Abstract
The effect of zinconium alloying on the formability and the wedability of 17% chromium steels has been investigated by means of various tests.
Alloying of zirconium whose content exceeds the value equivalent to the total amount of carbon and nitrogen (Zr≈7.4× (C+N) ) is found effective to improve the characteristics of the formability and the weldability of the steels. However, in the case of so much carbon and nitrogen contents, both the formability and the weldability of the steels containing zirconium are not improved, because of the precipitation of a large amount of zirconium carbides, zirconium nitrides or chromium carbides.
When the Zr/ (C+N) ratio in the steels is too large, both the formability and the weldabilty are not excellent, because of the precipitation of a large amount of metallic compounds consisting of mainly iron and zirconium. The formability of the steels containing less than 0.01% (C+N) is not improved by alloying of zirconium, except of the bore expanding property.
The range of optimum zirconium (Zr≈10× (C+N) ), carbon and nitrogen contents in the 17% chromium steels is found.
