Iron-nickel alloy with a high level of ductility and a low expansion coefficient
The invention relates to a solid-solution strengthened iron-nickel alloy with a high level of ductility and an expansion coefficient <5×10 −6 /K in the temperature range between room temperature and −200° C. Said alloy consists of (in wt. %): between 0.005 and 0.05% of C; <0.02% of S; between 1 and 2% of Cr; between 35 and 38% of Ni; between 0.3 and 1.5% of Mn; <0.5% of Si; between 1.0 and 3.5% of ΣMo+W; between 0.2 and 1.0% of Ti; between 0.2 and 1.0% of Nb; <0.02% of P; and between 1.0 and 4.0% of Co; Fe constituting the remainder, in addition to production-related impurities.
1. A welding additive material comprising a solid solution-strengthened iron-nickel alloy that has a high level of ductility and an expansion coefficient <4.5×10 −6 /K in the temperature range between room temperature and −200° C., the alloy comprising, in weight %:
C 0.02-0.03%
S <0.01%
Cr 1.2-1.8%
Ni 35-37%
Mn 0.8-1.3%
Si max. 0.3%
ΣMo+W 1.5-2.5%
Ti 0.4-0.7%
Nb 0.4-0.7%
P <0.01%
Co 1.2-1.8%
Fe Remainder and production-related impurities.
2. A welding additive material comprising a solid solution-strengthened iron-nickel alloy with a high level of ductility and an expansion coefficient <4.5×10 −6 /K in the temperature range between room temperature and −200° C., the alloy comprising, in weight %:
C 0.005-0.03%
S <0.01%
Cr 1.2-1.8%
Ni 36-37%
Mn 0.8-1.3%
Si max. 0.3%
Al 1.0-1.5%
Ti 0.4-0.7%
Nb 0.4-0.7%
P <0.01%
Co 1.2-1.8%
Fe Remainder and production-related impurities.
3. The welding additive material in accordance with claim 1 , wherein content of the following in the alloy is, in weight %:
Mo 1.2-1.8%
W 0.3-0.8%, with the proviso that ΣMo+W is ≦2.5% U.
4. The welding additive material in accordance with claim 3 , wherein content of the following in the alloy is, in weight %:
Co >1.4-1.7%.
5. The welding additive material in accordance with claim 1 , wherein content of the following in the alloy is, in weight %:
Mo >1.5% and <1.8%
W 0.4-0.7%.
6. The welding additive material in accordance with claim 5 , wherein content of the following in the alloy is, in weight %:
Co >1.4-1.7%.
7. The welding additive material in accordance with claim 1 , wherein content of the following in the alloy is, in weight %:
Co >1.4%-1.7%.
8. The welding additive material in accordance with claim 2 , wherein content of the following in the alloy is, in weight %:
Al 1.1 and 1.4%.
9. The welding additive material in accordance with claim 2 , wherein the content of the following in the alloy is, in weight %:
Co 1.4 and 1.7%.
10. An iron-nickel alloy article comprising a weld including the welding additive material of claim 1 or 2 .
11. An article according to claim 10 , wherein the iron-nickel alloy of the welding additive material has a nickel content of 36%.
12. The iron nickel alloy article in accordance with claim 10 , wherein the iron nickel alloy article is a pipeline for transporting liquefied gas.
13. An article including the welding additive material of claim 1 or 2 , wherein low temperature strength values of the welding additive material are greater than for the rest of the article.
14. The welding additive material in accordance with claim 1 or 2 , wherein the alloy has an expansion coefficient <4.5×10 −6 /K in a temperature range between room temperature and −165° C.
15. A metal article having a weld including the welding additive material of claim 1 or 2 .
16. A method of welding articles constituted of iron-nickel alloy, comprising MSG, WIG or plasma welding with a welding additive material of claim 1 or 2 .
17. A method in accordance with claim 16 , wherein the iron-nickel alloy of the welding additive material has a nickel content of 36%.