Wear Rate of Metals (AISI 630)

Present work aimed at investigating the wear resistance of AISI 630 (UNS S17400) or 17-4 PH stainless steel hardened by precipitation hardening or aging at various hardness levels.

The PHs steels are an interesting family of steels for applying in highly stressed parts for its corrosion resistance and relative high hardness, attaining up to 49 HRC by low-temperature aging heat treatment, low distortion and excellent weldability.

The wear tests by sliding and/or abrasion were performed in a pin-on-disc tribometer whose pins had three different hardness levels (43, 37 and 33 HRC) obtained by varying the precipitation hardening treatment. The counterface discs were machined from the same steel composition and aged to the hardness of 43 HRC.

The steels wear resistances were evaluated, using sliding velocity of 0.6 m/s, normal load of 30 N, total sliding distance of 2400 m and controlled room temperature and humidity of 27 °C and 60%, respectively.

From the analysis of plotted graphs of cumulative lost volume versus sliding distance, it was observed the different wear rates as function of the heat treatment and hardness. Due to the pins different hardness, the wear resistance varied substantially.

The wear mechanisms were also investigated through scanning electron microscopy observations of the worn surfaces of the pins. It can be asserted that the decrease in the pin hardness yields to lower pin wear resistance.

The disc wear was more severe as the difference in hardness between pin and disc increased. It was presented a list of mean wear resistance, establishing the best heat treatment that minimize the wear in this material for sliding wear applications.

For the investigated range of heat treatment and hardness, the 17-4 PH steel pins with hardness of 43 HRC showed the best wear resistance of 1941 and the pin with 33 HRC the worst wear resistance of 1581.
Keywords

    Wear testWear resistancePH stainless steelHeat treatment

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