Transverse rupture strength of a PM tool steel

Abstract

Powder Metallurgy has been reported as a suitable alternate processing route for the manufacture of tool steels. The advantage of this technique is in being able to obtain a refined and more uniform microstructure that improves properties such high wear resistance and toughness. A molybdenum containing AISI M3:2 tool steel, (trade name Sinter 23), manufactured from spherical gas-atomized powders by hot isostatic pressing followed by hot working was tested in three-point bending tests after various heat treatments. Transverse rupture strength (TRS) samples were cut and heat treated at four distinct austenitizing temperatures. Each austenitizing temperature was combined with three tempering temperatures, giving a total of twelve different hardening conditions. Hardness tests were carried out to establish correlations among the effectiveness of heat treatment, the hardness values and the TRS results. At least five parallel samples were tested in each heat treatment condition.

A Review on Fatigue Mechanisms and Approaches for Hard metals

“…It is very significant to recognize that there is no complete consideration of material performance for multifaceted services conditions where heterogenous structure are exposed to numerous loading and rupture techniques [41]. The fatigue crack growth (FCG) threshold determined the validation of subsequent actual toughness under repeated loading [42].…”

“…Therefore, fatigue statistics of the cemented carbides are extremely restricted. While statistics ofstress vs. life (S/N) has been developed studies shows that cyclic constitutive behaviour of alloys are published [31], [41]. The authors opinion rules that testing of fatigue materials is introduced within bounds ofthree main approaches [31], [37].…”

“…Understanding of fatigue cemented carbide is described as the progressive degradation due to repeated changes in stress and other physical forces that may cause deformation to occurs especially on surface of material. This section of deformation is divided into three parts as explained in the text below.Fatigue failure is classified into three categories [11], [14] thermal-mechanical fatigue, high cycle fatigue, and low cycle fatigue and depending on number of times that is required to create the deformation to occur [40], [41]. Low Cycle Fatigue is where a component or structure deteriorates when strain reaches the inelastic range and can be severe with expected multiple excursions.…”

“…The FE-SAFE moduleis used for simulation of samples under different strain amplitudes for the purpose of determiningfatigue failure of different material parameters.The estimation methods for fatigue life under uniaxialfatigue specimen analysis is comprehensively analyzed through stress-strain method [46], [59], [67]. According to stress-strain response, fatigue failure of the materialslife of specimens are calculatedand the methodology described [24], [40], [41]. The historical analysis of linear and non linear was conducted in structure and cumulative fatigueat critical locations evaluated and compared with fracture damage observasation [38].…”

“…Therefore monitoring of crack propagation during fatigue loading is done by Fractography where theoretical models of crack growth behavior were evaluated [35], [39]. However, monitoring of fatigue crack growth (FCG) cannot be done by high-resolution under system described above without aspecial testing device [40].The testing of method of unnotched and notched using transverse rupture strengths at a given life (cycles) is used asestimatedmethod with three-point bending scheme [41], [10]. Transverse rupture strength is dominated in fatigue mechanisms of cemented carbides with low Co content of fatigue behaviour determined by fracture toughness [74].…”