Wear and fatigue resistances of metastable steel-copper pseudoalloys

Abstract

As a rule the quality of parts made of powder materials is evaluated by the criteria of structural strength, which very often do not reflect their actual operating capacity. This is connected not only with the scale factor, because specimens of rather large size are required for correct determination of crack resistance, but also with the special features of porous steels with a nonuniform concentration. The present paper concerns results of a study of the fatigue and wear resistances of metastable steel -copper pseudoalloys that are copper-infiltrated powder steels.

Isothermal decomposition of supercooled austenite in chromium-nickel steel-copper pseudoalloys

“…We should note the consistent increase in the concentration homogeneity of the distribution of nickel and chromium upon impregnation (Table 1) cipal difference in the diagrams of binary alloys in the Cu -Ni and Cu -Cr systems [16]. The level of concentration inhomogeneity chosen for steel-copper pseudoalloys corresponds to the greatest values of their fatigue resistance and wear resistance [ 13]. For each composition and method of heat treatment there exists an optimum distribution of the alloying elements that provides a maximum proportion of the "f -+ ot transformation under the given load [12,17].…”

“…The measured values of the coefficient of variation of the concentration of the alloying elements in infiltrated alloys turned out to be 2 -3 times lower than in the steel not impregnated with copper (Table l ). It should be noted that in both cases considered the value of'c is sufficient tbr the traditional heat treatment to be effective [12,13]. The calculations were made for steel PA-ZhGrl.5Kh2N having a quite long incubation period, because the error in its determination increases with the acceleration of the decomposition.…”