Tribology in Metal Working

This thesis focuses on the tribological performance of tool surfaces in two steel working operations, namely wire drawing and hot rolling. In all forming operations dimensions and surface finish of the products are of utmost importance. Forming basically includes three parts – forming conditions excluded – that may be changed; work material, tool and (possibly) lubricant. In the interface between work material and tool, the conditions are very aggressive with – generally or locally – high temperatures and pressures. The surfaces will be worn in various ways and this will change the conditions in the process. Consequently, the surface finish as well as the dimensions of the formed product may change and in the end, the product will not fulfil the requirements of the customer. Therefore, research and development in regard to wear, and consequently tribology, of the forming tools is of great interest. The investigations of wire drawing dies focus on coating adhesion/cohesion, surface characteristics and material transfer onto the coated steel both in laboratory scale as well as in the wire drawing process. Results show that it in wire drawing is possible to enhance the tribological performance of drawing dies by using a lubricant together with a steel substrate coated by a polished, dual-layer coating containing both hard and friction-lowering layers. The investigations of hot rolling work rolls focus on microstructure and hardness as well as cracking- and surface characteristics in both laboratory scale and in the hot strip mill. Results show that an ideal hot work roll material should be made up of a matrix with high hardness and a large amount of complex, hard carbides evenly distributed in the microstructure. The surface failure mechanisms of work rolls are very complex involving plastic deformation, abrasive wear, adhesive wear, mechanical and thermal induced cracking, material transfer and oxidation. This knowledge may be used to develop new tools with higher wear resistance giving better performance, lower costs and lower environmental impact.

Integrated Product Development in Truck Industry - A Case Study on Product Development Processes

This paper presents the result from a case study at Scania on product development processes. The objective with the case study was to gather information on Scania’s product development process (PDP) including the use of CAD and simulation tools, and project work. The objective was also to find any deviations or different interpretations among the employees on the PDP. To gather the information, semi-structured tape-recorded interviews have been used to ensure that individual interpretations from the interviewees could be gathered. Scania uses a defined and structured PDP which facilitates concurrent and cross-functional work. The PDP is implemented and followed to various degrees. The newly employed personnel may have difficulties with communication, both to find and to give information. Although, newly graduated personnel may find it easier to adapt to changes, and also to use a structured process which they have studied at universities. It was also known during the case study that the PDP is a major support for the newly employed personnel, which in turn decreases the time to get into the same working process as the more experienced personnel. Employees with decades of experience know the right sources from which to both give and gather information. Also, the terminology and definitions in the product development process may not be used as intended. This makes it difficult for other project members or teams who need to interpret the information received. At the same time, the routines among the more experienced personnel, which have been set-up throughout the years, make them more inflexible in adapting changes. The findings in the case study as well as challenges with implementing the PDP are known to Scania and are a part of the continuing work with improvement.

Implementation of Video Monitoring In Aluminium Industry

The aim was to evaluate results and experiences from development of new technology, a training program and implementation of strategies for the use of a video exposure monitoring method, PIMEX. Starting point of this study is an increased incidence of asthma among workers in the aluminium industry. Exposure peaks of fumes are supposed to play an important role. PIMEX makes it possible to link used work practice, use of control technology, and so forth to peaks. Nine companies participated in the project, which was divided into three parts, development of PIMEX technology, production of training material, and training in use of equipment and related strategies. The use of the video exposure monitoring method PIMEX offers prerequisites supporting workers participation in safety activities. The experiences from the project reveal the importance of good timing of primary training, technology development, technical support, and follow up training. In spite of a delay of delivery of the new technology, representatives from the participating companies declared that the experiences showed that PIMEX gave an important contribution for effective control of hazards in the companies. Eight out of nine smelters used the PIMEX method as a part of a strategy for control of workers exposure to fumes in potrooms. Possibilities to conduct effective control measures were identified. This article describes experiences from implementation of a, for this branch, new method supporting workers participation for workplace improvements.