Special Alloy Ball Valves  

Besides standard material such as CF8M, WCB, CF8 & CF3M in ASME standard or 1.4408, 1.4308, 1.0619 in EN standard or SCS14, SCS13, SCS16 in JIS standard, special alloy valves can also be offered for demanding process conditions.

Valve body and parts can be cast in special alloy such as Duplex 2205 (4A CD3MN),  Super Duplex 2507 (5A CE3MN) Ni base material, Hastelloy C276 (CW12MW), Hastelloy C-22 (CX2MW), Alloy 20 (CN7M), 254 SMO (CK3MCuN) for desalination or sea water.

Material often stocked in 2-pc Flanged RF & high performance 3-pc Firesafe Ball Valves.

1" AF-35 3-pc Fire safe Ball Valve in Duplex (2205, 4A CD3MN)

Duplex (2205 / F51 / 4A CD3MN

Duplex stainless steels are in most cases, tougher than ferritic stainless steel. Strength of duplex stainless steel can in some cases be double that for austenitic stainless steel. Whilst duplex stainless steels are considered resistant to stress corrosion cracking, they are not as resistant to this form of attack as ferritic stainless steel. However, the corrosion resistance of the least resistant Duplex stainless steel is greater than that for the most commonly used grades of stainless steel such as 304 and 316.

Duplex stainless steels are also magnetic, a property that can be used to easily differentiate them from common austenitic grades of stainless. Due to excellent corrosion resistance and high strength, the most widely used duplex stainless steel is 2205. The name 2205 comes from a typical composition of 22% Chromium and 5% Nickel.

Duplex stainless steels are extremely corrosion resistant. They have high resistance to intergranular corrosion. Even in chloride and sulphide environments, Duplex stainless steel exhibit very high resistance to stress corrosion cracking. Super duplex grades are even more resistant to corrosion.

Duplex stainless steels are graded for corrosion performance, normally determined by their alloy content. The term first used in the 1980s and was used to classify Duplex that had a pitting resistance of >40 (based on Cr% + 3.3Mo% + 16N%).

Duplex stainless steel typically for the following applications:

Chemical processing, transport and storage

Oil and gas exploration and offshore rigs, as well as refining

Marine environments

Pulp & paper manufacturing

Chemical process plants

Super Duplex (2507 / F53 / 5A CE3MN)  

Super Duplex has all the benefits of other duplex steel, specifically the strength benefits of their biphasic structural composition of equal parts austenitic and ferritic stainless steel. This microstructure makes all duplex steels around twice as strong as regular single structure ferritic or austenitic steels, but Super Duplex has a higher chromium and molybdenum content, giving it considerably increased resistance to corrosion.

Super Duplex (2507 / UNS S32750) with 25% chromium, 4% molybdenum, and 7% nickel is designed for demanding applications which require exceptional strength and corrosion resistance, such as chemical process, petrochemical, and seawater equipment. It has excellent resistance to chloride stress corrosion cracking, high thermal conductivity, and a low coefficient of thermal expansion. The high chromium, molybdenum, and nitrogen levels provide excellent resistance to pitting, crevice, and general corrosion.

Super Duplex, due to its higher nickel content, is more expensive than duplex stainless steel. Super duplex, however, can withstand corrosive environments such as in marine or petrochemical industries for a longer time than duplex and is higher in strength.

Super Duplex is particularly suited for following applications:

Heat exchangers, tubes and pipes for processing gas and oil

Pipes in processes containing chlorides

Cargo tanks – piping for chemical tankers

Shafts, rotors and hydraulic lines


1" AF-35 3-pc Fire safe Ball Valve in 254 SMO (CK3MCun)

1/2" AF-35 3-pc Fire safe Ball Valve in 254 SMO (CK3MCun)

2" AF-35 3-pc Fire safe Ball Valve in 254 SMO (CK3MCun)

3" AF-35 3-pc Fire safe Ball Valve in 254 SMO (CK3MCun)

254 SMO (A351 CK3MCuN) is an austenitic stainless steel that consists impact toughness resistance to pitting corrosion, crevice corrosion and chloride stress corrosion  cracking, and with strength nearly twice that of 300 series stainless steel. In some applications it has been found to be a more cost effective substitute for high nickel and titanium alloys.

254 SMO / 6Mo is a so-called super austenitic stainless steel. By increasing the molybdenum content to 6%, it achieves a pitting resistance equivalent number (PREN) > 43, which is similar to that of a super duplex stainless steel (SDSS).

When comparing 254 SMO vs super duplex stainless steels, it is non-magnetic, potentially more straightforward to weld and has a wider operating temperature range.  However, it is considerably more expensive due to its greater nickel and molybdenum content and has a significantly lower strength. Therefore, it will mostly be used in applications where the use of super duplex stainless steels is limited. This could include applications at lower temperatures (<-50 degC) where the impact strength of SDSS drops, or at higher temperatures (>250 degC) where there is a risk of forming deleterious phases if exposed for extended periods.

