Detailing

Flanges are suited for engineering related industries and fabrication industries and thus their application differ from each industry. Years of research by great scholars have contributed to the development of various types of flanges in different material grades, varied specifications and standards.

A brief overview about flanges is given below:

Types of Flanges

Flanges are available in several types and sub-types, which again can be obtained in different specifications of shape, sizes and surface finishes. Following are the types of flanges that are readily available in the market:

• Back-up flange: These are bell-shaped flanges that facilitate concentrated pressure on the tips of the teeth on the clinch ring

• Slip-on flange: These bored flanges are slightly larger than the outer diameter of the matching pipe and are provided with pipe slips for non leakage. These are used in lower pressure applications.

• Blind flange: Designed without bores, these are used to close the ends of piping systems.

• Lap-joint flange: These have curved radius at the bore and face to accommodate a lap joint stub end for finding application in systems requiring frequent dismantling for inspection.

• Threaded flange: Can be assembled without welding, these flanges are suitable for extremely high pressure services

• API flanges: These are precision turned and are available in varied sizes

• Welding neck flange: Drilled with the wall thickness, these flanges are suitable for high pressure and temperature varying applications

• Industrial flange: Available in several types like weld-neck, slip-on, blind, socket weld, lap joint, spectacles, ring joint, orifice, long weld-neck and deck flange

• Forged flanges: available in various types like slip-on, blinds, welding neck, socket welding, threaded lap-joint, spectacle blinds, and orifice

• Stainless steel flanges: Ideal for petrochemical, process and water works industries

• Raised-face flanges: Offered in varying diameters, thickness and surface finishes

• Socket weld flange: These have low hub for helping the pipe to slip into the flange prior to welding. These are welded on both the sides for preventing leakage.

• Lap joint flanges: Used with either a stub end or taft in low pressure applications

• Ring type joint: Used to ensure leak proof flange connections in high pressure applications

Grades of raw material of flanges

All these flange types are available in different material of construction, ranging from stainless steel to alloys. The raw material and grades of flanges available in the market are as follows:

• Carbon steel - ASTM/ASME SA-105, A-350 LF-2, LF-3, A694, SA-516-70, A36

• Chrome alloys - A-182-F-1, F-5, F-6, F-7, F-9, F-11, F-12, F-22, F-51

• Stainless steel - A-182 - F-304, 304L, 316, 316L, 309, 310, 317L, 321, 347,

• Alloy 20

• Aluminum - 1100, 2014, 3003, 5083, 5086, 6061, 7075

• Hastalloy - B-2, C-276, G, X

• Inconel - 600, 601, 625, 718

• Incolloy - 800, 825

• Monel - 400

• Copper - C11000

• Naval brass - (Bronze)

• Titanium

Types and Standards of Flanges

Flanges are offered worldwide in several industry-recommended standards so that 5its users can avail them easily. Following are the standards in which flanges are offered:

• ANSI/ASME forged flanges

• MSS-SP-44 flanges/ANSI B 16.47 SERIES A

• API TYPE 6A - RTJ Face Flanges

• API-605 FLANGES/ANSI B 16.47 SERIES B

• A.G.A. orifice unions - Furnished with or without hardware

• ASME boiler code flanges

• CL. 125 lightweight flanges - For low pressure applications

• Plate flanges - From 1/4" thru 8" Thick, Including AWWA C-207,and all other special designs

• ANSI long weld-necks & special body connectors

• Spectacle blinds

• Special ring flanges