Affiliation:
1. Division of Engineering Materials Department of Management and Engineering Linköping University 581 83 Linköping Sweden
2. Division of Building, Energy and Environmental Engineering Department of Technology and Environment University of Gävle 801 76 Gävle Sweden
3. Ericsson AB 164 40 Kista Sweden
4. SSAB Special Steel SE‐61380 Oxelösund Sweden
5. Division of Energy Systems Department of Management and Engineering Linköping University 581 83 Linköping Sweden
Abstract
Hardening of carbon steel products by austenitization and immersion in a quenching medium is a widely used heat treatment to obtain a hard and strong martensitic structure. To avoid the undesired consequences, such as residual stresses or insufficient hardening depth, the cooling rates must be accurately measured and controlled. This can be achieved using the impinging water jet quenching technique. The aim of this work is to perform hardening of four low‐alloyed 70 mm cylindrical carbon steel bars, using impinging water jet quenching technique with different jet flow rates, and to analyze its effect on thermal evolution and residual stresses. The temperature evolution during quenching experiments is recorded and used as input to a comprehensive quenching model to predict phase transformations, final hardness, and residual stresses of cylindrical bars. All four quenching experiments result in a fully hardened martensitic state. Furthermore, a decrease in jets’ flow rate, within a certain interval, results in different thermal histories and in lower compressive residual stresses on the surface. The results from quenching simulations show promising hardness, microstructure, and residual stress predictions that are validated by hardness measurements, optical microscopy, and residual stress analysis using X‐Ray diffraction method.