GB/T 47380-2026Self-locking, two lug anchor nuts, with counterbore and MJ threads for aerospace - Dimensions (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document is modified to adopt ISO 3223:1998 "Aerospace - 1100 MPa (ambient temperature)/235°C, 1100 MPa (ambient temperature)" MJ threaded countersunk double-ear fixed bracket self-locking nut dimensions (temperature)/315°C and 1100MPa (ambient temperature)/425°C.

This document includes a new chapter on "Terms and Definitions".

The technical differences between this document and ISO 3223:1998, and the reasons therefor, are as follows.

---ISO 5855-2 has been replaced with the normatively referenced GB/T 43924.2 (see Table 1) to adapt to my country's technical conditions and increase operability.

Actual nature;

---The requirement for high-temperature connection of metal caps and nuts (see Chapter 3 of ISO 3223:1998) has been removed, increasing operability;

---The provision that "unspecified details are determined by the manufacturer" (see paragraph 1 in ISO 3223:1998) has been removed to comply with domestic regulations.

Require.

The following editorial changes have been made to this document.

---To align with existing standards, the standard name has been changed to "Dimensions of MJ Threaded Double-Ear Self-Locking Nuts with Countersunk Heads for Aerospace Use";

---The presentation of the structure diagram has been modified (see Figure 1) to better suit the domestic industry's charting practices.

Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.

This document was proposed and is under the jurisdiction of the National Aircraft Standardization Technical Committee (SAC/TC435).

1 Scope

This document specifies strength grades of 1100MPa1)/235°C2), 1100MPa1)/315°C2), and 1100MPa1)/425°C2).

Structure and dimensions of MJ threaded double-ear self-locking nut with countersunk head for aerospace applications (hereinafter referred to as "nut").

This document applies to the design of MJ threaded double-ear self-locking nuts with countersunk head for aerospace applications.

1) When tested using bolts of the highest strength grade, the minimum tensile load that the nut can withstand at ambient temperature without breaking or...

Cracks.

2) After the nut has been subjected to the maximum operating temperature, its original properties will not be permanently changed upon returning to room temperature. The maximum operating temperature depends on the material or surface treatment of the nut.

The rational state.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 43924.2 Aerospace MJ Threads Part 2: Limiting Dimensions of Bolt and Nut Threads (GB/T 43924.2-2024, ISO 5855-2:1999, MOD) ISO 8788 Aerospace-Nuts, metric-Tolerances

3 Terms and Definitions

This document does not contain any terms or definitions that need to be defined.

4 Structure and Dimensions

The structure and dimensions of the nut are shown in Figure 1 and Table 1.The dimensions and tolerances of the nut are for the part surface after coating and before applying lubricant.