Poul Henningsen

Simulation of defects in metal forming - an example

The present paper describes a systematic investigation of possible flow imperfections in forging of an H-shaped profile. The influence of geometry and volume of the slug and of friction in the tool/workpiece interface on flow are investigated by numerical as well as physical modelling. A comparison between two different FE- codes, DEFORM ans Forge2 and physical modelling applying parafin wax shows good agreement between the different methods of analysis. Based on the results of formability diagram has been established for forging of H-shaped profiles.

Measurements of Normal and Frictional Forces in a Rolling Process

Abstract To improve the quality of frictional data and to validate the simulations in rolling, a load transducer for measuring normal and frictional stresses in the deformation zone has been developed. The transducer consists of a strain-gauge-equipped insert embedded in the surface of the roll. The length of the insert exceeds the contact length. By analysing the output from the insert, the frictional stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by less disturbance of lubricant film and material flow and limited penetration of material between the transducer and roll. The transducer is tested at laboratory conditions and is expected to be running in industrial conditions in 2004.

Methods and devices used to measure friction in rolling

Abstract Friction at the workpiece-die boundary, in both bulk forming and sheet forming is, arguably, the single most important physical parameter influencing the processing of metals; yet it remains the least understood. Hence there is a need for basic research into metal-die interface mechanisms. To gain a good understanding of the mechanisms at the interface and to be able to verify the friction and tribology models that exist, friction sensors are needed. Designing sensors to measure frictional stress in metal working has been pursued by many researchers. This paper surveys methods that have been used to measure friction in rolling in the past and discusses some of the recent sensor designs that can now be used to measure friction both in production situations and for research purposes.