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BS EN ISO 3506-2:2020 – TC

$217.84

Tracked Changes. Fasteners. Mechanical properties of corrosion-resistant stainless steel fasteners – Nuts with specified grades and property classes

Published By Publication Date Number of Pages
BSI 2020 92
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This document specifies the mechanical and physical properties of nuts, with coarse pitch thread and fine pitch thread, made of corrosion-resistant stainless steels, when tested at the ambient temperature range of 10 °C to 35 °C. It specifies property classes in relation to austenitic, martensitic, ferritic and duplex (austenitic-ferritic) steel grades for nuts.

ISO 3506-6 provides general rules and additional technical information on suitable stainless steels and their properties.

Nuts conforming to the requirements of this document are evaluated at the ambient temperature specified in paragraph 1. It is possible that they do not retain the specified mechanical and physical properties at elevated and/or lower temperatures.

NOTE 1

Fasteners conforming to the requirements of this document are used without restriction in applications ranging from –20 °C to +150 °C; however, fasteners conforming to this document are also used for applications outside this range down to –196 °C and up to +300 °C. For more details, see ISO 3506-6 .

Outside the temperature range of –20 °C to +150 °C, it is the responsibility of the user to determine the appropriate choice for a given application, in consultation with an experienced fastener metallurgist and by taking into account e.g. stainless steel composition, duration of exposure at elevated or low temperature, the effect of the temperature on the fastener mechanical properties and clamped parts, and the corrosive service environment of the bolted joint.

NOTE 2

ISO 3506-5 3

3

Under preparation.

is developed in order to assist in the selection of appropriate stainless steel grades and property classes intended for use at temperatures up to +800 °C.

This document applies to nuts:

  • with ISO metric thread in accordance with ISO 68-1 ,

  • with diameter/pitch combinations in accordance with ISO 261 and ISO 262 ,

  • with coarse pitch thread M5 to M39, and fine pitch thread M8×1 to M39×3,

  • with thread tolerances in accordance with ISO 965-1 and ISO 965-2 ,

  • with specified property classes, including proof load,

  • with different nut styles: thin nuts, regular nuts and high nuts,

  • with a minimum nut height m ? 0,45 D,

  • with a minimum outside diameter or width across flats s ? 1,45 D (see Annex A),

  • of any shape, and

  • able to mate with bolts, screws and studs with property classes in accordance with ISO 3506-1 .

Stainless steel grades and property classes can be used for sizes outside the diameter limits of this document (i.e. for D < 5 mm or D > 39 mm), provided that all applicable chemical, mechanical and physical requirements are met.

This document does not specify requirements for functional properties such as:

  • torque/clamp force properties,

  • prevailing torque properties, or

  • weldability.

