This bulletin is under the jurisdiction of the Committee on Standardization of Tubular Goods. This bulletin is not intended as a design manual. Its purpose is to provide minimum joint tensile strength of round thread casing subjected to combined bending and internal pressure. Development of formulas and determination of material constants and formula coefficients are given in Bul 5C3@ and are based on the results of an API sponsored research project where 26 tests were made on 5? in. x 17 Ib/ft grade K-55 short round thread casing.