Effect of Yttrium Content on the Transformation of Inclusions in a Si–Mn-Killed Stainless Steel

To investigate the effect of yttrium (Y) addition on nonmetallic inclusions in FeCrAl alloys, a series of laboratory experiments and thermodynamic calculations are carried out as a function of reaction time and Y addition amount. Without Y addition, the main inclusion in FeCrAl alloys is AlN, and only a small amount of Al2O3 inclusions is evident. The higher content of Cr in FeCrAl alloy promotes the formation of Al2O3. Y addition can effectively modify Al2O3 inclusions to YAlO3 or YS inclusions. With the addition of 0.0046 wt% Y, the evolution route of inclusions in FeCrAl alloys with reaction time is Al2O3 → YAlO3‐Al2O3 → YAlO3. The variation in Al2O3 inclusions with increasing Y content is Al2O3 →YAlO3 → YS. The experimental results are consistent well with the thermodynamic calculation results.

Section: Discussionmentioning

confidence: 99%

Section: Thermodynamic Analysis Of Inclusion Formationmentioning

confidence: 99%

Effect of Yttrium Addition on Nonmetallic Inclusions in FeCrAl Alloys

Chen

Zhu

Wang

et al. 2023

“…[2][3][4] The dispersion, size distribution, composition, and morphology control of inclusions in steels have significant impact on properties of the steel, [5][6][7][8][9][10][11] and inclusions could also be effectively modified by rare earth elements. [12][13][14][15][16][17] Besides, the microstructure and property of steels could be significantly improved by an appropriate addition of rare earth elements. [18][19][20][21][22][23] Li et al [24] found that the evolution path of a Si-Al killed 253 MA steel was Si-Al-O!Ce 2 O 3 (Ce 2 O 2 S) !Ce-Si-Al-O, which was in liquid state under 1773 K. Ren et al [25] found that when the cerium content in an aluminum-killed steel increased from 0 to 280 ppm, the modification sequence of inclusions was Al 2 O 3 !…”

mentioning

confidence: 99%

Effects of Cerium Addition on Inclusions and Solidification Structure of a Low‐Nickel Si–Mn‐Killed Stainless Steel

Zhang

Ren

Huang

et al. 2023

Self Cite

The effect of cerium on inclusions and solidification structure of a low‐nickel Si–Mn‐killed stainless steel is studied using laboratory experiments. When the cerium content in steel increased from 0 to 250 ppm, modification sequence of inclusions is Si–Mn(–Al)–O and MnS → Ce–Si–Mn–O–S → Ce(–Si)–O–S → CeS and CeC2. The number density and area fraction of inclusion first decrease with the increase in the cerium content and then increase due to the formation of CeC2 inclusions when the cerium content is bigger than 150 ppm, which is precipitated in solid steel during solidification. When the cerium content increases from 0 to 250 ppm, the fraction of equiaxed grain zones of steel ingot first increases and reaches a maximum value when the cerium content is 54 ppm; then the fraction of equiaxed grain zones decreases with the increase of the cerium content. 2D lattice misfit calculations are performed and it is found that there are no heterogeneous nucleation cores in the steel without cerium during solidification. For the steel with cerium, Ce4.67Si3O13, Ce2O2S, and CeS inclusions act as heterogeneous nucleation cores, increasing the fraction of the equiaxed grain zone. Bigger effective heterogeneous nucleation cores number density leads to a larger fraction of the equiaxed grain zone.

Effect of Cerium on the Cleanliness and Properties of an Al‐Killed Low‐Sulfur Steel

Jia,

Liu,

Ren

et al. 2024

Effects of the cerium content on inclusions, microstructure, and performance of an Al‐killed low‐sulfur steel are studied. As the cerium content in the steel increases from 0 to 190 ppm, the evolution path of the inclusion composition is Al2O3→CeAlO3→Ce2O2S + Ce2O3, and the inclusion size first decreases and then increases. When the cerium content is 76 ppm, the inclusion size reaches the minimum value. The addition of the ferrocerium is beneficial to the grain refinement of the Al‐killed low‐sulfur steel due to the low disregistry between inclusions and the steel matrix. The grain size of the steel decreases first, and it changes little after the cerium content reaching 76 ppm. The grain refinement is beneficial to increase steel properties. However, excessive inclusions in steel with a high cerium content reduce the tensile strength and the plasticity of the Al‐killed low‐sulfur steel.