Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ASTM B21 found under Bar Metal by American Society For Testing And. The National Stock Number assigned to this part is 9530001671921, and the Federal Supply Class is 9530 Bars And Rods Nonferrous Base Metal. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like ASTM B21.