Abstract
The cold formability of ferritic-pearlitic steels is one of the base parameters for material choice for different forming parts. One of the key factors is the pearlite morphology, which is strongly dependent on chemical composition and previous treatment history. The carbides in pearlite occur mainly in the lamellar form. One of the ways of improving the ductility along with formability is the change of lamellar carbides to globular carbides. This can be conventionally done by soft annealing, which is characterised by long processing times and high energy costs. This paper presents a new processing modification which can lead on the one hand to significant shortening of carbide spheroidization times and on the other hand to intensive refinement of grain size even for low-carbon steels. Low temperature thermomechanical treatment with variation of the heating temperature around Ac1 and incremental deformation was examined on low carbon plain RSt-32 steel. After the thermomechanical treatment conditions were optimized, the refinement of the ferritic grains from an initial 30 μm to circa 5 μm took place, and the time necessary for carbide spheroidization was shortened from several hours to several seconds.
Highlights
Cold forming of components is used in a wide range of applications, in the engineering industry
Because of the long time necessary for the origination of spheroidization structures, this process is very demanding in terms of energy costs
In order to shorten the time for carbide spheroidization, a range of variations of the ASR process parameters was tested with heating temperatures just below Ac1 with integrated deformation
Summary
Cold forming of components is used in a wide range of applications, in the engineering industry. The new process is called ASR (Accelerated Spheroidization and Refinement) and is characterised by annealing times many times shorter than traditional methods and a resulting spheroidization structure with more even distribution of carbide. In order to shorten the time for carbide spheroidization, a range of variations of the ASR process parameters was tested with heating temperatures just below Ac1 with integrated deformation. In order to obtain a suitable carbide morphology, even distribution and intensive refining of grains, it was necessary to optimize the range of parameters.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
