ISO 4955:2016 specifies requirements for the grades listed in Table 2, which are usually employed for products for which the resistance to the effects of hot gases and the products of combustion at temperatures in the region above 550°C and/or to long-term mechanical stress is the main requirement.

NOTE 1 Grades mentioned in this International Standard may also be used for corrosion and creep resistant purposes.

ISO 4955:2016 is applicable to the following:

- flat products;

- bars, sections, rod, semi-finished products and forgings.

NOTE 2 Hammer-forged semi-finished products (blooms, billets, slabs, etc.), seamless rolled rings and hammer-forged bars are in the following, covered under semi-finished products or bars and not under the term "forgings".

NOTE 3 Not all of the grades included in this International Standard are necessarily available in all product forms.

NOTE 4 In Table 2, two alloys are listed in addition to the steels since they belong to the heat resistant grades.

NOTE 5 Heat resistant wire in the cold worked condition is covered by ISO 16143-3.

NOTE 6 Corrosion resistant stainless steels for which resistance to corrosion is of primary importance are covered by ISO 16143-1 and ISO 16143-2.

NOTE 7 Heat-resistant steels for valves are covered by ISO 683-15.

In addition to this International Standard, the general technical delivery requirements of ISO 404 are applicable.