US BoltsHead MarkingGrade andMaterialNominal Size Range(inches)Mechanical PropertiesProof Load(psi)Min. Yield Strength(psi)Min. Tensile Strength(psi)307ALow carbon steel1/4" thru 4"N/AN/A60,000No MarkingsGrade 2Low or medium carbon steel1/4" thru 3/
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