Static, dynamic, and cyclic strength of stud metal in large hydraulic units

Abstract

The microstructure and the mechanical properties of stud metal (steel 40Kh) M90×4 for fixing covers of large hydraulic units were studied. The mechanical properties were determined by static, dynamic, and cyclic tests of samples cut out of a stud in the longitudinal and transverse directions and at different distances from the surface. The character of the change in the microstructure and the mechanical properties over the cross section of a stud was determined. Static and cyclic tests of model and actual studs together with nuts were performed. The load and stress values under which the chain cutting of turns of a threaded joint occurs were determined. A strong influence of the scale factor on the durability of studs was established by cyclic tests.