Usualy Hosemann’s Axial Expansion Joint are made of stainless steel SUS304=1.4301 or SUS321=1.4541 (max working temp. 550 °C), sometimes where Expansion Joint high working temperature up to 1050 °C we are using stainless steel type SUS310S.
Basic Axial Expansion Joint usualy has welded stub pipes at the end or sometimes flanges on request, we are able to produce compensators with any size of stub pipes or any standard or non standard flanges type.
Each compensator is produced according client requirements, so you can not really say that “standard metal expansion joints” existing.
Axial Metal Expansion Joint, Axial Metal Compensator