Evaluation of surface and sub-surface integrities of a mold steel under different grinding conditions

In a context where there is a continuous search for more environmentally friendly machining processes (for example, the implementation of the minimum quantity of lubrication—MQL—cooling–lubrication technique) and the constant concern with the high heat generation during the grinding process, there i...

Full description

Saved in:

Bibliographic Details
Published in:	Journal of the Brazilian Society of Mechanical Sciences and Engineering Vol. 41; no. 10; pp. 1 - 10
Main Authors:	Guimarães, Cleudes, da Silva, Rosemar Batista, Ruzzi, Rodrigo de Souza, de Mello, Antonio Vitor, Hübner, Henrique Butzlaff, Fiocchi, Arthur Alves, Fonseca, Maria Cindra
Format:	Journal Article
Language:	English
Published:	Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2019 Springer Nature B.V
Subjects:	Abrasive machining Abrasives Aluminum Aluminum oxide Compressive properties Cooling Die steels Engineering Grinding wheels Heat generation Injection molding Lubrication Mechanical Engineering Microhardness Molds Parameters Performance evaluation Residual stress Silicon carbide Surface finish Surface grinding Surface roughness Technical Paper Workpieces Conventional grinding wheels Mold steel MQL technique Surface grinding Microhardness
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	In a context where there is a continuous search for more environmentally friendly machining processes (for example, the implementation of the minimum quantity of lubrication—MQL—cooling–lubrication technique) and the constant concern with the high heat generation during the grinding process, there is still a lack of information about grinding of steel for molds and dies. Thus, the present work sought to evaluate the performance of tangential surface grinding of a steel for plastic injection molds, testing by two types of conventional abrasives (green silicon carbide and white aluminum oxide) under three different equivalent chip thicknesses. The performance of the MQL cooling–lubrication technique compared to the conventional one (flood coolant) was also evaluated. The output parameters to assess the surface integrity were the surface roughness ( R a parameter), residual stresses and SEM images of the ground surfaces, as well as microhardness below the machined surface. The results shown that both conventional abrasives types have potential to be used in grinding of this steel, once low surface finish values ( R a < 0.2 μm) and workpieces free of damages were fabricated. Silicon carbide (SiC) grinding wheel in general outperformed the aluminum oxide (Al 2 O 3 ) one in terms of surface roughness after machining under severest conditions ( R a < 0.35 μm). Residual stresses were predominantly compressive irrespective of the cooling–lubrication technique and type of abrasive employed. Despite lower surface roughness and compressive residual stresses generated after grinding with the Al 2 O 3 grinding wheel, drop in hardness below the machined surface was observed, unlike when machining with SiC grinding wheel. MQL technique proved to be more effective than conventional coolant technique under the conditions investigated, irrespective of the grinding wheel used, and in some situations, it outperformed the conventional technique.
ISSN:	1678-5878 1806-3691
DOI:	10.1007/s40430-019-1930-5