As the professional definition of the grading of mechanical anchor, Grade5.8, Grade 8.8 is often heard. What’s the real meaning of such grading?
According to regulation of GB/T3098. 1-2000, anchor’s performance rate divides into Grade 4.8, 5.8, 6.8, 8.8, 10.9, 12.9. Grade 5.8 & 8.8 are widely used. Then what these performance rates stand for? How to choose a suitable mechanical anchor?
Grade 6.8: standard value of its tensile strength is 600MPa, and yield strength is 480 MPa. Its elongation is less than 8%--the design specification of steel structure. Therefore, we do not recommend you to use it.
As for Grade 10.9 & 12.9 mechanical anchor with high strength, after heat-treatment, it will possess high rigidity. Later corrosion prevention coating will increase the probability of hydrogen brittleness. Therefore, it’s also not our recommends.
Grade 8.8: the standard value of tensile strength is 800 MPa, and yield strength is 640 MPa. Grade 8.8 anchor is the most used and the most cost-effective one.
Editor: NJMKT
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