Short-time creep, fatigue and mechanical properties of 42CrMo4 - Low alloy structural steel

The proper selection of materials for the intended use of the structural member is of particular interest. The paper deals with determining both the mechanical properties at different temperatures and the behavior in tensile creep as well as fatigue testing of tensile stressed specimens made of low alloy 42CrMo4 steel delivered as annealed and cold drawn. This steel is usually used in engineering practice in design of statically and dynamically stressed components. Displayed engineering stress - strain diagrams indicate the mechanical properties, creep curves indicate the material creep behavior while experimental investigations of fatigue may ensure the fatigue limit determination for considered stress ratio. Also, hardness testing provides an insight into material resistance to plastic deformation. Experimentally obtained results regarding material properties were: tensile strength (735 MPa / 20&#176;C, 105 MPa / 680&#176;C), yield strength (593 MPa / 20&#176;C, 76 MPa /680&#176;C). Fatigue limit in the amount of 532.26 MPa, as maximum stress at stress ratio <i>R</i> = 0.25 at ambient temperature was calculated on the basis of experimentally obtained results. Regarding the creep resistance it is visible that this steel can be treated as creep resistant at high temperatures (including 580&#176;C) when applied stress is of low level (till 0.2 of yield stress).