1.1 This specification covers hot-coiled, heat-treated helical compression springs with tapered, closed, squared and ground ends made of hot-wrought round steel bars 3/8 in. (9.5 mm) and larger in diameter. 1.2 This specification also serves to This specification covers the standard for hot-coiled, heat-treated helical compression springs with tapered, closed, squared and ground ends made of hot-wrought round steel bars. Cross sections for hot-wrought round, square, and round-cornered square