Flanges are used in hydraulic systems that require high pressure and high pulsation. The flanges are manufactured according to SAE J518 code 61 and 62. Code 61 signifies the pressure ratings mentioned below, also called 3000 psi. Code 62 signifies the pressure rate 41.4 MPa, also called 6000 psi.
Many of the flanges are also available in stainless steel design.