This part of GB/T 3098 specifies mechanical properties of bolt, screw, stud and screw rod (hereafter referred to as "fasteners") made of fine grain non-heat treatment steel when tested at 10℃~35℃.
The fasteners, which comply with this part under the specified ambient temperature, may fail to reach the specified mechanical and physical properties under higher or lower temperature.
Fasteners under the scope of this part of GB/T 3098 shall:
——be a fine grain non-heat treatment steel produced by thermomechanical rolling process;
——conform to common thread specified in GB/T 192;
——be M6~M16 coarse thread and M8×1~M16×1.5 fine thread;
——conform to diameter/pitch combination specified in GB/T 193;
——conform to thread tolerance specified in GB/T 197 or GB/T 22029.
This part is not applicable to set screw and similar tension-free fasteners (see GB/T 3098.3).
This part does not specify the following performance requirements:
——Weldability;
——Corrosion resistance;
——Shear stress resistance;
——Fatigue resistance.
2 Normative References
The following documents contain provisions which, through reference in this part of GB/T 3098, constitute provisions of this standard. For dated references, subsequent amendments to (excluding corrigendum), or revisions of, any of these publications do not apply. However, the parties coming to an agreement according to this standard are encouraged to study whether the latest editions of these documents apply. For undated references, the latest edition of these referenced documents applies.
GB/T 192 General Purpose Metric Screw Threads—Basic Profile (GB/T 192-2003, ISO 68-1:1998, ISO general purpose screw threads—Basic profile—Part 1: Metric screw threads, MOD)
GB/T 193 General Purpose Metric Screw Threads—General Plan (GB/T 193-2003, ISO 261:1998, ISO general purpose metric screw threads—General plan, MOD)
GB/T 196 General Purpose Metric Screw Threads—Basic Dimensions (GB/T 196-2003, ISO724:1993, ISO general purpose metric screw threads—Basic dimensions , MOD)
GB/T 197 General Purpose Metric Screw Threads—Tolerances (GB/T 197-2003, ISO 965-1:1998, ISO general purpose metric screw threads—Tolerances—Part l: Principles basic data, MOD)
GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223 (all parts) Iron Steel and Alloy
GB/T 224 Determination of Depth of Decarburization of Steel (GB/T 224-2008, ISO 3887:2003, MOD)
GB/T 226 Test Method for Macrostructure and Defect of Steel by Etching (GB/T 226-1991, neq ISO 4969:1980)
GB/T 228 Metallic Materials—Tensile Testing at Ambient Temperature (GB/T 228-2002, eqv ISO 6892:1998)
GB/T 229 Metallic Materials—Charpy Pendulum Impact Test Method (GB/T 229-2007, ISO 148-1:2006, Metallic Materials Charpy pendulum impact test Part 1:Test method, MOD)
GB/T 230.1 Metallic Materials—Rockwell Hardness Test—Part 1: Test Method (Scales A, B, C, D, E, F, G, H, K, N, T) (GB/T 230.1- 2009, ISO 6508-1:2005.MOD)
GB/T 231.1 Metallic Materials—Brinell Hardness Test—Part 1: Test Method (GB/T 231.1-2009, ISO 6506-1:2005, MOD)
GB/T 1979 Standard Diagrams for Macrostructure and Defect of Structural Steels
GB/T 2101 General Requirement of Acceptance Packaging, Marking and Certification for Section Steel
GB/T 2975 Steel and Steel Products—Location and Preparation of Test Pieces for Mechanical Testing (GB/T 2975-1998. eqv ISO 377: 1997)
GB/T 3098.1 Mechanical Properties of Fasteners-Bolts, Screws and Studs (GB/T 3098.1-2000, idt ISO 898-1:1999)
GB/T 3098.3 Mechanical Properties of Fasteners—Set Screws (GB/T 3098.3-2000, idt ISO 898-5:1998)
GB/T 3098.13 Mechanical Properties of Fasteners—Torsional Test and Minimum Torques for Bolts and Screws with Nominal Diameters 1mm to 10mm (GB/T 3098.13-1996, idt ISO 898-7:1992)
