QC/T 518-2013 (English Version) PDF

Scope: This standard specifies the tightening torque of threaded fasteners for automobiles. This standard applies to tightening by controlled torque that meets the following conditions: 　——The mechanical properties of external threaded parts comply with grades 8.8, 10.9 and 12.9 specified in GB/T 3098.1; 　——The mechanical properties of internally threaded parts comply with GB/T 3098.1. T 3098.2 or GB/T 3098.4, and has the strength to fully utilize the load-bearing capacity of the threaded connection pair; 　——the hexagonal dimensions of the internal and external threaded parts comply with the standard series specified in GB/T 3104; 　——the bolt-nut connection pair and Threaded connection pairs other than bolts and nuts; 　——Threads comply with GB/T 196, and thread accuracy is not less than level 6 specified in GB/T 197; 　——Externally threaded parts bear axial tensile load during tightening; 　——The design tensile force of bolts or screws is 90% of the yield point σs or yield strength σ0.2. This standard does not apply to set screws in which externally threaded parts bear compression force during tightening, self-tapping screws and wood screws tapped from externally threaded parts, threaded fasteners using spring washers or elastic washers, and effective torque types. Tightening of threaded fasteners.

QC/T 518-2013 Referenced Document

GB/T 196 General purpose metric screw threads--Basic dimensions
GB/T 197 General purpose metric screw threads—Tolerances*， 2018-03-15 Update
GB/T 3098.1 Mechanical properties of fasteners.Blots, screws and studs
GB/T 3098.2 Mechanical properties of fasteners.Nuts*， 2015-12-10 Update
GB/T 3098.4 Mechanical properties of fasteners-Nuts-Fine pitch thread
GB/T 3104 Fasteners--Widths across flats of hexagon products
GB/T 5277 Fasteners--Clearance holes for bolts and screws
QC/T 715 Measuring method for friction coefficient of screw thread pair of automobiles