This part of GB/T 3098 (hereinafter referred to as this part) is among series of national standards under the general title of Mechanical Properties of Fasteners, which consist of:
——GB/T 3098.1—2010 Mechanical Properties of Fasteners-Bolts, Screws and Studs;
——GB/T 3098.2—2000 Mechanical Properties of Fasteners-Nuts-Coarse Thread;
——GB/T 3098.3—2000 Mechanical Properties of Fasteners - Set Screws;
——GB/T 3098.4—2000 Mechanical Properties of Fasteners - Nuts - Fine Pitch Thread;
——GB/T 3098.5—2000 Mechanical Properties of Fasteners - Tapping Screws;
——GB/T 3098.6—2000 Mechanical Properties of Corrosion-Resistant Stainless-Steel Fasteners - Bolts, Screws and Studs;
——GB/T 3098.7—2000 Mechanical Properties of Fasteners - Thread Rolling Screws;
——GB/T 3098.8—2010 Mechanical Properties of Fasteners - Parts for Bolted Connections for Use at temperatures from -200 ℃~+700 ℃;
——GB/T 3098.9—2010 Mechanical Properties of Fasteners - Prevailing Torque Type Steel Nuts;
——GB/T 3098.10—1993 Mechanical Properties of Fasteners Bolts, Screws, Studs and Nuts Made of Non-Ferrous Metals;
——GB/T 3098.11—2002 Mechanical Properties of Fasteners - Self-drilling Tapping Screws;
——GB/T 3098.12—1996 Mechanical Properties of Fasteners - Cone Proof Load Test on Nuts;
——GB/T 3098.13—1996 Mechanical Properties of Fasteners - Torsional Test and Minimum Torques for Bolts and Screws with Nominal Diameters 1mm to 10mm;
——GB/T 3098.14—2000 Mechanical Properties of Fasteners - Widening Test on Nuts;
——GB/T 3098.15—2000 Mechanical Properties of Fasteners - Stainless Steel Nuts;
——GB/T 3098.16—2000 Mechanical Properties of Fasteners - Set Screws Made of Stainless Steel;
——GB/T 3098.17—1996 Mechanical Properties of Fasteners - Preloading Test for the Detection of Hydrogen Embrittlement - Parallel Bearing Surface Method;
——GB/T 3098.18—2004 Mechanical Properties of Fasteners - Blind Rivets Testing;
——GB/T 3098.19—2004 Mechanical Properties of Fasteners - Blind Rivets with Break Pull Mandrel;
——GB/T 3098.20—2004 Mechanical Properties of Fasteners - Wing Nuts with Specified Proof Torque;
——GB/T 3098.21—2008 Mechanical Properties of Fasteners - Part 21: Tapping Screws of Stainless-Steel;
——GB/T 3098.22—2009 Mechanical Properties of Fasteners Made of the Fine Grain Non-Heat Treatment Steel—Bolts, Screws and Studs.
It is Part 9 of GB/T 3098.
This part is identical to ISO 2320:2008 Prevailing Torque Type Steel Nuts - Mechanical and Performance Properties (English version), and revised from the following aspects:
——The international standards in "Normative References" are superseded by corresponding Chinese standards (Chapter 2).
This part replaces GB/T 3098.9-2002 Mechanical Properties of Fasteners-Prevailing Torque Type Steel Hexagon Nut.
This part has the following main changes compared with GB/T 3098.9-2002:
——Temperature range for all metal type nuts is adjusted to -50℃ to +150℃ (clause 1);
——Terms and definitions are added (clause 3);
——Symbols and definitions are added (clause 4);
——Test data table for working performance of class 5 and class 9 nuts (clause 8) is added;
——Appendix B is added;
——Test data table for working performance of nuts is adjusted (clause 8);
——Test procedures for prevailing torque performance are adjusted (9.3.4);
——Part of clause 4 and clause 5 and the mechanical performance data sheet in clause 7 in the original standard are removed and superseded by corresponding standards;
——Clause 9 of original standard is removed;
——Appendix A of original standard is removed but manual form is allowed.
Appendix A of this part is normative and Appendix B is informative.
This part is proposed by China Machinery Industry Federation.
This part is under the jurisdiction of the National Technical Committee on Fasteners of Standardization Administration of China (SAC/TC 85).
Responsible drafting organization of this part: China Productivity Center for Machinery.
Participating drafting organizations of this standard: Product Quality Supervision Testing Center of Mechanical and Industrial Universal Parts, China National Center for Quality Supervision and Test of Standard Parts.
The previous editions of the standard superseded by this part are:
——GB 3098.9—1993, GB/T 3098.9—2002;
——GB 928—1980.
NATIONAL STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
中華人民共和國國家標準
GB/T 3098.9-2010
Mechanical Properties of Fasteners-
Prevailing Torque Type Steel Nuts
緊固件機械性能 有效力矩型鋼鎖緊螺母
1 Scope
This part of GB/T 3098 specifies the mechanical and performance properties for prevailing torque type steel nuts when tested at an ambient temperature range of 10℃ to 35℃. It includes a single test to determine the prevailing torque properties (performance properties) and/or the torque/clamp force properties.
