uses 
  ActiveX, MSHTML_TLB, SHDocVw_TLB, 
  ComCtrls, OleCtrls; 

procedure TForm1.Button1Click(Sender: TObject); 
var 
  HTMLDocument: IHTMLDocument2; 
  PersistFile: IPersistFile; 
begin 
  HTMLDocument := WebBrowser1.Document as IHTMLDocument2; 
  PersistFile  := HTMLDocument as IPersistFile; 
  PersistFile.Save(StringToOleStr('c:\SavedFile.html'), System.True); 
end;