SX
309 Technical Data
Summary
SX
309 is a highly alloyed austenitic stainless
steel used for its excellent oxidation resistance, high
temperature strength and creep resistance. The lower
nickel content of SX309 improves resistance to sulphur
attack at high temperatures. It is tough and ductile,
and can be readily fabricated and machined. SX
309S is the low-carbon version of SX 309, and
is recommended for applications where sensitisation, and
subsequent corrosion by high temperature gases or condensates
during shutdown may pose a problem.
SX 309 is manufactured to
ASTM A 167 and SX 309S to ASTM A240 specifications.
Typical
Applications
SX 309 / 309S is used exclusively
for its high temperature oxidation resistance. It
is common for SX 309, 310 and 321 to be used in the same
piece of equipment in the various temperature regions.
Chemical
Composition (ASTM A240)
| SX |
C |
Mn |
P |
S |
Si |
Cr |
Ni |
309
309S |
0.20 max
0.08 max |
2.00
max |
0.045
max |
0.030
max |
1.00
max |
22.0 -
24.0 |
12.0 -
15.0 |
Typical Properties in
the Annealed Condition
The properties quoted in
this publication are typical of mill production and unless
indicated should not be regarded as guaranteed minimum
values for specification purposes.
1.
Mechanical Properties at Room Temperature
| |
SX
309 |
SX
309S |
| |
TYPICAL |
MIN |
TYPICAL |
MIN |
| Tensile
Stength MPa |
560 |
515 |
540 |
515 |
| Proof Stress
(0.2% Offset)
MPa |
285 |
205 |
280 |
205 |
Elongation
(Percent
in 50 mm) |
54 |
40 |
54 |
40 |
| Hardness
(Brinell) |
164 |
|
159 |
|
| Endurance
(fatigue) limit
MPa |
260 |
|
260 |
|
2.
Properties at Elevated Temperatures
The values quoted are those
for SX 309
Short Time Elevated Temperature
Tensile Stress
| Temperature |
oC |
550 |
650 |
750 |
850 |
950 |
1 050 |
| Tensile
Stress |
MPa |
440 |
360 |
240 |
150 |
70 |
30 |
Creep
Data
Stress to develop a creep
rate of 1% in the time indicated at the temperature indicated.
| Time |
TemperatureoC |
550 |
600 |
650 |
700 |
750 |
800 |
10 000
h
100 000 h |
Stress
MPa
Stress MPa |
100
75 |
80
50 |
60
30 |
30
20 |
25
10 |
10
5 |
Creep
Rupture Stress
| Time |
Temperature
oC |
600 |
700 |
800 |
900 |
1 000 |
1 000 h
10 000 h
100 000 h |
Stress
MPa
Stress MPa
Stress MPa |
180
150
100 |
90
50
40 |
35
30
20 |
20
10
5 |
5
2
- |
Maximum
Recommended Service
Temperature
(Oxidising Conditions)
Continuous
1 100oC
Intermittent
980oC
Thermal
Processing
1. Annealing.
Heat between 1 050oC and 1 150oC
and water quench. This treatment ensures that all
carbides are in solution.
2. Stress
Relieving 250-400oC for 1 hour.
3. Hot
Working
Initial forging and pressure
1 150-1 200oC
Finishing temperature
1 000oC
Note:
Soaking times to ensure uniformity of temperature are
up to 12 times that required for mild and carbon steels.
