Assessment of micro-abrasive wear tribological properties of H10 tool-steel under conditions of “constant normal force ⇒ variable pressure” and “constant pressure ⇒ variable normal force”

Abstract

In industrial applications, tools of H10 tool-steel used in mechanical and metallurgical manufacturing processes, such as rolling, extrusion, forging, sheet metal stamping, milling and turning, frequently present significant levels of micro-abrasive wear, which occurs under specific circumstances of “constant normal force”, resulting in a “variable pressure” physical condition, or “constant pressure”, resulting in a “variable normal force” physical condition. Consequently, results of micro-abrasive wear generated under these tribological conditions can help engineers design materials and tools with a longer working life span when they are working under mechanical and metallurgical manufacturing processes. Observing the relevance of this subject, the purpose of this work is to assess the micro-abrasive wear tribological properties of H10 tool-steel submitted to experimental conditions of “constant normal force ⇒ variable pressure” or “constant pressure ⇒ variable normal force”. Ball-cratering wear tests were conducted on quenched and tempered AISI H10 tool-steel; the counter-body was a quenched and stress-relieved AISI 52100 bearing steel sphere and the abrasive slurries were prepared mixing abrasive particles of silicon carbide with distilled water. During the micro-abrasive wear tests, the abrasive slurry was, continuously, agitated and fed between the sphere and the tested material; values of coefficient of friction were, simultaneously, acquired, as well. After the tests, each wear crater was analyzed by optical microscopy, SEM and CAD software. The results were discussed based on the behavior of the “Steady-State Wear Regime”, “wear volume”, “wear rate”, “micro-abrasive wear modes”, “pitch between grooves”, “coefficient of friction” and, finally, validated by ANOVA. With the attainment of the Steady-State Wear Regime, it was possible to present the following conclusions: (i) wear volume and wear rate increased under conditions of “constant pressure ⇒ variable normal force”, (ii) there was the predominance of “grooving abrasion”, with the action of “micro-rolling abrasion” wear phenomenon, (iii) the pitch between grooves presented, approximately, the same value of the average abrasive particles size and (iv) the coefficient of friction remained in a tribological condition classified, statistically, as “constant”.