Effect of multicomponent modifier on microstructure and mechanical properties of high Ni–Cr–Mo cast iron

Abstract

The microstructure and mechanical properties of high Ni–Cr–Mo indefinite chilled cast iron with the addition of a newly developed multicomponent modifier consisting of mixed rare earths, Si–Ca alloy and Bi–Sb alloy have been investigated through optical microscopy, X-ray diffraction and scanning electron microscopy, along with hardness, impact toughness and wear resistance measurements. After the addition of the modifier, the grain sizes of the primary austenite and eutectic carbides are found to be greatly refined, and the typically highly continuous net-like carbides become less interconnected but rather appear more blocky shaped. Such microstructure changes lead to mechanical property improvement in the cast specimen, with its hardness increased from 43 to 50 HRC, impact toughness from 6·3 to 7·8 J cm−2 and ⩾20 increase in abrasive wear resistance.

Enhancement of the Quality of the Shell-Core Bond Interface in Duplex Work Rolls Manufactured by Centrifugal Casting Used in Hot Strip Mills

“…In this case, it is verified that this effect also reaches the region of the shell in contact with the core. In previous studies by the authors, it was similarly found that if the ladle is not inoculated with FeSi-La, then there is an improvement in the impact toughness inside the working layer [29,30,32]. In the present study, we have verified that this effect is maintained in the region of the shell-core bond.…”

“…Setting both factors at their respective +1 (0.6 kg/T SiCaMn) and −1 (without FeSi-La) levels leads to an increase in said toughness. In a previous study by the authors, it was found that inoculation with SiCaMn promoted discontinuity of the carbide network [32], which increased the toughness of the shell [29]. In this case, it is verified that this effect also reaches the region of the shell in contact with the core.…”

Control over the Percentage, Shape and Size of the Graphite Particles in Martensitic White Castings Alloyed with Cr, Nb and Mg

“…The composition of FeSi alloys includes elements such as Ca, Al, and Ba, which, due to their high affinity with O, precipitate forming small oxide particles that can act as agents for the nucleation of graphite [19]. The use of inoculants with high percentages of Ca may promote a decrease in the grain size of the primary austenite and discontinuity of the carbide network [20]. La could increase the number of counts of graphite [21] and promote a finer structure of the carbide network [22].…”

Enhanced Fracture Strength in the Working Layer of Rolls Manufactured in Ni-Hard Cast Iron Alloyed with Mo, Nb and Mg

“…Mg acts as a nucleator of graphite [20]. Inoculation with SiCa promotes a decrease in the grain size of the primary austenite and discontinuity of the carbide network [21], which could increase the toughness of the material. The presence of Lanthanum improves the mechanical properties of white cast irons [22].…”