Bolt Procedure

7/30/2019 Bolt Procedure

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FASTENERS TESTING PROCEDURE

Prepared By

Justin. A

Reviewed BY

Jessen P Abraham

Approved By

Ramasamy.S

Date: 28.07.2013 Fasteners Test Procedure ARIES-MT-F-001

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Sl.No Description of content Page ref.

1 Scope 3

2 Reference Documents 33 Testing Machine 4

4 Tension testing of machined test specimens 4

5 Tension testing procedure 7

6 Full size bolt test method 8

7 Full size bolt procedure 10

8 Hardness test for externally fastener 11

9 Hardness test for internally fastener 12

10 Proof load test 14

11 Proof load procedure 15

12 Acceptance criteria 1613 report 18

14 Annexure 1 19



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1. SCOPE

The test procedures cover for conducting tests to determine the mechanical

properties of externally and internally threaded fasteners, washers, and rivets.

Property requirements and the applicable tests for their determination are specied in

individual product standards. In those instances where the testing requirements are unique or

at variance with these standard procedures, the product standard shall specify the controlling

testing requirements.

These test procedures describe mechanical tests for determining the following properties.

a. Tension testing of machined test specimen

b. Axial tension testing of full size

c. Hardness test

d. Proof load test

2. REFERENCE DOCUMENTS

a. Client / Engineer requirements

b. Standard specification for carbon and alloy steel externally threaded metric fasteners asper ASTM F 568M

c. Mechanical properties of fasteners made of carbon steel and alloy steel-

Part 1: Bolts, screws and studs with specified property classes – Coarse thread and fine

pitch thread as per ISO 898-1.

d. Standard test methods for determining the mechanical properties of externally and

internally threaded fasteners, Washers, and Rivets as per ASTM F 606

e. Standard test methods and definitions for mechanical testing of steel products as per

ASTM A370. Mechanical properties of fasteners made of carbon steel and alloy steel

part 2: Nuts with specified property classes – Coarse thread and fine pitch thread as per

ISO 898-2.

f. Test methods for Rockwell hardness and Rockwell superficial hardness of metallic

materials as per ASTM E18.

g. Metallic materials – Rockwell hardness test – Part 1: Test method (scales

A,B,C,D,E,F,G,H,K,N,T) as per ISO 6508-1

h. Metallic materials – Tensile testing – part 1: Method of test at room temperature.



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3. TESTING MACHINE

a. Fine manufacturing industries, India, Model No. TFUC-1000, Capacity 1000 kN is the

Computerized universal testing machine used for the tensile test. Tensile test yield strength and

Offset percentage of proof stress used for Electronic Extensometer.

b. The Machine an accuracy of ± 1% guaranteed from 2% to 100% of capacity of the

machine.

c. Universal testing machine calibrated annually according to ASTM E4-09a and BS EN ISO

7500-1.

d. Universal Calibration services can be undertaken in presence of National /

International inspection agencies like UKAS.

4. Tension testing of machined test specimen

a. When bolts and studs cannot be tested full size, conduct tests using test specimens

machined from the bolt or stud (Test Methods ASTM E 8).

b. Bolts and studs 9 16 in. in diameter and smaller may be machined concentric with the axis of the

bolt or stud. The specimen shall have a turned section as large as feasible and shall have a gage length

four times the diameter of the specimen. See Fig. 1 and Fig. 2.

Fig 1 : Tension test specimen for bolt with Turned – Down shank



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Fig 2 : Examples of small-size specimens proportional to standard 2 – in gauge length specimen

c. Bolts and studs 5 8 in. in diameter through 1 1 4 in. in diameter may have their shanksmachined concentric with the axis of the bolt or stud, leaving the bolt head and threadedsection intact

as shown in Fig. 1.

d. Alternatively, bolts and studs5 8 in. in diameter through 1 1 4 in. in diameter may have

theirshanks machined to a test specimen with the axis of thespecimen located midway between the axis

and outside surfaceof the bolt or stud as shown in Fig. 3. Bolts of a small crosssection that will not

permit taking the 0.500-in. round, 2-in.gage length test specimen shall have a turned section as largeas

feasible and concentric with the axis of the bolt or stud.

