Safety cast components for the automotive industry. The metallic charge, the presence of micro elements and their most relevant effects

The Automotive Industry keeps on demanding increasing requirements to the cast components. The critical situation generated by the extraordinary price increase of the raw materials has not meant any flexible position, on the contrary, new stronger demands reappear according to the constant development of the market.
Economical reasons, market demands and weight reduction policies introduce new concepts in the sheet steels used in the car bodies. Many of these new sheet steels incorporate macro and micro alloys as a common source. We are talking about a new material in which elements as Al, Ti, Zn, Nb, and Mn are present in a very significant way.

This work establishes the relationship between some of the mentioned trace elements, incorporated to the iron through the metallic charge, and the solidification model and metallurgical characteristics. An special attention is paid in certain particular influences and on the development of a wide range of iron casting defects related to these trace elements.
The final conclusions of this paper refer to the metallurgical influence from the residual elements:

• The amount of Zn dissolved in the iron depends not only on the metallic charge, but also on the melting operative and on the metal conditioning treatments.
• The micro-segregation mechanisms associated to the presence of Nb, V and Ti have as well an special influence on machinability and on the formation of reticular carbides.
• The trace elements affect the metallurgical quality of the iron and its solidification model.