PSI - Issue 65

A.V. Sulitsin et al. / Procedia Structural Integrity 65 (2024) 282–289 A.V. Sulitsin, , S.V. Brusnitsyn, D.O. Levin, D.A. Usov, V.K. Dubrovin / Structural Integrity Procedia 00 (2024) 000–000 5

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It is known (see, e.g., Maltsev (1964)) that the best modifying effect can be obtained by using complex modifiers containing several elements with a modifying effect. It was believed that magnesium neutralizes the harmful effect of sulfur, which is contained in copper (0.01 wt. %), forming a compound MgS, which is a crystallization center. Cerium also binds impurities into refractory compounds, forming additional crystallization centers. The presence of nickel improves the absorption of magnesium and cerium by the melt. In addition, the introduction of nickel into the melt can lead to the formation of intermetallic compounds NiAl or Ni 3 (Si, Mn), which will contribute to an increase in σ b and δ of brass. In this regard, experiments were carried out on modifying 70Cu-13Zn-7Mn-5Al-2Fe-2Si-1Pb brass. The alloy was smelted in an ILK-1.2 induction channel furnace. The melt temperature was 1150 ºС. Ingots were cast in a steel mold with a diameter of 50 mm and a height of 400 mm. Metal was taken from the furnace using a heated graphite ladle. First, a control ingot was cast, then all subsequent ingots were cast with melt modification in the ladle. Considering that the nickel content in 70Cu-13Zn-7Mn-5Al-2Fe-2Si-1Pb brass should not exceed 0.1 wt.%, the amount of the introduced ligature varied in the experiments within 0.01…0.20% of the melt weight. To perform metallographic examination and determine mechanical properties, the ingots were cut along the longitudinal axis. One half was used to study the macro- and microstructure, and the second half was used to make samples to determine mechanical properties. To determine the grain size at half the height of the ingot, three areas were marked: in the center, at half the radius, and at the surface. The obtained values were averaged. The dependence of the average grain size on the quantity of modifier added to the alloy is shown in Fig. 3.

Fig. 3. The dependence of the average grain size on the quantity of modifier added to the alloy 70Cu-13Zn-7Mn-5Al-2Fe-2Si-1Pb.

It has been established that with an increase in the quantity of modifier, the average grain size decreases by more than 2 times, while with an increase in the quantity of modifier over 0.1 wt.%, the average grain size does not change. Fig. 4 shows the dependence of mechanical properties on the quantity of modifier added to the alloy.

Fig. 4. The dependence of mechanical properties on the quantity of modifier added to the alloy 70Cu-13Zn-7Mn-5Al-2Fe-2Si-1Pb.