Niobium Influence on As-Sintered 316L and 434L Stainless Steels and Performance at Low Temperature (300 ℃)

摘要

Niobium has a strong carbide former character. It is added to the austenitic steel mainly in order to avoid chromium carbide precipitation during the slow cooling at temperatures located around 700 ℃, thus preventing the decreasing of the chromium content in the steel, that would produce a drop in corrosion resistance. Stainless steel powders are one the most oxidation-resistant commercial powders. Both austenitic and ferritic types were studied with Nb additions that improve the high temperature properties. The main objective of this work was to study and to improve physical properties such as density and dimensional change; mechanical properties (hardness and tensile strength) and oxidation temperature influence (300 ℃) on 316L and 434L P/M stainless steels reinforced with niobium. The materials were sintered at 1230 ℃ in vacuum. Oxidation experiments were carried out during an interval of 10 days.