High Hub Blind Flanges | ASME B16.5 | Class 150-2500

PM Industries manufactures, supplies, and stocks High Hub Blind Flanges in a range of materials, pressure ratings, and pipe sizes. A high hub blind flange is a solid flange with no center bore, used to close and seal the end of a piping run, nozzle, or pressure vessel opening. The distinguishing feature is the raised hub on the back face, which adds thickness and stiffness to the flange body beyond what a standard flat blind flange provides.

That additional hub height matters under load. A standard blind flange under internal pressure deflects across its face like a plate under uniform load. The higher the pressure and the larger the diameter, the greater that deflection, and the greater the bending stress in the flange body and the gasket contact area. The hub in a high hub blind flange increases the section modulus of the flange body, reducing deflection and bending stress at the seating surface. For large-diameter and high-pressure closures, that structural improvement is the reason high hub blind flanges are specified rather than standard blinds.

Removability is a practical advantage over permanent closures like weld caps. In systems that need periodic inspection access, hydrostatic test connections, or future tie-in points, a blind flange provides the pressure-tight end closure with the option to open the line again without cutting or welding. High hub blind flanges serve that same function with the structural capability to handle conditions where a standard blind would be undersized.

High-pressure and high-temperature service is where the structural benefit of the hub is most relevant. In pressure classes 600, 900, 1500, and 2500, particularly in larger bore sizes, the deflection and bending stress calculations for standard blind flanges often push toward the limits of acceptable flange stress per ASME code. High hub blind flanges address that by adding material where it's most effective structurally, at the center of the face where deflection is greatest.

Material selection covers the full range of process requirements. Carbon steel high hub blind flanges (A105) cover standard process service. Stainless steel grades (304L, 316L, 321) cover corrosion-resistant applications. Alloy steel grades (A182 F11, F22, F91) cover elevated temperature service in power and petrochemical applications. Duplex and nickel alloy grades cover aggressive corrosive and sour service conditions.

High hub blind flanges are available with full material certification to ASTM, ASME, and applicable specifications including NACE MR0175 for sour service. Contact PM Industries for material selection, pressure class, face type, dimensions, and pricing.

Specification High Hub Blind Flange

Standards	ANSI/ASME B16.5, B16.48, GOST, DIN, EN-1092, B16.47 Series A & B, AWWA, BS Flanges
JIS Standard	5K, 10K, 16K, 20K, 30K, 40K, 63K
DIN Flanges	DIN 2527, 2627, 2631, 2656, 2576, 2673, 2629, 2628, 2566

Flanges are Available in Following Materials

Stainless Steel	SS 201, SS 202, SS 301, SS 304, SS 304L, SS 310, SS 310S, SS 316L, SS 316TI, SS 317, SS 317L, SS 321, SS 347, SS 409, SS 409M, SS 409L, SS 410, SS 410S, SS 420, SS 430, SS 431, SS 441, SS 444, SS 446, SS 17-4PH, SS 904L.
Duplex Steel	UNS S32205, UNS S31803 Flange
Super Duplex Steel	UNS S32750, UNS S32760 Flanges
Carbon Steel	Carbon steel A105 Flanges, A36 Flanges, IS 2062 Flanges, A350 LF2 Flanges, F42 Flanges, F52 Flanges, F56 Flanges, F60 Flanges, F65 Flanges, F70 Flanges, F80 Flanges, IBR flanges, A694 Flanges, SS400, SF440, ST37-2 Flanges, S235JrG2 Flanges, P250GH Flanges, C22.8 Flanges, etc.
Alloys Steel	Alloy 20, F1, F5, F9, F11, F22, F91 Flanges
Copper Alloys	Cu-Ni 70/30, Cu-Ni 90/10, C 24000, C 75700, C 51100, C 22000, C 27200, C 21000, C 26800, C 52100, C 77000, C 52000, C 11000, C 74500, C 23000, C 28000, C 12200, C 76400, C 51900, C 75400, C 26000, C 51000, C 10200, C 27000
Nickel Alloys	Nickel 200, 201
Inconel	Inconel 600, 601, 625, 718, 800, 825, X-750
Monel	Monel 400, k500
Hastelloy	Hastelloy C-22, C-276, C-4, X
Titanium	Grade 1, 4, 5(Ti 6Al-4V), 6(Ti 5Al-2.5Sn), 7, 11, 6Al-2Sn-4Zr-2Mo, Grade 12, 6Al-6V-25n, Grade 23(Ti 6AL-4V ELI), 8Ai-1Mo-1V, Grade 5 ELI, Grade 9(3Al-2.5V), 6Al-7Nb.
Aluminium	6063, 1100, 6082 A96082, 1050, 2017, 2024 A92024, 7050 A97050, 5083 A95083, 2014A A92014, 2011 A92011, 6061 A96061 A86061, 5754, 7085, 2050, 7071 7020, 7178, 5052 A95052, 7150, 7075 A97075 A87075, 7575, 2219, 7175
Pressure Rating	Class 150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS
Types	Threaded, Plate, Screwed, Forged.
Supporting material	Gasket, Ring Joint, Flange Bolts
Size range	1/2" (15 NB) to 48" (1200NB) DN10~DN5000
High Temperature	Above 200°C (400°F) For Class 150 Or Above 400°C (750°F)
Low Temperature	Above -29 Degree C (−20°F)
Production technique	Forged, machined and Heat treated
Custom design	As per your drawing
Origin	Indian / USA / Korean / West Europe / Japan
Pressure Class	PN 6 TO PN 100
Coating/Surface Treatment:	Zinc Plated, Anti-rust Paint, Oil Black Paint, Yellow Transparent, Cold and Hot Dip Galvanized.
European/African/Russian Standard Flanges	Available
Test	Direct-reading Spectrograph, X-ray detector, UItrasonic flaw detector, Magnetic particle detector, Hydrostatic testing machine.
Marking Standard	Name of Manufacturer
	Schedule
	Type of Flange Facing
	Pressure Class
	Nominal Pipe Size, etc
Test Certificates	EN 10204/3.1B, NACE MR0103, NACE MR0175
	Raw Materials Certificate
	100% Radiography Test Report
	Third Party Inspection Report, etc

