This standard specifies the test procedure for nuts made of free-cutting steel that are judged to be rejected by GB/T 5779.2 surface defect inspection. The performance level conforms to GB/T 3098.2 or GB/T 3098.4. The nominal diameter of the thread is 5-39MM Product grade for A and B grades.
1986GB 5779.2-1986 Surface discontinuities of fasteners on nuts for general requirements
GB/T 3098.14-2000 Mechanical properties of fasteners-Widening test on nuts has been changed from GB 5779.2-1986 Surface discontinuities of fasteners on nuts for general requirements.