How to prevent any keyboard events and their default behavior on element in Angular 6

Question

I am trying do prevent any keyboard activity on Angular Mat Header. I want to block keyboard navigation, entering steps using header. I want to use buttons only How to stop any keyboard activity on that element as preventDefault() does not work.

public ngAfterViewInit(): void {
    this.elRef.nativeElement.querySelector('mat-step-
    header').addEventListener('keydown', (e) => {

      // What should go here?

    });
}