Finding the right ASME B16.5 blind flange is an important choice that you can't make if your project involves high-pressure pipes in oil and gas, chemical processing, or power generation. This guide shows procurement engineers and EPC workers every important step, from reading the specs to choosing a good maker, so they can confidently go from evaluating to buying. This guide has information that you can use right away, whether you are in charge of a new offshore platform or a chlor-alkali plant restart.
Understanding ASME B16.5 Blind Flanges: Specifications and Standards
What Defines a B16.5 Blind Flange?
A blind flange is a solid disc that is made to seal the end of a pipe run without going through the pipe. Following the rules of ASME B16.5 blind flanges, it works with NPS ½ to NPS 24 and has pressure ratings from Class 150 to Class 2500. In addition to ASME standards, ANSI, BS, DIN, and JIS standards are also met by LINHUI TITANIUM when they make titanium blind flanges from ½" to 96" (DN40–DN1600) at Class 600. The standard has strict rules about the bolt-circle diameter, flange thickness, raised face finish (125–250 AARH), and ring-type joint (RTJ) profiles. These rules make sure that the parts can be swapped out in global supply chains.
Material Grades and Face Styles
Choice of material has a big effect on how long something will last. Stainless steel is good for oxidising media, carbon steel is good for utility lines with moderate pressure, and titanium alloys—especially Grade 2 and Grade 5 (Ti-6Al-4V)—are used in places where chloride stress corrosion cracking would destroy other metals in months. Titanium's natural TiO₂ oxide film stops etching even when seawater stays still. Face styles like raised face (RF), flat face (FF), and RTJ cover with different types of materials. When you want to stop galvanic contact at the binding interface, titanium blind flanges work best with PTFE or spiral-wound seals that are wrapped with titanium.
How to Choose the Right Blind Flange for Your Project
Match Pressure, Temperature, and Environment
To keep the system working right, the pressure, temperature, and environment must all be just right. Before an ASME B16.5 blind flange buy order is sent out, the highest allowed working pressure, the design temperature, and the fluid makeup must all be set. Pressure-temperature values are given by material group, as shown in ASME B16.5 Table 2-3. The table shows that titanium's strength drops faster than steel above 300°C. This means that your operating envelope should be checked against the table. Titanium Grade 2 blind flanges always work better than stainless steel options for offshore saltwater injection lines, chlor-alkali plants that deal with wet chlorine gas and geothermal brine systems because the alloy doesn't pit when chloride levels stay the same.
Blind Flange vs. Other Flange Types
Finding the right type of hinge for the job saves a lot of money on repairs. Here is a comparison of the four most popular types used in industrial pipes:
- Blind flange: Ends a pipe end completely. Picked for oil and gas handling high-pressure headers that need ports for testing pressure, getting to inspection areas and isolating the system. Because it has solid discs, there is no chance of flow-through during maintenance windows.
- The weld neck flange sends stress to the pipe wall through a hub that is curved. Preferred in service with repetitive pressure or high shaking, like compressor discharge lines, where resistance to wear is very important.
- Slip-on flange: This type of flange slides over the pipe and needs two fillet welds. In low-pressure utility lines, where orientation freedom is more important than load distribution, this material works well.
- The threaded flange is used in small-bore, low-pressure monitoring lines where welding isn't possible or isn't allowed for safety reasons.
The most bending moment load is put on blind flanges because the full system pressure acts on a closed face. There is no way around dimensional compliance and grade proof. The approval of the supplier is also very important. Make sure that the suppliers have ISO 9001:2015 and have been checked by outside groups like TUV, SGS, or DNV. LINHUI TITANIUM has ISO 9001:2015, TUV Nord AD2000-W0, PED 2014/68/EU, and approvals from DNV, ABS, BV, GL, and Lloyd's Register. This gives big EPC companies the complex tracking they need.
Installation, Inspection, and Maintenance Best Practices
Step-by-Step Installation Protocol
To put it together, clean the face of the lip. Make sure that the raised face or RTJ groove doesn't have any scratches that are deeper than Ra 6.3 µm. Surface flaws let leaks happen when the pressure changes. To tighten nuts in a cross-pattern design, use a measured torque wrench and numbers from the ASME PCC-1 standards. Use anti-seize powder on stainless or Inconel studs that are used with titanium blind flanges to keep them from galling. When joining titanium to stainless steel in an electrolyte, you must use galvanic isolation kits with dielectric sleeves and washers. Never use carbon steel fasteners against a titanium flange face when the environment is wet.
Inspection and Testing Protocols
Every LINHUI TITANIUM ASME B16.5 blind flange goes through several quality checks before it is shipped. As part of the program, the dimensions are checked against ASME B16.5 tables, Positive Material Identification (PMI) is used to confirm the chemical composition and stop grade substitution, ultrasonic testing (UT) is used to look for internal holes or forging inclusions, and dye penetrant inspection (DPI) is done on sealing faces and bores. Material test records that follow EN 10204 3.1 give heat-number tracking. For Class 600 service in the field, the minimum maintenance plan includes pressure hydrotests at 1.5 design pressure and eye checks for crevice rust at bolt holes every so often.
Procurement Strategies and Partnering with Trusted Suppliers
Evaluating Total Cost of Ownership
The price of the item is only one part of a responsible buying plan. Titanium is better for corrosive-service uses because it has a lower lifecycle cost, which includes replacement costs, planned downtime, and cathodic protection costs. NACE International benchmarks say that offshore sites that use titanium blind flanges on cooling loops see service life increases of more than 80% compared to copper-nickel parts. When you buy in bulk, you save money on each unit and are guarantyd priority production slots with qualified manufacturers, which is very helpful when turnaround times are measured in days instead of weeks.
