Effect of hot rolling parameters on recovery mechanism in 436 (17%Cr, Nb-Mo) ferritic stainless steel

Ferritic stainless steel (FSS) grades are widely used for applications that require high strength and corrosion resistance. Their cost and versatility in the steel market have attracted a lot of interest from both industry and academic research. Despite their desirable properties, these steels grades experience surface defects as a result of microstructural evolution that evolves due to softening mechanism. The current study simulated the roughing hot rolling processes of AISI 436 (17%Cr, Nb-Mo) FSS to study the effects of inter-pass time and strain on the precipitation behaviour and the softening mechanisms in 436 FSS. The softening mechanisms and the resulting microstructures were investigated using SEM-EBSD technique. The results revealed Particle Stimulated Nucleation of new grains during the simulated roughing rolling which promoted recrystallisation due to strain accumulation. Stored deformation energy was found to increase with an increase in interpass time and strain.University of Pretoria; MINTEK and Columbus Stainless Steel (Middleburg).http://www.satnt.ac.za/index.php/satntMaterials Science and Metallurgical Engineerin

Electron backscatter diffraction postprocessing techniques for studying recrystallisation phenomenon of Ferritic Stainless Steel

The following article looks at using scanning electron microscopy- electron back scatter diffraction techniques to study recrystallisation structures produced through hot rolling of 436 ferritic stainless steel. Characterisation of recrystallisation textures was undertaken through analysis of misorientation angle distribution diagrams, orientation distribution function maps, inverse pole figures and Taylor factor maps. These techniques were applied in a case study where typical industrial hot rolling conditions were simulated through uniaxial compression tests in a Bähr Dilatometer 850D, whereby the effect of strain rate and interpass time on recrystallisation structures was investigated

An investigation into the properties of 3D printed Ti6Al4V FCC lattice structures with different strut thicknesses

Metal additive manufacturing of titanium and its alloys can produce complicated geometries cost-effectively while maintaining biocompatibility. It is known that the material property differences between bone and Ti6Al4V cause stress shielding, leading to bone failure around the implant. Using lattice structures is effective at reducing elastic modulus while improving osteointegration. However, it is important first to characterise the as-printed material to investigate the effects of lattice structures on the bulk material properties. Understanding the microstructure, porosity, and related mechanical properties can discern the bulk material properties of the unit cell. The microstructure of printed samples was found to be martensitic. The printed samples contained porosity with strut thickness deviations ranging from the design from 44.29 % (t = 0.50 mm) to 28.43 % (t = 1 mm). It was found that the high amount of porosity resulted in considerable variation in compression material properties