This part applies to prevailing torque all metal type nuts and prevailing torque non-metallic insert type nuts:
——With general purpose thread according to GB/T 192;
——With diameter/pitch combination according to GB/T 193;
——With coarse pitch thread M3 to M39 and mechanical properties according to GB/T 3098.2;
——With fine pitch thread M8×1 to M39×3 and mechanical properties according to GB/T 3098.4;
——Within the temperature range of -50℃ to +150℃ for prevailing torque all metal type nuts;
Note 1: See Clause 7, paragraph 3.
——Within the temperature range of -50℃ to +120℃ for prevailing torque non-metallic insert type nuts.
Note 2: See Clause 7, paragraph 4.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the editions cited apply. For undated references, the latest editions of the normative documents (include any amendment) apply.
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 3098.1 Mechanical Properties of Fasteners-Bolts, Screws and Studs (GB/T 3098.1—2010, ISO 898-1: 2009, MOD)
GB/T 3098.2 Mechanical Properties of Fasteners-Nuts-Coarse Thread (GB/T 3098.2—2000, idt ISO 898-2: 1992)
GB/T 3098.4 Mechanical Properties of Fasteners - Nuts - Fine Pitch Thread (GB/T 3098.4—2000, idt ISO 898-6: 1994)
GB/T 5277 Fasteners-Clearance Holes for Bolts and Screws (GB/T 5277—1985, eqv ISO 273: 1979)
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, MOD)
GB/T 16823.3 Fasteners—Torque/Clamp Force Testing (GB/T 16823.3—2010, ISO 16047: 2005, IDT)
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 16823.3 and the following apply.
3.1
Prevailing torque type nut
Nut which is not free-running on a mating thread by virtue of a self-contained prevailing torque feature, and which provides a degree of resistance to rotation independent of clamping or compression forces.
3.2
Prevailing torque developed by the nut
Torque necessary to rotate the nut on its mating threaded component and with no axial force in the mating component.
3.3
Prevailing-on torque
Torque to rotate the nut on its mating threaded component when there is no axial load.
3.4
Prevailing-off torque
Torque to rotate after backing off the nut until the removal of the axial load in the externally threaded component in the following 360° rotation of the nut.
3.5
Prevailing torque all metal type nut
Nut which has a one piece or a multiple piece metal construction and derives its prevailing torque characteristics from a controlled distortion of the nut thread and/or body or from metallic insert(s).
3.6
Prevailing torque non-metallic insert type nut
Nut which has a multiple piece construction and derives its prevailing torque characteristics from insert(s) of non-metallic material located and retained in the nut.
3.7
Seating point
Point in the tightening process where clamp force first appears.
4 Symbols
For the purpose of this part, the following symbols apply together with those defined in GB/T 16823.3.
D nominal diameter, mm
d4 diameter of the hole of the fixture, mm
Fp Proof load, N
F65 Lower load limit for the evaluation of the coefficient of total friction, N
F75 Upper load limit for the evaluation of the coefficient of total friction, N
F80 Test clamp force, N
P Pitch of the thread, mm
TFv Prevailing-on torque, N·m
TFd Prevailing-off torque, N·m
T65 Lower torque limit for the evaluation of the coefficient of total friction, N·m
T75 Upper torque limit for the evaluation of the coefficient of total friction, N·m
T80 Test torque corresponding to 80 % of the proof load, N·m
μtot Coefficient of total friction
5 Thread
Threads for prevailing torque type nuts shall be in accordance with GB/T 9145 except for the prevailing torque feature.
——For prevailing torque non-metallic insert type nuts, the GO gauge shall be rotated (by hand) until the inserts;
——For prevailing torque all metal type nuts, the GO gauge shall be suitable for free installation (by hand) to one pitch at least.
6 Lubrication
At the option of the manufacturer a lubricant may be applied to the manufacturing lot to fulfill the performance requirements.。
7 Mechanical Properties of Prevailing Torque Type Nuts
The mechanical properties of prevailing torque type nuts shall conform to GB/T 3098.2 or GB/T 3098.4.
With regard to proof load, the test method specified in 9.2 shall apply.
For prevailing torque all metal type nuts, users shall consult an experienced fastener materials expert for temperatures outside the range of -50℃ to +150℃ to determine appropriate choices for a given application.
For prevailing torque non-metallic insert type nuts, use at or near the temperature limits of -50 ℃ and +120℃ may reduce the prevailing torque capability and may require the use of an adequate non-metallic material. Users shall consult an experienced fastener materials expert for temperatures outside the range of -50℃ to +120℃ to determine appropriate choices for a given application.
Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Symbols
5 Thread
6 Lubrication
7 Mechanical Properties of Prevailing Torque Type Nuts
8 Performance Requirements for Prevailing Torque Properties
9 Test Method
Appendix A (Normative) Temperature Resistance of Prevailing Torque Non-Metallic Insert Type Nuts
Appendix B (Informative) Basis for the Evaluation of the Total Coefficient of Friction, μtot
