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Showing posts with label Pump Casing. Show all posts
Showing posts with label Pump Casing. Show all posts

ASTM A990: Standard Specification for Duplex Stainless Steel Castings

ASTM A990 is a standard specification for duplex stainless steel castings used in pressure-containing applications such as valves, flanges, and fittings. This standard covers five different grades of duplex stainless steel castings, each with unique properties and characteristics.

The five grades covered by ASTM A990 include CD3MN, CD4MCu, CD4MCuN, CE3MN, and CE8MN. CD3MN is a duplex stainless steel with a high chromium content and moderate amounts of nickel, molybdenum, and nitrogen. It offers good corrosion resistance in various environments, including seawater, and is often used in valves, pumps, and other pressure-containing components.

CD4MCu is a duplex stainless steel with higher levels of chromium, molybdenum, and copper than CD3MN. It has excellent resistance to pitting and crevice corrosion and is commonly used in marine and chemical processing applications.

CD4MCuN is a modified version of CD4MCu that also contains nitrogen for improved corrosion resistance. This grade is well-suited for applications in harsh environments, such as offshore oil and gas production.

CE3MN is a duplex stainless steel with a high nitrogen content and low nickel content. It offers good resistance to corrosion and stress corrosion cracking in chloride-containing environments and is often used in chemical processing and pulp and paper production.

CE8MN is a duplex stainless steel with higher levels of nitrogen and molybdenum than CE3MN. It has excellent resistance to pitting and crevice corrosion and is often used in seawater applications.

The mechanical properties of the duplex stainless steel castings specified in ASTM A990 depend on the grade and the heat treatment process. The minimum tensile strength and yield strength requirements for each grade are specified in the standard, as well as the maximum hardness values.

ASTM A990 also specifies the chemical composition and testing requirements for each grade of duplex stainless steel castings. The chemical composition requirements ensure that the castings meet the specified corrosion resistance and mechanical properties, while the testing requirements ensure that the castings meet the quality standards set forth in the specification.

In conclusion, ASTM A990 is an important standard specification for duplex stainless steel castings used in pressure-containing applications. Understanding the different grades and their properties can help engineers and designers select the appropriate material for their specific application. By following the requirements set forth in ASTM A990, manufacturers can ensure that their duplex stainless steel castings meet the necessary quality and performance standards

 

CF8M corrosion resistant alloy : composition, applications, properties and weldability

DESCRIPTION

CF-8M is a molybdenum bearing modification of of CF8 alloy and is the cast equivalent of wrought AISI 316 stainless steel. The presence of molybdenum increases the general corrosion resistance and the resistance to pitting by chlorides. The alloy is used in mildly acidic and alkaline conditions and for handling citric, oxalic and phosphoric acids.

COMPOSITION
                     C         Mn      Si        Cr    Ni      Mo      P        S
Min %                                 18        9    2.0
Max %        0.08    1.50     2.0(i)   21     12      3.0    0.04    0.04
Notes (i) Silicon 1.5% Max in ASTM A351

APPLICATIONS
Impellors, propellors, pump casings, valve bodies, press plates.

PRODUCT FORMS
Horizontal and vertical centrifugal castings; static castings.

PHYSICAL PROPERTIES
Density (lbs/in3)              0.280
Liquidus(oF)                   2550
Thermal Conductivity      9.4 @ 212oF
(Btu/h/ft2/ft/oF)              12.3 @ 1000oF
Thermal Expansion         8.9 @ 70-212oF
(10-6in/in oF)                 9.7 @ 70-1000oF
Magnetic Permeability    1.5-2.5

MECHANICAL PROPERTIES
(Typical Values at Room Temperature - Solution Annealed at 1950-2100oF, Water Quenched.)
                                                                                     ASTM Specs A351, A743 & A744
U.T.S.                  K.S.I.                   80.0                     70  Min
Y.S.                     K.S.I.                   42.0                      30 Min
Elong.                  %                          50                        30 Min
Brinell                  H B                       156-170
Charpy 'Key'       ft-lbs                     52 @ -400oF

WELDABILITY
CF-8M may be welded by the SMAW, GTAW and GMAW processes.
Electrodes
Preheat                                   None
Post weld heat treatment         1900oF min. water quench
Procedures for welding CF-8M alloy are available from Kubota Metal Corporation.

RELATED SPECIFICATIONS
ASTM A351, A743, A744, , J92900
Nearest wrought grade: AISI 316.



Source: http://www.kubotametal.com

 
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