The interest in natural gas as an energy source is constantly increasing. New finds are being discovered every year. However, gas resources are most often far from the consumers. This creates a need to transport and store the gas. So that it can be transported great distances, natural gas is cooled to such a low temperature that it condenses and becomes a liquid. In its liquid form, the gas takes up 600 times less space. This makes it easy to transport by sea to land-based storage tanks. From here, it goes to the consumers.
The above processes place great demands on both parent and filler metals, which must have good mechanical properties at low temperatures. To meet the industry’s severe requirements, Avesta Welding has developed 4 new electrodes: 308L/MVR-NF, 308L/MVR Cryo, 316L/SKR-NF and 316L/SKR Cryo, all of the rutile type -16.
The weld metals from these electrodes fulfil the toughness requirements at cryogenic temperature, giving lateral expansion > 0.38 mm and Charpy V toughness > 32 J at –196°C.
|
308L/MVR-NF |
308L/MVR Cryo |
316L/SKR-NF |
316L/SKR Cryo |
| C |
0.02 |
0.02 |
0.03 |
0.02 |
| Si |
0.5 |
0.5 |
0.4 |
0.3 |
| Mn |
1.9 |
1.7 |
2.3 |
1.2 |
| Cr |
19.4 |
19.0 |
17.5 |
17.2 |
| Ni |
12.9 |
10.3 |
13.8 |
11.9 |
| Mo |
- |
- |
2.5 |
2.7 |
Rp0.2
N/mm2 |
400 |
450 |
430 |
450 |
Rm
N/mm2 |
520 |
570 |
560 |
570 |
| A5 % |
40 |
43 |
37 |
35 |
Impact,
-196oC, J |
37 |
35 |
42 |
42 |
| Lateral exp. mm |
0.60 |
0.55 |
0.60 |
0.70 |
| Ferrite WRC-92, FN |
0 |
4 |
0 |
4 |
The -NF type produces a fully austenitic weld metal. Thus, it is also suitable for use in structures where low magnetic permeability is required.
The Cryo type has a carefully controlled ferrite content in the range of 3 - 8 FN.
The electrodes have been developed to give the same flexibility that distinguishes Avesta’s 3D electrodes, i.e. good weldability in position welding applications.
The electrodes are available in diameters 2.5, 3.25 and 4.0 mm.
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