specification for steel fasteners & stainless steel

of 14 Effective from …………… Specification No. TI/SPC/OHE/FASTENERS/0120 Rev.1

GOVERNMENT OF INDIA MINISTRY OF RAILWAYS

RESEARCH DESIGNS AND STANDARDS ORGANISATION MANAK NAGAR, LUCKNOW-226011

Specification for Steel Fasteners & Stainless Steel Fasteners for 25 kV A.C. Traction

Overhead Equipment 1. SCOPE: This Specification covers the requirements of Steel Fasteners and Stainless Steel

Special Head/Hexagon straight Bolts and Screws, Flat Countersunk Nib Bolts and Screw, U-Bolts, J-Bolts, Hexagon Nuts and Lock Nuts and Plain and Spring Washers used on 25 kV

A.C. and 2x25 kV AC Traction Overhead Equipment. The term Fasteners shall include Bolts, Nuts, Lock Nuts and washers. The term nut shall include lock Nut. The term Bolt shall include Screw, Special head Bolt/Screw. This Specification supersedes RDSO Specification No.ETI/OHE/18(4/84) with A & C Slip No.1 to 5.

2. GOVERNING SPECIFICATIONS: The Fasteners shall generally conform to the respective

Indian Standards unless specified otherwise herein. The provisions of the governing Specifications shall be applied in the manner altered/amended or supplemented by this Specification. In preparation of this Specification reference has been made to the following

Specifications.

S.N. Specification No. Specification Title.

i IS: 1363-2002 Black Hexagon Bolts Nuts And Lock Nuts (Diameter 6 to 39 mm) & Black Hexagon Screws (Diameter 6 to 24 mm).

ii IS:1367(Part2,3,5,6, 7,9,10,13,14/sec.-1:2002,18)

Technical supply conditions for threaded Steel Fasteners.

iii IS:1570(Part5) 1985 Schedule for Wrought Steels (Stainless & heat resisting Steels).

iv IS: 2016- 1967 Plain Washers

v IS: 3063 – 1994 Spring Washer for Bolts, Nuts & Screws.

vi BS: 2061 – 1953 Phosphor Bronze Spring Washer for General Engineering purpose.

vii IS: 549 – 2005 Split Pins.

viii IS: 9549 – 1980 Dimension for Split Pin holes, Wire holes and head Slots For Bolts.

ix IS: 9519 – 2005 Dimensions for width across flats for Hexagon Head Bolts & Nuts.

x IS: 8353 – 1977 Flat Countersunk Nib Bolts.

xi IS:730– 1978 Hook Bolts for corrugated sheet roofing.

xii IS: 1368 – 1987 Dimensions for ends of Bolts and Screws.

xiii IS: 4172 – 2005 Dimension for radii under the head of bolts and screws.

xiv IS: 5369 – 1975 General requirements for Plain Washers and Lock Washers.

xv IS: 4206 – 1987 Dimensions for nominal lengths and thread lengths for Bolts, Screws and Studs.

xvi IS:4213-I,II,III,IV,V ISO metric Screws threads.

xvii IS: 2334 – 2001 Gauging practice for ISO metric Screw threads.

xviii IS: 1369 – 1995 Dimensions for Screw thread run out sand undercuts.

xix IS: 2614 – 1969 Methods for sampling of Fasteners.

xx IS: 2629 – 1985 Recommended practice for Hot Dip Galvanising of Iron and Steel.

xxi IS: 4211 – 1993 Thread pitch gauges for ISO metric Screws threads (Pitch range 0.25 to 6.0 mm).

xxii IS: 6745 – 1972 Methods for determination of mass of Zinc coating on Zinc coated Iron & Steel articles.

xxiii IS: 2633 – 1986 Method for testing uniformity of coating on zinc coated articles.

xxiv IS: 9141 – 1979 Code of practice for packing of Fasteners.

xxv IS: 3203 - 1982 Methods of testing local thickness of electroplated coatings.

3. DEVIATION FROM SPECIFICATION: Any deviation from this Specification calculated to

improve the performance, efficiency and utility of Fasteners, proposed by the Tenderer, shall

be given due consideration, provided full particulars with justification thereof are furnished. 4. SERVICE CONDITIONS: The Fasteners are used in conjunction with various

fittings/components of Traction Overhead Equipment including those carrying current. The Fasteners are used very widely under the severe weather conditions. The limiting conditions, which have to be withstood in service, are indicated below:

S.N. Weather condition Limiting conditions

(i) Maximum temperature of Air in shade 45° C

(ii) Minimum temperature of Air in shade 0° C


(iii) Max. temperature attainable by an object exposed to sun(current carrying object)

100° C

(iv) Maximum Relative humidity 100%

(v) Average Annual Rainfall 1750 to 6250 mm

(vi) Average number of dust storm days per annum 35 days (Maximum)

(vii) Number thunder storm days per annum 35 days (Maximum)

(viii) No. of Rainy days per annum 120 days (Maximum)

(ix) Maximum wind pressure 200 Kg/Sq. meter

(x) Altitude Not exceeding 1000 m

(xi) The Fasteners are subjected to chemical pollution from the effluent gases of Chemical Plants, exhaust of Diesel locomotives and saline atmosphere in coastal areas.

5. MATERIAL: 5.1 Ferrous Fasteners: Steel Fasteners shall conform to Grade-C Specified in IS: 1367 (Part-

2)–2002. Bolts/Screws shall comply with mechanical property class 4.6 of IS: 1367 (Part-3)–2002. Nuts shall comply with the mechanical property class 04, 4 or 5 (as applicable) of IS: 1367(Part-6)–1994.

5.2 Stainless Steel Fasteners: The Stainless Steel Fasteners (Bolts, Nuts, Lock Nuts &

Washers etc.) shall conform to Grade AISI 316 Property Class 50 or equivalent Grade A4, Property Class 50 of IS:1367 (part-14/sec.-1):2002/ISO 3506-1:1997.

