In‐Depth Oxide Scale Growth Analysis of B and Ti Microalloyed AISI 304 in Oxygen‐Containing Furnace Atmospheres and CH₄ Burn‐Simulating Furnace Atmospheres

Abstract

The effects of boron and titanium microalloying on scale‐layer formation and structure on AISI 304 austenitic stainless steel are studied. The research is focused on a steel slab's oxide scale formation in a reheat furnace prior to hot rolling. The studied boron microalloying amounts are 7, 35, and 55 ppm and the studied titanium microalloying amounts are <100 and 400 ppm. In‐depth temperature and atmosphere tests span from 1100 to 1300 °C for an O2‐containing atmosphere and 1100 to 1250 °C in an H2O‐containing atmosphere, both using 25 °C increments. Research shows that microalloying 55 ppm B reduces scale growth at above 1175 °C in an H2O atmosphere, all microalloying elements show significant scale growth reduction at 1175 °C in an O2 atmosphere, microalloying 35 and 55 ppm B increases scale growth amounts at above 1225 °C in an O2 atmosphere, while microalloying 400 ppm Ti reduced it. The inhibiting effect on scale growth that results from boron microalloying is tied to silicon oxide infiltration of the steel substrate.

Laboratory‐scale simulation of industrial neutral electrolytic pickling as a bipolar system—Parameters affecting indirect polarization pickling of annealed stainless steel

“…The sodium sulfate concentration of electrolyte solution used in study was significantly lower than the electrolyte concentration used at the industrial pickling plant. 2,18 To estimate the factorial effect of each parameter, the results were analyzed using Equation (6), in which the average current efficiency of samples with high parameters (+) are compared to samples with low parameters (−).…”

“…1 During production, stainless steel is heated, and a scale consisting of several elements including chromium, iron, manganese, nickel, silica, and others, is formed, depending on the alloying of stainless steel. [2][3][4][5] At first, the oxide phase mainly consists of chromium oxide, with lesser amounts of other oxides as pointed out by an anonymous peer reviewer. As the scale thickens, phase of mixed oxides is formed.…”

“…Stainless steel is the most important synthetic metal alloy used in the world, and global demand has been forecasted to keep increasing 1 . During production, stainless steel is heated, and a scale consisting of several elements including chromium, iron, manganese, nickel, silica, and others, is formed, depending on the alloying of stainless steel 2‐5 . At first, the oxide phase mainly consists of chromium oxide, with lesser amounts of other oxides as pointed out by an anonymous peer reviewer.…”

Thermodynamic Prediction and Experimental Verification of Multiphase Composition of Scale Formed on Reheated Alloy Steels

“…The complexity of such RICHARD scale structures has been reported for different steel compositions, such as low to medium carbon steels, [4,6,[15][16][17][18] ferritic stainless steels, [19][20][21] and austenitic stainless steels. [7,[22][23][24][25] These high temperature oxidation studies were performed to document the scale growth kinetics and the mechanisms of scale formation. Characterization of the scale was performed using scanning electron microscopy coupled with energy-dispersive X-ray (SEM/EDX), Raman spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction to document microstructure, chemistry, and oxide phases present in the scale layers for the different steels.…”

Influence of Nickel on High‐Temperature Oxidation and Characteristics of Oxide Layers in Two High‐Strength Steels

“…Asai et al reported that the addition of nickel (Ni) also reduced the scale removability. Laukka et al found that above 1225 °C in an O 2 atmosphere, oxide growth increased in the presence of boron (B), but reduced by titanium (Ti) addition.…”