You can find metals for forging at your local hardware store or home improvement store, but you should also consider visiting your local machine shop. For example, in the United States, there are several machine shops that specialize in metalworking and welding. These shops may be able to help you find the exact metal you're looking for
You might also want to talk with your local manufacturer or supplier of hardware or industrial supplies. They may have a list of suppliers they use and recommend that's close by.
where to get metal for forging