5.3 Plain Washers: Plain Washers shall conform to IS: 2016 – 1967. Galvanised Steel Plain

Washers (Punched, Type A) shall be used with galvanized Steel Bolts. Bronze, Stainless Steel or Copper Washers (punched, Type A) shall be used with Stainless Steel Bolts.

5.4 Spring Washers: Spring Washers shall conform to IS: 3063 – 1994. Galvanised Steel Spring Washers with flat ends (type B) shall be used with Galvanised Steel Bolts. Phosphor Bronze Spring Washers, conforming to BS: 2061– 1953, shall be used with Stainless Steel Bolts.

6. GENERAL REQUIREMENTS:

6.1 Workmanship The Bolts and Nuts shall be clearly finished, sound & free from defects which may affect their serviceability, and shall be consistent with the grade prescribed. The Fasteners shall have full surfaces and edges in keeping with the method of manufacturing used. These shall be free from burrs although barely perceptible thin burrs, which result for example, from slotting and trimming operations, may be left out.

The Black Grade Bolts may have reasonable die–seem on the shank; but in no

case the shank diameter with such seams shall exceed the maximum permissible diameter. The Stainless Steel Bolt, Nut, Locknut, Plain Washer, Spring Washer shall be

supplied in natural finish. The Washers shall be free from cracks, burrs, pits and other defects. The holes of Plain Washers shall be reasonably concentric with the outer periphery. All sharp edges shall be removed. The surfaces of Washers shall be free from die marks and shall be finished smooth. The ends shall be so severed as to prevent tangling.

6.2 Bolts and Nuts shall be classified by their nominal diameter. The dimensions of hexagons,

chamfers, shank diameter and other dimensions for different nominal sizes of Bolts and Nuts, whether ferrous or stainless steel shall be in accordance with Table 1.

6.3 Unless otherwise shown in the Purchaser’s Drawings, the Nuts shall have single chamfer, and Lock Nuts shall have double chamfer.

6.4 Bolts shall be drilled for Split Pins wherever shown in the Purchaser’s Drawings. Split Pin holes shall be at right angles to the axis of Bolts. The dimensions for Split pin holes for a particular size of Split pin shall be according to IS: 549–1974.

6.4.1 The tolerance in the location of split pin holes shall be according to IS: 9549–1980.

7. DIMENSIONS: 7.1 The dimensions for hexagon Bolts, Screw and Nuts shall be in accordance with Table 1,

read in conjunction with the relevant Purchaser’s Drawings and IS:9519 – 2005 “Specification for modified dimensions of width across flats for hexagonal Bolts/ Screws and Nuts of normal series”.

7.2 The dimensions for Special Head Bolts and Screws, U–Bolts, J-Bolts shall be as shown in

the Purchasers Drawings.

7.3 Dimensions of Flat Countersunk Nib Bolts/Screws shall conform to IS: 8353–1977 and those of J Bolts shall conform to IS: 730–978.


7.4 Dimensions of ends of Bolts and Screws shall be as per IS: 1363 – 2002 and the

dimensions for radii under the head of Bolts and Screws shall be as per IS: 4172 – 1987. The Cone Point/ Truncated Cone Point ends of Bolts and Screws shall be as shown in

Purchaser’s Drawings. 7.5 Dimensions of Plain and Spring Washers shall be as shown in IS: 2016 -1967 and IS:

3063-1994 respectively. The permissible deviations from dimensions of Plain Washers shall be in accordance with Table 3 and 4 of IS: 5369 -1975.

7.6 The dimensional tolerances for Galvanized Steel and Stainless Steel Bolts, Screws and

Nuts shall be as per Table 1. 8. LENGTHS AND THREADED LENGTHS: The lengths and threaded lengths of

Bolts/Screws shall be generally as per IS: 4206 – 1987. However, exact lengths and threaded lengths shall be as shown in Purchaser’s Drawings.

9. THREADS (INTERNAL AND EXTERNAL): 9.1 The threads shall be ISO metric. The internal and external thread profile shall be in

accordance with IS: 4213 (Part I)–1976.

Table – 1 (Refer Fig.1 of Annexure-I) INDICATING THE DIMENSIONS AND TOLERANCES ON BOLTS AND NUTS AND THREADS OF BOLTS AND

NUTS

S.N. Size

Dimension

M10 M12 M14 M16 M18 M20 M22 M24

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

1

NOM

d MAX

MIN

10

11.24

(10.90) 9.79

(9.64)

12

13.44

(13.10) 11.72

(11.57)

14

15.44

(15.10) 13.72

(13.57)

16

17.44

(17.10) 15.72

(15.57)

18

19.44

(19.10) 17.72

(17.57)

20

21.64

(21.30) 19.63

(19.48)

22

23.64

(23.30) 21.63

(21.48)

24

25.64

(25.30) 23.63

(23.48)

2

NOM

s MAX

MIN

16

16.34

(16.00)

15.72

(15.57)

18

18.34

(18.00)

17.72

(17.57)

21

21.34

(21.00)

20.31

(20.16)

24

24.34

(24.00)

23.31

(23.16)

27

27.34

(27.00)

26.31

(26.16)

30

30.34

(30.00)

29.31

(29.16)

34

34.34

(34.00)

33.15

(33.00)

36

36.34

(36.00)

35.15

(35.00)

3 c MIN 17.76 (17.59)

20.02 (19.85)

22.95 (22.78)

26.34 (26.17)

29.73 (29.56)

33.12 (32.95)

37.46 (37.29)

39.72 (39.55)

4

NOM

k MAX

MIN

7

7.79

(7.45)

6.70

(6.55)

8

8.79

(8.45)

