GB/T 70 series national standard includes:
- GB/T 70.1 Hexagon Socket Head Cap Screws;
- GB/T 70.2 Hexagon Socket Button Head Screws;
- GB/T 70.3 Hexagon Socket Countersunk Head Screws;
- GB/T 70.4 Hexagon Socket Button Head Screws with Collar;
- GB/T 5281 Hexagon Socket Head Shoulder Screws
This Part is the Part 2 of GB/T 70.
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1 Scope
This Part of GB/T 70 specifies the type dimension, technical requirement and marking of hexagon socket button head screws from M3 up to and including M16, with performance levels 08.8, 010.9, 012.9, 012.9, A2-070, A2-080, A3-070, A3-080, A4-070, A4-080, A5-070 and A5-080, product grade A and with reduced loadability according to Table 3.
This Part is applicable to hexagon socket button head screws screwed in thread within engine body with internal hexagonal wrench.
2 Normative References
The following documents for the application of this Standard are essential. Any dated reference, just dated edition applies to this Standard. For undated references, the latest edition (including any amendments) applies.
GB/T 2 Fasteners - Ends of Parts with External Thread (GB/T 2-2001, idt ISO 4753: 1999)
GB/T 70.5 Gauging of Hexagon Sockets (GWT 70.5-2008, ISO 23429:2004, IDT)
GB/T 90.1 Fasteners-Acceptance Inspection (GB/T 90.1-2002, idt ISO 3269: 2000)
GB/T 90.2 Fasteners - Marking and Packaging
GB/T 193 General Purpose Metric Screw Threads - General Plan (GB/T 193-2003, ISO 261: 1998, MOD)
GB/T 1237 System for Fasteners (GB/T 1237-2000, eqv ISO 8991: 1986)
GB/T 3098.1 Mechanical Properties of Fasteners - Bolts, Screws and Studs (GB/T 3098.6-2000, ISO 898-1: 2009, MOD)
GB/T 3098.6 Mechanical Properties of Fasteners - Stainless Steel Bolts, Screws and Studs (GB/T, 3098.6-2014, ISO 3506-1:2009, MOD)
GB/T 3103.1 Tolerances for Fasteners - Bolts, Screws, Studs and Nuts (GB/T 3103.1-2002, ISO 4759-1: 2000, IDT)
GB/T 5267.1 Fasteners - Electroplated Coatings (GB/T 5267.1-2002, ISO 4042: 1999, IDT)
GB/T 5267.2 Fasteners - Non-Electrolytically Applied Zinc Flake Coatings (GB/T 5267.2-2002, ISO 10683: 2000, IDT)
GB/T 5267.4 Passivation of Corrosion-Resistant Stainless-Steel Fasteners (GB/T 5267.4-2009, ISO 16048: 2003, IDT)
GB/T 5276 Fasteners; Bolts, Screws, Studs and Nuts; Symbols and Designations of Dimensions (GB/T, 5276-1985, eqv ISO 225: 1983)
GB/T 5779.1 Fasteners - Surface Discontinuities - Bolts, Screws and Studs for General Requirements (GB/T 5779.1-2000, idt ISO 6157-1:1988)
GB/T 5779.3 Fasteners - Surface Discontinuities - Bolts, Screws And Studs for Special Requirements (GB/T 5779.3-2000, idt ISO 6157-3: 1988)
GB/T 9145 General Purpose Metric Screw Threads - Limits of Sizes for the Screw Threads of Coarse Quality and Preferable Plan (GB/T, 9145-2003, ISO 965-2: 1998, MOD)
GB/T 16938 Fasteners - General Requirements for Blots, Screws, Studs and Nuts (GB/T 16938-2008, ISO 8992: 2005, IDT)
3 Dimensions
See Figures 1 and 2 for the type dimensions of screws.
