Bolts and Nuts for High-Temperature Applications – Ambiguities in European Standards

[Vahid.A]

Hello,

Austenitic stainless steel bolts and nuts can be used in high-temperature applications, and their maximum temperature limit is quite high in the ASME Sec II Part D standard. For example, B8 grade (SS304) is allowed up to 816°C (though some technical limitations, like relaxation, restrict its actual use at such high temperatures).

However, in European standards, these grades seem absent for high-temperature applications. ISO 3506-1 and ISO 3506-2 limit their use to 300°C, and they’re not even included in ISO 3506-5, which is specifically for high-temperature fasteners. This seems a bit odd.

have I overlooked a relevant European standard, or is this omission intentional? Any clarification would be appreciated.

 

[MintJulep]

It's right there in the abstract.

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[1] 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.

 

[Vectrex]

Hi,

I could not find anything related as well in ISO standards (except for the reply above), and I think they are not covered in those. You can check EN 10269, ASTM A453, or ASTM A193.

So I don't think you missed something; rather, those standards do not cover them.