7.70

(7.55)

9

9.79

(9.45)

8.70

(8.55)

10

10.79

(10.45)

9.70

(9.55)

12

12.89

(12.55)

11.60

(11.45)

13

13.89

(13.55)

12.60

(12.45)

14

14.89

(14.55)

13.60

(13.45)

15

15.89

(15.55)

14.60

(14.45)

5 da MAX 12.54

(12.2)

15.54

(15.2)

17.54

(17.2)

19.54

(19.2)

21.54

(21.2)

24.74

(24.4)

26.74

(26.4)

28.74

(28.4)

6 a MAX 5.0 6.0 7.5 7.5 9.0 9.0 9.0 11.0

7 b b1 MIN

b2 MIN

b3 MIN

26

32

-

30

36

49

34

40

53

38

44

57

42

48

61

46

52

65

50

56

69

54

60

73

8

NOM

m MAX

MIN

8

8.79

(8.45) 7.70

(7.55)

10

10.79

(10.45) 9.70

(9.55)

11

11.89

(11.55) 10.60

(10.45)

13

13.89

(13.55) 12.60

(12.45)

15

15.89

(15.55) 14.60

(14.45)

16

16.89

(16.55) 15.60

(16.45)

18

18.89

(18.55) 17.60

(17.45)

19

19.99

(19.65) 18.50

(18.35)

9

NOM

f MAX

MIN

5

5.62

(5.38) 4.77

(4.62)

7

7.69

(7.45) 6.70

(6.55)

8

8.69

(8.45) 7.70

(7.55)

8

8.69

(8.45) 7.70

(7.55)

9

9.69

(9.45) 8.70

(8.55)

9

9.69

(9.45) 8.70

(8.55)

10

10.69

(10.45) 9.70

(9.55)

10

10.69

(10.45) 9.70

(9.55)

10 r MIN 0.3

(0.4)

0.5

(0.6)

0.5

(0.6)

0.5

(0.6)

0.5

(0.6)

0.7

(0.8)

0.7

(0.8)

0.7

(0.8)

11 l ≤ 150

>150

1±0.90

1±1.80

1±0.90

1±1.80

1±0.90

1±1.80

1±0.90

1±1.80

1±0.90

1±1.80

1±1.05

1±2.10

1±1.05

1±2.10

1±1.05

1±2.10

12 Pitch P 1.5 1.75 2 2 2.5 2.5 2.5 3

13 Pitch

Dia

Meter

Bolt MAX

MIN

Nut MAX

MIN

8.994

8.782

9.250

9.026

10.829

10.593

11.113

10.863

12.663

12.413

12.966

12.701

14.663

14.413

14.966

14.701

16.334

16.069

16.656

16.376

18.334

18.069

18.656

18.376

20.334

20.069

20.656

20.376

22.003

21.668

22.386

22.051

14 MAJOR

Diamet

er

Bolt MAX

MIN

Nut MAX

MIN

9.968

9.593

-

10.00

11.966

11.541

-

12.00

13.962

13.512

-

14.00

15.962

15.512

-

16.00

17.958

17.428

-

18.00

19.958

19.428

-

20.00

21.958

21.428

-

22.00

23.952

23.352

-

24.00


9.2 The diameter and pitch and combination shall be according to IS: 4213(Part II) - 1976.

The pitch shall be coarse. 9.3 The basic dimensions for profiles of ISO metric Screw threads shall be as per IS: 4213

(Part III) – 1976. 9.4 The tolerance class for ISO metric Screws threads shall be coarse as given in Table 5 of

IS: 4213(Part IV)-1976.

9.5 The deviations from basic dimensions for Nut and Bolt threads of the tolerance class specified in clause 9.4 shall be as tabulated in Table – 1.

The tolerance class shall be 7H for Nuts and 8g for Bolt threads. The limits of sizes for tolerance class 7H for Nut threads and 8g for Bolt threads are given in Table-1. These limits are applicable to ferrous Fasteners in black condition and to Stainless Steel Fasteners in finished condition.

9.6 The thread runouts and undercuts shall be as per IS: 1369-1995. 10. GALVANISING OF FERROUS FASTNERS

10.1 Dimensions 10.1.1 Fasteners with internal Threads: Prior to galvanizing and subsequent tapping the

dimensions of Fasteners with internal threads shall conform to the relevant standards. Internal threads shall be tapped over-size after galvanizing and they shall be oiled for corrosion protection. The oversize tapping allowance shall be as given in Table below. These allowances are applicable to major, pitch and minor diameters, the amended

diameters being subject to the same manufacturing tolerances of the appropriate grade of threads stated in the relevant fastener standard.

TABLE:ALLOWANCES FOR INTERNAL THREADS To ACCOMMODATE GALVANISED EXTERNAL THREADS

S.N. Nominal Size Internal Threads Diametral Allowances (mm)

(i) Below M 16 +0.40

(ii) M 16 to M22 + 0.50

(iii) Over M 22 and up to and including M36 + 0.65

10.1.2 Fasteners with External Threads: Prior to galvanizing, the dimensions of fasteners with

external threads shall conform to the relevant standards including thread sizes. (a) The thickness of galvanized coating on external threads shall be so controlled in the

galvanizing process that galvanized fasteners with external threads can be assembled by hand with internally threaded fasteners complying with 10.1.1.

(b) Galvanized external threads shall not be recut.

10.1.3 Coating Requirements 10.1.3.1 Mass of Coating: The mass of coating per square meter of the surface shall comply with

the minimum average and minimum individual sample coating given in Table below. The mass of coating shall be determined by one the following methods:-

a) The stripping test described in Append-IX B; or

b) Magnetic or Electronic thickness measuring devices as covered in IS: 3203-1965 ‘Method of testing local thickness of Electroplated coatings’. The mass of coating in g/m2

is found by multiplying the thickness in micrometers by 7.0.

