Surface layer hardening of metastable austenitic steel – Comparison of shot peening and cryogenic turning

Abstract

In this paper, the effect of shot peening and cryogenic turning on the surface morphology of the metastable austenitic stainless steel AISI 347 was investigated. In the shot peening process, the coverage and the Almen intensity, which is related to the kinetic energy of the beads, were varied. During cryogenic turning, the feed rate and the cutting edge radius were varied. The manufactured workpieces were characterized by X-ray diffraction regarding the phase fractions, the residual stresses and the full width at half maximum.The microhardness in the hardened surface layer was measured to compare the hardening effect of the processes. Furthermore, the surface topography was also characterized. The novelty of the research is the direct comparison of the two methods with identical workpieces (same batch) and identical analytics. It was found that shot peening generally leads to a more pronounced surface layer hardening, while cryogenic turning allows the hardening to be realized in a shorter process chain and also leads to a better surface topography. For both hardening processes it was demonstrated how the surface morphology can be modified by adjusting the process parameter.

Analysis of gas–solid two-phase flow and structure optimization of mobile shot blasting machine recovery device

“…Mobile shot blasting machine recycling device can realize the recycling of steel shot and automatic recycling of processing waste, but in the actual production and processing, the recycling rate of waste generated after shot blasting process is low 4 , and the dust particles generated during the recycling process are easy to cause environmental pollution, construction personnel are prone to lung diseases caused by inhalation of large amounts of dust 5 . Studies have shown that a more efficient and environmentally friendly recycling efficiency is achieved when the waste recovery efficiency reaches 90% 6 . Therefore, the efficient recycling of waste materials has received a lot of attention from researchers [7][8][9] .…”

“…In order to explore the effect of the size of the outlet pressure on the particle recovery efficiency, the number of particles needs to be counted in the plate of Setup Selections-Grid Bin Group in the post-processing of EDEM discrete element software to further calculate the recovery efficiency of both particles. Regarding the site of particle count, referring to the calculation method of wheat pellet and mixed biomass pellet recovery efficiency by Xu 24 and Zhou 44 , in the EDEM software, set the size of the exit pipe near the recovery bin side as Center: x = − 225 mm, y = 138 mm, z = 0 mm, Dimensions: x = 50 mm In this option, the number of steel pellets and scrap particles entering the recycling pipe from the recycling bin will be obtained, taking position (2) to position (6) in turn (as shown in Fig. 12).…”

“…Regarding the calculation method of particle recovery efficiency, according to two scholars, Xu 24 and Zhou 44 , who calculated the recovery efficiency and separation efficiency of wheat pellets and mixed biomass pellets, the recovery efficiency of steel pellets is: the difference between the number of pellets at position 4 and position 1 divided by the sum of the number of pellets at position (5) and position (6), and the resulting value is the recovery efficiency of steel pellets. The recovery efficiency of the scrap particles is: the number of particles passing through position (1) divided by the sum of the number of particles in position ( 5) and position ( 6), the resulting value From the particle recovery efficiency graph in Fig.…”