Hub Blind Flange Standards

ASME/ANSI B16.5	High Hub Blind Flange
Pressure Class	150, 300, 600, 900, 1500, 2500 LBS DIN Standard ND-6,10, 16, 25, 40 Etc.
DIN EN 1092-1 Face Dimensions	PN 2.5, PN 6, PN 10, PN 16, PN 25, PN 40, PN 63, PN 100, PN 160, PN 250, PN 320, PN 400
BS 4504 SEC 3.1, BS 4504[PART 1], BS 1560 Boss	High Hub Blind Flange
Table	D, E, F, H
DIN Flanges	DIN 2637,2638, 2656, 2655, 2527, 2633, 2576, 2629, 2632, 2636, 2573, 2627, 2634, 2566, 2628, 2631, 2673, 2635, 2641,2642,
Pressure Class	PN 6 TO PN 100

Class 150 High Hub Blind Flange Dimensions

Item ID	Class 150 HH High Hubbed Blind Flanges Description
1FF .51RHHBLD	1/2 150 RF High Hubbed Blind ASME B16.5 001 lbs
1FF 1.51RHHBL	1 1/2 150 RF High Hubbed Blind ASME B16.5 004 lbs
1FF 11RHHBL	1 150 RF High Hubbed Blind ASME B16.5 002 lbs
1FF 21RHHBL	2 150 RF High Hubbed Blind ASME B16.5 005 lbs
1FF 31RHHBL	3 150 RF High Hubbed Blind ASME B16.5 009 lbs
1FF .751RHHBL	3/4 150 RF High Hubbed Blind ASME B16.5 002 lbs
1FF 41RHHBL	4 150 RF High Hubbed Blind ASME B16.5 017 lbs

SS Class 300 Hub Blind Flange Dimension table

Item ID	Class 300 HH High Hubbed Blind Flanges Description
1FF .53RHHBL	1/2 300 RF High Hubbed Blind ASME B16.5 002 lbs
1FF 13RHHBL	1 300 RF High Hubbed Blind ASME B16.5 003 lbs
1FF 1.53RHHBL	1 1/2 300 RF High Hubbed Blind ASME B16.5 006 lbs
1FF .753RHHBL	3/4 300 RF High Hubbed Blind ASME B16.5 003 lbs
1FF 23RHHBL	2 300 RF High Hubbed Blind ASME B16.5 008 lbs

600 Lbs High Hub Blind Flange Dimension

Item ID	Class 600 HH High Hubbed Blind Flanges Description
1FF .756RHHBL	3/4 600 RF High Hubbed Blind ASME B16.5 004 lbs
1FF .56RHHBL	1/2 600 RF High Hubbed Blind ASME B16.5 004 lbs
1FF 16RHHBL	1 600 RF High Hubbed Blind ASME B16.5 004 lbs
1FF 1.56RHHBL	1 1/2 600 RF High Hubbed Blind ASME B16.5 008 lbs
1FF 26RHHBL	2 600 RF High Hubbed Blind ASME B16.5 010 lbs