10.1.3.2 In case of dispute, the stripping test shall be the Referee test.

TABLE: MASS AND EQUIVALENT THICKNESS OF COATING

Minimum Average Minimum Individual Thickness

Mass (g/m2) Thickness (µm) Mass (g/m2) µm

375 54 300 43

15 Minor

Dia

Mete

Bolt MAX

MIN

Nut MAX

MIN

8.128

7.808

8.751

8.376

9.819

9.457

10.531

10.106

11.508

11.114

12.310

11.835

13.508

13.114

14.310

13.835

14.891

14.446

15.854

15.294

16.891

16.446

17.854

17.294

18.891

18.446

19.854

19.294

20.271

19.740

21.382

20.752

Note:-

1. Use b1 for l ≤ 130, b2 for 130 < l ≥ 200 and b3 for l > 200. 2. Modified dimensions for width across flats (Normal series) for M 10, M 12, M 14 and M

22mm as per IS: 9519 - 1980 shall also be acceptable. 3. The tolerances on the last four dimension i.e. Sl.No. 12 to 15 are applicable in black

condition for ferrous Nuts and Bolts and these for Sl. No. 1 to 11 are applicable after galvanising.

4. Figures in brackets, wherever shown, indicate the dimensions for Stainless Steel

Fasteners.


10.1.4 Uniformity of Coating: The uniformity of Zinc coating shall be such that the coating

shall withstand the Copper sulphate test as mentioned in IS: 2633- 1986. ’Methods of testing uniformity of coating on Zinc coated Articles (First Revision) ‘without showing

any adherent red deposit of metallic copper upon the base metal with the following exceptions:

a) A fine line of Copper on the crest of the Screw threads or on sharp edges of

Bolt/Nut or at or adjacent to any cut of abrasion present in the original Fastener shall not be considered a defect to cause rejection, and

b) Any deposit of metallic Copper with threads of Fasteners which have been re-

thread rolled after galvanizing, is allowable.

10.1.5 Adhesion of Coating: The coating shall withstand the knife test as per IS: 2629-1985.

10.2 All Ferrous Fasteners, including Washers, shall be hot dip galvanized for electro-galvanized, to achieve a uniform adherent coating of zinc. The minimum thickness of

zinc coating shall be of 400 g/m2(55 microns). 11. TESTS

11.1 The manufacturers shall carry out the specified tests, during production on the samples, taken at regular intervals, separately for the different sizes, grade & material, which are being manufactured under similar processes of productions to ensure conformity to relevant Specifications as also to maintain proper control over

the process of manufacture. The manufacturer shall at the time of inspection, produce a certificate showing the records of various inspections/tests which have been exercised during manufacture.

11.2 When the Purchaser requires additional tests, related to his order but not specified hereunder, such tests shall be subject of agreement between the Purchaser and the Manufacturer.

11.3 All the tests on the Fasteners shall be carried out at manufacturer’s works. The

manufacturer shall arrange, without making claim or charge, all the necessary machinery, apparatus, labour, assistance etc. required to get the prescribed tests conducted in the presence of Purchaser’s representative.

11.4

Table-1A for Tests to be conducted

NOTE(i): tests (v)(f), (v) (g), (v) (h), (v) (i) and (vii) for Stainless Steel fasteners only (ii): tests (iii), (vi) for Galvanized fasteners only.

Tests

Clause no.

Type Test

Routine Test

Acceptance Test

(i) Visual examination 12.1 YES YES YES

(ii) Measurement of dimensions 12.2 YES NO YES

(iii) Gauging of threads for Galvanized Bolts, Nuts 12.3 YES NO YES

(iv) Chemical composition 12.4 YES NO YES

(v) Mechanical tests 12.5 YES NO YES

(a) Tensile test 12.5.1 YES NO YES

(b) Elongation after fracture 12.5.2 YES NO YES

(c) Hardness test 12.6 YES NO YES

(d) Proof load test 12.7 YES NO YES

(e) Head soundness test 12.9 YES NO YES

(f) 0.2% permanent Strain test for

Bolts

12.8 YES NO YES

(g) Crushing test for Nuts 12.10 YES NO YES

(h) Bond test on Straight Bolts 12.11 YES NO YES

(i) Torsion test on Bolts and Nuts 12.12 YES NO YES

(vi) Galvanizing test for Galvanized Bolts,Nuts 12.13 YES No YES

(vii)

Inter-crystalline corrosion Bend test or Micro examination

12.14

12.15

YES

YES

NO

NO

YES

YES

(viii) Permanent set test on spring washers 12.16 YES NO YES

(ix) Twist test on spring washers 12.17 YES NO YES


11.4.1 Sampling procedure:

Lot: All the Fasteners in a consignment belonging to the same size, grade, material and manufactured under similar process of production and submitted for inspection at one

instance shall constitute a lot. 11.4.2 Scale of sampling

(a) Samples shall be selected at random and examined for each lot separately for ascertaining their conformity to the requirements of this specification. Only one set of samples as indicated in 11.4.2(b) shall be drawn from a lot for all the characteristics.

(b) Samples shall be drawn from each lot in accordance with Column 1, 2, 3 of Table 2 for visual and dimensional verifications and for inspection of physical and other properties.

11.4.3 Criteria for conformity

(a) Visual characteristics: All the fasteners drawn in accordance with clause 11.4.2(b) shall

be first examined for visual characteristics like type, finish, workmanship, duds, visual surface discontinuities and identification mark. To ascertain the conformity of the lot to

the requirements of all visual characteristics, except duds, the procedure given in 11.4.3.1(a)(i) shall be followed. For duds, procedure given in 11.4.3() (ii) shall be followed.

