Metal Expansion Joints kuma ana kiransa madaidaicin ƙwanƙolin ƙarfe, wanda aka haɗa shi da ƙwanƙolin ƙarfe da kayan haɗi kamar bututun ƙarewa, tallafi, flange da magudanar ruwa. Za a iya amfani da haɗin faɗaɗa ƙarfe don ɗaukar girman canje-canje na bututun, magudanar ruwa da kwantena waɗanda ke haifar da faɗaɗawar zafi da ƙanƙantar sanyi, ko don rama ƙaura, juyawa da matsugunan bututun, magudanan ruwa da kwantena. Hakanan ana iya amfani dashi don rage amo da rage girgiza.