Investigations into wear and galling mechanism of aluminium alloy-tool steel tribopair at different temperatures

Abstract

Aluminium alloys show poor formability at room temperature, and the production of complex components requires a series of high temperature forming processes, such as warm and hot forging, extrusion and hot sheet metal forming. Forming aluminium in these conditions subjects the tools to severe adhesive wear and galling, leading to increased energy needs, shorter tool life, lower part quality and increased cost. In this work, the wear mechanisms generated by aluminium alloys on forming tools have been studied by means of linear reciprocating sliding tests. Aluminium alloy AA2017 balls were slid against DIN 1.2344 (AISI H13) tool steel samples with various surface finishes at temperatures up to 450 ºC. The main results show that the observed wear mechanisms are extremely dependent on the system temperature, ranging from pure abrasive wear to formation of layers of compacted aluminium debris and gross aluminium transfer in the form of lumps. On the other hand, tool surface finish has a limited effect on gross material transfer, but does affect the material transfer micromechanisms.

The Role of Adhesive Forces and Mechanical Interaction on Material Transfer in Hot Forming of Aluminium

“…It is also consistent with results obtained in previous work on reciprocating sliding [5], showing a coexistence of adhesive and abrasive wear mechanisms, and accumulation of aluminium-based material transfer on surface irregularities. On the other hand, authors Jerina and Kalin [10] obtained slightly different results in a series of single-pass crossed-cylinder tests contacting aluminium alloy and hot work tool steel H13.…”

“…As the ball material (99% aluminium) is very soft at 450 ºC, formation of these scratches can only be related to the formation of hard particles of oxidized aluminium, that become trapped inside the contact possibly even embedding themselves in the ball. Similar observations were drawn on earlier work by the same authors [5] in reciprocating contact of aluminium alloy against tool steel.…”

“…In the one hand, Vilaseca et al [4] determined 450 ºC to be optimal for studying material transfer in aluminium ball on tool steel disk tests. On the other hand, studies leading to work [5] revealed a complex coexistence of abrasive and adhesive wear mechanisms in sliding tests at this temperature. Finally, Jerina and Kalin [10] observed increased Aluminium adhesion in the 300-500ºC range in a series of crossed-cylinder tests.…”

Análise Do Desgaste Na Interface De Pares Tribológicos Formados Pelo Aço Ferramenta Aisi M2 Nitretado a Plasma E Aço Inoxidável Aisi 316

“…Comprovando que o aço AISI 316 pode apresentar problemas relacionados a desgaste adesivo em materiais de dureza mais elevada [4]. Experimentos similares feitos por Pujante et al [16].…”

“…[12][13][14][15] Esta maior rugosidade superficial, após o tratamento, poderá acabar aumentando a fricção devido ao maior contato entre as asperezas de ambas as superfícies, e com isso, aumentando a adesão entre as superfícies e a temperatura gerada na interface ferramenta-peça. [12,16] Com objetivo de proporcionar um incremento na dureza superficial e manter uma baixa rugosidade superficial, foi desenvolvida a nitretação a plasma com gaiola catódica. Neste método de nitretação a plasma as amostras estão isoladas e envoltas por uma gaiola metálica cheia de furos, nos quais irão se formar os nitretos que serão depositados na superfície da ferramenta.…”