15 rows The highest metric class for strength, it exceeds Grade 8. Because there are so many different grades and fasteners all look about the same, medium carbon and … Jul 27, 2015 Anybody have insight into why the strongest bolt in the SAE classification system is a lower tensile strength than the highest in the Metric classification? (Grade 8 vs. 12.9) To meet the 12.9 strength you would need to go to a typical socket head cap screw. US Bolts: Head Marking Grade and Material Nominal Size Range (inches) Mechanical Properties ; Proof Load (psi) Min. Yield Strength (psi) Min. Tensile Strength

SAE vs. Metric bolt strength. Class for steel fasteners using Unified Screw Threads (the Imperial system) is described, as we all know, using SAE ( Society of Automotive Engineers ) Grades. The Property Class for Metric threads however is described using Classes. Each metric Class symbol consists of two numbers separated by a period. Steel Bolts - Metric Grades Steel Bolts - SAE Grades For metric bolts strength is according ISO 898 Mechanical properties of fasteners made of carbon steel and alloy steel described by property classes with designations 4.6, 4.8, 5.8, 8.8, 9.8, 10.9 and 12.9. A metric bolt designated as ISO class 6.8 roughly corresponds in strength to an SAE Grade 2 bolt. Bolts of ISO class 8.8 and the slightly stronger class 9.8 roughly correspond to an SAE Grade 5 bolt. An ISO Class 10.9 bolt roughly corresponds to an SAE Grade 8 bolt.

SAE J429 Grade 1, ASTM A307 Grade A are low carbon steel strength grades with essentially the same properties. ASTM A307 Grade B is a special low carbon steel grade of bolt used in piping and flange work. Its properties are very similar to Grade A except that it has added the requirement of a specified maximum tensile strength. Steel Bolts - SAE Grades SAE steel bolts - grades ranging grade 1 to 8.2 - proof and tensile strength What Is the Difference Between SAE Metric Sockets? . system, which is based on inches and the fractions thereof. SAE, which stands for the Society of Automotive Engineers , was used as the standard primarily on U.S.-made cars and trucks through the 1970s.