254SMO is used frequently in the following applications –

·        Equipment in pulp bleaching plants

·        Components in gas cleaning systems

·        Equipment for handling seawater, such as heat exchangers, ballast water systems, firefighting systems

·        and cooling water systems.

AF-35M 3-pc Metal Seat Ball Valve

 Can be offered for high temperature or critical applications.

1" AF-50 ANSI 150 2-pc Flanged Ball Valve in Hastelloy C276 (CW12MW)

Hastelloy C276 (A494 CW12MW) is a nickel-molybdenum-chromium superalloy with an addition of tungsten designed to have excellent corrosion resistance in a wide range of severe environments.

The high nickel and molybdenum contents make the nickel steel alloy especially resistant to pitting and crevice corrosion in reducing environments while chromium conveys resistance to oxidizing media. The low carbon content minimizes carbide precipitation during welding to maintain corrosion resistance in as-welded structures.

This nickel alloy is resistant to the formation of grain boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process application in an as welded condition. Alloy C-276 is widely used in the most severe environments such as chemical processing, pollution control, pulp and paper production, industrial and municipal waste treatment, and recovery of sour natural gas.

1" AF-50 ANSI 150 2-pc Flanged Ball Valve in Hastelloy C22 (CX2MW)

Hastelloy C22 (A494 CX2MW) is used in severely corrosive media with high chloride and temperature applications such as buffer solutions, active pharmaceutical ingredients (API), fabric softeners, cleaning supplies, and fish, soy and chili sauce. 

Hastelloy C22 is the most versatile nickel-chromium-molybdenum-tungsten alloy available today. With improved resistance to both uniform and localized corrosion, it will outperform other nickel alloys such as C-276, C-4, Alloy 20, and Alloy 625 in applications using a variety of mixed industrial chemicals.

Hastelloy C-22 The composition has many benefits that help enhance resistance to pitting, crevice corrosion, and stress corrosion cracking. It has excellent resistance to oxidizing aqueous media, including wet chlorine, mixtures containing nitric acid, and oxidizing acids with chlorine ions.

C-22 is a great alternative when super austenitic stainless steels (904L, and 254 SMO) and duplex stainless steels (2205 and 2507) cannot withstand highly aggressive media. This is because it is a nickel-chromium-molybdenum-tungsten alloy with better overall resistance to uniform and localized corrosion than any other Ni-Cr-Mo alloy, like Hastelloy C-276, C-4, and alloy 625.

1" AF-50 ANSI 150 2-pc Flanged Ball Valve in Alloy 20 (CN7M)

Alloy 20 (A351 CN7M) is a nickel-chromium-molybdenum stainless steel alloy developed for applications involving sulphuric acid. Its corrosion resistance also finds other uses in the chemical, food, pharmaceutical, and plastics industries. Alloy 20 resists pitting and chloride ion corrosion and its copper content protects it from sulphuric acid. It is often chosen to solve stress corrosion cracking problems, which may occur with 316L stainless.

Nickel 200 (A494 CZ100) is commercially pure (99.0%) nickel that is highly resistant to corrosion in many environments. It is proven for use in plant processes having exposure to caustic soda, other alkalies and anhydrous hydrofluoric acid.

Monel 400 (A494 M35-1) Superior corrosion resistance in reducing environments, no local corrosion, and stress corrosion cracking resistance. Chemical processes handling alkali chlorides and boiled acids and oil refining.

Inconel 600 (A494  CY40) is good strength and toughness from cryogenic to elevated temperatures. Used in process heaters and high purity water systems in nuclear reactors.

Inconel 625 (A494 CW6MC) is an acceptable material for heat exchanger tubing and flowing sea water. Exceptional corrosion resistance and fatigue strength in marine service. High temperature strength. Typical uses in chemical and food processing equipment, combustor/exhaust, shaft sleeves. 

AF-50M 2-pc Flanged Metal Seat Ball Valve

Can be offered for high temperature or critical applications.



Trade name

UNS nr.

Werkstoff nr.


Casting Grade




A182 F904L

A351 CN2MCuN

Alloy 20



B462 N08020

A351 CN7M

Duplex 2205



A182 F51

A890 Gr 4A

Super Duplex (F53)



A182 F53

A890 Gr 5A

Super Duplex (F55)



A182 F55

A890 Gr 6A

254 SMO S31254 1.4547 A182 F44 CK3MCuN

Nickel 200



B564 N02200

A494 CZ-100

Monel® 400



B564 N04400

A494 M35-1

Inconel® 600



B564 N06600

A494 CY40

Inconel® 625



B564 N06625

A494 CW 6MC

Hastelloy® C276



B564 N10276

A494 CW12MW

Hastelloy® C22



B574 N06022 

A494 CX2M2

Titanium GR. 2



B381 F2

B367 C2

*Minimum Order Quantity required for casting production when not in stock.


Please contact Anson Flow or send inquiry.

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