The core national standard corresponding to the topic you mentioned is GB/T 3098.1 “Mechanical Properties of Fasteners – Bolts, Screws and Studs”. It serves as the fundamental basis for the selection, grading, and acceptance of bolts, screws, and studs made of carbon steel and alloy steel.
1. Current standard version
Currently, the official platform indicates that the currently valid version remains GB/T 3098.1-2010 (implemented on October 1, 2011, replacing the 2000 version).
Note: Although there is industry information mentioning the revision trend of GB/T 3098.1-2025, as of today (May 2026), the public status on the National Standard Information Public Service Platform has not yet been displayed as current. It is recommended to refer to the real-time query on the official platform for actual use.
2. Standard core content
This standard is primarily applicable to carbon steel or alloy steel fasteners tested at ambient temperatures ranging from 10℃ to 35℃. The core points include:
Performance level marking: The marking method is “number.number”. The number before the decimal point ×100 represents the nominal tensile strength (MPa), and the number after the decimal point represents the yield ratio. For example, Grade 8.8 indicates a tensile strength of 800MPa and a yield strength of 800×0.8=640MPa.
Common grades and materials:
Grades 4.6, 4.8, 5.6, and 5.8: Typically made of low carbon steel or medium carbon steel (such as Q235), they do not require heat treatment (Grades 4.8/5.8) or need to ensure yield strength (Grade 5.6).
Grades 8.8, 9.8, and 10.9: Carbon steel or carbon steel with added boron/manganese/chromium, alloy steel, requiring quenching and tempering treatment (such as 35#, 45#, 40Cr quenching and tempering).
Grade 12.9: Typically made of alloy steel (such as 35CrMo, 42CrMo, etc.), it undergoes quenching and tempering, achieving the highest strength.
Specified performance indicators: including tensile strength, yield strength (or specified non-proportional tensile strength), elongation, reduction of area, hardness (Vickers/Rockwell/Brinell), impact absorption energy, etc.
Testing and Marking: It specifies testing methods for tensile strength, wedge load, impact, hardness, etc., as well as the performance level marking (such as “8.8”) that should be stamped on the head of qualified fasteners.
3. Other relevant mechanical performance standards
If it is a special scenario, other parts of the GB/T 3098 series may also be used:
GB/T 3098.6-2023: Stainless steel bolts, screws, and studs (such as A2-70, A4-80, etc.).
GB/T 3098.23-2020: Large-sized alloy steel bolts, screws, and studs of M42~M72.
GB/T 3098.22-2009: Bolts, screws, and studs (M6~M16) made of fine-grained non-quenched and tempered steel.