Fig 3. Location of standard round 2 –in gage length tension test specimen when turned from large size

bolt.



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e. The gage length for measuring the elongation shall be four timesthe diameter of the specimen. Fig. 2

illustrates an example ofthese small-size specimens. For arbitration purposes, machinedtest specimens

for bolts and studs 5 8 in. in diameter through1 1 4 in. in diameter shall be machined with the axis of

thespecimen located midway between the center and outsidesurface.

f. Bolts and studs 1 3 8 in. in diameter and larger mayhave their shanks machined to the dimensions of

a 0.500-in.round, 2-in. gage length test specimen with the axis of thespecimen located midway between

the center and outsidesurface of the bolt or stud as shown in Fig. 3.

g. Machined test specimens shall exhibit tensilestrength, yield strength (or yield point), elongation, and

reduction of area equal to or greater than the values of theseproperties specied for the product size inthe applicableproduct specication when tested in accordance with thissection.

h. Yield Strength

Yield strength is the stress at which amaterial exhibits a specied limiting deviation from the

proportionality of stress to strain. The deviation is expressed interms of strain, percent offset, total

extension under load, etc

Yield Point—Yield point is the rst stress in a material, less than the maximum obtainable stress, at

which an increase in strain occurs without an increase in stress. Yield point is intended for application

only for materials that may exhibit the unique characteristic of showing an increase in strain without anincrease in stress. The stress-strain diagram is characterized by a sharp knee or discontinuity.

Autographic Diagram Method—When a sharp kneed stress-strain diagram is obtained by an autographic

recording device, take the stress corresponding to the stress at which the curve drops as the yield point

(Fig. 4).

Fig 4 stress – strain diagram showing yield point corresponding with top of knee



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i.Tensile Strength

Calculate the tensile strength bydividing the maximum load the specimen sustains during atension test

by the original cross-sectional area of the specimen.

j. Elongation:

Fit the ends of the fractured specimen togethercarefully and measure the distance between the gage

marks tothe nearest 0.01 in. for gage lengths of 2 in. and under, and tothe nearest 0.5 % of the gage

length for gage lengths over 2 in. A percentage scale reading to 0.5 % of the gage length may beused.

The elongation is the increase in length of the gagelength, expressed as a percentage of the original

gage length. Inreporting elongation values, give both the percentage increaseand the original gage

length.

If any part of the fracture takes place outside of themiddle half of the gage length or in a punched or

scribed markwithin the reduced section, the elongation value obtained maynot be representative of the

material. If the elongation someasured meets the minimum requirements specied, nofurther testing is

indicated, but if the elongation is less than theminimum requirements, discard the test and retest.

k. Reduction of Area

Fit the ends of the fracturedspecimen together and measure the mean diameter or the widthand

thickness at the smallest cross section to the same accuracyas the original dimensions. The difference

between the areathus found and the area of the original cross section expressedas a percentage of the

original area, is the reduction of area.

5. Tension testing procedure

a. Completion of tensile test specimen preparation shall be ensured. Tensile Plate type test specimen

width and corresponding thickness of the reduced section shall be measured.

b. Tensile test reduced section minimum dimension of this test piece, maximum dimension of test piece

shall not exceed.

c. Cross sectional area shall be obtained by multiplying the width by the thickness.

d. The original cross-sectional area shall be calculated from the measurements of the appropriate

dimensions. The accuracy of the calculation depends on the nature and type of the test piece.

e. The gage marks for measuring elongation after fracture shall be made on the flat or on the edge of



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the flat tension test specimen and within the parallel section; for the gage length specimen, one or

more sets gage marks may be used, intermediate marks within the gage length being optional.

