These days the design/construction of motor vehicles is characterised by more and more exacting requirements:
- reduction of vehicle weight, with consequent reduced consumption and hence also reduced atmospheric pollution;
- increased structural strength, to respond to increasingly strict crash test standards;
- protection against corrosion of certain metals caused by oxidation.
To respond to these requirements the automotive industry is making increasingly widespread use of materials such as high strength steels, aluminium, galvanised sheet, etc., which demand particular operative solutions.
Repair work in the body shop will have to take account of this situation and welding, spot-welding and cutting operations will therefore require equipment that is able to cope efficiently with particular operational aspects relating, for example, to heat transfer, welding/cutting arc stability, the appearance of the finished job, and then the strength of the weld.
HIGH STRENGTH STEELS
Classified into various types (HSS, UHSS, AHSS-e.g boron steel), they are considerably lighter in weight than conventional steel and have improved mechanical properties as regards static and dynamic strength, mouldability and energy absorption. Their use for both structural and non- structural vehicle parts has significantly increased. Welding, spot-welding and cutting operations therefore require equipment that perfectly respects the properties of these materials and ensures a high quality finish for every job.
Present in the form of various alloys (Al&Si,Mg,Zn), it is characterised by being considerably lighter than steel, by its ductility, corrosion resistance and recyclability. Its high thermal conductivity and the presence of a surface film of oxide, alumina, require specific working methods such as TIG welding, AC/MIG pulsed welding, or capacitive discharge/MF inverter spot welding.
GALVANISED METAL SHEETS
Characterised by a protective treatment, galvanisation, of carbon steel and high strength steel sheet these materials have high corrosion resistance. Repair work should therefore prevent damage to this protection by making use of working methods with low heat transfer, such as MIG brazing.