(i) Visual characteristics (other than duds): If in the first sample the number of defective fasteners with respect to all visual characteristics, except duds, is less than or equal to the corresponding acceptance number (Ac) given in Column 5 of Table 2, the lot shall be

declared as conforming to the requirements for these characteristics.

TABLE 2 SCALE OF SAMPLING AND CRITERIA FOR CONFORMITY FOR INSPECTION (Clause 11.4.1, 11.4.2, 11.4.3)

Lot size Sample VISUAL

CHARACTERISTICS

DUDS DIMENSIONAL CHARACTERISTICS STAINLESS STEEL

FASTERNERS

Sam

ple

size

Cum

ulati

ve

size

Ac Re Ac Re Sam

ple

size

Cum

ulati

ve

size

BLACK FASTNERS

Major

defect

Major

defect Major

Defects

Minor

Defects

Ac R

e

Ac Re Ac R

e

Ac Re

AQL 4.0 0.65 2.5 4.0 1.5 2.5

1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 18 19

Upto

100

First

Second

20

20

20

40

1

4

4

5

0

1

2

2

8

8

8

16

0

1

2

2

0

1

2

2

0

1

2

2

0

1

2

2

101-300

First

Second

32

32

32

64

2

6

5

7

0

1

2

2

13

13

13

26

0

1

2

2

0

3

3

4

0

1

2

2

0

1

2

2

301-500

First

Second

50

50

50

100

3

8

7

9

0

1

2

2

20

20

20

40

0

3

3

4

1

4

4

5

0

1

2

2

0

3

3

4

501-

1000

First

Second

80

80

80

160

5

12

9

13

0

3

3

4

32

32

32

64

1

4

4

5

2

6

5

7

0

3

3

4

1

4

4

5

1001-

3000

First

Second

125

125

125

250

7

18

11

19

1

4

4

5

50

50

50

100

2

6

5

7

3

8

7

9

1

4

4

5

2

6

5

7

3001-

10000

First

Second

200

200

200

400

11

26

16

27

2

6

5

7

80

80

80

160

3

8

7

9

5

12

9

13

2

6

5

7

3

8

7

9

10001-

35000

First

Second

315

315

315

630

11

26

16

27

3

8

7

9

125

125

125

250

5

12

9

13

7

18

11

19

3

8

7

9

5

12

9

13

Over 35000

First

Second

500

500

500

1000

11

26

16

27

5

12

9

13

200

200

200

400

7

18

11

19

11

26

16

27

5

12

9

13

7

18

11

19

Note: Classification of major and minor defect is given in Appendix A of IS: 2614–1969.

[LEGEND + AQL= Acceptable quality Level]


If the number of defectives is greater then or equal to the corresponding rejection number (Re) given in Column 6 of Table 2, the lot shall be deemed as not meeting the

requirements for these characteristics. If the number of defectives is greater than the acceptance number but less than the

rejection number a second sample of the same x number of Fasteners selected as the first sample shall be taken to determine the conformity or otherwise of the lot.

The number of defectives found in the first and second sample shall be combined and if the combined number of defectives is less than or equal to the corresponding acceptance number the lot shall be declared as conforming to the requirements; otherwise not.

(ii) Duds: If the number of defective Fasteners in respect of duds is less than or equal to the corresponding acceptance number given in column 7 of Table 2, the lot shall be declared as conforming to the requirements for duds.

If the number of defective Fasteners is greater than or equal to the rejection number given in column 8 of Table 2, the lot shall be declared as not conforming to the requirements for duds.

If the number of defective Fasteners is greater than the acceptance number but less than the rejection number, a second sample of the same number of Fasteners selected as the first sample shall be taken to determine the conformity or otherwise of the lot.

The number of defective fasteners found in the first and second samples shall be combined and if the combined number of defective fasteners is less than or equal to the corresponding acceptance number, the lot shall be declared as conforming to the requirements for duds, otherwise not.

b) Dimensional characteristics: The lot which has been found satisfactory in respect of

visual characteristics [See 11.4.3(a)] shall be tested for dimensional characteristics like diameter, length etc. except pitch, basic dimensions of threads which will be tested as per clause 12.3 after stripping / case of Ferrous Fasteners. The Fasteners for this purpose shall be taken at random in accordance with column 9 and 10 of Table 2, from those already drawn for inspection of visual characteristics [see 11.4.3(a)] and tested

for dimensional characteristics. If the number of fasteners failing to satisfy the requirements for these characteristics is less than or equal to the corresponding acceptance number given in column 12,14,16 or 18 of Table 2, the lot shall be declared as to have not the requirements of the specification in respect of these characteristics. If the number of defectives is greater than or equal to the corresponding rejection numbers given in column 13,15,17 or 19 of table 2 the lot shall be deemed as not

confirming to these characteristics. In case the number of defective lies in between the acceptance and rejection number, a second sample of the same size shall be taken and inspected for dimensional characteristics and inference drawn accordingly.

(c) Physical, chemical & galvanizing requirements (i) From the samples taken in accordance with 11.4.2(b) and which have been subjected

to the visual and dimensional tests, samples in multiples of 5 or 6, as the case may be shall be drawn at random for mechanical, chemical and galvanising tests in case of

bolts and nuts. In case of spring washers, samples in multiples of 4 shall be selected for twist test and permanent set test.

(ii) Galvanized Fasteners BOLTS & NUTS: The samples selected in accordance with clause 11.4.3(c) (i) shall be

divided in following parts. Each part shall be subjected to Sl.No.(i),(ii),(iii),(iv), (v) (a), (v) (b), (v) (c), (v) (d) and (v) (e),(vi),(vii),(viii) and (ix) tests as per table 1A:

Should more than one sample fail in any test(s), the lot shall be rejected. If only one sample fails in any test, twice the number of samples shall be drawn and the test, twice the number of samples shall be repeated. The lot shall be accepted if there is no

failure in the re-test.

