This standard specifies the test procedure for nuts made of free-cutting steel that are rejected by the surface defect inspection of GB/T 5779.2. This standard applies to nuts: the performance level conforms to GB/T 3098.2 or GB/T 3098.4; the nominal thread diameter is 5 to 39 mm; the product grade is A and B. GB/T 3098.14-2000 Mechanical properties of fasteners Nut expansion test GB/T3098.14-2000 Standard download decompression password: www.bzxz.net

GB/T3098.14-2000
This standard is equivalent to the international standard ISO10484:1997 "Nut hole expansion test". The general title of GB/T3098 is "Mechanical properties of fasteners" and it includes the following parts: - GB/T3098.1--2000
GB/T 3098.2-2000
GB/T 3098. 3--2000
GB/T 3098. 4--2000
GB/T 3098.5--2000
GB/T 3098.6--2000
GB/T 3098. 7—2000
GB/T 3098.8-1992
GB/T 3098. 9—1993
GB/T 3098.10-
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
—1995
-GB/T 3098.11-
GB/T 3098.12-1996
-GB/T 3098.13—1996
GB/T 3098.14-2000
-GB/T 3098.15--2000
GB/T 3098. 16--2000
GB/T 3098.17—2000
Mechanical properties of fasteners
Mechanical properties of fasteners
Bolts, screws and studs
Nuts with coarse pitch
Set screws
Fine pitch thread
Self-tapping screws
Stainless steel bolts, screws and studs
Self-extruding screws
Heat-resistant threaded connections
Effective torque steel hexagonal locking nuts
Bolts, screws, studs and nuts made of non-ferrous metalsSelf-drilling and self-tapping screws
Nut cone proof load test
Mechanical properties of fasteners
1~10 mm
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Torque test and breaking torque of bolts and screwsNominal diameterNut expansion test
Stainless steel nuts
Stainless steel set screws
Preload test for hydrogen embrittlementParallel bearing surface methodThis standard is a revision of Article 4.2 of GB/T5779.2-1986. The main revisions are as follows:a) Only nuts made of free-cutting steel are specified (Chapter 1);b) Applicable to all performance levels (Chapter 1);c) Comparative tests and the provisions on the number of test samples are cancelled (Article 3.4);d) Provisions for effective torque nuts are added (Chapter 5).This standard was proposed by the State Bureau of Machinery Industry.This standard is under the jurisdiction of the National Technical Committee for Standardization of Fasteners.This standard was drafted by the Mechanical Science Research Institute.This standard is interpreted by the Secretariat of the National Technical Committee for Standardization of Fasteners. 179
GB/T3098.14--2000
ISOForeword
ISO (International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The formulation of international standards is usually carried out through ISO's various technical committees. Each member body can also participate in the committee if it is interested in the project carried out by a technical committee. Governmental and non-governmental international organizations related to ISO can also participate in this work. ISO has close ties with the International Electrotechnical Commission (IEC) in electrical standardization. The draft international standards adopted by the technical committee are distributed to all member bodies for voting. The formal publication of international standards requires at least 75% of the member bodies to vote in favor.
International Standard ISO10484 was formulated by ISO/TC2 Fastener Technical Committee SC1 Fastener Mechanical Properties Subcommittee. 180
1 Scope
National Standard of the People's Republic of China
Mechanical properties of fastenersWidening test on nuts
GB/T 3098.14--2000
idt ISO 10484:1997
This standard specifies the test procedures for nuts made of free-cutting steel that are rejected by the surface defect inspection in GB/T5779.2. This standard applies to nuts:
The performance level conforms to GB/T3098.2 or GB/T3098.4: the nominal diameter of the thread is 5~39mm;
The product grade is A and B.
2 Referenced Standards
The provisions contained in the following subtitles constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T3098.2—2000 Mechanical properties of fasteners Coarse thread of nut (idtISO898-2:1992) GB/T 3098. 42000
Mechanical properties of fasteners
GB/T 3098.9-—1993
GB/T 5779. 2—2000
3 Hole expansion test
3.1 Principle
Mechanical properties of fastenerswwW.bzxz.Net
Surface defects of fasteners
Fine thread of nut (idtISO898-6:1996) Effective torque steel hexagonal lock nut (eqvISO2320:1983) Nut (idt ISO6157-2:1995)
After removing the internal thread to the nominal diameter of the thread, push the tapered mandrel into the nut. Measure the percentage of hole expansion.
3.2 Test mandrel
The test mandrel shown in Figure 1 is used for measurements with an expansion of 6% or 4% respectively (Chapter 4). Its minimum hardness is ≥45HRC and the tapered part should be polished (surface roughness Ra=2.5μm). 3.3 Nut test piece
Remove the nut thread to make it equal to the nominal thread diameter (tolerance H12). The nut should be able to withstand the expansion test 3.4 Procedure
Before the test, apply disulfide (MoS2) lubricant to the mandrel. Insert the mandrel into the nut test piece as shown in Figure 2. Apply the load slowly, continuously and coaxially until the cylindrical part of the mandrel passes through the nut hole. The upper end of the mandrel should be tightened. For arbitration tests, the speed of mandrel insertion should not exceed 25mm/min. Approved by the State Administration of Quality and Technical Supervision on September 26, 2000, and implemented on February 1, 2001
4 Determination
The total expansion of the nut is:
Nuts with performance levels 4~~~12: 6%
Nuts with performance levels 04 and 05: 4%
GB/T3098.14--2000
If the nut wall is completely broken before reaching the specified minimum expansion value, the nut shall be judged as unqualified. In case of dispute, cut the side opposite to the crack. If the nut is divided into two halves, the nut shall be judged as unqualified. 5 Special cases -
Effective torque type nuts
For effective torque type nuts that comply with GB/T3098.9, the minimum expansion shall be less than 20% of the value of hexagonal nuts specified in Chapter 4.
1. 06 D(1. 04 D) ±0. 03
(001:)
+1. 1D3(H14)
1)F Load.
2)Hardening.
3)D Nominal diameter of nut thread.
1)D-Nominal diameter of nut thread. For the test of nuts with enlarged tapping size, the diameter D should be increased according to the major diameter of the internal thread,
2)m-Nominal height of the nut.
Test mandrel for expansion of 6% (1.06D) or
4% (1.04D) respectively
Figure 2 Test device
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