Rectangular 2-in. gage length specimens, and round specimens, gauge marked with a double-pointed

center punch or scribe marks. One or more sets of gage marks may be used; however, one set must be

approximately centered in the reduced section. These same precautions shall be observed when the test

specimen is full section.

f. The test machine shall be set up and zeroed in such a manner that zero force indication signifies a

state of force on the specimen, as indicated in the zeroing of the test machine.

6. Full size bolt test method

It is preferred that bolts be tested full size, and it iscustomary, when so testing bolts to specify a

minimumultimate load in pounds, rather than a minimum ultimatestrength in pounds per square inch.

Three times the bolt nominal diameter has been established as the minimum bolt length subject to the

tests described in the remainder of this section. Sections –A proof load, section –C proof load – time of

loading apply when testing boltsfull size. Section – D Axial tension testing of full size bolts shall apply

where the individualproduct specications permit the use of machined specimens.

Section – A. Proof Load— Due to particular uses of certainclasses of bolts it is desirable to be able to

stress them, whilein use, to a specied value without obtaining any permanentset. To be certain of

obtaining this quality the proof load isspecied. The proof load test consists of stressing the bolt witha

specied load which the bolt must withstand without permanent set. An alternate test which

determines yield strength of afull size bolt is also allowed. Either of the following Methods,1 or 2, may

be used but Method 1 shall be the arbitrationmethod in case of any dispute as to acceptance of

thebolts.

Section -B. Proof Load Testing Long Bolts—When full sizetests are required, proof load Method 1 is to be

limited inapplication to bolts whose length does not exceed 8 in. (203mm) or 8 times the nominal

diameter, whichever is greater. Forbolts longer than 8 in. or 8 times the nominal diameter,whichever is

greater, proof load Method 2 shall be used.

(a) Method 1, Length Measurement—The overall length ofa straight bolt shall be measured at its true

center line with aninstrument capable of measuring changes in length of 0.0001in. (0.0025 mm) with an

accuracy of 0.0001 in. in any 0.001-in.(0.025-mm) range. The preferred method of measuring thelength

shall be between conical centers machined on the center line of the bolt, with mating centers on the

measuring anvilsThe head or body of the bolt shall be marked so that it can beplaced in the same

position for all measurements. The bolt shallbe assembled in the testing equipment as outlined in



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Section - D. and the proof load specied in the product specication shallbe applied. Upon release of

this load the length of the bolt shallbe again measured and shall show no permanent elongation.

Atolerance of 60.0005 in. (0.0127 mm) shall be allowedbetween the measurement made before loading

and that madeafter loading. Variables, such as straightness and thread alignment (plus measurement

error), may result in apparent elongation of the fasteners when the proof load is initially applied.

In such cases, the fastener may be retested using a 3 percent greater load, and may be considered

satisfactory if the lengthafter this loading is the same as before this loading (within the0.0005-in.

tolerance for measurement error).

Section – C. Proof Load-Time of Loading—The proof load is tobe maintained for a period of 10 s beforerelease of load, whenusing Method 1.

(a) Method 2, Yield Strength—The bolt shall be assembledin the testing equipment as outlined in

section- D. As the load isapplied, the total elongation of the bolt or any part of the boltwhich includes

the exposed six threads shall be measured andrecorded to produce a load-strain or a stress-strain

diagram.

The load or stress at an offset equal to 0.2 percent of the length of bolt occupied by 6 full threads shall

be determined by themethod described in yield point off set methods. This loador stress shall not be

less than that prescribed in the product specication.

Section -D. Axial Tension Testing of Full Size Bolts—Bolts areto be tested in a holder with the load axially

applied betweenthe head and a nut or suitable xture (Fig. 5), either ofwhich shall have sufficient thread

engagement to develop thefull strength of the bolt. The nut or xture shall be assembledon the bolt

leaving six complete bolt threads unengagedbetween the grips, except for heavy hexagon structural

boltswhich shall have four complete threads unengaged between thegrips. To meet the requirements of

this test there shall be a tensile failure in the body or threaded section with no failure at the junction of

the body, and head. If it is necessary to record or report the tensile strength of bolts as psi values the

stress area shall be calculated.



