LEADING METAL GASKETS MANUFACTURER, EXPORTER & SUPPLIER
Manufacturer, Exporter & Supplier of Premium Industrial Gaskets
All Types of Monel Industrial Gaskets in Monel 400, K-500 & R-405 — Precision Manufactured for HF Acid Service, Marine Engineering & Highly Corrosive Chemical Environments
Sunflex Metalloy is a specialist manufacturer of Monel industrial gaskets — supplying the complete range of gasket types across all major Monel nickel-copper alloy grades to the chemical and specialty chemical processing, HF acid alkylation, marine and naval engineering, offshore oil and gas, pharmaceutical manufacturing, chlor-alkali, and desalination industries. From precision Ring Type Joint (RTJ) and Spiral Wound gaskets for high-pressure chemical process and offshore service, to Kammprofile, Corrugated, Metal Jacketed, Lens Ring, and Solid Metal designs for the most aggressive corrosive environments, we manufacture every form of Monel sealing solution to ANSI, ASME, DIN, BS, JIS, API, and NACE standards — in both standard and fully custom dimensions.
Monel alloys occupy a unique position in the industrial gasket materials hierarchy — their nickel-copper composition delivers a combination of corrosion resistance, mechanical strength, and toughness that no other single alloy family can match across the specific range of environments where Monel excels. Most critically, Monel is virtually the only metallic gasket material with reliable resistance to hydrofluoric acid (HF) in all concentrations and across a wide temperature range — making it the mandatory specification for gaskets in HF alkylation units and fluorine processing equipment. Every Sunflex Metalloy Monel gasket is manufactured from certified raw material with full chemical and mechanical traceability, and supplied with MTC as per EN 10204 3.1 or 3.2.
Grades Available: Monel 400 · Monel K-500 · Monel R-405 · UNS N04400 · UNS N05500 · UNS N04405
Monel is a family of nickel-copper alloys — predominantly nickel with approximately 28% to 34% copper plus small additions of iron, manganese, and other elements — originally developed for marine and chemical engineering applications where the combination of corrosion resistance and mechanical toughness required exceeded what either pure nickel or pure copper could individually deliver. The result is an alloy family of outstanding versatility in aggressive corrosive environments — offering excellent resistance to seawater, a broad range of mineral and organic acids in reducing conditions, neutral and alkaline salt solutions, and atmospheric corrosion, combined with good mechanical strength and excellent toughness from cryogenic temperatures up to approximately 480°C.
The most defining and commercially critical property of Monel alloys is their resistance to hydrofluoric acid (HF). Monel 400 is uniquely resistant to HF acid across all concentrations, from dilute solutions to anhydrous hydrofluoric acid, and across a wide temperature range — making it the mandatory material specification for gaskets in HF alkylation refinery units, fluorine chemical production facilities, and hydrofluoric acid handling systems where any other metallic gasket material would corrode rapidly and fail.
Beyond its HF resistance, Monel offers a critically important advantage over austenitic stainless steel in many chemical and marine environments — it does not suffer from chloride-induced stress corrosion cracking (SCC). Monel 400 is immune to SCC in the vast majority of chloride environments encountered in marine, offshore, and chemical service, making it a fundamentally more reliable gasket material in these conditions despite its higher cost.
| Grade | UNS | Composition | Key Properties | Primary Application |
|---|---|---|---|---|
| Monel 400 | N04400 | 63% Ni, 28–34% Cu | Outstanding HF resistance, excellent seawater & reducing acid resistance, no SCC in chloride | HF alkylation, marine piping, chemical processing, offshore |
| Monel K-500 | N05500 | 63% Ni, 29% Cu + Al, Ti | Age-hardened — ~3× yield strength of Monel 400, same corrosion resistance | High-strength chemical plant, pump and valve trim, instrument connections |
| Monel R-405 | N04405 | 63% Ni, 28% Cu + S | Free-machining grade — best machinability in Monel family | Precision machined gaskets, instrument fittings, valve seats, complex profiles |
Sunflex Metalloy manufactures all eight major Monel gasket types — each engineered for the specific pressure classes, temperature ranges, flange configurations, and the uniquely aggressive chemical and marine environments where Monel is the required or preferred gasket material.
Monel Ring Type Joint (RTJ) gaskets are precision-machined solid Monel sealing rings designed for use with RTJ flange faces — delivering high-integrity metal-to-metal sealing in the most corrosive chemical process, HF acid service, and marine engineering applications where the chemical resistance and toughness of Monel are required at the flanged joint. The Monel ring seats into the precision-machined trapezoidal groove of the RTJ flange under bolt loading, deforming plastically to create a high-integrity metal-to-metal seal.
