On the function of lead (Pb) in machining brass alloys
Artikel i vetenskaplig tidskrift, 2022

Lead has traditionally been added to brass alloys to achieve high machinability, but the exact mechanisms at work are still debated. Lead-free brass alternatives could be developed if these mechanisms were better understood. Accordingly, machinability characteristics were investigated for two brass alloys with similar mechanical properties and phase composition, but with very different machining characteristics because one has 3 wt.% lead (CuZn38Pb3) while the other has only 0.1 wt.% (CuZn42). The effect of the lead was investigated using infrared temperature measurement, electron microscopy, secondary ion mass spectroscopy, quick-stop methods, and high-speed filming. Neither melting of lead nor its deposition on the tool rake surface takes place during machining thus confirming its limited lubrication and tribological effects. Instead, the main role of lead is to promote discontinuous chip formation. Lead deforms to flake-like shapes that act as crack initiation points when the workpiece material passes through the primary deformation zone. This effect prevents the development of stable tool–chip contact, thus lowering cutting forces, friction, and process temperature.

Machining

Chip formation

Brass alloys

Lead

Författare

Jakob Johansson

Lunds universitet

Per Alm

Seco Tools AB

Rachid M’Saoubi

Lunds universitet

Seco Tools AB

Per Malmberg

Chalmers, Kemi och kemiteknik, Kemi och biokemi

Jan Eric Ståhl

Lunds universitet

V. Bushlya

Lunds universitet

International Journal of Advanced Manufacturing Technology

0268-3768 (ISSN) 1433-3015 (eISSN)

Vol. In Press

Ämneskategorier

Tribologi

Bearbetnings-, yt- och fogningsteknik

Annan materialteknik

Infrastruktur

Infrastruktur för kemisk avbildning

DOI

10.1007/s00170-022-09205-0

Mer information

Senast uppdaterat

2022-05-20