2507 Duplex(Cr-Ni-Mo-N)

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1. Introduce

– Super duplex stainless steel containing approximately 25%Cr, 7%Ni, 4%Mo

– Reduced toughness and corrosion resistance for prolonged exposure to temperatures above approximately 316°C

– UNS S32750

* Duplex Stainless Steel

[Characteristics]

50:50 austenitic and ferritic organization
Good corrosion resistance and strength, resistance to chloride erosion and crevice corrosion
→ Influence of Cr, Mo, W, N
Better chloride stress corrosion cracking resistance, strength, toughness, and plasticity than 300 series austenitic stainless steels

[Type]

UNS NO.	Grade	Chemical Composition	Characteristics
S32304(2304)	Lean Duplex	21Cr-3Ni-Mo-Cu-N	Low alloy type, Mo-free, PREN value 24 to 25, can be used in place of AISI 304 or 316 for stress corrosion resistance
S32205(2205)	Duplex	22Cr-5Ni-3Mo-N	Heavy alloy type, PREN value 32 to 33
S32550(255)	Duplex	24Cr-5Ni-3Mo-N	High alloy type, alloy containing approx. 25%Cr, Mo, N, Cu, W, PREN value 38~39, better corrosion resistance than approx. 22%Cr duplex stainless steel
S32750(2507)	Super Duplex	25Cr-7Ni-4Mo-N	Super duplex stainless steel, PREN value of 40 or higher, contains high amounts of Mo and N

* Physicochemical Features

Corrosion resistance (Chlorine corrosion environment)
→ SUS 316L ≒ 2304<2205<2507
Mechanical strength (1.5~2 times better than austenitic series)
→ 2304<2205<2507

* PREN (Pitting Resistance Equivalent Number : Formula resistance index)
: Numerical value of resistance to pitting in chloride environment of stainless steel
: Pitting resistance is determined by the chemical elemental composition of stainless steel
→ Cr, Mo, N

* UNS

Abbreviation for the Unified Numbering System for Metals and Alloys
Unified unique numbering system for metals and alloys
A representative number compatible with metals and alloys defined in several material-related codes, including ASTM, AISI, ASME, AWS, etc.

* S : Heat and corrosion resistant (stainless) steel

2. Property

: Corrosion resistance, strength, pitting, crevice corrosion, stress corrosion cracking resistance

Element	Impact
Cr, Ni, Mo, N	Provides corrosion resistance, oxidation resistance, erosion and crevice corrosion resistance

[2507 Duplex Chemical Composition (%)]

C	Mn	P	S	Si
Max. 0.030	Max. 1.20	Max. 0.035	Max. 0.020	Max. 0.80

Cr	Ni	Mo	Cu	N
24.0~26.0	6.0~8.0	3.0~5.0	Max. 0.5	0.24~0.32

[2507 Duplex Mechanical Properties]

Tensile Strength (Mpa)	Yield Strength (Mpa)	Elongation (%)
Min. 800	Min. 550	Min. 15

[2507 Duplex Physical Properties]

Density (g/㎤)	Melting Range (℃)	Specific Heat (0-100℃), J/kg*℃
7.8	1396~1450	460

3. Standard & Specification

– Specification : UNS S32750

ASME

SA240, SA276, SA479, SA182

Product Form	ASTM
Bar, Rod	A276
Sheet, Plate	A240
Tube, Pipe	A790, A789
Fittings	A182

4. Available Form

– Bar, Rod

– Sheet, Plate, Strip

– Coil, Wire

– Pipe, Tube

5. Application & Product

– Chemical, Marine, Oil & Gas, Power Generation

Application	Product
Chemical	Chemical process pressure vessels, Piping, Heat exchangers
Marine	Desalination equipment, Deep subsea structures, Pipelines
Oil & Gas	Oil field piping
Power Generation	Seawater treatment equipment for nuclear power plants, seawater desalination equipment