Effect of Cr, Mo and Al on Microstructure, Abrasive Wear and Corrosion Resistance of Ni-Mn-Cu Cast Iron

Abstract

Results of a study on influence of Cr, Mo and Al on the microstructure, abrasive wear and corrosion resistance of Ni-Mn-Cu cast iron in the as-cast and heat-treated conditions are presented. Because of the chilling effect of first two elements (tendency to create hard spots), graphitising Al was added to the alloys, with the highest concentration of Cr and Mo. All castings in the as-cast condition showed an austenitic matrix, guaranteeing good machinability. Heat treatment of raw castings, consisting in annealing at 500 °C for 4 h, resulted in partial transformation of austenite. As a result the carbon-supersaturated acicular ferrite, morphologically similar to bainitic ferrite was formed. The degree of this transformation increased with increasing concentrations of Cr and Mo, which successively decreased the thermodynamic stability of austenite. A change of matrix structure made it possible to significantly increase hardness and abrasive-wear resistance of castings. The largest increment of hardness and abrasion resistance was demonstrated by the castings with the highest total concentration of Cr and Mo with an addition of 0.4% Al. Introduction of Cr and Mo also resulted in an increase of corrosion resistance. In the heat-treated specimens, increasing the concentration of Cr and Mo resulted in a successive decrease of the depth of corrosion pits, with an increase in their number at the same time. This is very favourable from the viewpoint of corrosion resistance.

Corrosion Resistance of L120G13 Steel Castings Zone-Reinforced with Al2O3

“…Corrosion tests were carried out with the gravimetric and potentiometric methods. A 3% aqueous NaCl solution was used as the corrosive environment [25][26][27][28]. During gravimetric measurements, in order to increase the aggressiveness of the 3% NaCl solution, its aeration was used.…”

“…In each case, the potentiodynamic tests were conducted with the anodic polarisation at the rate of 1 mV/s. Corrosion resistance was determined on the basis of the following electrochemical parameters: cathode-anode transition potentials (E K-A ), open cell potential (E OC ), as well as corrosion current density (i corr ) and polarisation resistance (R p ) [26][27][28][29][30].…”

Influence of Spheroidizing Treatment on the Graphite and Mechanical Properties of Cast High-nickel Austenitic Ductile Iron

“…[16][17][18][19][20] Chemical elements and inoculation process have a significant influence on the mechanical properties of CHNADI. [21][22][23][24][25][26][27][28] Farjad Alabbasian et al 29) observed the effect of inoculation and casting modulus on the microstructure and mechanical properties of CHNADI, and its tensile property was improved by increasing graphite nodularity and nodule quantity and decreasing the carbide formation tendency in the inoculation process. Choi et al 30) found that adding 0.02%-0.04% rare earth elements could improve the nodularity of graphite nodules and mechanical properties of thin-walled ductile iron castings.…”

Effect of Mo Concentration on the Microstructure Evolution and Properties of High Boron Cast Steel

“…Moreover, with the rapid development of industrial technology, the wear of mechanical parts becomes increasingly severe. Therefore, materials with superior wear resistance are urgently demanded [4,5].…”