Valve field troubleshooting — gate galling (adhesive wear, Stellite hardfacing), pressure lockup (thermal expansion ΔP=βΔT/κ_T, DBB cavity), wire drawing erosion, cavitation (σ=P2-Pv/P1-P2), flashing, fugitive emissions (API 624, ISO 15848), seat leakage classes (API 598), check valve slam (Joukowski ΔP=ρcΔv), stem packing failures, high operating torque, valve passing, hydrostatic test lockup, fire-safe testing (API 607), sour service HIC/SSC (NACE MR0175), cryogenic valve issues, stuck-open/stuck-closed root causes, ball valve blowout prevention.
