The elastic metal bellowed parts absorbing the heat induced expansion or contraction of pipelines conveying hot or cold fl uids or subject to drastic changes in ambient temperatures are called expansion joints. If no measures are taken against changes in size of pipelines, high pressure resulting from expansion or contraction creates problems at connection points and equipment. The most proper and affordable solutions to eliminate those problems are the metal bellow expansion joints designed to compensate different types of size chances, which do not necessitate any maintenance. In brief, assemblies comprising single or multiple bellows used to compensate the change in size and to eliminate the problems caused by it due to the heat induced expansion and contraction in pipelines, ducted air systems and tanks can be called expansion joints.