ASTM A240 S32750 | 2507 Plate, Sheet & Strip

Characteristics, Classifications & Manufacture

Plates, sheets, strips manufactured in accordance with ASTM A240 UNS S32750 (alloy 2507) are widely used for pressure vessels and for general applications including architectural, building, construction, and aesthetic applications. UNS S32750 (Alloy 2507) is a super duplex stainless steel grade with PREN value between 40 and 43. As a duplex stainless steel, it has improved stress-corrosion cracking resistance and higher strength, compared with austenitic stainless steels, and improved toughness and ductility, compared with ferritic stainless steel. Due to the increased addition of chromium, molybdenum, nickel and nitrogen, alloy 2507 (S32750) exhibits better resistance to general corrosion and chloride stress-cracking corrosion than standard duplex stainless steel alloy 2205 (S32205). The high yield strength of flat products made of ASTM A240 S32750 offers designers the use of thin-wall material with adequate pressure-containing and load-bearing capacity. This can lead to major reductions in weight and welding time.

ASTM A240 UNS S32750 flat products can be classified as plate – 3/16″ [5.00 mm] and over in thickness and over 10″ [250 mm] in width; sheet – under 3/16″ [5.00 mm] in thickness and 24″ [600 mm] and over in width; strip – cold rolled material under 3/16″ [5.00 mm] in thickness and under 24″ [600 mm] in width. They may be manufactured by the hot rolling, cold rolling or a combination of both hot & cold rolling process. The products shall be solution annealed at the temperature between 1880°F [1025°C] and 2060°F [1125°C], followed by a water quench.

Chemical Composition Requirements

Element	Composition, %
C	≤0.030
Mn	≤1.20
P	≤0.035
S	≤0.020
Si	≤0.80
Cr	24.0–26.0
Ni	6.0-8.0
Mo	3.0-5.0
N	0.24-0.32
Cu	≤0.50

*Composition requirements for ASTM A240 UNS S32750 based on heat analysis; PREN = Cr + 3.3 Mo + 16N shall be greater than 41.

Mechanical Test Requirements

Test	Requirement
Tensile Strength min. MPa [ksi]	795 [116]
Yield Strength min. MPa [ksi]	550 [80]
Elongation in 2", min. %	15
Hardness max, HBW	310
Hardness max. HRC	32

*Tensile & hardness test requirements for ASTM A240 UNS S32750 at room temperature.

Applications in ASME BPVC VIII-1, ASME B31.1 & B31.3

ASTM A240/ ASME SA-240 UNS S32750 plates can be used for the construction of pressure vessels in accordance with Section VIII Division 1 of ASME Boiler and Pressure Vessel Code. The maximum temperature limit is 600°F [315°C] and the minimum design temperature without impact testing requirements is -20°F [-29°C]. The ASTM A240 S32750 plates, sheets & strips can be used for the manufacture of piping components in accordance with ASME B31.1 and ASME B31.3. In power piping of ASME B31.1, the minimum design metal temperature is -20°F [-29°C] and the maximum temperature limit is 480°F [250°C]. In process piping of ASME B31.3, the minimum design metal temperature without impact testing requirements is -60°F [-51°C] and the maximum temperature limit is 600°F [315°C].

Temp. °F	S ksi
100	33.1
200	33.0
300	31.2
400	30.0
500	29.6
600	29.4

*Maximum allowable stresses, S, for ASME SA-240 S32750, for metal temperatures, not exceeding; abstracted from Table 1A of ASME Section II Part D.

Temp. °F	S ksi
100	33.1
200	33.0
300	31.2
400	30.1
500	29.6
600	29.4

*Maximum allowable stresses in tension, S, for ASTM A240 S32750, for metal temperature, not exceeding; abstracted from Table A-3 of ASME B31.1.

Temp. °F	S ksi
-60~100	38.7
200	38.5
300	36.4
400	35.1
500	34.5
600	34.3

*Basic allowable stresses in tension, S, for ASTM A240 S32750, at metal temperatures; abstracted from Table A-1 of ASME B31.3.