Sample Results
Image Description Grade Minimum Tensile Strength based on Head Markings
(ksi)Avg. Rockwell Hardness
(Number
of Tests)Estimated Tensile Strength based on Rockwell Hardness
(ksi)Avg. Brinell Hardness
(Number
of Tests)Estimated Tensile Strength based on Brinell Hardness
(ksi)Maximum Load
(lb)Tensile Strength based on Tensile Test
(ksi)Silver with "307A OF" markings ASTM A307 60 B94.3 (6) 84 192 (4) 91 unknown# unknown Gray with no markings SAE Grade 2 74 B94.3 (7) 98 241 (4) 116 unknown unknown Gold with 3 marks SAE Grade 5 120 B101.5 (7) 118 272 (3) 132 unknown unknown Hexagonal socket head with no markings SAE Grade 8 150 B105 (4) 132 369 (2) 181 unknown unknown Note for all specimens:
Nominal major diameter = 0.75 in.
As = 0.334 in.2
N = 10 threads/in.Tests performed by Jeff Thomas on April 12, 2000.
# Unknown because test fixture broke on first specimen.
Rockwell Images
Brinell Images