Which code defines TRIM materials, i've been searching and found in API 600 a table with basic trim mateials, this is the right one or there is other. API 6D don't mention it neither ASME B16.34. My valve is a 20" gate type API 6D.
Trim materials is selected at the agreement between the customer and supplier based on the environment and conditions the valved is exposed to during service
API 600 applies to gate valves and may be a reasonable starting point. Material compatibility is a greater issue in the chemical industry than the oil and gas business. You need to know the fluid to consider what metals and resilient components are attacked by the fluid. Other criteria include the temperature, the pressure drop (for control valves), velocity, erosion, etc. Hard facing is common for control valves and seating surfaces.
For some processes a licensor recommends the trim.