ASTM A182 F51 Duplex Stainless Steel Flanges

ASTM A182 F51 Blind Flange is a Duplex Stainless Steel Flange that highly suitable for applications dealing with environments containing chlorides and hydrogen sulphide. It has to withstand remarkable mechanical stress due to the system pressure and the required bolting forces.

F51 Blind Flange differs from other flange in that it does not have a center hole and is used to block the flow of the fluid. Moreover, it is sold at a premium average cost per kilogram due to it is easier to manufacture.

F51 Forged Flanges

The common specification standards of forged A182 F51 Blind Flanges are ASME B16.5 and ASME B16.47. ASME B16.47 Blind Flange has larger diameter than ASME B16.5 Blind Flange.

ASME B16.47 Flange is form NPS 26 through NPS 60 in ratings classes 75, 150, 300, 400, 600, and 900. And further divided into series A and series B for blind flange and weld-neck flange. Series A can withstand more external loading than Series B type, and series b needs more but smaller fasteners (bolts & nuts) than series a flanges.

They are common used in Aerospace, Nuclear Engineering, Chemical Industry, and Heat Treating Industry.

Duplex Steel ASTM A182 F51 Blind Flange

ASTM A182 F51 is a Duplex Stainless Steel (DSS) with 50% ferrite and 50%   austenite, so it is also called Ferritic-Austenitic Stainless Steel.

It has many alias, the most common one is UNS S31803, and other alias are

• 4462
• X2CrNiMoN 22-5-3
• Z3CND22-05 Az
• SUS 329J3L

This duplex steel is more common in Pressure Systems, Forged Flanges, Valves Fittings, Couplings, Rings, Shafts, and other Forgings.

ASTM A182 F51 Blind Flange Factory

Zizi Engineering manufacture A182 F51 Blind Flange with top class material, and here are some details about the material.

Heat Treating Requirements:

• Heat Treat Type: Solution treat and quench.
• Austenitizing /nSolutioning Temperature, min °F (°C):1870 [1020]
• Cooling Media liquid
• Quenching Cool Below °F (°C) 500 [260]

A182 F51 Chemical Composition, %

C	Mn	P	S	Si	Ni	Cr	Mo
0.03	2.00	0.03	0.02	1.00	4.5-6.5	21-23	2.5-3.5

A182 F51 Mechanical Property

Tensile Strength ksi [Mpa]	Yield Strength ksi [Mpa]	Elongation in 2 inch or 4D, min,%	Reduction of Area, min, %
90 [620]	65 [450]	25	45

Characteristics of ASTM A182 UNS S31803 Duplex Steel Flange

A182 Duplex Steel Flange offers a high resistance to general corrosion, pitting, stress and crevice corrosion, as well as a high mechanical strength and good weldability.

Because the content of austenite and ferrite are basically equivalent, A182 F51 Blind Flange has the advantages of both. And those superior performances make it developed fast and is ranked with martensitic, austenitic and ferritic stainless steel.

The characteristics of duplex stainless steel flanges are:

• Good corrosion resistance, including the corrosion of chloride stress, pitting, and wear. It retains the properties of ferrite that resistant to chloride stress corrosion, avoid cracking from stress, and the performance of pitting corrosion resistance is same as AISI 316L.
• Fine comprehensive mechanical properties. The yield strength is 450 Mpa, almost is twice of general austenite stainless steel.
• Good weldability. In contrast to austenite and ferrite, it is not prone to hot crack, or sensitive to the welding heat which changes the toughness of material. Generally, it is no preheating and heat treatment before and after welding.
• Compared with austenitic stainless steel, it has large thermal conductivity and smaller linear expansion, and higher heat transfer efficiency.
• It still has the brittle tendency like high-chromium ferritic stainless steel, therefore, the working temperature should under 300° The lower the chromium content in duplex stainless steel, the less harmful the brittleness.