Lead-Free Cu-Si-Zn Brass with Tin Addition

Abstract

In this work, lead-free silicon brass (Cu-Si-Zn) with tin addition was studied to investigate on the comparative influence of the adding and non-adding tin on the microstructures and microhardness. In order to produce new alloy compositions, varied amount of silicon (0.5, 1.0, 2.0, 3.0 wt%) were incorporated. The ranges of chemical compositions were copper contents between 58.7 and 60.3 wt%, tin content 0.6 wt% and zinc remaining. The silicon brasses were prepared by melting pure elements with a graphite crucible using an induction furnace. The chemical composition of each alloy has been determined by X-ray fluorescence spectrometry (XRF). Microstructures of the as-cast silicon brass ingots have been observed by optical microscopy and scanning electron microscopy. The respective chemical analysis of the phases was determined by energy dispersive X-ray spectroscopy (EDS) and the hardness was measured by Vickers hardness test. The results revealed that the hardness of 60Cu-0.5Si-39.5Zn brass was 123.4 HV. The higher silicon content improved the higher hardness of samples. Moreover, the addition of tin together with silicon increased amount of beta (β) phase and more uniform dispersive gamma (γ) phase than those of the silicon addition alone. It could be concluded that the tin addition enhanced the hardness of lead-free Cu-Si-Zn brass and trended to be helpful for machining.

Bismuth Formation in Lead-Free Cu–Zn–Si Yellow Brass with Various Bismuth–Tin Alloy Additions

“…It was also noted that tin was dissolved in the solid solution beta phase more than that in the alpha phase, which was in accordance with the previous research. 7) While bismuth was insoluble in the brass alloy and formed only pure bismuth particles as shown in this study. It was noted that the microstructures observed in the present work were different from a traditional CuZnBi alloy microstructure as shown schematically in Fig.…”

Effect of addition of tin on the microstructure and machinability of α-brass

“…The addition of Sn to the brass alloy promoted the formation of β -and G-phases. Previous research showed that the hardness of the G-phase is more than that of β ', which in turn is harder than the α-phase [8,17,33]. Therefore, the formation of these phases caused the hardness of the Cu-30 wt-% Zn brass to increase.…”

“…Bi also segregates to the grain boundaries, which causes the brittleness of the casting part to increase [5][6][7]. Si, which expands the stability of hard phases in the microstructure and hence enhances machinability, is another substitute for Pb in brass alloys [8]. However, an increase in the rate of tool wear, which increases the cost of machining, is a significant disadvantage of this element [9].…”

Grain characteristics, electrical conductivity, and hardness of Zn-doped Cu–3Si alloys system

“…The combined addition of phosphorus and magnesium has proved effective in improving the electrical conductivity of Cu-1.5Ni-0.3Si alloys [24]. Puathawee et al [32] recorded an average hardness of 123.4 HV for Cu-2Si alloy via the addition of 39.5wt% Zn. Li et al [16] and Wang et al [22] developed Cu-Ni-Si-Cr-Zr alloys of average hardness (197 HV) and electrical conductivity (32.7%IACS).…”