Min Yield Strength (psi) Min Tensile Strength (psi) 307A Low carbon steel 1/4" thru 4" N/A N/A 60,000 No Markings Grade 2 Low or medium carbon steel 1/4" thru 3/4" 55,000 57,000 74,000 Over 3/4" thru 11/2" 33,000 36,000 60,000 3 Radial Lines Grade 5 Medium carbon steel, quenched and tempered 1/4" thru 1" 85,000 92,000 1,000Stainless steel (304N) Strength of Metals SI Units Strength of Metals Imperial Units Example Strength of Copper at 100 o C As indicated in the first figure the strength of copper is reduced to approximately 95 % at 100 o C With an Ultimate Tensile Strength σ u of 2 MPa for copperFor the annealed austenitic stainless steel, its yield strength is a very low proportion of the tensile strength, typically only 4045%, but only a few % of cold work will increase the yield by 0 or 300MPa, and in severely cold worked material like spring temper wire or strip, the yield is usually about 8095% of the tensile strength Temperature And Stre