Marine & Offshore
Deck, ballast, and seawater valves exposed to salt spray and immersion.
Stainless Steel · SS304 / SS316 · Corrosion Resistant
Stainless steel worm gear operators resist corrosion in marine, chemical, desalination, and food-grade environments where cast iron would degrade. SS304 and SS316 housings and external components withstand saltwater, washdown, and aggressive media while retaining the self-locking worm action and ISO 5211 mounting of the standard range.
Application Foundation
A stainless steel worm gear operator replaces the standard ductile-iron housing and external hardware with corrosion-resistant stainless steel for service in marine, offshore, chemical, desalination, and hygienic environments. Stainless construction resists salt spray, washdown chemicals, and humid atmospheres that would corrode cast iron, extending service life and protecting the gear set.
Grade selection drives performance: SS304 suits general corrosive and washdown duty, while SS316 adds molybdenum for chloride and seawater resistance. Operators retain the self-locking worm action and ISO 5211 mounting of the standard range. Per-model stainless specifications — torque, dimensions, and weights — are confirmed per order against your valve and environment.
Engineering Data
| Grade | Key Alloying | Corrosion Profile | Typical Environment |
|---|---|---|---|
| SS304 (1.4301) | 18% Cr, 8% Ni | General corrosion & washdown resistance | Food & beverage, indoor chemical, coastal sheltered |
| SS316 (1.4401) | 16% Cr, 10% Ni, 2% Mo | Chloride & seawater resistance (Mo added) | Marine, offshore, desalination, aggressive chemical |
Grade compositions are nominal per the standard stainless designations (AISI 304 / 316). Material selection is matched to the media, chloride level, and temperature of your application. Per-model operator torque and dimensions are not material-dependent in the catalog and are confirmed per order — request a datasheet.
| ISO 5211 Flange | Typical Valve Size Band* | Common Valve Families | Matson Models Offering This Flange |
|---|---|---|---|
| F05 | Small bore | Ball, plug, small butterfly | M07 |
| F07 | Small–medium bore | Butterfly (wafer), ball, plug | M07, M10 |
| F10 | Medium bore | Butterfly, ball, plug | M07, M10, M12 |
| F12 | Medium bore | Butterfly (lug), ball, gate top-work | M12, M14 |
| F14 | Medium–large bore | Butterfly, trunnion ball, gate | M12, M14, M14A, M15 |
| F16 | Large bore | Butterfly (double flange / AWWA), ball, gate | M14, M14A, M15, M16 |
| F25 | Heavy / large bore | Large AWWA butterfly, high-pressure ball, large gate | M16 |
*Valve size band is indicative only — actual flange depends on the valve manufacturer's top-work, stem, and torque rating. Flange and Matson single-stage model data are from the Matson worm gearbox catalog (M07–M16, 200–4,400 N·m). Two-stage and electric-actuator series extend up to 160,000 N·m. Confirm the exact flange against your valve datasheet.
Per-model specifications (dimensions, weights, drive-bushing details, material grades): available on request — request a datasheet. Send your valve tag, bore, pressure class, environment class, and required output torque and our engineers return a model recommendation with the matching ISO 5211 / ISO 5210 interface.
Operation
Stainless steel is specified for valve gear operators wherever corrosion would shorten the life of a cast-iron housing — coastal and offshore platforms, chemical plants, desalination trains, and food-grade process lines. The chromium content forms a passive oxide layer that resists rust, and the smooth, cleanable surface suits hygienic washdown duty.
The choice between SS304 and SS316 depends on chloride exposure: SS316's molybdenum content gives markedly better resistance to seawater and aggressive chlorides, making it the standard for marine and offshore service. Both grades keep the self-locking worm action and ISO 5211 mounting, so corrosion protection is added without changing how the operator integrates with the valve.
Engineering
By Industry
Deck, ballast, and seawater valves exposed to salt spray and immersion.
Aggressive-media isolation valves requiring chloride resistance.
Reverse-osmosis, brine, and treated-water valves in saline service.
Hygienic washdown valves needing cleanable, corrosion-free surfaces.
Common Questions
SS304 contains roughly 18% chromium and 8% nickel and resists general corrosion and washdown chemicals. SS316 adds about 2% molybdenum, which markedly improves resistance to chlorides and seawater. For marine, offshore, and aggressive chemical valve service, SS316 is the standard; SS304 suits indoor chemical, coastal-sheltered, and food-grade duty.
Yes. SS316 stainless steel operators are specified for seawater and marine service because the molybdenum content resists chloride pitting. Sealed IP67 or IP68 housings keep water out of the gear set. For continuous immersion or splash-zone duty, declare the exposure so the correct grade, sealing, and fasteners are selected.
Stainless steel is corrosion-resistant, not corrosion-proof. SS304 and SS316 form a passive oxide layer that resists rust in most environments, but very high chloride, acidic, or crevice conditions can still attack the surface. Matching the grade — SS316 for chlorides — and using sealed housings gives long service life in marine and chemical duty.
A valve gear box, or gear operator, is a worm-and-wheel reduction unit mounted between the handwheel and the valve stem. It multiplies handwheel torque, holds the valve position with a self-locking worm, and mounts to an ISO 5211 flange. A stainless steel gear box adds SS304 or SS316 construction for corrosion-resistant service.
Yes. We manufacture custom stainless operators with SS304 or SS316 housings, stem couplings, and external hardware under OEM and engineering orders. Provide the media, chloride level, temperature, valve torque, and mounting flange, and our engineers confirm the grade, sealing, and a model recommendation against your valve datasheet.
Send your media, chloride level, valve torque, and mounting flange. We confirm SS304 or SS316 grade, IP sealing, and a model recommendation, with per-model stainless specifications on request.