Page 3 - SA 316
P. 3
Temperature °C Temperature °F Temperature °C Temperature °F
160 Risk of SCC 904L
Boiling
140
100 212 120 248
100 304L/ 316L 212
80 176
80 176 60 140
40 Solubility
20 68
60 140 0 20 40 60 80 100
904L NaOH, weight %
316L
40 104
304L Fig 4 – Isocorrosion diagram 0.1 mm/year, in sodium
hydroxide.
20 0 20 40 60 80 100 68
Temperature °C Temperature °F
160 320
140 284
Broken line curve represents the boiling point 120 248
100 212
Fig 3 - Isocorosion diagram 0.1 mm/year 80 176
for austenitic stainless steels in natural 60 304L/ 316L 140
aerated sulphuric acid of chemical purity 40 13% Cr steel 104
20 40 80 100 68
0 20 60 HNO 3 weight %
Fig 5 – Isocorrosion diagram 0.1 mm/year, in nitric
Hot forming cid. Broken line represents the boiling point
PROCESSING
Hot forming should be carried out in a temperature range of 1150-800° C (2102-
1472°F). If the final forming temperature falls below 950°C ( 1742°F), an annealing
solution (1050-1150°C, 1922-2102 °F) is necessary.
The cleanliness of the surface is very important (avoid oil contamination). A
neutral or slightly oxidising atmosphere is required. Due to the low thermal
conductivity, the holding time of temperature may be longer than for a carbon
steel
( 50%). Quenching must be done fastly after forming.
Cold forming
The alloy can be cold formed without any problem. The cold hardening of the steel
explains why it may require more powerfull equipments than for a structural steel.
Molybdenum bearing implies also some more powerfull equipments than Cr-Ni
austenitic stainless steels.
Pickling
A nitro-hydrofluoric acid bath (10-20% HNO 3 – 1,5-5% HF) at 20-60°C ( 68-142°F)
is used for the picking treatment. A 10-20% H 2 S0 4 – 1,5-5% HF pickling bath may
also be used. Passivation- decontamination treatments may be performed with a
10-20% weight nitric acid solution.
Cutting
Thermal cutting (plasma, thermal sawing…). After cutting pickling or grinding are
necessary to eliminate the oxide formed layer.
Mechanical cutting (shearing, stamping, cold sawing…).
Welding
The alloy can be easy welded without hot cracking phenomenon, using an
adequate filler metal (from 5 to 15% ferrite). The alloy is not sensitive to cold
cracking phenomenon. All welding processes can be used including filler
processes.
Filler material
Electrode E316L-15 or E316L-16 (ASME Sect II – Part C SFA5-4)
Wire ER 316L (ASME Sect II - Part C SFA 5-9)
