Nihonweld NT-AL 4047/NM-AL 4047 description: NT-Al 4047 is more commonly referred to as “718 aluminum” or Al Si 12. It is an aluminum filler metal which contains approximately 12% silicon. This alloy is commonly used not only in MIG or TIG applications, but also as a general purpose brazing alloy providing a free-flowing filler metal and good corrosion resistance. NT-AI 4047 has an approximate melting range of 1070-1080F and the post anodizing color tint is grayish-black.