life of welded load carrying structures with to quality

Because of the economic effectiveness and high productivity of welding, contemporary load carrying structures of materials handling and earth-moving machines mostly are manufactured by this technology. Actually every product must be designed and made to a required level of quality. In industrial practice, this level is estimated on the basis of a set of factors belonging to one of three main groups: operational safety, economics, and activities of competitors. Within the scope of the first group the required level of quality is obligatory and must be certified. The general rules for meeting this requirement are described in the International Standards ISO 9000-9004 and European Standards EN 29000-29004. According to these Standards every fabricated and previously designed product must fulfil essential aspects of the term quality, expressed as 'conformance with requirements', in which fatigue life always plays an essential role (it is the main feature of quality). The fatigue life is created primarily within the design and development process and subsequently in the fabrication phases. The quality of any industrial product can be divided into quality of design and quality of workmanship. In the case of welded structures the quality is determined first by the type of joint (butt, fillet, etc.), and second by defects located in the weld joint. These problems are addressed using the particular example a telescopic boom of a truck crane. Factors affecting fatigue life, like the type of weld joint and the defects are considered, always as a function of the loading intensity.

Keywords:

• Fatigue Life
• Quality
• Carrying Load Structures
• Welded Joints