12. METHOD OF TESTS

12.1 Visual Examination: All the Bolts & Nuts shall be visually examined for finish, workmanship, chamfers and Identification mark and for visual surface discontinuities referred in IS: 1367 (Part 9) – 1993 and IS: 1367(Part 10) – 2002. Stainless Steel Fasteners shall be examined for bright finish also. The bolts shall be examined for straightness of shank and for any eccentricity of shank with respect to head. Nuts & washers shall be examined for eccentricity of the holes, crack, burrs, pits and other defects. Zinc coating on Ferrous Fasteners shall be examined for defects defined in

Appendix A of IS: 2629 – 1985.


12.2 Measurement of Dimensions: The dimensions of Fasteners, including lengths and threaded lengths of Bolts, shall be measured with the help of suitable gauges/devices

and shall be within the limits specified in Clause 7 & 8 of this Specification or these specified in purchaser’s drawings.

12.3 Gauging of threads: These tests shall be done in black condition of Galvanized

Fasteners after stripping. The thread pitch for particular diameter combination [See Table 1 of IS: 4213 (Part –II - 1976) and Table 1] shall be measured with the help of thread pitch gauges conforming to IS: 4211-1993. The thread profile shall be checked with the help of gauges in accordance with IS: 2334-2001. The limits of sizes of Nut and Bolt threads for tolerance Class 7H and 8g respectively are specified in Table -1.

12.4 Chemical composition

12.4.1 Ferrous fasteners: Chemical analysis of the Galvanized Steel Bolts shall be carried out in accordance with IS: 228 1987 and parts shall conform to Clause 4 of IS: 1367(Part 3) – 2002 i.e. Carbon shall not exceed 0.55%, Sulphur 0.06% and phosphorus 0.05% for bolts. The chemical composition for Ferrous Nuts shall be as

follows:

Property Class

Carbon %Maximum

Manganese Minimum

Phosphorus %Maximum

Sulphur %Minimum

4,5 0.50 - 0.110 0.150

04 0.58 0.25 0.060 0.150

12.4.2 Stainless Steel Fasteners shall be analyzed in accordance with IS: 228-1987 and

parts. The chemical composition shall conform to Grades mentioned in clause 5.2.

12.5 Mechanical Tests

12.5.1 Tensile Test for Bolts

(a) G.S. Bolts: The tensile test shall be carried out on all sizes of Bolts in finished

condition, where a free threaded length equal to one diameter of Bolt shall also be

subjected to tensile load. The fracture shall occur in the shank or thread of Bolt and

not at the junction of the head and the shank. The calculation of the tensile strength

is based on the stress area. The tensile strength shall not be less than 400 N/mm2.

(b) Stainless Steel Bolts and Studs: The Tensile Test shall be carried out on all sizes of

Bolts and Studs in finished condition, where a free threaded length equal to one

diameter of Bolt shall also be subjected to tensile load. The fracture shall occur in the

shank or thread of Bolt and not at the junction of the head and the shank. The

calculation of the tensile strength is based on the stress area. The tensile strength

shall not be less than 500 N/mm2.

(c) Test Rig: For the purpose of tensile test the rig shall be designed accordingly. The

speed of testing shall not exceed 25 mm/min. The grips of testing machine should be

self-aligning to avoid side thrust on the specimen".

12.5.2 Determination of percentage elongation after fracture

(a) G.S. Bolts: The elongation test shall be carried out on full size Bolts in finished

condition where it is possible to mark the gauge length equal to 5.65 √So on the

shank. Where it is not possible to mark the gauge length on the shank, machined

test pieces shall be used for the purpose of determination of percentage elongation

after fracture as per clause 8.1 IS:1367 (Part 3):2002. The load shall be applied in

the manner as in 12.5.1(c) The elongation after fracture in both the cases shall not

be less than 22%. The applicability of the elongation test on the full size Bolts in

finished condition and on machined test pieces (Refer Drawing No. ETI/C/0073(Mod.

A) Shall be as under:-


Nominal thread /

shank diameter(mm)

Dimensions for Bolts as per Drawing. No. ETI/C/0073 (Mod. A)

Machined Test Pieces In finished condition

12 60/30 and below 120/36 and above.

14 All sizes


18 All sizes


24 All sizes

(b) Stainless Steel Bolts and Studs: The extension after fracture of stainless steel Bolts

and studs shall be measured during the tensile test [see sub- clause 12.5.1(b)]. The

extension shall not be less than 0.6 d (where d is nominal diameter of Bolt).

12.6 Hardness Test: Hardness test for Galvanized Steel Fasteners shall be carried out after removal of zinc coating. On steel Bolts, the test shall be carried out in accordance with Clause 8.4 of IS: 1367(Part 3)-2002 and on Steel Nuts in accordance with clause 8.2

of IS: 1367(Part.6)-1994. On Stainless Steel Bolts and Nuts this test shall be carried

out in accordance with IS: 1586-2000 or latest version. The values of hardness shall be within the ranges given in Table 3 below.”

Table 3 [Ref: IS: 1367 (Part-V)-2002 or Latest]

Fastener Property class Nominal size Hardness

Min Max

Steel Bolts 4.6 All 120 HV 220 HV

Steel Nuts

04 All 188 HV 302 HV

4 Over M16 to M39 117 HV 302 HV

5 M10 – M 16 130 HV 302 HV

Over M16 to M39 146 HV 302 HV

Stainless steel Bolts & Nuts 50 All - 95 HRB

12.7 Proof load test on Bolts and Nuts: Proof load test on Bolts and Nuts shall be carried out

in accordance with Clause 8.5 of IS: 1367 (Part 3) - 2002 and Clause 8.1 of IS: 1367

(Part.6)-1994 respectively. The Stainless Steel Bolts shall be capable of being fully loaded upto the proof load, as prescribed in Table 4. Steel and Stainless Steel Nuts shall

be capable of being fully loaded upto proof loads indicated in Table 5.”

