Valve Seat: The detachable surface parts in valve are used to support the valve spool in the fully closed position and constitute a sealed part. Generally, valve seat diameter is the maximum flow diameter of the valve. PRODUCT PARAMETERS FOR OUR high performance valve seat This part can be illustrated by a table shown below: name Description Chemical composition Max thickness Hardness Bond strength Porosity Limit temperature Costing characterlzation wt.% mm HV0.3 MPa % â?? WC-CoCr WC86/Co10/Cr4 Coï¼?9-11 Crï¼?3.5-4.5 Cï¼?3.5-4.5