Final Heat Treatment as a Possible Solution for the Improvement of Machinability of Pb-Free Brass Alloys

Metals

AlkiviadisS. Paipetis¹  ConstantineN. David²  DimitriosS. Sagris²  GeorgeA. Pantazopoulos³  AnagnostisI. Toulfatzis³ 

[1] Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece;Department of Mechanical Engineering, Technological Education Institute of Central Macedonia, 62124 Serres, Greece;ELKEME Hellenic Research Centre for Metals S.A., 56th km Athens—Lamia National Road, 32011 Oinofyta, Greece;

关键词: chip morphology;    power consumption;    cutting force;    surface roughness;    lead-free brasses;    turning;    machinability;    heat treatment;   

DOI  :  10.3390/met8080575

来源: DOAJ

【 摘 要 】

Heat treatment was performed in order to improve the machinability of three lead-free extruded and drawn brasses, namely CuZn42 (CW510L), CuZn38As (CW511L), and CuZn36 (C27450), based on the concept of microstructural modification. The examined machinability criteria were the following: chip morphology, power consumption, cutting force, and surface roughness. All the above quality characteristics were studied in turning mode in “as received” and “heat treated” conditions for comparison purposes. The selected heat treatment conditions were set for CW510L (775 °C for 60 min), CW511L (850 °C for 120 min), and C27450 (850 °C for 120 min) lead-free brass alloys, according to standard specification and customer requirement criteria. The results are very promising concerning the chip breaking performance, since the heat treatment contributed to the drastic improvement of chip morphology for every studied lead-free brass. Regarding power consumption, heat treatment seems beneficial only for the CW511L brass, where a reduction by 180 W (from 1600 to 1420 W), in relation to the as-received condition, was achieved. Furthermore, heat treatment resulted in a marginal reduction by 10 N and 15 N in cutting forces for CW510L (from 540 to 530 N) and CW511L (from 446 to 431 N), respectively. Finally, surface roughness, expressed in terms of the average roughness value (Ra), seems that it is not affected by heat treatment, as it remains almost at the same order of magnitude. On the contrary, there is a significant improvement of maximum height (Rt) value of CW511L brass by 14.1 μm (from 40.1 to 26.0 μm), after heat treatment process performed at 850 °C for 120 min.

【 授权许可】

Unknown