The most harmful impurities in tin bronze are aluminum, silicon and magnesium. When their content exceeds 0.005%, the resulting SiO2, MgO and Al2O3 oxide inclusions will contaminate the melt and reduce the performance of some aspects of the alloy.
When smelting tin bronze, since the boiling point of zinc is relatively low and has a greater affinity with oxygen, the melt should be deoxidized and then put into the furnace for melting. Chuangrui tin bronze plate can supplement deoxidation, which is more helpful to avoid The danger of producing SnO2. The zinc and phosphorus in the melt have a comprehensive deoxidation structure, and the resulting 2ZnO·P2O5 is easier to separate from the melt, and it is beneficial to improve the fluidity of the melt.
Using a dry charge, or even preheating the charge first before melting, can reduce or even avoid gas uptake by the melt. Appropriate proportions of new metal and process waste also contribute to stable melt quality. The amount of process waste should generally not exceed 20% to 30%. Melts that are slightly contaminated with impurities can be oxidized by blowing air or by adding an oxidant (eg copper oxide CuO). Scrap that is seriously polluted by certain impurity elements can be refined by solvent or inert gas, including remelting, to improve its quality.
Appropriate feeding and melting sequences, including smelting with a power-frequency iron-core induction furnace with strong melt agitation, are beneficial to alleviating and avoiding segregation. Adding an appropriate amount of nickel to the melt is conducive to accelerating the solidification and crystallization speed of the melt, and has a certain effect on reducing and avoiding segregation. Similar additives, zirconium and lithium can also be selected. A mixed smelting method of separately melting copper alloy lead and then injecting the lead melt into the copper melt at 1150-1180°C can be adopted. Under normal circumstances, smelting tin bronze containing phosphorus is mostly covered with carbonaceous materials such as charcoal or petroleum coke without solvent. The covering agent used when smelting tin bronze containing zinc should also include carbon-containing materials such as charcoal. During continuous casting, it is appropriate to control the tapping temperature at 100-150°C above the alloy liquidus.
Post time: Jun-28-2022