Investigation of the machinability performance of cu-ni-mo alloyed iron metal powder materials

Powder metallurgy (PM) enables a swift and economical production of materials with complex shapes. One of the primary advantages of this technique is that it allows the tailoring of a piece in a shape very close to its final form. However, an examination of this industry indicates that almost half of the powder metal pieces that are manufactured needs machining. In this study, cylindrical compact samples that are made of iron powder pre-alloyed with Cu-Ni-Mo (trade name Distaloy AB) were manufactured using powder metallurgy method. For this purpose, the mixtures of pre-alloyed iron powder were pressed in a steel die from both sides to make cylindrical raw samples which would be sintered later in cracked ammonia atmosphere. The machinability of the sintered samples was tested by orthogonal cutting on a CNC turning lathe. In these tests, the cutting speed, the feed rate, and the depth of cut were chosen as 50, 150 and 250 m/min; 0.05, 0.1 , and 0.15 mm/rev, and 0.2, 0.4 and 0.6 mm, respectively. The cutting tool was selected as Secomax CBN200 such that the rake and clearance angles were 0° and 5°, while no coolant was used. Chip morphology, chip flow, surface roughness, hardness, tool wear, cutting insert and work piece surface temperatures and cutting force were observed during the cutting processes. The findings indicate that the size, shape and colour of the chips vary with cutting parameters. In addition, chip flow, hardness and cutting force increased with the increase in cutting speed, depth of cutting as well as feed rate. On the other hand, surface roughness increased in parallel with cutting speed, but decreased with feed rate and depth of cut. It was also found that cutting tool wear as well as cutting insert and work piece surface temperatures increased with the increase in cutting speed.