Experimental studies of the mechanical properties distribution in the M16 bolt core

摘要

The work describes the concept of experimental test of the mechanical properties distribution in cross-section of the M16 bolt, class 5.8. For the tested bolts identification of material structures by analysis of metallographic scans was performed. Hardness profile in the bolt core cross-section with HV5 method was specified. Tensile tests on two series of samples differing in geometrical properties were conducted. In the first series the axial bolt hole was gradually increased which reduced the impact of the core adjacent material. In the second series solid sample diameter was decreased which reduced the impact of surface adjacent material. During experimental tests the dependencies of ultimate tensile strength and yield strength on cross-section field for both sample series were defined. In order to specify the impact of the sample geometry on the behaviour during the tests FEM analysis was performed for both forms of samples whilst adopting common model of non-linear material.