The purpose of the Expert Commentary is to provide the reader with a guide to the standard, to include:
- An overview of what the standard is about
- An explanation of any challenging or complex concepts or requirements
- Any guidance on the relationship with the standard and its portfolio, and the wider regulatory environment
What is BS EN ISO 3506-1 and BS EN ISO 3506-2:2020 about?
This sits within a six-part series of international standards on the mechanical and physical properties of stainless steel fasteners. BS EN ISO 3506-1:2020 covers specific types of bolt, screw and stud. BS EN ISO 3506-2:2020 covers specific types of nut.
Who is BS EN ISO 3506-1 & BS EN ISO 3506-2:2020 for?
- Manufacturers and distributors of stainless steel fasteners
- Structural and consulting engineers
- Construction and civil engineering contractors and larger sub-contractors
- Test houses and laboratories
- Industries associated with oil and gas production and distribution
Why should you use BS EN ISO 3506-1 & BS EN ISO 3506-2:2020?
It specifies property classes in relation to austenitic, martensitic, ferritic and duplex (austenitic-ferritic) steel grades for fasteners.
It applies to bolts, screws and studs with:
— ISO metric thread in accordance with ISO 68-1
— Diameter/pitch combinations in accordance with ISO 261 and ISO 262
— Coarse pitch thread M1,6 to M39, and fine pitch thread M8×1 to M39×3
— Thread tolerances in accordance with ISO 965-1 and ISO 965-2
— Specified property classes and of any shape
Together with BS EN ISO 3506-2:2020 and BS ISO 3506-6:2020 it
provides additional advice and guidance for most applications where these products will be required.
There are other standards which deal specifically with specialized areas such as oil and gas but this considerably revised document provides an excellent foundation for any assessment.
NOTE: This standard does not specify requirements for functional properties such as: torque/clamp force properties, shear strength, fatigue resistance, or weldability.
What’s new about BS EN ISO 3506-1 and BS EN ISO 3506-2:2020?
The standard has been revised to reflect the standardization of duplex stainless steels. The main changes are:
a) Annexes common to several parts of the ISO 3506 series have been withdrawn from this document and are now included in a new document (ISO 3506-6)
b) Duplex (austenitic-ferritic) stainless steels for property classes 70, 80 and 100 have been added
c) Property class 100 for austenitic stainless steel grades as well as grade A8 have been added
d) Finish has been added
e) The matching of stainless steel bolt and nut grades has been added
f) Calculated minimum ultimate tensile loads and minimum loads at 0,2 % non-proportional elongation and rounding rules have been added
g) Reduced loadability for fasteners due to head or shank design has been added
h) Requirements and guidance for inspection procedures have been added
i) Operational temperature ranges have been clarified
j) The applicability of test methods, also in relation to full or reduced loadability, has been added
k) The tensile test procedure has been entirely amended, and application to fasteners with reduced loadability has been added
l) The wedge tensile test and hardness test have been improved
m) Marking and labelling have been improved, and fasteners with reduced loadability have been included
n) Mechanical properties at elevated temperatures and application at low temperatures have been improved
The structure and content of this document have been brought in line with ISO 898-1