Flange bolts, as compared to regular bolts contain a circular washer like disk attached on the lower part of the head of the bolt. This circular flange in the Stainless Steel Flange Bolts eliminates the need to add another washer in the assembly.12 Point Flange Bolts Stainless Steel is used as a specialty fastener in the oil and gas industry due to the recessing head, which is not visible when the ends of the bolts are clamped together.