TABLE 4- PROOF LOAD VALUES FOR STEEL BOLTS, STEEL & SS NUTS–ISO METRIC COARSE THREADS

Nominal Size

Pitch of the

thread mm

Nominal stress area Of Mandrel

mm2

Proof load N

Steel Bolt Steel Nuts Stainless Steel Nuts,

(Proof Stress 500 N/mm2)

Property Class

4.6 of IS: 1367 (Part-6)-1994

04 4 5

M6 1 20.1 4520 7640 ---- 11700 10000

M7 1 28.9 6500 11000 ---- 16800 14500

M8 1.25 36.6 8240 13900 ---- 21600 18300

M10 1.5 58 13000 22000 ---- 34200 29000

M12 1.75 84.3 19000 32000 ---- 51400 42200

M14 2 115 25900 43700 ---- 70200 57500

M16 2 157 35300 59700 ---- 95800 78500

M18 2.5 192 43200 73000 97900 121000 96000

M20 2.5 245 55100 93100 125000 154400 122500

M22 2.5 303 68200 113100 154500 190900 152000

M24 3 353 79400 134100 180000 222400 476500

M27 3 459 103000 174400 234100 289200 229500

M30 3.5 561 126000 213200 286100 353400 280500

M33 3.5 694 156000 263700 353900 437200 347000

M36 4 817 184000 310500 416700 514700 408500

M39 4 976 220000 370900 497800 614900 488000

12.8 Stress at 0.2% Permanent Strain Test (For Stainless Steel Bolt only) :This test shall be

conducted in accordance with IS: 1608 – 2005 or latest version. The stress at 0.2% permanent strain shall not be less than 205 N/mm2.


12.9 Head soundness test for Bolts

12.9.1 This test is not applicable to U Bolts, J Bolts and Flat Countersunk Nib Bolts. 12.9.2 This test shall be carried out as illustrated in Figure 2 (enclosed) and in Figure 4 of IS:

1367(Part-3) - 2002. 12.9.3 The Bolt shall be inserted in a special Steel Die of the dimensions given in Table II of IS:

1367(Part-3)-2002. The hole in the die shall be at an angle of 600 to its upper surface. 12.9.4 When struck several blows with a hammer the head of Bolt or Screw should be bent to

an angle (90-60)0 without showing any sign of cracking at the fillet between Shank and head.

12.9.5 Where Screws are threaded upto the head the test will be regarded as established even

if a crack should appear in the first thread, provided that head does not snap off. 12.10 Crushing test on Nuts (Stainless Steel only): The Nut under test shall be placed

edgewise on an anvil and crushed by hammering till its threads come in contact with a mandrel, the diameter of which shall be 0.9 D1 where D1 is the minor diameter of Nut described in Figure 1 of IS:4213(Part. I):1976. After crushing, the Nut shall not exhibit

any fracture or crack at any point. The Nut may then be broken for further chemical analysis and inspection of structure.

12.11 Bond Test on Straight Bolts (Stainless Steel only) 12.11.1 This test is applicable only to straight Bolts. 12.11.2 The threaded part of the Bolt shall be so held in the jaws of a Vice that the threaded part

projects for a distance equal to at least half the nominal diameter. The projecting part shall then be bent by hammering so that the axis of free portion is at an angle of 165 degree to the axis of the portion held in the Vice. On examination, the bend shall not exhibit any crack (see Figure-3).

12.12 Torsion test on Bolts and Nuts (For Stainless Steel Bolts & Nuts only) 12.12.1 A torsion test shall be conducted on Stainless Steel Bolts and Nuts. The test shall be

conducted as described in 12.12.2 in case of straight Bolts and as described in 12.12.3 in case of U Bolts. The ultimate torsional strength shall be not less than that specified in Table 6.

TABLE – 6 ULTIMATE TORSIONAL MOMENTS FOR STAINLESS STEEL BOLTS AND NUTS

Diameter of Bolt (mm) Ultimate Torsional Strength (Minimum) (kg-m)

10 6.5

12 12

14 16

12.12.2 The head of the Bolt shall be gripped in a Vice and a Steel Plate slipped over the

thread, the diameter of the hole drilled in this steel plate being 11 mm in case of 10mm diameter Bolts, 14 mm in case of 12 mm diameter Bolts and 16 mm in the case of 14 mm diameter Bolts. A Flat Steel Washer is then placed between the Steel Plate and the

Nut (but none between Plate and head of Bolt). The total thickness of the Steel Plate and the Washer shall be so chosen that the position of Nut on the threaded portion of Bolt is the same as when the Bolt is in actual use. The test shall be carried out without lubrication of the parts in contact with each other. The torque shall be applied by means of Torque Spanner, the design of which is subject to the approval of the purchaser. The torque shall be increased in steps until the Bolt fractures. After each increment of

torque, the Nut shall be unscrewed and the threads on both Bolt and Nut examined.

12.12.3 The torsion test on U Bolts shall be conducted in a manner similar to that described in

12.12.2, but the U Bolt shall be prevented from deforming in the course of the test by seating it on a mandrel, the radius of curvature of which is equal to that of the inner edge of the U Bolt. A Steel Plate with two drilled holes shall be slipped over the two limbs of the U Bolt, the diameter of the holes in the Steel Plate bearing the same

relationship to the diameter of the Bolt as in the case of straight Bolts. The steep Plate may be integral with the mandrel. A Flat Steel Washer shall then be placed between the Steel Plate and the Nut on each limb (Fig 4). The torsion test shall then be carried out as described in 12.2.2 after gripping the mandrel in a Vice. It is sufficient if the test is conducted on one limb of the U-Bolt.