What to Require from a Qualified Manufacturer
An ASME B16.5 blind flange supplier that works on global energy projects must show a number of skills that can't be skipped. Since 2000, LINHUI TITANIUM has been making titanium products in Xi'an, China, which is the starting point of the Belt and Road Initiative. The company runs two plants with 30 production lines that are only used for titanium. Each year, they deliver 800 tonnes of product. Anti-rust oil, black painting, and yellow painting are all options for treating the surface. Shipments are sent to clients in Southeast Asia, Africa, the CIS countries, North America, and the Gulf area by DHL, FedEx, air freight, or sea freight. Long-term relationships with KOC, KNPC, PETRONAS, LUKOIL, and PDO show that the supply system is stable.
Advantages and Applications of Blind Flanges in Industrial Projects
In harsh conditions, titanium ASME B16.5 blind flanges provide a unique mix of mechanical and chemical performance that regular steel parts can't match. The main benefits of important service are:
- The self-regenerating TiO₂ oxide film guards against chloride attack, acidic media, and microbiologically influenced corrosion (MIC). This makes the parts perfect for offshore firewater pipes and desalination seawater injection lines.
- High strength-to-weight ratio: Titanium is about 45% lighter than carbon steel (4.51 g/cm³), which means that offshore topsides and aerospace structures can have less dead weight without losing the ability to contain pressure.
- Standard compatibility: Titanium blind flanges are dimensionally compatible with ASME B16.5, ANSI, BS, DIN, and JIS, which means they can bolt straight into existing pipe infrastructure without the need for custom fittings.
There are measurable gains in many areas because of these advantages. They keep the pipes for brine in geothermal power from being worn down by salty water. In the chlor-alkali process, they keep wet chlorine gas lines closed while they are being fixed without breaking down like mild steel does. In offshore oil and gas, they separate cooling loops where biofouling-driven rust would normally cause shutdowns that weren't planned.
Conclusion
To choose the right blind flange, you need to know about the pressure class, material grade, face style, and qualified suppliers. At the general level, each variable has an effect. Titanium ASME B16.5 blind flanges made to ASTM B381 Grade 2 or Grade 5 standards are a tried-and-true way to handle high-pressure, toxic work in the chemical and energy industries. LINHUI TITANIUM is a reliable partner for large-scale procurement programs around the world because it can do integrated manufacturing, has been in business for 21 years, and has a lot of international certifications.
FAQ
What is the difference between a blind flange and a blank flange?
An ASME B16.5 blind flange is a fully standardized component manufactured to meet specific dimensional tolerances, bolt-circle patterns, and pressure-temperature ratings. A blank flange is a generic flat plate cut to seal a pipe end but carries no formal pressure-class certification. In regulated industries—oil and gas, nuclear, and chemical processing—only ASME-certified blind flanges satisfy inspection and code compliance requirements.
Can a titanium blind flange be mated directly with a stainless steel flange?
Dimensionally, yes; technically, it requires precaution. Titanium is more noble than stainless steel. When an electrolyte like seawater contacts the joint, the stainless steel acts as an anode and corrodes rapidly. Isolation kits consisting of dielectric sleeves and washers are mandatory at the bolt circle to prevent galvanic corrosion.
What factors affect lead time for custom blind flanges?
Production schedules are affected by size ranges above NPS 24, non-standard alloy grades, special face finishes, and third-party inspection hold points. LINHUI TITANIUM's two-factory configuration and 30 production lines allow parallel processing, reducing lead times for bulk orders even on customized specifications.
How do I verify that a supplier meets ASME B16.5 compliance?
Request Positive Material Identification (PMI) data, dimensional inspection records signed by a qualified inspector, and EN 10204 3.1 material test reports. Confirm the manufacturer holds ISO 9001:2015 certification and has been audited by recognized third-party bodies such as TUV, SGS, or DNV.
Partner with LINHUI TITANIUM for Your Next Industrial Project
Since 2000, LINHUI TITANIUM has supplied premium ASME B16.5 blind flange products to energy majors and EPC contractors across 60+ countries. As a trusted manufacturer, we back every order with ISO/SGS/TUV certification, EN 10204 3.1 documentation, and responsive global logistics. Contact our technical team today for specifications, volume pricing, and lead-time confirmation. Reach us at linhui@lhtitanium.com or visit https://www.lhtitanium.com/ to request a quote.
References
1. ASME B16.5 – Pipe Flanges and Flanged Fittings: NPS 1/2 Through NPS 24, American Society of Mechanical Engineers, 2017.
2. ASTM B381 – Standard Specification for Titanium and Titanium Alloy Forgings, ASTM International, 2019.
3. NACE International – Corrosion Control in the Oil and Gas Industry, NACE International Publication, 2013.
4. Boyer, R., Welsch, G., & Collings, E. W. – Materials Properties Handbook: Titanium Alloys, ASM International, 1994.
5. ASME PCC-1 – Guidelines for Pressure Boundary Bolted Flange Joint Assembly, American Society of Mechanical Engineers, 2019.
6. Schutz, R. W., & Baxter, C. F. – Titanium for Offshore and Marine Applications, Materials Performance, NACE International, 2003.
