Used and surplus W12 beams for sale! Buy and sell W12 beams with Eiffel Trading. W12 Beams are a wide flange steel beam where the dimension from flange to flange is 12". Inventory typically ranges from W12x50 beams, W12x74 beams, W12x120 beams, and other sizes. W12 beams are a great size for templates, waler beams, bracing and various other applications.