Effect of 1.5 wt% Copper Addition and Various Contents of Silicon on Mechanical Properties of 1.7102 Medium Carbon Steel

Abstract

Requirements for mechanical properties of steels are constantly increasing, and the combination of quenching and tempering is the method generally chosen for achieving high strength in medium carbon steels. This study examines the influence of various silicon contents from 1.06 to 2.49 wt% and the addition of copper (1.47 wt%) on the behavior of 1.7102 steel starting with the as-quenched state and ending with the tempered condition at the temperature of 500 °C. The microstructure was characterized by SEM and TEM, the phase composition and dislocation density were studied by XRD analysis, and mechanical properties were assessed by tensile and hardness testing, whereas tempered martensite embrittlement was assessed using Charpy impact test and the activation energy of carbide precipitation was determined by dilatometry. The benefit of copper consists in the improvement of reduction of area by tempering between 150 and 300 °C. The increase in strength due to copper precipitation occurs upon tempering at 500 °C, where strength is generally low due to a drop in dislocation density and changes in microstructure. The increasing content of silicon raises strength and dislocation density in steels, but the plastic properties of steel are limited. It was found that the silicon content of 1.5 wt% is optimum for the materials under study.

Using Regression Analysis for Automated Material Selection in Smart Manufacturing

“…Moreover, values of A 5,3 = 1.133, A 5,4 = 0.880, and A 5,6 = 0.518 indicate that an increase in the content of other additives (i.e., Cu, Ni, As, S, and P) can impact relative elongationat-break δ r , relative narrowing ψ, and Brinell hardness HB. This fact corresponds to the study results [42,43].…”

Effect of Cu Alloying on Mechanical Properties of Medium-C Steel after Long-Time Tempering at 500 °C

“…However, this strengthening mechanism only occurs in the case of low dislocation densities [ 20 ]. Therefore, no strengthening effect of copper was observed in previous work [ 13 ]. On the contrary, a deterioration of toughness and plastic properties was found in Cu-containing steels [ 13 , 21 ].…”

“…Therefore, no strengthening effect of copper was observed in previous work [ 13 ]. On the contrary, a deterioration of toughness and plastic properties was found in Cu-containing steels [ 13 , 21 ].…”

“…However, the mechanical properties of this steel with copper addition were lower compared to the same Cu-free steel. The strengthening due to copper addition was first measured after tempering at 500 °C [ 13 ]. Another study compared the hardness of Cu-alloyed and Cu-free medium-carbon-bearing steel after tempering at 450 °C, and the decrease in hardness was gentler in Cu-alloyed steel than in Cu-free steel [ 14 , 25 ].…”

“…In particular, the alloying of steels with copper is seen as an effective way to further increase the strength of steels. Especially in near-pure iron and low-carbon steels, high yield strength increases of up to 300 MPa can be achieved [ 7 , 8 , 9 , 10 , 11 , 12 ], but the strengthening effect of copper is also observed in medium-carbon steels, precipitation-hardened martensitic steel, and other steels [ 13 , 14 , 15 , 16 , 17 , 18 ]. The solubility of Cu in ferrite is very low, and Cu precipitates out from a solid solution when the Cu content is higher than 0.5 wt.% [ 9 , 16 ].…”