Metric Hex Bars :Spec. Across Flats, mm Across Flats Tol. Stainless Steel:Hex Bar (Metric) 304, 316 Cold Finish >3mm to 6mm 0/-.075mm:Stainless Steel:Hex Bar (Metric) 304, 316 Stainless Steel Tube and Pipe, 304, 316 SS Pipe304 Stainless Steel. 304 / 304L stainless steel pipe is a strong, tough metal with high corrosion protection, high temperature resistance and the ability to be sterlized. It has high workability and can be manufactured to tight tolerances and welded. These alloys are the most commonly used of the stainless steel alloys and are a cost-effective choice for most applications. Stainless Steel Tube and Pipe, 304, 316 SS Pipe304 Stainless Steel. 304 / 304L stainless steel pipe is a strong, tough metal with high corrosion protection, high temperature resistance and the ability to be sterlized. It has high workability and can be manufactured to tight tolerances and welded. These alloys are the most commonly used of the stainless steel alloys and are a cost-effective choice for most applications.