ACCORDING TO THE PERFORMANCE GRADES OF HIGH-STRENGTH BOLTS,THEY ARE DIVIDED
INTO 8.8,10.9 AND 12.9,OF WHICH THE TORSIONAL SHEAR TYPE IS ONLY USED IN 10.9.IN THE MARKINGMETHOD,THE NUMBER BEFORE THE DECIMAL POINT REPRESENTS THE TENSILE STRENGTH AFTERHEAT TREATMENT,AND THE NUMBER AFTER THE DECIMAL POINT REPRESENTS THE YIELD RATIO,THAT IS,THE RATIO OF THE MEASURED YIELD STRENGTH TO THE MEASURED ULTIMATE TENSILESTRENGTH.GRADE 8.8 INDICATES THAT THE TENSILE STRENGTH OF THE BOLT ROD IS NOT LESS THAN800MPA,AND THE YIELD RATIO IS 0.8;GRADE 10.9 INDICATES THAT THE TENSILE STRENGTH OF THEBOLT ROD IS NOT LESS THAN 1000MPA,AND THE YIELD RATIO IS 0.9.
