常用双相钢编号及基本的材料属性

Stainless Steel

1. Composition

z The microstructure consists of roughly 50% austenite and 50% ferrite.

z Generally, the content of the relative phase needs to reach 30%.

2. Basic material characteristics

z Twice strength of austenitic and ferritic stainless steels.

z Wide range of corrosion resistance to match application.

z Good toughness down to minus 80 deg C but not genuine cryogenic applications.

z Particular resistance to stress corrosion cracking.

z Weld able with care in thick sections.

z More difficult to form and machine than austenitic.

z Restricted to 300 deg C maximum.

3. Part of the type

Type CN US SE DE

Duplex Steel

Low Alloy 00Cr23Ni4N UNS

S32304

SS2327

(SAF2304)

W.Nr.1.4362 Middle Alloy

00Cr18Ni5Mo3Si2 UNS

S31500

SS2376

(3RE60)

W.Nr.14417 00Cr22Ni5Mo3N UNS

S31803

SS2377

(SAF2205)

W.Nr.14462 High Alloy

00Cr25Ni5Mo2 UNS

S32900SS2324

(10RE51)

W.Nr.14460 00Cr25Ni7Mo3WCuN UNS S31260W.Nr.14501

Super

Duplex Steel Super

00Cr25Ni7Mo4N UNS

S32750

SS2328

(SAF2507)

W.Nr.14410 00Cr25Ni6Mo3CuN UNS

S32550W.Nr.14507

4. Duplex steel Material properties

4.1. 00Cr23Ni4N (UNS S32304/SFA2304)

z DESCRIPTION

URANUS® 35N (UR 35N) is a 23% Cr, 4% Nickel, Mo free duplex stainless steel (23.04). The alloy UR 35N has similar corrosion resistance properties similar to 316L. Furthermore, its mechanical properties i.e. yield strength, are twice those of 304/316 austenitic grades. This allows the designer to save weight, particularly for properly designed pressure vessel applications. The alloy is particularly suitable for applications covering the -50°C/+300°C (-58°F/572°F) temperature range. Lower temperatures may also be considered, but need some restrictions, particularly for welded structures. With its duplex microstructure, low nickel and high chromium contents, the alloy has improved stress corrosion resistance properties compared to 304 and 316 austenitic grades.

z COMPONENT

Grade C Cr Fe Mo Ni N 2304

Min - - - - - - Max 0.020 23.0 71.8 0.30 4.80 0.10

z PROPERTIES

Physical Properties 20℃ 100℃ 200℃ 300℃ Density /Kg/m 3 7.80 -- - -

Mechanical Properties

20℃

100℃

200℃

300℃

Tensile Strength, Yield (MPa) 400 330 280 250 Tensile Strength, Ultimate (MPa) 670 540 500 - Modulus of elasticity (GPa)

200 194 186 180 Elongation at break (%)

40 Shear Modulus 77.0 Poissons ratio

0.30

-

-

-

Thermal Properties 20℃ 100℃ 200℃ 400℃

Coefficient of Thermal Expansion (µm/m-°C) - 13.0 - 14.5

Specific Heat Capacity (J/g-°C) 0.500 0.530 0.560 - Thermal Conductivity (W/m-K) 15.0 16.0 17.0 18.0

Note:

4.2. 00Cr18Ni5Mo3Si2 (UNS S31500) z DESCRIPTION

Duplex stainless steel, UNS S31500.

Sandvik 3RE60 is a duplex stainless steel (austenitic-ferritic) of the ELC type. The material is characterized by the following properties:

¾ high resistance to stress corrosion cracking in chloride-bearing environments ¾ good resistance to general corrosion and pitting

¾ high mechanical strength – roughly twice the proof strength of austenitic grades ¾ good resistance to erosion corrosion and corrosion fatigue ¾ physical properties that present design advantages ¾ good weldability

z COMPONENT

Grade

C Cr Fe Mn Mo Ni N P Si S S31500

Min - - - - - - - - - -

Max 0.030 18.5 71.2 1.50 2.60 4.500.0700.030 1.60 0.030