... C 4.Standard:GB/T12777-2008 Stainless steel bellow expansion joint/bellow compensator/flexible joint ... GB/T12777-2008 national standardmaterialcarbon steel , stainless steel , alloy steel , low-temperature steel certificationISO9001:2000 Features large ... electricity, steel, aviation, shipbuilding, spin, electric power, metallurgy, food machinery, petro-chemical, environment protection equipment, heat ...