Development of an integrated method for fully characterizing multiphase inclusions and its application to calcium-treated steels

Blais, Carl; L’Éspérance, Gilles; LeHuy, H.; Forget, C.

doi:10.1016/s1044-5803(96)00153-2

Cited by 39 publications

(24 citation statements)

References 9 publications

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“…Therefore, MNIs in the interior of steels could not be completely eliminated by ESR (Fang, 2002;Li et al, 1997). Accordingly, in our study, the pink multiphase inclusions consist of a core of calcium aluminates inclusions (at different ratios of the CaO and Al 2 O 3 contents) and a shell of TiN inclusions (Atkinson and Shi, 2003;Blais et al, 1997). It has been believed that calcium aluminates inclusions with the deformation index of zero increase the opportunity of surface failure during polishing (Hui et al, 1998), which may lead to the formation of holes on the polished surface.…”

Section: Characterization Of the Holes And The Mnismentioning

confidence: 72%

The effect of multiphase nitride inclusions on the surface roughness of 2083 plastic molds

Tang

Wan

et al. 2008

Journal of Materials Processing Technology

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Section: Characterization Of the Holes And The Mnismentioning

confidence: 72%

The effect of multiphase nitride inclusions on the surface roughness of 2083 plastic molds

Tang

Wan

et al. 2008

Journal of Materials Processing Technology

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“…MnS precipitating during cooling and solidification can dissolve with CaS and generate a solid of (Mn, Ca) S [14]. The modification of inclusions by calcium treatment is more complex in this steel containing Al, Mn, and S. It is proposed Al 2 O 3 -CaS inclusions had a detrimental effect on the magnetic properties of a Ca-treated non-oriented electrical steel [28], but the complex inclusions mCaO.nAl 2 O 3 -(Mn, Ca) S with duplex phase can be a protective film on the rack face, which improves the durability of the tool [29]. 95CrMo hollow steel is made for drill rods because of its high fatigue resistance, good toughness, strong anti-vibration performance, and low notch sensitivity.…”

Section: Introductionmentioning

confidence: 95%

Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Long

Wang

et al. 2020

Materials

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In order to study the effect of Ca and sulfur contents on the characteristics of inclusions, industrial experiments using 95CrMo steel were conducted. SEM-EDS detections and stereological analysis were used to probe the characteristics of inclusions, including their compositions, morphologies, size, number density, and distribution. The results indicate that there were mainly three types of inclusions in 95CrMo steel billets with 6–18 ppm Ca and 30–100 ppm S: inclusions with single-phased morphology mainly composed of oxides; isolated MnS/CaS-only inclusions; inclusions with multi-phased morphology. The three-dimensional inclusion size distribution suggests that there were more Type-1 inclusions with a small size in low S containing steels. The average diameter of all types of inclusions increased with increasing Ca or S content in 95CrMo steel, indicating that the formation of MnS and CaS coarsened their size. The density distribution of inclusions indicates that the more inclusions there are, the more easily they aggregate and collide. Moreover, it is presumably concluded that the formation of sulfide in the outer layer of oxide inclusions weaken the attraction between oxide inclusions. The equilibrated transformation and formation of inclusions during the cooling process of 95CrMo steel was discussed based on thermodynamic calculation. The equilibrated transformation trajectory of inclusions in 95CrMo steel during the cooling process was Ca2SiO4 + MgO → Ca3MgSi2O8 → Spinel + CaS, which was corresponding to the detected results. The precipitation regular of sulfide was obtained. The formation mechanism for three types of inclusions was discussed.

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“…The works of Averin [7], Lou [8], and Jiang et al [9] have shown that Ca can partially transform MnS into CaS, and they can form a solid solution with each other to generate a new phase of (Mn,Ca)S. The hardness of (Mn,Ca)S is relatively high and the ductility is relatively low, and thus it can improve the transverse impact toughness of the steel after rolling. Carl [10] studied the effects of Ca treatment on inclusions in steel, and found that some of the Ca in steel combines with Al2O3 and forms liquid calcium-aluminate, which can be the nucleation core of (Mn,Ca)S inclusions in the subsequent solidification process.…”

Section: Modification Mechanism and Route Of Ca On Sulfidesmentioning

confidence: 99%

Key Elements of Sulfide Modification in the Sulfur-based Free-cutting Steel

Li¹,

Huang²,

An³

et al. 2017

Proceedings of the 2017 2nd International Symposium on Advances in Electrical, Electronics and Computer Engineering (ISAEECE 20

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Sulfides are beneficial inclusion in free-cutting steel, and can cause chips to break easily as an internal source of stress concentration when cutting steel, and also lubricate the tool and workpiece, thus reducing tool wear and improving machinability. Sulfide morphology directly determines the performance of the free-cutting steel, and it is possible to improve the machinability of the free-cutting steel by changing the MnS inclusions into small, dispersive, spherical or spindle-shaped inclusions, thus making them difficult to deform. In aluminum-killed steel treated with Ca or Mg, there are numerous small and dispersive complex inclusions with an oxide core (CaO· Al2O3 or MgO· Al2O3) and a sulfide surface layer ((Mn,Ca)S or (Mn,Mg)S). Mg can form simple oxides like MgO, MgS or Mg-O-S. Mg can also form complex inclusions with an oxide core (MgO) and sulfide surface layer (MnS or Mn-Mg-S). Overview of Sulfide in Sulfur-based Free-cutting SteelThe sulfide in sulfur-based free-cutting steel usually exists as (FeMn)S[1]. MnS are beneficial inclusions which can cause chips to be easily broken as an internal source of stress concentration when cutting steel, and can also lubricate the tool and workpiece and reduce tool wear, thus improving machinability [2,3]. MnS is one of the most common plastic nonmetallic inclusions in free-cutting steel, and is commonly used to improve machinability. The size, shape and distribution of MnS have a significant impact on the performance of the resulting steel. MnS can suppress the grain growth and promote the precipitation of intragranular ferrite, by improving w(Mn)/w(S) to generate more MnS while decreasing the generation of FeS, which has a low melting point, thus finally improving the high temperature ductility of the steel [4].MnS has good deformability and is easy to extend along the rolling direction in the rolling process, which causes anisotropy and significantly decreases the transverse properties of the material [5], and these elongated MnS inclusions are ready sources of cracks and expansion channels in slab steel, thus reduce the life of the material [6]. In order to suppress such harmful effects, it is helpful to form hard inclusions which are difficult to deform by adding an appropriate amount alloying elements, like Ca, Ti, Mg, RE and so on. These hard inclusions distribute around the MnS and suppress its deformation, and make the MnS spindle-shaped or spherical (L /W≤3). Such inclusions deform less during hot processing, and this steel has good machinability. Modification Mechanism and Route of Ca on SulfidesCa is the currently most widely used alloying element to modify sulfides. The works of Averin [7], Lou [8], and Jiang et al. [9] have shown that Ca can partially transform MnS into CaS, and they can form a solid solution with each other to generate a new phase of (Mn,Ca)S. The hardness of (Mn,Ca)S is relatively high and the ductility is relatively low, and thus it can improve the transverse impact

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Development of an integrated method for fully characterizing multiphase inclusions and its application to calcium-treated steels

Cited by 39 publications

References 9 publications

The effect of multiphase nitride inclusions on the surface roughness of 2083 plastic molds

The effect of multiphase nitride inclusions on the surface roughness of 2083 plastic molds

Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents

Key Elements of Sulfide Modification in the Sulfur-based Free-cutting Steel

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