This paper presents a review of the state-of-art research on surface integrity characterization, especially the characteristics of residual stresses produced in machining of hardened steels, titanium and nickel-based superalloys using the geometrically defined tools. The interrelationships among residual stresses, microstructures, and tool-wear have been discussed. Current research on residual stress modeling and simulation using finite element method has been critically assessed. Also, the rationale for developing multi-scale simulation models for predicting residual stresses in machining has been presented. At the end, possible future work has been proposed.

Surface integrity characterization and prediction in machining of hardened and difficult-to-machine alloys: a state-of-art research review and analysis

This paper provides an approach using tensile tests at elevated temperatures to estimate mechanical properties of the work material for both elastic and plastic deformations in a broad range of strain, strain rate, and temperature in machining. The proposed method has been applied to estimate mechanical properties of hardened AISI 52100 steel in hard machining. Tensile testing is shown capable of estimating the mechanical properties of both elastic and plastic regions with large strains at elevated temperatures. Flow stresses at high strain rates in machining can be obtained by extrapolating the data from tensile tests by using the velocity-modified temperature. Flow stress data from tensile and cutting tests is consistent with regard to the velocity-modified temperature. Temperature is the dominant factor of mechanical properties of this material, while the effect of strain rate is secondary. Cutting forces and chip geometry predicted by the 3D FEM simulation of hard turning using the material property data obtained from the developed method agree well with the experimental data. @DOI: 10.1115/1.1413775#

Mechanical Properties of Hardened AISI 52100 Steel in Hard Machining Processes

This article discusses the cooling strategies for cryogenic machining from a materials viewpoint. It is argued that, because different materials respond to temperature and machining processes differently, different cooling strategies are needed to improve the machinabilities of materials by cryogenic machining. In this work, five workpiece materials such as AISI1010 low-carbon steel, AISI1070 high-carbon steel, AISIE52100 bearing steel, titanium alloy Ti-6Al-4V, and cast aluminum alloy A390 were studied experimentally at various temperatures. Based on the experimental results of the cryogenic properties of the materials and their known machining characteristics, the cooling strategies for cryogenic machining of these materials were analyzed.

Cooling strategies for cryogenic machining from a materials viewpoint

Strain, strain rate and velocity fields determination at very high cutting speed

A fiber-optic two-color pyrometer with high spatial and temporal resolution has been applied to measure temperatures at an external turning process. Different measurement positions have been realized at the chip and the workpiece. The measurements have been performed at three different workpiece materials: carbon steel AISI 1045, aluminum alloy AA 7075, and titanium alloy Ti6Al4V. The influences of different parameters like cutting speed, feed, and position of the measurement spot on the temperatures have been investigated. The cutting speed has been increased from conventional values up to 100 m/s for AISI 1045, 117 m/s for AA 7075, and 10 m/s for Ti6Al4V. Additionally, a review of radiation thermometry techniques and applications regarding time resolved temperature measurements in metal cutting will be presented.

Cornelis Spaans

Papers

The fundamentals of three-dimensional chip curl, chip breaking and chip control