Vehicle manufacturers are faced with a difficult task of significantly improving fuel economy and safety while maintaining competitive position in the market. This can be accomplished, among other things, by utilizing higher strength steel. A newly developed steel sheet for cold stamping (ColdStamp-Steel) is ideal for car body structural and safety components such as pillars, roof frame, rocker, tunnel, and other.

ColdStamp-Steel is offered as Grade A and Grade B with good formability and they are suitable for cold stamping. In comparison to the commercial steel sheets for cold stamping, the Grade A and Grade B possess higher strength at the same ductility. Table below shows the mechanical properties of the hot rolled Grade A after quenching and low temperature tempering and the hot rolled Grade B after quenching, low and high temperature tempering.

ColdStamp Graph 1.PNG

Figure below shows tensile diagrams of the hot rolled Grade B sheets of 0.06”/1.50 mm thickness after quenching, low and high temperature tempering.

ColdStamp Graph 2.PNG

The hot rolled Grade A and Grade B sheets can be cold rolled to obtain the required properties.

The hot rolled Grade A and Grade B sheets can be coated by galvanizing, galvannealing, aluminizing, and other common used coating processes.

Grade A is weldable with conventional processes. Grade B is weldable with conventional processes by adapting the parameters. Given the increase of the carbon equivalent, it is necessary to increase welding force and adapt welding cycles to get good quality of spotweld.

Publications:

U.S. Patent No 9869009  “High Strength Low Alloy Steel and Method of Manufacturing” 

New Steel Sheet Available for Cold Stamping: Advanced Materials & Processes, April 2016, p. 9.