Stainless steel blind flanges 1.4404/316L

Stainless steel blind flanges 1.4404/316L (also called blind or blank flanges) are solid flanges used to close off the end of a pipe, valve or pressure vessel opening. They provide a secure, pressure-rated seal for isolation, testing and maintenance of pipework. The product name reflects the material grade: EN 1.4404 (commonly specified in Europe) is the same basic alloy as AISI/ASTM 316L (often referenced in the US; UNS S31603). The “L” denotes a low-carbon version of 316 that improves weldability and reduces the risk of sensitisation.

What a blind flange is and how it is used

A blind flange is a flat, solid disc with bolt holes matching the mating flange. It is bolted to the flange face to stop flow or to allow pressure testing of a pipeline without removing sections of pipe. Typical uses include:

• Temporarily or permanently closing pipe ends during commissioning or maintenance
• Isolating sections of a system for repairs or modifications
• Providing access points for pressure testing (hydrostatic tests) and leak checks
• Acting as end caps on tanks, vessels, and pipe spools

Material: 1.4404 / 316L — what that means

These blind flanges are manufactured from an austenitic stainless steel grade known in Europe as 1.4404 and in US standards as 316L (UNS S31603). Key characteristics:

• Corrosion resistance: Good resistance to chlorides and many chemicals—suitable for marine and many industrial environments.
• Low carbon content: The “L” grade has reduced carbon to improve weldability and reduce carbide precipitation (sensitisation) during welding.
• Mechanical properties: Ductile and tough across a wide temperature range; used where strength, formability and corrosion resistance are required.

Industries and typical applications

Stainless steel blind flanges 1.4404/316L are widely used across small and large-scale projects. Examples of sectors and use cases:

• Marine & offshore: Pipe terminations, isolation points and test points on ships, platforms and ports.
• Chemical & petrochemical: Corrosion-resistant closures in aggressive media and process lines.
• Food & beverage, pharmaceutical: Hygienic closures where corrosion resistance and cleanability are essential.
• Water treatment & desalination: Ends of pipelines, sampling points, and isolation during maintenance.
• Power generation & HVAC: Steam, cooling and utility lines requiring robust seals.
• Automotive, fabrication, and garage projects: Small-scale repairs, custom builds and testing rigs.

Standards, face types and compatibility

Blind flanges in this material are produced to common flange standards and face types so they mate with standard pipe flanges. Depending on your project you will find flanges specified to European (EN/PN) or American (ASME/ANSI) systems and with different face finishes (raised face, flat face, ring-type joint). When selecting a blind flange, check:

• Bolt hole pattern and diameter (to match mating flange)
• Pressure rating / class (PN or ASME class)
• Face type required for your gasket and sealing method

Choosing the right blind flange — practical advice

To choose the correct stainless steel blind flange 1.4404/316L, consider:

• Service media: Is the fluid corrosive or chloride-rich? 316L is a good general choice for many corrosive environments, but for very aggressive chloride conditions (e.g. hot sea water) higher-alloy grades may be required.
• Temperature and pressure: Ensure the flange’s pressure rating and temperature limits suit your system.
• Connection standard: Match the flange to the pipework standard (EN/PN or ASME class) used in your installation.
• Gasket type: Select a gasket and face type compatible with the flange and operating conditions.

Installation and maintenance

Basic tips for reliable performance:

• Use the correct bolt pattern and torque sequence to ensure even compression of the gasket and a leak-free joint.
• Choose gasket materials compatible with the process fluid and temperature.
• Inspect bolt material and torque regularly, especially in corrosive or vibration-prone installations.
• For long-term corrosion protection, ensure good drainage and avoid deposits that may trap chlorides.

Who buys stainless steel blind flanges 1.4404/316L?

Typical buyers include pipeline engineers, maintenance and commissioning teams, fabricators, shipyards, mechanical contractors, plant managers and hobbyist fabricators. Whether you are fitting a one-off garage project or equipping an offshore facility, 316L blind flanges offer a reliable, corrosion-resistant solution.

Why choose stainless steel (not aluminium or plain carbon steel)

Our range focuses exclusively on stainless, acid-resistant and heat-resistant steels. For systems needing durability against corrosion, hygiene, or welding during fabrication, 1.4404/316L stainless steel blind flanges outperform aluminium and plain carbon steel in longevity and corrosion resistance—especially in wet or chemically aggressive environments.

If you need help selecting the correct size, pressure rating or face type for your application, contact our technical team with details of your pipe standard, diameter and service conditions.