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Jan-Eric Ståhl

Jan-Eric Ståhl


Jan-Eric Ståhl

On the function of lead (Pb) in machining brass alloys


  • Jakob Johansson
  • Per Alm
  • Rachid M’Saoubi
  • Per Malmberg
  • Jan Eric Ståhl
  • Volodymyr Bushlya

Summary, in English

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.


  • Production and Materials Engineering
  • SPI: Sustainable Production Initiative
  • NanoLund: Center for Nanoscience
  • Department of Mechanical Engineering Sciences

Publishing year





International Journal of Advanced Manufacturing Technology

Document type

Journal article




  • Manufacturing, Surface and Joining Technology


  • Brass alloys
  • Chip formation
  • Lead
  • Machining




  • ISSN: 0268-3768