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.

Fig 5 . Tension testing full- size bolt.

7. Full bolt test procedure

a. Ensure the specifications of the received bolt.

b. Measuring the bolt diameter and length.

c. Calculate the original cross section area of the bolt.

d. Attaching the jigs of bolt to the jaw of machine.

e. The test machine shall be set up to zero in such a manner that zero force indication signifies a

state of force on the specimen, as indicated in the zeroing of the test machine.

f. Fit the bolt to the jigs.

g. Ensure the jigs & bolt assemblies

h. Directly apply the tensile load to the bolt.

i. Determination of yield strength: When yield strength is measured using software, the yield

strength will be automatically given by the system.

j. Determination of tensile strength: Calculate the tensile strength by dividing the maximum load

carried by the test specimen by the original cross-sectional area of the test specimen. When

software is being used in testing, the value is automatically given by the system



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k. Determination of elongation: Fit the fractured ends together carefully and measure the distancebetween the gage marks to get the increased (final) gage length. Calculate the elongation by

dividing the difference in gage lengths (original and final) by the original gage length. When the

software is used enter the final gage length to the system to give the percentage automatically.

Note: Bolt dia should be maximum 20mm and length should be minimum 75mm according to our

facilities.

8. Hardness Tests for Externally Fasteners

Tests shall be conducted after the removal of any surface oxide, decarburization, plating or

other coating. All readings shall be within the hardness values listed in the product specication. The

average of all readings on the same part shall be considered as the product hardness. Test results shall

conform to the product specication for the lot represented by the test specimens to be considered

conforming. Test specimen preparation and hardness test shall be conducted in accordance for Rockwell

hardness test. The method used is at the option of the manufacturer, with regards to the size and grade

of the products.

Routine Test Locations—for testing the hardness of the nished product, the following test locations can

be used:

a. For hex and square head bolts; test shall be conducted on the wrench ats, top of head, unthreadedshank, end of bolt or at the arbitration location.

b. For studs, products without parallel wrench ats and for head styles other than hex and square; tests

shall be conducted on the unthreaded shank, end of the bolt or stud or at the arbitration location.

c. Stress relieved products are measured anywhere on the surface or through the cross section. Refer to

the product specication for particular test location or use the arbitration location.

d. The Rockwell Hardness Scale may be used for all product diameters.

Laboratory Inspection—After observing product hardness and routine Test Locations, a minimum of

three readings shall be taken on each sample of nished product.

Arbitration Test Location—Hardness tests shall be conducted at the mid-radius (r/2) of a transverse

section through the threads taken at a distance of approximately one diameter from the point end of

the bolt or one end of the stud. Four readings shall be taken from the point end of the bolt or one end of

the stud. Four readings shall betaken approximately 90° to one another on the same plane, if product



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size permits. Smaller diameter products may also usethe opposite parallel surface area of the bolt head

end assectioned above. (See Fig. 6).

Fig 6. Hardness Arbitration test location

9. Hardness Tests for internally Fasteners

a. Product Hardness—For routine inspection of both heat treated and non heat-treated nuts, hardness

shall be determined on the bearing face or wrenchats after removal of any oxide, decarburization,

plating, or other coating material. Rockwell or Brinell hardness shall be used at the option of themanufacturer, taking into account the size and grade of the product.

b. The preparation of test specimens and the performance of hardness tests for Rockwell testing shall

be in conformance with the requirements of test Methods.

c. Readings when taken on the bearing face shall be halfway between the major diameter of the thread

and one corner. The reported hardness shall be the average of two hardness readings located 180°

apart. The readings when taken on the wrench ats shall be one third of the distance from a corner to

the center of the wrench face. The reported harness shall be the average of two readings located from

opposite corners.

d. Sample nuts shall be sectioned laterally at approximately one half ( 1 2 ) of the nut height. Such

samples need not be threaded, but shall be part of the manufacturing lot that was formed (in the case

of heat-treated nuts, formed and heattreated) with the product to be shipped. All readings shall be

conducted on a Rockwell Hardness testing machine.

e. Non heat-Treated Nuts (See Fig. 7)—Two readingsshall be taken 180° apart at the core (halfway

between themajor diameter if threaded, or blank hole if not threaded) anda corner of the nut. The



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reported hardness shall be the averageof the two readings, and in addition both readings shall bewithin

the hardness values listed in the product specication.

