Introduction:

The occurrence of mixed fracture mechanisms in mechanical elements is frequent, due to the action of multiple factors that intervene during their design, manufacturing and operation.

Objective:

To establish the causes of failures in tripod columns on trucks, based on the characterization of the base metal and the welded joints in the failure region.

Materials and Methods:

Visual inspection of the failures, chemical and microstructural characterization by optical microscopy of the columns, as well as tensible test of the base material were carried out.

Results and Discussion:

The integrated visual inspection analysis and the results of chemical and metallographic characterization reveal that the material of the columns is not recommended for welded structures and that measures such as preheating and thermal treatment after welding were not taken. Due to the characteristics of the steel and the location of the detected cracks, they may be associated with diffusible hydrogen cracking.

Conclusions:

The failure of the columns was the result of a combination of several factors, highlighting design and manufacturing errors in the selection of a non-recommended material and the non-execution of attenuation measures during the execution of the welding, also linked to factors such as, possible overloads or improper operation of the equipment.

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