Heat Treatment Effects on Static and Dynamic Mechanical Properties of Sintered SINT D30 Powder Metal

Abstract

Low cost, low material waste and good accuracy in components with complex geometry are the main reasons for powder metallurgy to be considered as a promising manufacturing process for the future. Like wrought steel, sintered steel can also be heat treated to increase surface hardness and to improve strength. This paper compares mechanical properties of the hardened sintered steel with the sintered steel of the same powder metal SINT D30. Firstly, the static strength of both samples is determined by quasi-static tensile tests. Results are compared in stress strain diagram and they show that the tensile strength of the hardened sintered steel SINT D30 can surpass 700 MPa. The main focus of this study is however fatigue behaviour of the sintered steel. Both sets of samples are tested on a pulsating test machine with the load ratio of R = 0. The first sample is subjected to a load that corresponds to 90 % of the yield strength and is then gradually lowered to achieve one million stress cycles without breakage. Obtained results are then presented as Wöhler curves and compared in S-N diagram.

Bending Fatigue Analysis of PM Gears

“…To validate the proposed approach, expected service life with 95% probability of failure was calculated with material parameters from our material characterisation work [7,8]. Sintered pinions were then produced and tested on a custom build back-to-back gear-testing rig until tooth breakage.…”

“…Final density of specimen gears was 7.03 g/cm 3 . Mechanical properties of sintered gears (Young`s module E = 142 GPa, Poisson`s ratio ν = 0.27, tensile strength R m = 842 MPa) were determined in previous mechanical testing [7,8]. Tested pinion with 9 teeth and 5 mm tooth width was paired with wrought carburized tempered steel gear with 31 teeth and 20 mm tooth width at centre distance of 80 mm.…”

Fatigue and fracture parameters of diffusion alloyed Cu–Ni–Mo sintered steel

“…Force data was obtained directly from the machine, and deformation was measured with an extensometer at thinned section of the specimens. More information on our quasi-static uniaxial testing is given in [13].…”

“…The results show much higher R p0.1 and the absence of R p0.2 in the hardened specimens. Detailed information on static mechanical testing and properties can be found in [13]. …”

“…In this paper, previously studied heat treatment effects on the static and fatigue behaviour of typical sintered steel [13,14] are reviewed and upgraded with a study of fracture mechanics' parameters to provide a comprehensive study of mechanical response in the case of a dynamically loaded PM part. The fatigue properties of a given material can aid in estimating the service life of a particular component [15], and fracture mechanics' parameters can provide crucial information on the critical defect size within a dynamically loaded system [16,17].…”