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 As shown below, here are some tables helping you know more about basic High Performance Valve Seat data: 1. Common base material and chemical composition Common base material and chemical composition�wt.%� Mat Type C Si Mn P S Cr Mo Ni Cu Nb Al Ti Co Fe 4130 0.28-0.33 0.15-0.35 0.4-0.6 �0.025 �0.025 0.8-1.1 0.15-0.25 �0.03 �0.03 Bal 4140 0.38-0.45 0.15-0.35 0.75-1.0 �0.025 �0.025 0.8-1.1 0.15-0.25 Bal 410 0.08-0.15 �1.0 �1.0 �0.025 �0.025 11.5-13.5 �0.75 Bal 410SS �0.08 �1.0 �1.0 �0.025 �0.025 11.5-13.5 �0.6 Bal F6NM �0.05 �0.6 0.5-1.0 �0.025 �0.025 11.5-14.0 0.5-1.0 3.5-5.5 Bal F51 �0.03 �1.0 �2 �0.025 �0.025 21-23 2.5-3.5 4.5-6.5 Bal 17-4PH �0.07 �1 �1 �0.025 �0.025 15.0-17.5 3.0-5.0 3.0-5.0 0.15-0.45 Bal Inconel625 �0.1 �0.5 �0.5 �0.015 �0.015 20-23 8-10 Bal 3.15-4.15 �0.4 �0.4 �1 �5 Inconel718 �0.08 �0.35 �0.35 �0.015 �0.015 17-21 2.8-3.3 50-55 �0.3 4.75-5.5 0.2-0.8 0.65-1.15 �1 Bal