Monel 400 RTJ gaskets are the standard specification for HF alkylation unit flanged connections — where the mandatory requirement for HF acid resistance makes Monel the only acceptable metallic RTJ ring material. Monel K-500 RTJ rings are specified where the higher strength of the age-hardened grade provides an advantage in high-pressure connections. Sunflex Metalloy manufactures Monel RTJ gaskets in both oval and octagonal profiles and RX type to ASME B16.20 and API 6A specifications, across all standard API ring numbers and in custom dimensions.
Monel Spiral Wound gaskets are semi-metallic sealing elements constructed by spirally winding a thin Monel metallic strip alternately with a soft filler material — typically PTFE or flexible graphite — to produce a resilient, self-energizing gasket assembly with the full corrosion resistance of Monel in a spiral wound format. The Monel winding strip provides resistance to the aggressive chemical environments — particularly HF acid, reducing mineral acids, and chloride-containing media — where stainless steel winding strips would suffer rapid corrosion attack.
Monel 400 spiral wound gaskets are the standard specification in HF acid alkylation unit process piping. PTFE is the standard filler for Monel winding gaskets — providing full chemical resistance, non-stick surface characteristics, and compatibility with the broadest range of aggressive process fluids encountered in HF and chemical service. Sunflex Metalloy manufactures Monel spiral wound gaskets to ASME B16.20 in all standard sizes and in fully custom dimensions.
Monel Corrugated Metal gaskets are manufactured by precision-forming a Monel alloy sheet into a series of concentric corrugations across the gasket face — creating multiple raised contact ridges that concentrate the available bolt load onto narrow sealing lines and establish multiple independent sealing paths simultaneously. The all-Monel construction ensures the full corrosion resistance of the alloy is retained across the entire corrugated gasket profile.
Monel corrugated gaskets are particularly valuable in chemical process vessel and column flange applications where available bolt load is limited, where the process chemistry mandates Monel material, and where the multi-line sealing geometry of the corrugated design provides an additional margin of sealing assurance. Available plain (bare Monel) for service in highly aggressive media, or with a PTFE overlay for enhanced conformability in moderate-temperature chemical service.
Monel Metal Jacketed gaskets consist of a compressible soft filler core — typically PTFE, flexible graphite, or ceramic fibre — enclosed within a formed Monel metal outer jacket. The Monel jacket provides the outer sealing surface and chemical protection for the soft inner filler, resisting the aggressive chemical environments — HF acid, reducing mineral acids, seawater, and chloride-containing media — that would rapidly attack standard metallic jacket materials.
The ductility of Monel 400 makes it well-suited as a jacketing material — the formed Monel jacket deforms under bolt compression to conform to the flange face and establish effective sealing contact without requiring high clamping forces. PTFE is the standard filler for Monel jacketed gaskets — providing full chemical compatibility with HF and other aggressive process media. Sunflex Metalloy manufactures Monel jacketed gaskets in single-jacketed and double-jacketed configurations in Monel 400 and Monel K-500 grades.
Monel Solid Metal gaskets are manufactured entirely from solid Monel bar, plate, or sheet stock — no composite layers, no filler materials, no bonded components of any kind. The all-Monel single-material construction delivers the complete, undiluted chemical resistance, mechanical strength, and toughness of the Monel alloy at every point across the gasket sealing face — providing maximum sealing integrity and maximum corrosion resistance.
Monel 400 is the standard grade for solid metal gaskets in HF acid, marine, and general chemical service. Monel K-500 is specified where higher mechanical strength is required alongside the same corrosion resistance — approximately three times the yield strength of Monel 400 in the age-hardened condition. Monel R-405, the free-machining grade, is preferred for complex precision-machined solid gasket profiles where tight dimensional tolerances and fine surface finishes are required at optimised manufacturing cost.
Monel Lens Ring gaskets are precision CNC-machined solid Monel sealing rings with a convex spherical cross-section profile — designed to deliver reliable high-pressure sealing in the most aggressively corrosive chemical and process environments. The convex spherical profile contacts the matching concave conical seat of the mating flange or fitting at a single circular line, concentrating the assembly load onto a very narrow contact area to generate high sealing stress.
Monel 400 lens ring gaskets are specified in HF acid alkylation unit instrument connections, sampling connections, and high-pressure chemical process piping where the operating environment mandates Monel material throughout the system. Monel R-405, the free-machining grade, is particularly well-suited for lens ring production — its excellent machinability allows the precise convex spherical profile and fine surface finish required for reliable lens ring sealing to be achieved efficiently and consistently. Sunflex Metalloy manufactures Monel lens ring gaskets to DIN 2696 and custom specifications.
