Fasteners General Guide

8/20/2019 Fasteners General Guide

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TRAINING MANUAL- PIPING

FASTENERS

Uhde India Limited

DOC No. : 29040-PI-UFR-0012

Rev. : R0

Page : 1

CONTENTS

Page

0.0 Cover Sheet 1

1.0 Introduction 2

2.0 Classification 2

3.0 Application 2 – 3

4.0 Dimensional Standards 3 – 5

App licable Rev is ion:

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Date:

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First Edition: R0

Prepared: DNL

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Checked: AKB

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Approved: RUD

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File Name: C- 12 Server: PUNE: KUMUS 207 VKO: KUMUS 209

Directory: PUNE: Refer \ Pi \ Training Manual VKO: Refer \ Training Manual




FASTENERS

Uhde India Limited

DOC No. : 29040-PI-UFR-0012

Rev. : R0

Page : 2

1.0 INTRODUCTION:

The flanges are drilled to receive bolts which, if of the proper material, will develop the fullflange strength and result in a satisfactory joint at the service intended.

The term 'bolting material' covers bolts, studs and stud bolts.

As per ASME B16.5, one can use either square head machine bolts or studs for making a joint. Bolts and studs are available in either fully threaded or partially threaded condition. Thefully threaded structure ensures an equal distribution of elongation when the bolts aretightened and avoid concentration of stresses that exist in partially threaded stock due tovarying cross-sections.

Also, studs are preferred over bolts due to ease of insertion during assembly. At places, likebolting of two valves together, there may not be sufficient clearance available for insertingbolts due to valve body contour and use of studs is the only possible solution

2.0 CLASSIFICATION:

Since bolting material does not come in contact with fluid, its material compatibility with fluid isnot important. The selection of bolt material is determined based on service conditions and itis wasteful to specify expensive alloys when carbon steel material is entirely suitable. It isimportant for bolting material to have good tensile stress.

As per ASME B16.5, bolting material has been divided into three categories as follows:

i. High strength bolting:

Bolting materials having allowable stresses not less than those for ASTM A193 grade B7 arelisted as high strength bolts. ASME B16.5 Table 1B is enclosed for reference.These and other materials of comparable strength may be used in any flanged joint.

ii. Intermediate strength bolting:

Bolting materials listed as intermediate strength in Table 1B, and other bolting of comparablestrength, may be used in any flanged joint, provided the user verifies their ability to seat theselected gasket and maintain a sealed joint under expected operating conditions.

iii. Low strength bolting:

Bolting materials having not more than 30 ksi specified minimum yield strength are listed aslow strength in Table 1B. These materials and others of comparable strength shall be usedonly in Classes 150 and 300 joints, and only with gaskets of group no. 1a. Flanged joints

using low strength carbon steel bolts shall not be used above 400°F or below -20

°F.

3.0 APPLICATION:

i. For flanged joints in piping system where one or both flanges are of cast iron, bolts /studs conforming to ASTM A307 Gr. B and nuts conforming to A194 Gr. 2 are usually used.Equivalent IS standards for such fasteners is IS 1367 CI. 6.6 / IS 1367 CI. 6.

ii. For carbon steel flanges having ASME 150 rating on non-critical services, bolts / studsconforming to ASTM A307 and nuts conforming to ASTM A194 Gr. 2 or fasteners conformingto IS 1367 CI. 6.6 / IS 1367 CI. 6. are usually used.




FASTENERS

Uhde India Limited

DOC No. : 29040-PI-UFR-0012

Rev. : R0

Page : 3

iii. For carbon steel flanges on process and critical services involving medium andmoderately high pressures and temperatures, bolts / studs conforming to ASTM A193 Gr. B7along with heavy hexagonal head nuts conforming to ASTM A194 Gr. 2H are usually used.

iv. For very severe service conditions involving high temperatures upto 1100°F bolts / studs

conforming to ASTM A193 Gr. B7 along with nuts conforming to ASTM A194 are usuallyused.

v. For low temperature carbon steel flanges, studs conforming to ASTM A320 Gr. L7 alongwith nuts conforming to ASTM A194 Gr. 4 are usually used.

vi. For all flange joints in plastic piping, low strength bolts / studs are usually acceptable. Useof washers is recommended for joints in plastic piping.

vii) Some times in plastic piping, handling corrosive fluids, it is recommended that thefasteners are supplied with cadmium plating or galvanized coating. This is in order to havecorrosion resistance against spillages, etc.

4.0 DIMENSIONAL STANDARDS:

Dimensional standards usually adopted for fasteners are as follows:

Studs bolts : ASME B 18.2.1Studs : DIN 976 Type B / DIN 934Nuts : ASME B 18.2.2Male Threads : ASME B 1.1 C1. 2A

Coarse series (UNC)Female Threads : ASME B 1.1 C1. 2A

Coarse series






FASTENERS

Uhde India Limited

DOC No. : 29040-PI-UFR-0012

Rev. : R0

Page : 5

GENERAL NOTE :

Bolting material shall not be used beyond temperature limits specified in the governing code.

NOTES:

1. Repair welding of bolting material is prohibited.

2. These bolting materials may be used with all listed materials and gaskets.

3. These bolting materials may be used with all listed materials and gaskets, provided it hasbeen verified that a sealed joint can be maintained under rated working pressure andtemperature.

4. These bolting materials may be used with all listed materials that are limited to Classes150 and 300 joints. See para. 5.4.1 for required gasket practices.

5. These materials may be used as bolting with comparable nickel and special alloy parts.

6. This austenitic stainless steel material has been carbide solution treated but not strainhardened. Use A194

7. Nuts may be machined from the same material or may be of a compatible grade of ASTM A194.

8. Maximum operating temperature is arbitrarily set at 500°F, unless material has beenannealed, solution annealed or hot finished, because hard temper adversely affectsdesign stress in the creep rupture stage.

8. Forging quality not permitted, unless the producer last testing or working these parts,tests them as required for other permitted conditions in the same specification andcertifies their tensile, yield and elongation properties to equal or exceed the requirementsfor one of the other permitted conditions.

9. This ferritic material is intended for low temperature service. Use A194 Grade 4 or Grade7 nuts.

10. This austenitic stainless steel material has been carbide solution treated and stainhardened. Use A194 nuts of corresponding material.

11. This carbon steel fastener shall not be used above 400°F or below -20°F. See also note(4). Bolts with drilled or undersized hands shall not be used.

12. Acceptable nuts for use with quenched and tempered bolts are A194 Grades 2 and 2H.

Mechanical property requirements for studs shall be the same as those for bolts.

14. This special Alloy is intended for high temperature service with austenitic stainless steel.

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Fasteners General Guide