examination.

8.8.1.5 carbon restoration: A process of restoring surface car!mn loss by hez:.trearing in a furnace atmosphere of prop. erly controlled carbon potential.

If tke mcroscope is of e type with a ground glass screen. thy: extent d c!ecarburization can be measured directly with a scele If ar: eyepiece is used for measurement. it should be of en iw p,rop.riatl: type, containing a cross-hair or a scale.

,1., I-.,. “’ ‘,

\

i /

Figure 5 .- Zones of decarburizafion

16

IS1367(Part3):1991 is0 898-1:1988

8.6.2.2 Hardness method (Referee method for partial d&,rburiZ.&Bnl

The hardness measurement method is applicable Only for threads with pitches, P. of 1.25 mm and larger.

The hardness measuwnents are made at three points in accordance with figure 6. Formulae for E are given in table 3. The load shall be :100 g.

The hardness determination for point 3 shall be made on the pitch line of the thread adjacent IO the thread on which detar- minations at points 1 and 2 are made.

The Vickers hardness value at point 2 shall be equal !o or greater than that at point 1 minus,30 Vickers units. In this case the height of the non-dewrbwized zone E shall be at least as specified in table 13.

..Tbe Yickers hardness value at point 3 shall be equal to or less <than that at point 1 plus 30 Vickers units.

Complete decarburization up to the maximuQ specified in table 3 cannot be detected by the hardness measurement method.

8.9 Retempering test

The mean of three hardness readings on a bolt or screw tested before and after retempering shall not differ by more than 20 Vickers points when retempered and held at a temperature 10 “C less than the specified minimum tempering temperature for 30 min.

8.70 Surface integrjty test

For the surface integrity test. see IS0 6157-l and IS0 6157-3.

The surface integrity test is applied to test programme A test bolts before machining.

HV,>,WV,-30 HV+ HV, +30

Figure 6 - Hardness measurements for decarburation test

Table 13 - Values for H, and t

Pitch of the thread, P1l mm 0.5 0.13 0.7 0.8 1 1.25 1.5 1.75 2 2.5 3 3.5 4

mm 0,307 0,368 0,429 0.491 0.613 0,767 0,920 1,074 1.227 1.534 1,940 2.!47 ‘2.454 -.-- .._.._ .._----..-..-.--

0,154 0,194 0,215 0,245 0.307 0,334 0.460 0,637 0,614 0.767 0,920 1.074 1.227 - _....._..,.. ._ . ,.........,-,. ..---

mm 0,205 0,245 0.286 0,327 0,ti 0,511 0,613 .0,7X 0.818 1.023 1.227 1.431 1,636 .____ _,._ _..... .i-. _. -- ..-

0.233 0.27s 0.327 0.3% 0,460 0,575 0,690 0,806 0.920 1.151! 1.380 I.810 1,841 -

1) Foi P < 1 mm. mitrwcopic method only.

17

IS 1367 ( Part 3 ) : 1991 IS0 898 - 1 : 1988

9 Marking

9.Y Symbols

Marking symbols are shown in table 14.

9.2 identification

9.2.7 Hexagon mlts and screws

Hexagon bolts anti screws shall be marked with the designation symbol of the property class described in clause 3.

Tix marking is obl!gatory for all property classes, preferably on the top of the head by indenting or embossing or on the side of the head by indeo:ing isee figure 7).

Marking is required for hexagon bolts and screws with nominal dianeters d > 5 mm where the shape Of the pr~tfua allows it, pre!erably on the head.

9.2.2 Hexagon socket head cap screws

Hexagon socket head cap scr&vs shall be marked with the des!gn;?tion symbol of rhe property ClaSs described in clause 3.

The ms+ng is obligatory for property classes equal to or higher Iha:) 8.8, preferably on the side of the head by indenting or 0,) the top of the head by indenting or embossing lsce figure g).

Marking is required for hexagon socket head cap scwws with. nominal diame!ers rl > 5 mm where the shape of ihc produr:t BIIONS i:. preferat,ly on the head.

The clock-lace marking system as given for nuts in IS0 898.2 may be :Ised as an alternative method on small hexagon socket hea<! cw screws.

8.8 :r- - -. t Figure 7 - Examples of marking on hexagon bolts and screws

Figure 8 - Examples of marking on hexagon socket head cap screws

Table 14 - Marking symbols

Property de55 3.6 4.6 ’ 4.8 6.6 5.8 6.8

Marking ~yr,,boltJ. 21 3.6 4.6 ! 4.8 5.6 5.8 6.8

1) The !ili-stop in the mar!+: symbol m%y he omiited. 2) When low carbon maRe”SitiC *tee,* sre “sod for properly Class 10.9 bee table 2). the syiGlbol IO.9 *ha,, be “nderlined: 1O.Y.

18

IS 1367 (‘Part 3 ) : 1991 IS0 696 - 1: 1966

Table 15 - identification marks for studs

Property C1891 9.9 9.9 10.9 12.9

Identification mark 0 + q n, 9.2.3 Studs

Studs shall be marked with the d&sign&n symbol of the propeny class described in clause 3.

The marking is obligatory for property classes equal to or higher than 8.8, preferably on the extreme end of the threaded portion by indenting (see figure 9). For studs with interference fit, the marking shall be at the nut end.

Marking is required for studs with nominal diameters equal to or greater than 5 mm.

Figure 9 - Marking of stud

The symbols in table 15 are permissible as an alternative identification method.

9.2.4 Other types of b&Its and .screws

The same marking sy~teti as described in 9.2.1 and $2.2 shall be used for.other types of bolts and screws of properN,clas.sos 4.6, 5.6 and all classes equal to or higher-than 8.8, as described in the appropriate International Standards or. for special com- ponents, as agreed between the interested parties.

9.3 Marking of left-hand thread

Bolts and screwswith left-hand thread shall be marked with the symbol shown in figure 10, either on the top 01 the head or the point.

f$Hk t .ql Figure 10 - Left-hand thread marking

Marking is required for bolts and screws with nominal thread diameters d > 5 mm.

AlteYnative marking for left-hand thread may be used for hexagon bolts and screws as shown iti figure 11.

1) s is the width aeros~ flats. 2) k is the height of the head

Figure 11 - Alternative left-hand thread mark.ing

9.4 Alternative marking

Alternative or optional permitted marking as state? in ‘9.1 to 9.3 should be left to the choice of the manufacturer.

9.5 Trade (identification) marking

The trade (identification) marking of the’manufacturer is mandatory on all products which are marked with propsrty classes.

19

IS 1367 (Part3) :199-l IS0 898 - 1 : 1988

Annex

Properties at elevated temperature (This annex does not forman integral part of the Star.dard.1

r 1 Temperature, T

+20 I +,@I -r--A3 I rxn I +?M --I

ELI-- -.- -. - 12.9 10.9 8.8 5.6 llca 640 940 300 102l 590 875 270 --x-n -& -& .9%5 875 215 510 745 925 480 705 195 -’

-

The data shown in table 16 is for guidance only and is an approximate presentation of the reduction in the mechanical properties which will be experienced when tensile-tested at elevated temperatures. Such data shall not be used as test requirements for bolts, screws and studs.

20

is- 1367-part03

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