The role of sampling position on fatigue of austempered ductile iron

Abstract

In the present study the effect of an austempering heat treatment on the quasi-static and fatigue behaviour of ductile iron was studied. 40 mm Y-blocks were used for the investigations with the risers cut off before heat treatment. Testing specimens with as-cast (pearlitic) and austempered microstructure were taken out from two different positions of the Y-blocks. The austempering heat treatment increases tensile strength, yield strength, elongation at fracture and fatigue strength. Tensile and fatigue tests verify that the mechanical properties are lower close to the riser. This is explained by the varying microstructure in the Y-blocks.

Fatigue analysis of the vehicle brake disc

“…**With the analysis results obtained, it was observed that the G4000 gray cast iron brake disc reached infinite life in 1*10 6 cycles under a stress of 300 MPa. **Experimentally obtained fatigue values of gray cast iron were determined by Wohlfahrt et al (2010) and the fatigue values we obtained theoretically in our study coincide. The value obtained experimentally according to the S-N graph and the theoretically obtained value in the S-N graph in our study were compared Wohlfahrt et al (2010) obtained theoretical results parallel to their experimental study values.…”

“…In this study, pearlitic (G4000) gray cast iron material with the following mechanical properties, yield strength 552 MPa, modulus of elasticity 120 GPa, and Poisson's ratio 0.3, was used (Tartaglia, 2012). (Wohlfahrt et al, 2010) Figure 4 shows the experimental S-N fatigue diagram of the untreated cast iron material in the curve shown in blue in the examination performed by Wohlfahrt (2010). In our study, comparisons will be made by considering this curve.…”

Östemperlenmiş Küresel Grafitli Dökme Demirlerde İndüksiyonla Yüzey Sertleştirmenin Yorulma Sınırı Üzerine Etkisi

“…Ösferritin ince olması tane sınırlarının artmasına böylece yorulma sınırıının artmasında etkili olmaktadır [36]. Artan tane sınırları iç gerilmelerin hareketini engelleyerek bu gerilmelerin birleşmesini geciktirerek çatlak oluşumunu yavaşlatmaktadır [37]. İYS+KGDD ve İYS+ÖKGDD numunelerinin yorulma sınırlarında KGDD ve ÖKGDD numunelerine yorulma sınırlarına göre önemli bir artış gözlenmiştir (Tablo 4).…”

“…Ösferritin ince olması tane sınırlarının artmasına böylece yorulma sınırıının artmasında etkili olmaktadır [36]. Artan tane sınırları iç gerilmelerin hareketini engelleyerek bu gerilmelerin birleşmesini geciktirerek çatlak oluşumunu yavaşlatmaktadır [37].…”

Physically Based Fatigue Assessment of the Nodular Cast Iron ASTM 80‐55‐06 (EN‐GJS‐600) at Different Testing Frequencies

“…In the literature, there are a few contributions dealing with the fatigue behavior of nodular cast irons. Lifetime‐oriented investigations were done to evaluate the geometrical size and mean stress effect19 as well as the influence of the sampling position20 on the fatigue behavior. Furthermore, fatigue tests with mechanical stress–strain hysteresis measurements21, 22 and in some cases temperature measurements23 are described for different nodular cast iron grades.…”