Blind Flanges & Pipe Caps: Complete Solutions for Pipeline Closure & End Treatment

Jun 09, 2026

Introduction: Pipeline Closure Safety Guards
Blind flanges and pipe caps are dedicated fittings for sealing pipe ends in piping systems. Blind flanges provide bolted closure that can be opened for future expansion or maintenance. Pipe caps provide permanent welded closure. Both are indispensable for pressure testing, future connection provision, and pipeline isolation. Wenqiang Stainless Steel supplies full-range blind flanges and pipe caps.

Blind Flanges: Features & Applications
A blind flange is a solid flange disc without bore, bolted to a mating flange. Primary applications include: pipeline end closure, pressure test end plates, future expansion provision, and isolation of active pipeline sections. Blind flanges can withstand higher pressures than same-class through-bore flanges (no bore weakening effect) but are correspondingly heavier.
Pipe Caps: Features & Applications
Stainless steel pipe caps are welded to pipe ends for permanent closure. Wenqiang supplies butt-weld caps (GB/T 12459, ASME B16.9) and socket-weld caps (ASME B16.11). Available in hemispherical and ellipsoidal shapes — hemispherical caps offer higher pressure capacity while ellipsoidal caps require less installation space.

Blind Flanges & Pipe Caps: Complete Solutions for Pipeline Closure & End Treatment
Frequently Asked Questions
Q1: How is blind flange thickness determined?
A: Blind flange thickness follows ASME B16.5 or GB/T 9119 standards based on pressure class and nominal diameter. For example, a Class 150 DN100 blind flange is approximately 25.4mm thick; Class 300 is approximately 31.8mm.
Q2: What's the difference between a blind flange and a spectacle blind?
A: A blind flange is a solid plate that requires bolt removal to open. A spectacle blind (figure-8 blind) has a solid plate and an open ring connected by a strap — it can be rotated between open and closed positions without bolt removal.
Q3: Can Wenqiang custom-manufacture non-standard blind flanges?
A: Yes. Wenqiang supports non-standard blind flange fabrication including special bolt patterns, increased thickness designs, and necked blind flanges. Lead time approximately 10-15 days.