With our day to day life surrounded by machines all around us, it is impossible not to notice flanges all around us. A flange is an external or internal ridge or rim provided for support andattachment to another object that it gets attached to. Some of the most common example of flanges are iron beams in the form of I-beam or T-beam, on the lens mount of a camera, ski shoes with rim on the toes and heel part of shoes, rail cart wheel with flange on one side of wheel, microwave, piping system where pipes are joined. Flanges can be combined with other flanges to form a flange. Flanges not only provide easy access for cleaning but also for inspection and modification.Since the work of flange is to keep the system in place and together without any leakage or failure, it is very important to identify the usage and material for manufacturing the flanges. The flange is generally manufactured in the same material as the material of connecting machines as different material can compromise on stability. Some of the most common flange materials are stainless steel, carbon steel, aluminium, nickel alloy, plastic etc and are listed below:Stainless Steel – Known for its corrosion resistant property, sanitation and durability, it is perfect for the drinking water application or any system that needs to remain clean throughout its service life. Stainless steel flanges are higher in cost and have a long service life. They should also be replaced at the appropriate time, even if the flange is still in good working order.Carbon Steel– Carbon steel flanges are used where toughness is required and sanitation is low on priority. Carbon steel is used in the fuel lines and on a shipping vessel as they can bear the vibrations and heat very well. Carbon steel flanges require a monitoring on tight connection during installation.Aluminium – Aluminium flanges are used when a light weight option is required. Aluminium is a good option for lighter weight options and less pressure on the structure option. It is also used as a face of stainless steel flanges.Nickel Alloy – Nickel Alloy shares many characteristics as stainless steel. It adds strength to the construction of the flange and offers resistance to corrosion. Being an alloy and premium material at par with stainless steel, it is expensive and will be costly for a large system. The manufacturing of the flanges follows the international standard ASTM. These ASTM standards, define the specific manufacturing process of the material by determining the exact chemical composition of pipes, fittings and flanges, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., which are specified by "Grade". ASTM examples are mentioned below:ASTM A105 specification chalks out the standards for forged steel piping components made of carbon which are flanges, fittings, valves to be used in pressure system at high temperature service conditions.ASTM A182 defines the specification for forged/rolled alloy and stainless steel pipe flanges, forged fittings and valves and parts of high temperature service.ASTM A350 informs about the several grades of carbon and low alloy steel that are used to manufacture forged or ring rolled flanges, forged fittings and valves for low temperature service.There are other ASTM standards available that defines the different material specifications.Some of the examples for Grade are:A carbon steel flange can be identified with Grade F9 or F11.A stainless-steel flange with Grade F316 or Grade F321After welding, the flange is considered as the most widely used joining method in case of requirement of dismantling of the joints and requires continuous maintenance. Though it is widely used and manufactured using the ASTM standards, it is globally accepted providing the same specifications flanges across the world.