PDF Catalog

PDF Pages PDF Title
1 compares BS EN ISO 3506-2:2020
2 TRACKED CHANGES
Text example 1 — indicates added text (in green)
3 National foreword
Compliance with a British Standard cannot confer immunity from legal obligations.
Amendments/corrigenda issued since publication
8 Foreword
10 Introduction
11 Fasteners — Mechanical properties of corrosion-resistant stainless steel fasteners —
Part 2:
1 Scope
13 2 Normative references
14 3 Terms and definitions
3.1
3.2
3.3
3.4
3.5
34 Symbols
15 45 Designation, marking and finish systems
4.1 Designation
16 Figure 1 — Designation system for stainless steel grades and property classes for nuts
4.2 Marking
4.2.2 Manufacturer’s identification mark
17 4.2.3 Nuts
Figure 2 — Marking with material designation and manufacturer’s identification mark
18 4.2.4 Packages
4.3 Finish
5.1 Designation of nut styles
5.2 Designation system for stainless steel grades and property classes
5.2.1 General
19 Figure 1 — Designation system for stainless steel grades and property classes for nuts
5.2.2 Designation of stainless steel grades (first block)
20 5.2.3 Designation of property classes (second block) for regular nuts (style 1) and high nuts
5.2.4 Designation of property classes (second block) for thin nuts (style 0)
5 Chemical composition
21 Table 1 — Stainless steel grades — Chemical composition
6 Design of bolt and nut assemblies
Table 1 — Property class combination of nuts to bolts, screws and studs
22 6 Mechanical properties
Table 2 — Mechanical properties for nuts — Austenitic steel grades
23 7 Materials
7.1 Chemical composition
24 Table 2 — Stainless steel grades — Chemical composition
7.2 Heat treatment for martensitic stainless steel nuts
25 7.3 Finish
7.4 Corrosion resistance
8 Mechanical and physical properties
26 Table 3 — Mechanical properties for nuts — Austenitic and duplex grades
Table 4 — Mechanical properties for nuts — Martensitic and ferritic grades
27 Table 5 — Proof load values for regular and high nuts with coarse pitch thread (full loadability)
Table 6 — Proof load values for regular and high nuts with fine pitch thread (full loadability)
28 Table 7 — Proof load values for thin nuts with coarse pitch thread (reduced loadability)
Table 8 — Proof load values for thin nuts with fine pitch thread (reduced loadability)
29 9 Inspection
9.1 Manufacturer’s inspection
9.2 Supplier’s inspection
9.3 Purchaser’s inspection
9.4 Delivery of test results
710 Test methods
7.1 Hardness HB, HRC or HV
7.2 Proof load
30 10.1 Proof load test
10.1.1 General
10.1.2 Applicability
10.1.3 Apparatus
10.1.4 Testing device
31 Figure 2 — Axial tensile test
Figure 3 — Axial compressive test
32 10.1.5 Test procedure
10.1.6 Addition to test procedure for prevailing torque nuts
10.1.7 Test results and requirements
33 10.2 Hardness test
10.2.1 General
10.2.2 Test procedure
Hardness determined on a surface
Hardness determined on a longitudinal section (core hardness)
Figure 4 — Location of hardness readings (longitudinal section)
34 10.2.3 Test results and requirements
11 Nut marking and labelling
11.1 Nut marking
11.1.1 General requirements for marking
11.1.2 Marking of property class for nuts with full loadability (regular and high nuts)
Table 10 — Property class marking symbol for nuts with full loadability (regular and high nuts)
11.1.3 Marking of property class for nuts with reduced loadability (thin nuts)
35 Table 11 — Property class marking symbol for nuts with reduced loadability (thin nuts)
11.1.4 Additional marking
11.2 Manufacturer’s identification mark
11.3 Marking on the nuts
11.3.1 Hexagon nuts
36 Figure 5 — Examples of marking for hexagon nuts with full loadability
Figure 6 — Examples of marking for hexagon nuts with reduced loadability
37 Figure 7 — Alternative groove marking (for grades A2 and A4 only)
11.3.2 Other types of nuts
11.3.3 Left-hand thread marking
Figure 8 — Example of marking for left-hand thread
11.4 Marking of the packages (labelling)
38 (informative)
A.1 General
A.2 Steel group A (austenitic structure)
A.2.1 General
A.2.2 Steel grade A1
39 A.2.3 Steel grade A2
A.2.4 Steel grade A3
A.2.5 Steel grade A4
A.2.6 Steel grade A5
A.3 Steel group F (ferritic structure)
A.3.1 General
A.3.2 Steel grade F1
A.4 Steel group C (martensitic structure)
A.4.1 General
A.4.2 Steel grade C1
A.4.3 Steel grade C3
40 A.4.4 Steel grade C4
A.5 Steel group FA (ferritic-austenitic structure)
Table A.1 — Examples of compositions of steels with ferritic-austenitic structure
41 (informative)
42 Table A.1 — Minimum height of hexagon nuts
A.2 Nuts with diameters D 39 mm
43 Annex B
(informative)
44 Table B.1 — Stainless steel composition specifications
46 Annex B
(normative)
Table B.1 — Thread dimensions of the test mandrel – Coarse pitch thread
47 Table B.2 — Thread dimensions of the test mandrel — Fine pitch thread
48 Annex C
(informative)
49 Table C.1 — Stainless steels for cold heading and extruding
50 Annex D
(informative)
Table D.1 — Austenitic stainless steels with particular resistance to chloride induced stress corrosion
51 Table E.1 — Influence of temperature on ReL and Rp0,2
Table E.2 — Application of stainless steel bolts, screws and studs at low temperatures
52 Annex F
(informative)
Figure F.1 — Time-temperature diagram of intergranular corrosion in austenitic stainless steels, grade A2
53 Annex G
(informative)
54 Bibliography
56 undefined
58 European foreword
Endorsement notice
61 Foreword
63 Introduction
65 1 Scope
66 2 Normative references
3 Terms and definitions
67 4 Symbols
68 5 Designation systems
5.1 Designation of nut styles
5.2 Designation system for stainless steel grades and property classes
5.2.1 General
69 5.2.2 Designation of stainless steel grades (first block)
70 5.2.3 Designation of property classes (second block) for regular nuts (style 1) and high nuts (style 2)
5.2.4 Designation of property classes (second block) for thin nuts (style 0)
6 Design of bolt and nut assemblies
71 7 Materials
7.1 Chemical composition
72 7.2 Heat treatment for martensitic stainless steel nuts
73 7.3 Finish
7.4 Corrosion resistance
8 Mechanical and physical properties
78 9 Inspection
9.1 Manufacturer’s inspection
9.2 Supplier’s inspection
79 9.3 Purchaser’s inspection
9.4 Delivery of test results
10 Test methods
10.1 Proof load test
10.1.1 General
10.1.2 Applicability
10.1.3 Apparatus
10.1.4 Testing device
81 10.1.5 Test procedure
10.1.6 Addition to test procedure for prevailing torque nuts
10.1.7 Test results and requirements
82 10.2 Hardness test
10.2.1 General
10.2.2 Test procedure
83 10.2.3 Test results and requirements
11 Nut marking and labelling
11.1 Nut marking
11.1.1 General requirements for marking
11.1.2 Marking of property class for nuts with full loadability (regular and high nuts)
84 11.1.3 Marking of property class for nuts with reduced loadability (thin nuts)
11.1.4 Additional marking
11.2 Manufacturer’s identification mark
11.3 Marking on the nuts
11.3.1 Hexagon nuts
86 11.3.2 Other types of nuts
11.3.3 Left-hand thread marking
11.4 Marking of the packages (labelling)
87 Annex A (informative) Design principles of stainless steel nuts
89 Annex B (normative) Thread dimensions of the test mandrel for proof load
91 Bibliography
BS EN ISO 3506-2:2020 - TC
$217.84