Effect of different production phases on residual stress field in double-layer cast rolls

B. Podgornik, S. Milanović, J. Vižintin

Journal of materials processing technology, 210 (2010) 1083–1088.

Abstract

The aim of this investigation was to determine the effect of different production operations and parameters on residual stress level in double-layer cast rolls. Using a hole-drilling method, residual stress depth distribution in surface layer was measured around and along the body of the double-layer cast roll after casting, heat treatment, turning and grinding. Furthermore, using different turning and grinding parameters (speed, feed), and heat treatment parameters (temperature, time), influence of these parameters on residual stress level and distribution was determined. Results of the investigation show that the conditions in the casting pit have an influence onthe residual stress field generated in double-layer cast rolls, with surfaces exposed to faster cooling rates in general showing higher residual stress values. Very critical phase in rolls production is coarse grinding, which if not carried out properly will generate very high tensile stresses in the roll surface and cause surface cracking or even roll fracture. Heat treatment on the other hand results in uniform compressive residual stress field in the roll's surface. However, reduction in tempering time and especially increase in hardening temperature lead to increased residual stresslevel in the roll surface. Final machining of the roll surface further influences residual stress level in the roll. Increase in turning speed of up to 40% results in compressive residual stress increase of up to 60%, while less than 30% increase in feeding rate gives almost 100% increase in residual stress level.

Keywords: residual stress, heat treatment, obdelovanje, machining, double-layer cast rools, toplotne obdelave, povratne napetosti

URL: http://dx.doi.org/10.1016/j.jmatprotec.2010.02.017

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