Fig 7. Non heat - Treated nut

f. Heat-Treated Nuts (See Fig. 8)—Two sets of threereadings 180° apart shall be taken. The three

readings shall betaken across the section of the nut at the following positions:

Position 1—As close to the major diameter, as possible, if threaded, orhole side wall if the nut is blank,

but no closer than 2 1 2 mes the indentdiameter.

Position 2—At the core (halfway between the major diameter, ifthreaded, or hole side wall, if blank) anda corner of the nut.

Position 3—As close to the corner of the nut as possible, but no closerthan 2 1 2 mes the indent

diameter.

Fig 8 . Heat - Treated nut



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g. The reported hardness shall be the average of all sixreadings. In addition all readings shall be within

hardnessvalues listed in the product specication.

h. For nuts on which hardness and proof load tests areperformed, acceptance based on proof load

requirements shalltake precedence in the event of controversy with hardness tests.

10. Proof load test

A sample nut shall be assembled on a hardened threaded mandrel or on a bolt conforming

to the particular specication. A load axial with the mandrel or bolt and equal to the specied proof load

of the nut shall be applied.

The nut shall resist this load without stripping or rupture. If the threads of the mandrel are damaged

during the test the individual test shall be discarded.

Assemble the nut to be tested on a hardened threaded mandrel or a test bolt as i llustrated in Fig. 9 a)

Tension Method or Fig. 9(b) Compression Method. The hardened test mandrel and the tension method

shown in Fig. 9(a) shall be mandatory as a referee if arbitration is necessary. Apply the specied proof

load for the nut against the nut. The nut shall resist this load without stripping or rupture, and shall be

removable from the test bolt or mandrel by the ngers after the load is released. Occasionally it may be

necessary to use a manual wrench or other means to start the nut in motion. Use of such means is

permissible, provided the nut is removable by the ngers following the initial loosening of not more thanone-half turn of the nut. If the threads of the mandrel or test bolt are damaged during the test, discard

the test.

The test bolt shall have threads appropriate to the standard specied for the nut being tested and shall

have a yield strength in excess of the specied proof load of the nut being tested.Mandrels shall have a

hardness of 45 HRC minimum and shall have threads conforming to Class 3A except that the maximum

major diameter shall be the minimum major diameter plus 0.002 in. or 0.25 times the major diameter

tolerance (whichever is greater) of Class 3A threads.

The proof load shall be determined at a free running cross head speed not exceeding 1.0 in/minute and

shall be held at load for 10s minimum.



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Fig 9. a. Tension method

Fig 9. B Compression Method

11. Proof load procedure

a.We are using the compression method for proof load test to the nut.



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b. Choose the bolt specification either same as nut or higher specification.

c. Keep the appropriate support block on the machine bed.

d. Zeroing of the test machine: The testing machine shall be set up in such a manner that zero force

indication signifies a state of zero force on the specimen.

e. The magnitude of the application of compression load to the nut should be greater than the load

mentioned as per standard to the nut.

f. While loading ensure the non-displacement of the nut. Hold the proof load for 10s

12. Acceptance criteria

Fasteners acceptance criteria as per ASTM F568M



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13. Report

Test information to be reported shall include the following when applicable:

a. Material Grade and sample identification

b. Applicable test code

c. Test specimen dimensions

d. Original gage length

e. Yield load and yield strength

f. Tensile load and tensile strength

g. Gauge length after testing

h. Elongation

I. Reduction of area

j. Hardness Value

k. Proof load

l. Percentage of Chemical composition



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Annexure 1