Study of residual stresses and distortions after steel quenching with vegetable oils
C. Civera1, B. Rivolta2, R. L. Simencio-Otero3, J. G. Lucio3, G. E. Totten4, and L. C. F. Canale3
1 Siderval Spa, Talamona (SO), Italy
2 Politecnico di Milano, Dipartimento di Meccanica, Milano, Italy , 20156.
3 Universidade de Sao Paulo, Escola de Engenharia de Sao Carlos, Sao Carlos, SP, 13566 Brazil.
4 Department of Mechanical and Materials Engineering, Portland State Univ., Portland, OR 97201
Although quenching is necessary to increase the mechanical properties of steel, this process is often accompanied by high thermal stresses and transformation stresses which may lead to high residual stresses and distortions and possible cracking. Therefore, it is desirable to develop quenching processes that maximize the material properties while minimizing the residual stresses and distortions. This means that there is often a compromise between the factors involved to assure overall optimal process performance.
The objective of this work was to measure and compare the experimental results of residual stresses and dimensional changes that arise after quenching AISI 4140 and AISI H13 steel grades into two commercially available petroleum-derived oils and six different vegetable oils. Quenching was performed with six soybean oil derived fluids and two fully formulated commercially available petroleum-based oils. The distortions evaluations were carried out on modified C-ring test specimens of AISI 4140 and AISI H13 steels. Residual stresses were experimentally determined on cylindrical samples by two different methods: X-ray analysis and hole-drilling method according to ASTM E837-08. A detailed analysis of the residual stresses was carried out. The obtained results were related to the experimental heat transfer coefficient and viscosity of each fluid.