scope:

This part of ISO 3506 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. This part of ISO 3506 applies to nuts: - with nominal thread diameter D u 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 W 0,5D. This part of ISO 3506 does not define corrosion or oxidation resistance in particular environments. However, some information on materials for particular environments is given in Annex D. Regarding definitions of corrosion and corrosion resistance, see ISO 8044. The aim of this part of ISO 3506 is the classification of corrosion-resistant stainless steel nuts into property classes. Some materials can be used at temperatures down to - 200 °C, some can be used at temperatures up to + 800 °C in air. Information on the influence of temperature on mechanical properties is found in Annex E. Corrosion and oxidation performances and mechanical properties for use at elevated or sub-zero temperatures can be agreed on between the user and the manufacturer in each particular case. Annex F shows how the risk of intergranular corrosion at elevated temperatures depends on the carbon content.