[rounin]

Aproximadamente asi:

Código Delphi [-]
 
const
  MyMinimum = 0;
  MyMaximum = 1000;
 
procedure TForm1.FormCreate(Sender: TObject);
var i: Integer;
begin
  Chart1.AllowPanning := pmHorizontal; 
 
  Chart1.LeftAxis.AutomaticMaximum := False;
  Chart1.LeftAxis.AutomaticMinimum := False; 
 
  Chart1.OnZoom := Chart1Zoom;
 
  //Chart1.OnUndoZoom := Chart1UndoZoom;

  Chart1.LeftAxis.Minimum := MyMinimum;
  Chart1.LeftAxis.Maximum := MyMaximum;
end;
 
procedure TForm1.Chart1Zoom(Sender: TObject);
begin
  (Sender as TChart).LeftAxis.Minimum := MyMinimum;
  (Sender as TChart).LeftAxis.Maximum := MyMaximum;
end;