Effect of autogenous GTAW on the reciprocating sliding wear behavior of a carbon martensitic steel

Abstract

Martensitic steels have been successfully employed in resource-based industries where components must endure aggressive conditions. In industrial practice, many parts of these components are joined by welding techniques. The aim of this work was to understand the influence of welding on the wear resistance of quenched and tempered carbon martensitic steel subjected to dry linear reciprocating sliding micro-wear tests. Weld-joints were produced using autogenous Gas Tungsten Arc Welding process (GTAW). Micro-wear tests were performed at base metal (BM), weld metal (WM), coarse grained heat affected zone (CG-HAZ) and lowest hardness region of heat affected zone (LHR-HAZ). LHR-HAZ was softened during welding process so plastic deformation was facilitated, and consequently adhesion, material displacement and micro-ploughing. WM and CG-HAZ presented a similar martensitic structure, which explain the similarities found on wear behavior. These regions presented the lowest worn volume average values (w). It was interesting to note that despite its highest microhardness value, the highest w was observed for BM. For some BM samples, debris had a key role promoting material loss by micro-cutting which causes great extent of material removal compared to other micro-wear mechanisms as micro-ploughing and adhesion. Due to debris action BM also presented a great dispersion in w results. The results suggest that material loss of welded joint and BM was strongly controlled by micro-wear mechanisms.

Use of the Ball-Cratering Method to Assess the Wear Resistance of a Welded Joint of XAR400 Steel

“…On the other hand, only small differences in the wear rates between the lower and upper weld areas were found in the joint (zones 5 and 6), about half those observed in zone 4. Such results confirm the previous observations [ 17 , 18 ] that the material in the HAZ is the least resistant to wall wear.…”

“…On the other hand, only small differences in the wear rates between the lower and upper weld areas were found in the joint (zones 5 and 6), about half those observed in zone 4. Such results confirm the previous observations [17,18] that the material in the HAZ is the least resistant to wall wear. peak compared with relevant volume-weighted grain diameters (closed circles), (D) plots of the mean grain size (bars) and grain size dispersion (error bars) determined from FW20 and FW80 linewidths of (200) peak compared with relevant volume-weighted grain diameters (closed circles).…”

“…On the other hand, only small differences in the wear rates between the lower and upper weld areas were found in the joint (zones 5 and 6), about half those observed in zone 4. Such results confirm the previous observations [17,18] that the material in the HAZ is the least resistant to wall wear. The decreasing abrasion resistance of the welded material is associated with unfavorable microstructural changes and the growth of austenite grains that correspond to the temperature gradients that are responsible for the amount of heat exchanged via thermal conduction and radiative processes.…”

“…The fact that the welding negatively affects the hardness of high-strength materials is an issue that has been widely investigated in the literature [ 11 , 12 , 13 , 16 ]. Other works have demonstrated deterioration in the wear resistance in the weld- and heat-affected zones due to structural changes in these areas [ 15 , 17 , 18 ]. Welding processes were studied to analyze the details of microstructural modifications within several separate layers of the joints: base material (BM), partially heat-affected zone (PHAZ), heat-affected zone (HAZ), and others [ 19 , 20 ].…”