Gate Valves

Rising stem gate valves have the stem attached to the gate: as the valve opens, the stem rises above the handwheel, providing immediate visual position indication (stem exposed = valve open). Specify rising stem for above-ground installations, indoor plant rooms, or wherever visual position confirmation is required. Non-rising stem valves - where the stem rotates in place and a position indicator shows open/closed - are used in underground installations, valve pits, or where headroom above the handwheel is restricted.

API 600 covers cast steel gate valves in sizes 2" and larger (large bore), designed for Class 150 through 2500 service. API 602 covers small-bore gate valves (≤1.5") in forged steel with socket weld, butt weld, or threaded ends - these are the compact, high-pressure instrument-line isolators used on chemical injection, sample, and vent connections. For stainless steel gate valves in sizes 2"–12", API 603 applies.

No. Gate valves must only be used in the fully open or fully closed position. In partial-open position, the high-velocity fluid jet created by the restricted gate-to-seat gap causes wire drawing - progressive erosion of the gate and seat faces - leading to rapid seat degradation, loss of tight shut-off, and eventual valve failure. For any throttling, flow regulation, or frequent cycling service, use globe valves, control valves, or V-port ball valves.

For power plant and industrial steam service: WC6 (1.25% Cr – 0.5% Mo) body is rated to 510°C (950°F); WC9 (2.25% Cr – 1% Mo) to 565°C (1050°F); C12A / P91 (9% Cr – 1% Mo – V + Nb) to 620°C (1150°F) for ultra-supercritical steam. All high-alloy gate valves are supplied with full PMI (Positive Material Identification) and PWHT (Post-Weld Heat Treatment) documentation. Stellite hard-faced seats are standard for high-temperature steam service.