GB/T 4336 Test Method for Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method)
GB/T 4340.1 Metallic Materials—Vickers Hardness Test—Part 1: Test Method (GB/T4340.1-2009, ISO 6507-1:2005, MOD)
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 5267.3 Fasteners—Hot Dip Galvanized Coatings (GB/T 5267.3-2008, ISO 10684:2004, 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 5277 Fasteners—Clearance Holes for Bolts and Screws(GB/T 5277-1985, eqv ISO 273:1979)
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 Discontinities—Bolts, Screws and Studs for Special Requirements (GB/T 5779.3-2000, idt ISO 6157-3:1988)
GB/T 6394 Metal-methods for Estimating the Average Grain Size (GB/T 6394-2002, ASTM E112:1996, MOD)
GB/T 6478 Steels for Cold Heading and Cold Extruding (GB/T 6478-2001, neq ISO 4954:1993)
GB/T 9145 General Purpose Metric Screw Threads—Limits of Sizes for the Screw Threads of Medium Quality and Preferable Plan (GB/ T 9145-2003, ISO 965-2:1998, ISO general purpose metric screw threads Tolerances—Part2:Limits of sizes for general purpose external and internal screw threads Medium quality, MOD)
GB/T 10561 Steel - Determination of Content of Nonmetallic Inclusions - Micrographic Method Using Standards Diagrams (GB/T 10561 -2005, ISO 4967:1998, IDT)
GB/T 14981 Dimensions, Shape, Mass and Tolerances for Hot-rolled Wire Rods (GB/T 14981-2009, ISO 16124:2004, MOD)
GB/T 16825.1-2002 Verification of Static Uniaxial Testing Machines—Part 1 : Tension/compression Testing Machines—Verification and Calibration of the Force-measuring System (ISO 7500-1:2004, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system, IDT)
GB/T 22029 Hot-dip Galvanized Screw Threads—On External Screw Threads There is The Clearance for Accommodating the Hot-Dip Galvanized Coat (GB/T 22029-2008, ISO 965-4:1998, ISO general purpose metric screw threads Tolerances Part4:Limits of sizes for hot-dip galvanized external screw threads to mate with internal screw threads tapped with tolerance position H or G after galvanizing MOD)
GB/T 20066 Steel and Iron—Sampling and Preparation of Samples for the Determination of Chemical Composition (GB/T 20066-2006, ISO 14284:1996, MOD)
YB/T 5293-2006 Metallic Materials—Forging Test
3 Terms and Definitions
3.1
finished fasteners
the fasteners which have gone through all the manufacturing procedures and are not processed into machined test pieces. They may be either surface treated or not and may have full bearing capacity or reduced bearing capacity
3.2
machined test pieces
the test piece machined from finished fasteners in order to evaluate material performance
3.3
physical fastener
finished fasteners with rod diameter ds≈d2 or ds≥d2 or full thread screw (bolt) or full thread stud (screw rod)
3.4
waisted fastener
finished fasteners with rod diameter ds
3.5
grain
grain size may be expressed by mean area or mean diameter of grain and in the industrial production, it is expressed by the grain size number. The standard grain size number include No.1 to No.8, in which coarse grain is from No.1 to No.3 (diameter: 200μm~125μm), moderate grain is from No.4 to No.6 (diameter: 88μm~44μm) and fine grain is from No.7 to No.8 (diameter: 31μm~22μm).
This part specifies that the materials are ferrite and pearlite or bainite section steel and the mean ferrite grain size is 8μm or less.
3.6
thermomechanical rolling
thermomechanical rolling is controlled rolling, i.e. the metal temperature is controlled in the rolling process to get some precious characteristics which are unobtainable in the common rolling, such as refined grain structure, good plasticity and toughness and higher strength
