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The general problems of the high strength bolt detection
Nov 07, 2017

To ensure that the load, load wedge is unqualified.

Ensure that the load and load wedge is check goods under tensile load effect of mechanical function of the key projects (class A), on high strength fasteners, special priority.

To ensure that the load is check in rules under the tensile load of resistance to plastic deformation to goods, if the target can not meet the requirements, because the effect of pre-tightening force and work load, may occur plastic deformation, and then drop pre-tightening force, make the cohesion is loose.

Wedge experiment is check bolt load goods things of tensile strength and bonding strength, the target is unqualified, in a larger work load, especially under the effect of impact load or supporting surface under partial load effect, the present cracks or turn around, form a cohesive failure, and even the present safety accidents.

The decarburization layer overruns.

Decarburization layer is also A class project, because the decarburization, makes parts surface hardness and strength drops greatly affected fasteners of exterior contact strength and fatigue life spans of special thread parts of harm is more outstanding.

Decarbonizing formation is the primary cause of the original data, data transformation in the process of decarbonization and commodity decarburization heat treatment process.

Hardness is unqualified, hardness and checking is a priority for fasteners, mechanical function, the information on the functional level commodity chooses is not the same, fasteners, choose mechanical function is the basis of the first grade, while in the device and apply to load torque and the device according to the functional level decided that homework, for a specific data, hardness should be controlled in a reasonable level, high hardness may decline in commodity fatigue resistant function, some companies in order to improve the strength of the commodity, the hardness at higher levels to form some items overruns.