347/347H

Wst. 1.4550/1.4912

UNS S34700/S34709
Stock program: Available on request
Specification: ASTM A 269/A 213/A 312 EN10216-5 /EN ISO 1127 D4/T3/EN 10305 PED 97/23 EC
Maximum exposure temperature: 850°C / 1560°F

Alloy 347 is an austenitic, niobium, stabilized stainless chromium-nickel steel. It has slightly imposed corrosion resistance over 321 stainless steel in strongly oxidizing environments and is preferable for aqueous and low temperature environments due to its good resistance to inter granular attack. The 347H has high carbon (0.4 to 0.1%) for better high temperature creep properties.

Characteristics:

  • Excellent resistance to inter granular corrosion due to niobium stabilization
  • Good resistance to organic aids and salt solutions
  • Sensitive to pitting and crevice corrosion
  • Less resistance to stress corrosion crashing by chloride solutions

Market applications:

  • Oil refineries
  • Fires heater tubes
  • Power plants
  • Heat exchanges
  • High chemical process
  • High temperature stream service

Technische details

Chemische samenstelling
Fe
Cr
Ni
Mn
Si
P
C
S
Nb
347 min
Bal.
17.0
9.0
0.040
8xC
max
20.0
13.0
2.00
0.75
0.040
0.080
0.030
0.8
347H min
Bal.
17.0
9.0
0.040
10xC
max
20.0
13.0
2.00
0.75
0.040
0.100
0.030
1.0
Mechanische eigenschappen
347
347H
Tensile strenght (mpa, min) nl
515 – 690
515 – 740
Yield strength (0.2% offset mpa, min)
215 – 260
215 – 260
Elongation (%, min)
40
40
Density / weight (g / cm3 / kg)
7.9
7.9