An Experimental Study On Fatigue Behavior Of 40CrNiMoA Steel

Coupling bolt is one of the important components for the steam turbogenerator. Many catastrophes are caused by the failure of the coupling bolt. So it is necessary to impose the life management for the bolt. The material, 4OCrNiMoA, is now widely used by lots of manufactories. However, the fatigue behaviors of the material have poorly studied. The fatigue behaviors of 4OCrNiMoA are studied experimentally in this paper. The main work is as follows: 1 .The axial LCF experiments at room temperature in air on solid circular specimens of 4OCrNiMoA are performed, using the CSS-280 electric-hydraulic servo-controlled fatigue testing machine. Fatigue parameters of the material including cyclic stress-strain parameters and strain-life parameters are given in this paper. 2.The torsional LCF experiments under the same conditions on thin-walled tubular specimens of the material are performed, using the tension-torsion testing machine. Torsional fatigue parameters including cyclic stress-strain parameters and strain-life parameters are also given. 3.Several multiaxial fatigue life models are used to correlate the torsional fatigue and tensional fatigue. The precisions of these different models are discussed. The model based on torsion is presented by the experiments. ft is proved that this model has high precision. So multiaxial life model is found. Author: Pu Zelin (Thermal Engineering)Directedby: Kun Yang, ProfZongde Liu, Prof...