Roles of Inclusion, Texture and Grain Boundary in Corrosion Resistance of Low-Nickel Austenite Stainless Steel Containing Ce

Abstract

The roles of inclusion, texture and grain boundary in corrosion resistance of low-nickel austenite stainless steel containing Ce was investigated by using SEM, TEM, EBSD, XRD and testing technology of electrochemistry. The results revealed that the variation in corrosion resistance of 205 stainless steels containing Ce was higher than specimen without Ce, which depended on ∑3 n boundaries and Ce modifying inclusion treatment. Ce addition to steels was prone to forming fine and dispersive Ce multi-phase inclusions containing CeAlO 3 , CeS and Ce 2 O 2 S. When addition of Ce was up to 0.016 wt.%, its textures were characterized by pronounced γ-fiber textures comprising {111} < 110 > and {111} < 112 > components, as well as the frequency of ∑3 n boundaries related to {111} < 112 > , {111} < 110 > and {112} < 110 > components was significantly improved, which was in favor of corrosion resistance improvement. While adding 0.023 wt.%Ce element was detrimental to corrosion resistance of stainless steel.

Corrosion at the Weld Nugget of the Friction-Stir-Welded Medium Strength Steel: Effect of Microstructure

“…The corrosion resistance of hot-rolled and annealed 205 stainless steel has been evaluated in co-relation to the boundary characteristics and Ce concentration. [50] For the increment in Ce quantity up to 0.016 wt pct, the CSL and LAB fractions are increased at the cost of the HAB fraction. However, for 0.023 wt pct Ce, the fractions of CSL and LAB are reduced.…”

“…These interfaces elicit the local galvanic cell formation, where the second phase becomes anodic with respect to the ferrite matrix. [50] In galvanic corrosion, aggressive anions are responsible for producing microanodes of active metal (second phase and dislocation) and becoming surrounded by a large cathodic area of passive metal. Apart from number density, pitting is also characterized by the dimension of pits, i.e., depth and diameter.…”

“…The corrosion resistance of the multiphase steel depends on the (1) area fraction of the second phase, (2) matrix grain size, (3) nature of the grain boundary, (4) residual stress, and (5) defect density. [36,50,52,56,57,59,63,65] The consequence of the second phase, role of interfaces, and influence of grain size on corrosion resistance of the WN have been exemplified. Apart from the contribution of grain size and corresponding total grain boundary area, corrosion behavior also depends on the characteristic of grain boundary.…”

Transient Evolution of Nonmetallic Inclusions in a Si–Mn‐Killed Stainless Steel with Cerium Addition

“…[ 28–31 ] Rare‐earth elements had a strong affinity to oxygen and sulfur in the steel, [ 32 ] which could modify hard alumina [ 33,34 ] and elongated sulfides to rare‐earth oxides or rare‐earth oxy‐sulfides. [ 35 ] Cai [ 36 ] found that the composition of inclusions changed from MnS–Al 2 O 3 to CeAlO 3 to Ce–O–S with the increase of the cerium content in a low‐nickel austenite SS. Huang [ 37 ] and Wang [ 38 ] reported the evolution path of inclusions was MgO·Al 2 O 3 → CeAlO 3 → Ce–O–S in Al‐killed steels with the addition of cerium.…”

Agglomeration Characteristics of Various Oxide Inclusions in Molten Steel Containing Rare Earth Element under Different Deoxidation Conditions

“…[9][10][11] In a word, the deoxidization treatment determines the type of deoxidized products. Rare earth (RE) elements have been widely used in high-quality steel to improve the heat resistance, corrosion resistance, and mechanical properties of products, [12][13][14][15] which is usually added after deoxidization of molten steel. Due to the strong affinity between RE and impurity elements such as oxygen and sulfur, a number of RE inclusions can be formed by modifying deoxidized products and directly precipitating.…”