ASTM F436 thru hardened structural flat washers are used under bolt heads or nuts to increase the bearing surface area, or to offer protection so that the nut or bolt can be rotated without distortion of the bearing surface. They are designed for general purpose and structural use with bolts, nuts, studs, and other internally and externally threaded fasteners. Dimensional specifications are governed by ASTM F436. Dimensionally comparable to the low carbon SAE Washer, but manufactured from a higher grade of steel and heat treated. F436 washers are suitable for use with many fastener grades including B7, B16, L7, and A325 and A490 structural bolts. Also used with fasteners covered in A354 and A449. PTFE coating (commonly referred to as Teflon) is formulated with superior characteristics for maximum fastener life. Technical components include a tensile strength of up to 4,000 psi and an operating pressure up to 100,000 psi. The absence of nut locking oxides enable easy and safe removal. PTFE coatings have extreme chemical resistance and are ideal for applications including insulating piping, boiler rooms, water filled piping, water lines and more.