Behavior and Mechanism of Inclusion Deformation in Type 430 Stainless Steel During Isothermal Compression

作者：Ni, Hongwei^*; Gan, Wenliang; Liu, Chengsong^*; Cheng, Rijin; Wang, Yong; Zhang, Hua

来源：Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science , 2023, 54(2): 851-867.

DOI：10.1007/s11663-023-02731-6

• INTERSTITIAL-FREE STEEL
• MN-KILLED STEEL
• ELASTIC-CONSTANTS
• OXIDE INCLUSIONS
• NONMETALLIC INCLUSIONS
• SURFACE-DEFECTS
• SINGLE-CRYSTAL
• EDGE-CRACKING
• REFINING SLAG
• TEMPERATURE

To clarify the deformation behaviors and mechanism of various kinds of inclusions in type 430 stainless steel during hot rolling, isothermal compression experiments using Gleeble-3500 thermo-mechanical simulator were conducted with different deformation temperatures [1273 K to 1473 K (1000 degrees C to 1200 degrees C)], reduction ratios (25 to 75 pct), and strain rates (0.01 to 10 s(-1)). Experimental results showed that the typical inclusions in the as-cast of type 430 stainless steel were single-phase CaO-SiO2-Al2O3-MgO inclusions, single-phase MgO-Al2O3-TiO x -Cr2O3-MnO inclusions, and multi-phase CaO-SiO2-Al2O3-MgO + MgO-Al2O3-TiO x -Cr2O3-MnO inclusions. Only the CaO-SiO2-Al2O3-MgO phases in inclusions were deformable during isothermal compressive deformation as the temperature exceeded 1273 K (1000 degrees C) but the MgO-Al2O3-TiO x -Cr2O3-MnO phases did not. Higher deformation temperature, reduction ratio, and strain rate promoted the deformation of CaO-SiO2-Al2O3-MgO phases and resulted in larger average aspect ratio of them after the isothermal compression. The deformation behavior of multi-phase inclusions depended on the major phase, i.e., either CaO-SiO2-Al2O3-MgO or MgO-Al2O3-TiO x -Cr2O3-MnO. Young's modulus, solidus and liquidus temperatures, and liquefaction rate of inclusions were calculated and compared. Experimental and calculated results demonstrated that liquefaction rate higher than 40 pct could be a better index to quantitatively evaluating the deformability of inclusions during isothermal compression.