The test fixture shall be capable of withstanding the combination of clamp force and bearing-surface friction torque without measurable permanent deformation or displacement. Figure 1 gives basic requirements for test fixtures.
7.3 Test nuts for testing bolts, screws and studs
For testing bolts, screws and studs of property class 10.9 and below，the test nut shall be in accordance with ISO 4032 or ISO 8673（GB/T6170或GB/T6171），property class 10. For testing bolts，screws and studs ofproperty class 12.9，the test nut shall be in accordance with IS0 4033 or ISO 8674 property class 1 2
7.4 Test bolts or test screws for testing nuts
For testing nuts, the test bolt or screw shall be in accordance with ISO 4014, ISO 4017, ISO 4762, ISO 8765, ISO 15071 or ISO 15072 and shall have a property class corresponding to the property class of the nut to be tested, which shall be, however, not less than property class 8.8. The thread shall be rolled.
a) plain surface uncoated and degreased
b) zinc electroplated A1 J according to ISO 4042(GB/T5267.1) and degreased
Depending on the type of nut to be tested, the length of the protrusion of the test bolt or test screw shall be two-to-seven thread pitches when the nut is seated against the test-bearing surface or test washer. The thread length shall be such that a minimum of two full threads are within the clamp length when the nut has been tightened. The test bolt shall have a point that is flat and chamfered. The thread shall be free from burrs and contaminations that might affect the tightening torque.
Contact: Mr Sun
Tel: 021-68365595 ; 021- 68367795
Add: No.299 Xiangche Road,Chedun Town,Songjiang District,Shanghai