Iron-nickel-chromium-silicon alloy

Abstract

The invention relates to an iron-nickel-chromium-silicon alloy comprising (in wt.-%) 19 to 34% or 42 to 87% nickel, 12 to 26% chromium, 0.75 to 2.5% silicon, and additives of 0.05% to 1% Al, 0.01 to 1% Mn, 0.01 to 0.26% lanthanum, 0.0005 to 0.05% magnesium, 0.04 to 0.14% carbon, 0.02 to 0.14% nitrogen, and further comprising 0.0005 to 0.07% Ca, 0.002 to 0.020% P, a maximum of 0.01% sulfur, a maximum of 0.005% B, the remainder comprising iron and the usual process-related impurities

Description

REFERENCE TO RELATED APPLICATION[0001]This is a continuation-in-part of International Application PCT / DE2008 / 000965 filed Jun. 12, 2008.BACKGROUND OF THE INVENTION[0002]The invention relates to iron-nickel-chromium-silicon alloys having a longer service life and enhanced dimensional stability.[0003]Austenitic iron-nickel-chromium-silicon alloys having different nickel, chromium, and silicon contents have been used for some time as heat conductors in the temperature range up to 1100° C. This alloy group is standardized in DIN 17470 (Table 1) and ASTM B344-01 (Table 2) for use as heat conductor alloys. There are a number of commercially available alloys, listed in Table 3, for this standard.[0004]The sharp increase in the price of nickel in recent years has resulted in a desire to employ heat conductor alloys that have the lowest possible nickel content and to significantly increase the service life of the alloys employed. This makes it possible for the manufacturer of heating element...

AI Technical Summary

Benefits of technology

[0014]a) significantly improved oxidation resistance and concomitant long service life;

[0018]Due to their special composition, these alloys have a longer service life than the alloys in accordance with the prior art that have comparable nickel and chromium contents. In addition, it is possible to attain enhanced dimensional stability and less sagging than the alloys in accordance with the prior art.

Problems solved by technology

If the coil sags too much during operation, the spacing between the windings becomes uneven, resulting in uneven temperature distribution and shortening service life.

To compensate for this, more support points would be necessary for the heating coil, which increases costs.

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