Monel Octagonal and Oval Ring gaskets are precision-machined solid Monel sealing rings for use with Ring Type Joint (RTJ) flanges in high-pressure chemical process, HF acid, and marine engineering applications where the corrosion resistance of Monel is required at the RTJ flange connection. Both profiles seat into the trapezoidal groove of the RTJ flange and create a metal-to-metal seal through controlled plastic deformation of the Monel ring under bolt loading.
Monel 400 is the standard grade for oval and octagonal ring gaskets in HF alkylation, marine, and general chemical process RTJ applications — providing the definitive combination of HF acid resistance, seawater corrosion resistance, and immunity to chloride stress corrosion cracking. Sunflex Metalloy manufactures Monel oval and octagonal ring gaskets across all API standard ring numbers and in custom dimensions, with full material certification and NACE compliance documentation available.
Monel Kammprofile gaskets combine the outstanding chemical resistance of Monel with the precision multi-line sealing geometry of the Kammprofile design to deliver the highest tier of reusable sealing performance in the most corrosive chemical process and HF acid service environments. The gasket features a solid Monel metal core with precision CNC-machined concentric serrated grooves on both faces, covered with a bonded PTFE overlay — selected for its complete resistance to HF acid and the broadest range of aggressive chemical media encountered in Monel-specified process applications.
The use of Monel as the Kammprofile core material ensures that the gasket's structural element retains full corrosion resistance in HF acid, seawater, and aggressive chemical environments throughout the design service life of the plant, even in the event of partial PTFE overlay loss during operation. The solid Monel core is designed for reuse — at plant turnaround, the PTFE overlay is replaced while the Monel core is inspected, re-overlaid, and reinstalled — delivering long-term maintenance cost benefits in the most demanding chemical service environments.
Match your process environment, pressure class, and flange configuration to the right Monel gasket form:
| Gasket Type | Pressure Class | Temp Range | Flange Face Type | Reusable | Best Application |
|---|---|---|---|---|---|
| Ring Type Joint (RTJ) | Class 150–2500 | Cryo to 480°C | RTJ Groove | No | HF units, marine RTJ, chemical process |
| Spiral Wound | Class 150–2500 | Cryo to 480°C | RF, FF, T&G | No | HF alkylation piping, chemical columns |
| Corrugated Metal | Class 150–900 | Up to 400°C | RF, FF | No | Chemical vessels, limited bolt load flanges |
| Metal Jacketed | Class 150–900 | Up to 480°C | FF, RF, MF, T&G | No | Reactor closures, large chemical flanges |
| Solid Metal | Class 150–2500 | Cryo to 480°C | All types | No | HF service, marine, chemical plant |
| Lens Ring | High pressure | Up to 480°C | Conical seat | No | HF instrument connections, chemical fittings |
| Octagonal / Oval Ring | Class 150–2500 | Cryo to 480°C | RTJ Groove | No | HF alkylation RTJ, marine high pressure |
| Kammprofile | Class 150–2500 | Cryo to 480°C | RF, FF, MF, T&G | Yes (core) | HF heat exchangers, reusable chemical sealing |
Monel gaskets are available in three primary grades — each offering a distinct combination of corrosion resistance, mechanical strength, and machinability. Selecting the correct grade ensures optimal performance and value for your specific application.
Monel 400 (UNS N04400) — Your primary requirement is maximum corrosion resistance — HF acid resistance, seawater resistance, reducing acid resistance, or immunity to chloride stress corrosion cracking. Monel 400 is the standard, most widely specified Monel grade for the vast majority of chemical process, HF alkylation, marine, and offshore gasket applications. It is the correct choice for essentially all HF acid service gasket applications.
Monel K-500 (UNS N05500) — Higher mechanical strength is required alongside the same corrosion resistance as Monel 400. Monel K-500's age-hardening capability gives it approximately three times the yield strength of Monel 400 — making it the preferred grade for high-pressure chemical connections, precision instrument fittings in corrosive service, pump and compressor component sealing, and any application where greater gasket hardness and mechanical resistance to deformation under service loads is required.
Monel R-405 (UNS N04405) — Precision machining to tight tolerances is required and where the gasket form demands the best possible machinability in the Monel family. Monel R-405's sulfur addition significantly improves its free-cutting characteristics compared to Monel 400, allowing tighter tolerances and finer surface finishes to be achieved more consistently and economically. Corrosion resistance is essentially equivalent to Monel 400 — R-405 is selected purely for its machining advantage.
