Ural Federal University named after the First President of Russia B. N. Yeltsin, Yekaterinburg, Russia:

G. A. Tkachuk, Senior Lecturer, e-mail: g.shardakova@mail.ru
V. A. Maltsev, Director
V. V. Shimov, Head of Department
O. A. Chikova, Professor

This paper describes the results of a metallographic study that looked at the production defects observed in alloyed wrought brasses of L63, L68, LS 59-1А grades and in М2 copper processed by Revda Non-Ferrous Metal Processing Works. Conventional optical microscopy was applied for the microstructural analysis of the test pieces. To understand how production defects evolved, the authors looked at different processing stages – ingot, pressing billet, rolling billet, heat treatment, drawing. Three types of defects were observed: exogenous nonmetallic inclusions, segregation inclusions, discontinuities and cavities. No correlation was found between the microstructural characteristics and production defects. The authors demonstrate how one type of defects (e.g. exogenous nonmetallic inclusions, segregation inclusions, and cavities), if not eliminated at the initial processing stage, would lead to other defects (e.g. cracks) and a final fracture of the billet at one of the final processing stages. It was established that the L68 brass billets that are ready to crack would typically acquire a dual-phase structure (α + β). Apart from the main phases, i. e. α-solid solution of alloying elements in copper and β-phase on the basis of the CuZn electron compound, billets made from the LS 59-1А leaded brass grade contain free lead particles. Lead inclusions, as well as exogenous nonmetallic inclusions, tend to localize at grain boundaries or in the interdendritic regions. Exogenous nonmetallic inclusions are present in the microstructure of the L63, L68, LS 59-1А brass grades and in М2 copper at all stages of processing. It was established that the reliability of machines and structures designed for critical applications can only be ensured through quality control by metallography.

1. Pugacheva N. B., Ovchinnikov A. S., Lebed A. V. Analysis of defects of industrial brass blanks. Tsvetnye Metally. 2014. No. 10. pp. 71–77.
2. GOST 32597–2013. Copper and copper alloys. Defects of stocks and semifinished products. Moscow : Standartinform, 2014. 28 p.

3. Copper Development Association Inc. and ASTM International ASTM Standard Designations for Wrought and Cast Copper and Copper Alloys. New York, 2004.
4. Kutz M. Mechanical engineers handbook. Oxford : Wiley, 2015. 4224 p.
5. Maltsev V. M. Metallography of industrial non-ferrous metals and alloys. Moscow : Kniga po Trebovaniyu, 2012. 367 p.
6. Pugacheva N. B., Pankratov A. A., Frolova N. Yu., Kotlyarov I. V. Structural and phase transformations in  +  brasses. Russian Metallurgy (Metally). 2006. No. 3. pp. 239–248.
7. Hameed A. H., Abed A. T. Effect of secondary cooling configuration on microstructure of cast in semi-continuous casting of copper and brass. Applied mechanics and materials. 2014. Vol. 575. pp. 8–12.
8. Bagherian E.-R., Fan Y., Abdolvand A., Cooper M., Frame B. Investigation of the distribution of lead in three different combinations of brass feedstock. International Journal of Metalcasting. 2016. Vol. 3. pp. 338–341.
9. Momeni A., Ebrahimi G. R., Faridi H. R. Effect of chemical composition and processing variables on the hot flow behavior of leaded brass alloys. Materials Science and Engineering: A. 2015. Vol. 626. pp. 1–8.
10. Muikku A., Hartikainen J., Vapalahti S., Tiainen T. Experimental work on possibilities to predict casting defects in LPDC brass castings. Materials Science Forum. 2006. Vol. 508. pp. 561–566.
11. Garagnani G. L., Piasentini F., Cesa G. V. P. Microstructural and mechanical characterization of foundry copper alloys for artistic applications. Metallurgia Italiana. 2006. Vol. 98. pp. 39–46.
12. Nagata S., Kai H., Enokizono M. Non-destructive evaluation for internal defect of metal casting. Materials Science Forum. 2011. Vol. 670. pp. 151–157.
13. Liu Y., Liu J., Zhang S., Li H., Wu J. Formation mechanism and control measures on surface cracks on TP2 copper tube in horizontal continuous casting. Special Casting and Nonferrous Alloys. 2016. Vol. 36. pp. 975–979.
14. Liu J.-S., Chen D.-Y., Chen L.-P., Zhang S.-H. Effect of annealing treatment on microstructure and mechanical properties of TP2 copper tubes. Transactions of Materials and Heat Treatment. 2016. Vol. 37. pp. 107–113.
15. Fatemi A., Morovvati M. R., Biglari F. R. The effect of tube material, microstructure, and heat treatment on process responses of tube hydroforming without axial force. International Journal of Advanced Manufacturing Technology. 2013. Vol. 68. pp. 263–276.