Development of Ultra-High Strength Galvanized Steel for Automotive Bumper Reinforcements

With the increasing emphasis among automobile manufacturers for lighter and, therefore, more fuel efficient cars with improved corrosion resistance, there is a need for ultra high strength coated steels. This paper deals with the development of recovery annealed 120 ksi (827 MPa) minimum yield strength galvanized steel for automotive bumper reinforcements.

In this paper we will illustrate a technique used in the development of new products involving the use of:

1. (i)
   Laboratory simulation to establish chemistry and processing requirements to achieve the required mechanical properties. This includes percentage cold reduction and the appropriate thermal cycle for in-line annealing on a galvanizing line.
2. (ii)
   Computer prediction of galvanizing line operating parameters to achieve the heat treatment specified by the lab simulation.
3. (iii)
   Strip temperature control in order to maintain the required thermal cycle.