12.12.4 The test shall result in fracture of the Bolt, but not of the Nut. The values of torque at

fracture shall be not less then that indicated in Table-3. Further, on unscrewing the Nut


at any value of torque below the value specified in Table 3, the threads on Bolt and Nut shall be found to be undamaged and it shall be possible to work the nut along the entire

threaded length of the Bolt.

12.13 Galvanizing test: The Zinc coating on Galvanized Fasteners shall be tested for adherence, uniformity and mass. The mass of Zinc coating shall be measured on the unthreaded portion by stripping method (IS:6745 -1972) or by previously calibrated Elcometer (magnetic method). The uniformity shall be checked by Preece Test (IS:2633-1986) on the threaded portion of Bolts. It shall withstand at least five successive dips in one minutes. Adherence shall be checked on the shank or head by any one of the methods prescribed in clause 6.4 of IS 2629-1985.

12.14 Inter-Crystalline Corrosion Bend Test (For stainless steel only) 12.14.1 The Bend Test pieces shall not be larger than 12.5 mm (1/2 inch) diameter. The test

piece shall be sensitized by heating to a temperature of 6500C for the period stated in the relevant material specification, followed by cooling in air. All test pieces shall be immersed for 72 hours in boiling solution having the following composition: “111grams

Copper Sulphate(CuSo4.5 H2O), 98grams Sulphuric acid[Relative Density(d)=1.84 made upto 1litre with distilled water.”

Precautions shall be taken during the boiling to prevent concentration of the solution due to evaporation. After this preparation each test piece shall be bent through 90° round a radius equal to three times the diameter and thickness of the test piece, and shall withstand this treatment without cracking on the outer, convex surface.

12.15 Micro examination of Stainless Steel Fasteners (Test for freedom from Carbide precipitation) :Micro examination on transverse section

of Stainless Steel Bolts and Nuts shall be carried out to ascertain freedom from Carbide precipitation at grain boundaries. In case any sample shows evidence of Carbide precipitation, the lot represented by the same may be

reheat treated, and resubmitted as a new lot at the discretion of the purchaser.

Otherwise the lot shall be rejected. 12.16 Permanent Sat Test on Spring Washers: The Spring Washers under test shall be

compressed flat for 3 Minutes duration and released between two Plates having a hardness of 60 HRC, Minimum on release if the pressure, the free height (h2=2S indicated in IS:3063 1994) of the washer shall not be less then that given in Table 2 A

& Table 2 B of IS:3063-1994. This compression and removal of pressure shall then be repeated 20 times in quick succession after which the free height shall not have further reduced.

12.17 Twist Test on Spring Washers: A portion of the Washer shall be gripped in Vice jaws and

then equal portion shall be gripped in wrench jaws as shown in Figure 1 of IS: 3063-1994. Edges of the Wrench jaws shall be sharp and parallel to vice jaws. The Wrench

shall than be rotated in a direction that increases the free height of the Spring Washer till the Washer is twisted through on angle of 900. The Washer shall show no sign of fracture.

13. MARKING AND MODE OF DELIVERY

13.1 The Bolts shall be delivered assembled with their Nuts and Lock Nuts and Washers

(wherever required). The Nuts and Lock Nuts shall be fully screwed on by hand.

13.2 Bolts, Screws and Nuts shall be provided with identification marking as laid down in IS:

1367 (Part.3)-2002 & IS: 1367 (Part.6)-1994. For Hexagon head bolt and Screws, the marking is obligatory for all classes, preferably on the top of the head by indenting or embossing (see figure-1 of Annexure-2) or on the side of the head by indenting. In the

case of Bolts or Screws with flange, marking shall be on the flange where the manufacturing process does not allow marking on the top of head. For Stainless Steel Bolts and Screws, Grade A4 and Property Class 50 should be marked as property class (see figure-1 of Annexure-3).

For Hexagon nuts of threads ≥ M5 and all property classes shall be marked by indenting on the side (see figure-2 of Annexure-2) or bearing surface or by embossing on the chamfer. Embossed marks shall not protrude beyond the bearing surface of the

nut. For Stainless Steel Nuts, Grade A4 and Property Class 50 shall be marked as property class (see figure-2 of Annexure-3)


For Studs, if marking on unthreaded part is not possible, marking of property class only on the nut end of the stud is allowed (see figure-3 of Annexure-3). For studs with

interference fit, the marking shall be at the nut end with manufacturer’s identification marking only if it is possible. For Stainless Steel Studs, Grade A4 and Property Class 50

should be marked as property class (see figure-3 of Annexure-3). For Galvanized Plain Washers, manufacture’s identification shall be marked on the bearing surface (see figure-4 of Annexure-2). For Bronze, Stainless Steel and Copper Plan Washers, manufacturer’s identification shall be marked on bearing surface (see figure-4 of Annexure-3). For Galvanized steel Spring Washers, manufacturer’s identification shall be marked on bearing surface (see figure-5 of Annexure-2). For Phosphor Bronze Spring Washers,

manufacture’s identification shall be marked on bearing surface (see figure-5 of Annexure-3).

13.2.1 If the Fasteners are not properly marked by the manufacturers according to clause 13.2, then the whole lot shall be rejected. 13.3 The fasteners shall be packed as described in IS: 9141-1979.

13.4 Each package shall contain only one grade and dimension of Fasteners. 13.5 The packages shall be marked clearly and legibly with the following information.

a The product designation b A pictorial representation of the product

c Total number of pieces in the package d Net and gross mass of package,

e Name or Identification symbol of the manufacturer

f Purchase order No. and Consignee

g Date of Inspection and Inspecting Authority

h Any other information as required by Purchaser

ANNEXURE-1

specification for steel fasteners & stainless steel

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