ASTM Duplex Stainless Steel

Duplex stainless steels are Fe-Ni-Cr alloys consisting of ferritic-austenitic microstructure at room temperature. These steels generally possess beneficial combinations of the austenitic and ferritic phases. Duplex stainless steels exhibit greater toughness and better weldability than ferritic stainless steel (Nilsson, 1992). They have higher strength and better corrosion resistance than austenitic stainless steel (Atamert and King, 1992). Their good engineering performance has led to an increasing number of applications, mainly in corrosive environments such as sour gas pipelines and chemical reaction vessels.

GNEE offers a wide range of duplex stainless steel products in a variety of grades and specifications to meet the needs of different industries and applications. We are able to customize our products to meet customer requirements and provide flexible solutions.

Physical Properties of Duplex stainless steel

Property	2205	UR52N+
Density (g.cm³)	7.805	7.810
Modulus of Elasticity (GPa)	200	205
Electrical Resistivity (Ω.m)	0.85 x 10^-6	0.85 x 10^-6
Thermal Conductivity (W/m.K)	19 at 100 °C	17 at 100 °C
Thermal Expansion (m/m.K)	13.7 x 10^-6 to 100 °C	13.5 x 10^-6 to 200 °C

Properties of Duplex Stainless Steel

Strength: Duplex stainless steels are about twice as strong as regular austenitic or ferritic stainless steels.
Toughness and ductility: Duplex stainless steels have significantly better toughness and ductility than ferritic grades; however, they do not reach the excellent values of austenitic grades.
Corrosion resistance: As with all stainless steels, corrosion resistance depends mostly on the composition of the stainless steel. For chloride pitting and crevice corrosion resistance, their chromium, molybdenum and nitrogen content are most important. Duplex stainless steel grades have a range of corrosion resistance, similar to the range for austenitic stainless steels, i.e from Type 304 or 316 (e.g. LDX 2101©) to 6% molybdenum (e.g. SAF 2507©) stainless steels.
Stress corrosion cracking resistance: Duplex stainless steels show very good stress corrosion cracking (SCC) resistance, a property they have “inherited” from the ferritic side. SCC can be a problem under certain circumstances (chlorides, humidity, elevated temperature) for standard austenitics such as Types 304 and 316.
Cost: Duplex stainless steels have lower nickel and molybdenum contents than their austenitic counterparts of similar corrosion resistance. Due to the lower alloying content, duplex stainless steels can be lower in cost, especially in times of high alloy surcharges.Additionally, it may often be possible to reduce the section thickness of duplex stainless steel, due to its increased yield strength compared to austenitic stainless steel. The combination can lead to significant cost and weight savings compared to a solution in austenitic stainless steels.

Material Grade:

American Standard

Austenitic Steel:

TP304,TP304L,TP304H, TP304N, TP310S,TP316,TP316L,TP316Ti,TP316H, TP317,TP317L, TP321, TP321H,TP347, TP347H,904L…

Duplex Steel :

S32101,S32205,S31803,S32304,S32750, S32760

Others:TP405,TP409, TP410, TP430, TP439,...

Inspection & Test

1.100% PMI, Spectro Chemical Analysis Test for Raw Material
2.100% Dimension & Visual Examination
3. Mechanical Properties Test Include Tension Test Flattening Test (For Seamless tube/pipe)/ Flange Test (For Welded Pipe & Tube), Hardness Test ,Reversed Flattening Test.
4.Straightness Test (optional)
5.Roughness Test (optional)
6.Intergranular Corrosion Test(optional)
7.Impact Test (optional)
8.Grain Size Determinations (optional)
NOTES : ALL THE TESTS AND INSPECTION RESULT NEED TO BE SHOWED IN REPORTS ACCORDING TO STANDARD AND SPECIFICATION.