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QC/T 1103-201912-point head heat-resistant lock nuts (English PDF)

12角头耐热锁紧螺母

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Issued by

MIIT

Level / Type

Industry · Recommended

Issue date

August 2, 2019

Implementation date

January 1, 2020

Scope

QC/T 1103-2019 is the English-translated version of 12角头耐热锁紧螺母.

QC/T 1103-2019 is the Chinese automotive industry standard for 12-point head heat-resistant lock nuts used on vehicles where joints run hot. It sets out the nut type and dimensions, the technical requirements with their reference standards, and the product number.

It applies to nuts with M5 to M12 threads, material properties designated SB, product grade TA and working temperatures below 700 °C. Mechanical properties, tolerances and prevailing torque behaviour are referred to GB/T 3098.8, GB/T 3103.4 and GB/T 3098.9, the first two dealing with bolted connections for service from -200 °C to +700 °C, while surface discontinuities follow GB/T 5779.2 and superalloy designations follow GB/T 14992.

It is the nut counterpart of the 12-point head bolts in QC/T 1104. Issued on 2 August 2019, it has applied since 1 January 2020.

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Document preview — QC/T 1103-2019

National Standard of the People's Republic of China

Issued by: Ministry of Industry and Information Technology of the People's Republic of China

Foreword3
1 Scope4
2 Normative references4
3 Type size5
4 Technical requirements and reference standards6
5 Product number7

1 Scope

1.1 This standard specifies the type, size, technical requirements, reference standard and number of 12-point head heat resistant nuts for automobiles.

1.2 This standard is applicable to 12-point head heat resistant nuts for automobiles, which have thread specifications of M5 ~ M12, material properties abbreviated as SB, product grade of TA, working temperature below 700 °C.

2 Normative references

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this standard.

GB/T 90.1 Fasteners - Acceptance inspection

GB/T 90.2 Fasteners - Marking and packaging

GB/T 196 General purpose metric screw threads - Basic dimensions

GB/T 197 General purpose metric screw threads - Tolerances

GB/T 3098.8 Mechanical properties of fasteners - Parts for bolted connections for use at temperatures -200 °C ~ +700 °C

GB/T 3098.9 Mechanical properties of fasteners - Prevailing torque type steel nuts

GB/T 3103.4 Tolerances for fasteners - Bolt/nut assemblies for service temperatures from -200 °C ~ +700 °C

GB/T 5276 Fasteners - Bolts, screws, studs and nuts - Symbols and descriptions of dimensions

GB/T 5779.2 Fasteners - Surface discontinuities - Nuts

GB/T 14992 Classification and designation for superalloys and high temperature intermetallic materials

QC/T 326 Coding rules for automotive standardized parts […]

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 15 pages — is available in the English PDF.

Referenced standards

Normative references

Similar standards

QC/T 1104-2019|GB 21556.2-2025|GB/T 41157.4-2022|GB 4716-2024|GB/Z 24979-2010|GB/T 20021-2026

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