Blind Flange | Professional Non-Standard Custom Manufacturer
Blind Flange, also known as blank flange or end cap flange, is a solid and non-porous piping sealing component used for pipeline end closure, pipe section isolation and equipment port blocking. Featuring high pressure resistance, excellent sealing performance and reliable blocking safety, blind flanges are essential fittings for pipeline pressure testing, equipment maintenance and permanent pipeline closure. As a professional flange manufacturer based in Cangzhou, we supply standard blind flanges compliant with Chinese, American, German and Japanese standards. We also provide customized non-standard blind flanges with large diameters, thickened walls and high-pressure specifications. Drawing and sample processing are available with direct factory supply.
1. Structural Characteristics of Blind Flange
A blind flange is a solid forged disc structure with no borehole for fluid passage. It achieves complete pipeline blocking and zero leakage by compressing gaskets through bolt fastening. Manufactured by integral forging, it features high density, large thickness and strong impact and pressure resistance. Compared with custom welded blocking plates, standard blind flanges bear force evenly, resist deformation and maintain higher safety under medium and high-pressure working conditions.
With flat flange faces, precise sealing surface finish and accurate bolt hole positions, blind flanges match perfectly with standard pipe flanges. They can be disassembled and reinstalled repeatedly, suitable for temporary pressure test blocking, sectional pipeline isolation and permanent closure. Pipeline modification is convenient since only flange replacement is required without pipe cutting.
2. Common Materials and Specifications
We customize blind flanges with different materials according to medium characteristics, pressure grades and operating temperatures, adapting to normal pressure, high pressure, high temperature, low temperature and corrosive working conditions:
- Carbon Steel Blind Flange: 20#, Q235B, A105, 16Mn. With dense structure, stable pressure resistance and high cost performance, it is widely used for blocking and pressure testing of water supply, heating, oil, gas and general industrial pipelines.
- Stainless Steel Blind Flange: 304, 316L, 321, 2205 duplex steel. Featuring outstanding acid and alkali corrosion resistance and rust-proof performance, it is suitable for chemical, pharmaceutical, sewage treatment and seawater service pipelines.
- Alloy Steel Blind Flange: High-temperature resistant materials such as 15CrMo and 12Cr1MoV, specially applied for blocking high-temperature and high-pressure steam pipelines and process pipelines in boilers and power stations.
Specification coverage: Conventional sizes DN15-DN3000 and customized large-diameter products; Pressure grades include PN16, PN25, PN40, PN64, PN100, PN160 and full range of American standard Class150–Class2500. Custom thickened super-high-pressure blind flanges are available.
3. Implementation Standards and Sealing Types
All our blind flanges are produced in strict accordance with domestic and international industry standards, supporting domestic engineering projects and export orders. Core applicable standards include GB/T9119, HG/T20592/HG/T20615, ASME B16.5, EN1092, JIS B2220, etc.
A full range of customizable sealing faces are available, including RF (Raised Face), FF (Full Face), MFM (Male and Female Face) and RJ (Ring Type Joint). Among them, RJ ring joint high-pressure blind flanges are mostly used for key equipment ports in petrochemical, oil and gas and power station projects involving flammable, explosive, toxic, high-temperature and high-pressure media.
4. Working Conditions and Application Scope
With strong pressure resistance, tight blocking performance, high safety factor and easy disassembly, blind flanges are mainly used for pipeline end sealing, pipe section isolation, equipment port closure, hydraulic and pneumatic pressure testing and inactive pipeline blocking:
- Petrochemical industry: End blocking of oil and gas transmission pipelines, process section isolation and high-pressure equipment port sealing
- Power and thermal industry: Boiler steam pipeline blocking, standby unit port covering and high-pressure test port sealing
- Municipal engineering: Temporary and permanent blocking of water supply, heating, fire protection and sewage pipelines
- Chemical and pharmaceutical industry: Isolation of corrosive medium pipelines, flow cut-off for equipment maintenance and safety pipeline separation
- Equipment matching: Blocking of spare ports for pressure vessels, heat exchangers, pumps and valves, and pipeline pressure test sealing
5. Our Production and Customization Advantages
Equipped with complete production lines for forging, CNC machining and non-destructive testing, we meet the demands of standard spot supply and high-pressure non-standard engineering customization:
1. Reliable forging technology: Integrally forged blanks ensure uniform internal structure without interlayers, pores or looseness, providing stable overall pressure resistance and eliminating leakage risks under high pressure.
2. Powerful non-standard customization: We produce large-diameter, extra-thick, super-high-pressure and special-shaped non-standard blind flanges with special bolt pitches. No mold opening is required for both small-batch trial orders and large-scale engineering orders.
3. Strict and traceable quality inspection: Each batch of products is equipped with material certificates and factory inspection reports. UT and MT non-destructive testing are available for high-pressure projects to meet engineering acceptance and export customs clearance requirements.
4. Sufficient stock and stable delivery: Conventional specifications are in sufficient stock for fast delivery. The production cycle of customized products is strictly controlled to guarantee project construction schedules.
6. Common Purchasing FAQs
Q: What is the difference between blind flange, flat blocking plate and pipe head?
A: Blind flanges have standard bolt holes for detachable flange connection with high pressure resistance and safety, suitable for industrial high-pressure pipelines. Ordinary flat blocking plates are custom welded without standard holes and cannot be disassembled. Pipe heads are permanently welded end closures without detachability. The three types cannot be substituted in engineering applications.
Q: Can you customize high-pressure thickened non-standard blind flanges?
A: Yes. We support full-range non-standard customization. Super-high-pressure, large-diameter, thickened and widened, special-pitch and special-shaped blind flanges can be precisely produced according to customer drawings.
Q: Can you provide NDT inspection documents for high-pressure blind flanges?
A: We provide free certificates, material test reports and dimension inspection reports. UT ultrasonic testing and magnetic particle testing reports are available on demand to support high-pressure project acceptance and export customs clearance.
Inquiry & Cooperation
Whether you need in-stock standard blind flanges of GB, ASME and EN standards or custom high-pressure thickened non-standard blind flanges for engineering projects, simply provide your drawings, dimensions, materials and pressure parameters. Our technical team will verify specifications and offer accurate quotations promptly. We welcome long-term cooperation with global engineering companies, trading enterprises and terminal manufacturers.