ISO/TC 2/WG 17 - Stainless steel fasteners

This document specifies the mechanical and physical properties of bolts, screws, studs and nuts, with coarse pitch thread and fine pitch thread, made of corrosion-resistant stainless steels (i.e. martensitic stainless steels and precipitation hardening austenitic stainless steels) and nickel alloys, intended for use at high temperatures up to 800 °C. Tests in accordance with Clause 9 are performed at the ambient temperature range of 10 °C to 35 °C, and other tests can be performed at higher temperatures, see Clause 10. NOTE Fasteners specified in this document are also suitable when used at low temperatures, typically down to -50 °C. For more information, see ISO 3506-6. The term “fasteners” is used in this document when bolts, screws, studs and nuts are considered all together. ISO 3506-6 provides general rules and additional technical information on suitable stainless steels and nickel alloys as well as their properties. This document applies to fasteners: — 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 M3 to M39, and fine pitch thread M8×1 to M39×3, — with thread tolerances in accordance with ISO 965-1 and ISO 965-2, and — of any shape but with full loadability. Stainless steel and nickel alloy fastener symbols can be used for sizes outside the diameter limits of this document (i.e. for bolts, screws and studs with d d > 39 mm and for nuts with D D > 39 mm), provided that all applicable chemical, mechanical and physical requirements are met. Fasteners with reduced loadability (i.e. thin nuts and bolts, screws and studs with head or unthreaded shank weaker than the threaded shank) are not dealt with in this document. This document does not specify requirements for functional properties such as: — torque/clamp force properties, — shear strength, — fatigue resistance, — weldability, or — properties of bolted joints and fasteners in high temperature environment (see test methods at high temperature for fasteners in Clause 10).

This document specifies general rules and provides technical information on stainless steels and their properties, which are relevant when using other parts of the ISO 3506 series. It includes specifications for corrosion-resistant stainless steels and nickel alloys, which are suitable for the manufacture of fasteners. It applies to austenitic, martensitic, ferritic and duplex (austenitic-ferritic) stainless steel grades and nickel alloys for fasteners, and is intended to be used together with the relevant parts of the ISO 3506 series. Common designations of stainless steels and nickel alloys used for fasteners are given in Annex A.

ISO 3506-3:2009 specifies the mechanical properties of set screws and similar fasteners not under tensile stress made of austenitic stainless steel, when tested over an ambient temperature range of 10 °C to 35 °C. Properties vary at higher or lower temperatures. ISO 3506-3:2009 applies to set screws and similar fasteners: - with nominal thread diameter 1,6 mm ≤ d ≤ 24 mm; - of triangular ISO metric threads with diameters and pitches in accordance with ISO 68-1, ISO 261 and ISO 262; - of any shape. It does not apply to screws with special properties, such as weldability.

ISO 3506-4:2009 specifies the mechanical properties of tapping screws made of austenitic, martensitic and ferritic steel grades of corrosion-resistant stainless steels, when tested over an ambient temperature range of 10 °C to 35 °C. Properties vary at higher or lower temperatures. It applies to tapping screws with threads from ST2,2 up to and including ST8, in accordance with ISO 1478. It does not apply to screws with special properties such as weldability.

ISO 3506-2:2009 specifies the mechanical properties of nuts made of austenitic, martensitic and ferritic steel grades of corrosion-resistant stainless steels, when tested over an ambient temperature range of 10 °C to 35 °C. Properties vary at higher or lower temperatures. ISO 3506-2:2009 applies to nuts: - with nominal thread diameter d ≤ 39 mm; - of triangular ISO metric threads with diameters and pitches in accordance with ISO 68-1, ISO 261 and ISO 262; - of any shape; - with width across flats as specified in ISO 272; - with nominal heights m ≥ 0,5 d. It does not apply to nuts requiring properties, such as locking abilities and weldability.

ISO 3506-1:2009 specifies the mechanical properties of bolts, screws and studs made of austenitic, martensitic and ferritic steel grades of corrosion-resistant stainless steels, when tested over an ambient temperature range of 10 °C to 35 °C. Properties vary at higher or lower temperatures. ISO 3506-1:2009 applies to bolts, screws and studs - with nominal thread diameter d ≤ 39 mm, - of triangular ISO metric threads with diameters and pitches in accordance with ISO 68-1, ISO 261 and ISO 262, and - of any shape. It does not apply to screws with special properties, such as weldability.