Property class | | | | | |
Heat treatment | - Carbon steel or carbon steel with alloying additions
| - Carbon steel or carbon steel with alloying additions
| - Carbon steel with alloying additions (such as boron, manganese or chromium), quenched and tempered
| - Quenched and tempered alloy steel c
| - Quenched and tempered alloy steel d
|
Thread | - ① Before coating, the external thread shall use GB/T 197 which specifies tolerance class 6g ;
- ② Bolt threads and the external threads of other components shall be formed by thread rolling.
| - ① Before coating, the external thread shall use GB/T 197 which specifies tolerance class 6g ;
- ② Bolt threads and the external threads of other components shall be formed by thread rolling.
| - ① Before coating, the external thread shall use GB/T 197 which specifies tolerance class 6g ;
- ② Bolt threads and the external threads of other components shall be formed by thread rolling.
| - ① Before coating, the external thread shall use GB/T 197 which specifies tolerance class 6g ;
- ② Bolt threads and the external threads of other components shall be formed by thread rolling.
| - ① Before coating, the external thread shall use GB/T 197 which specifies tolerance class 6g ;
- ② Bolt threads and the external threads of other components shall be formed by thread rolling.
|
Tolerances | - Unspecified dimensional and geometrical tolerances shall comply with GB/T 3103.1 for product grade C
| - Unspecified dimensional and geometrical tolerances shall comply with GB/T 3103.1 for product grade C
| - Unspecified dimensional and geometrical tolerances shall comply with GB/T 3103.1 for product grade C
| - Unspecified dimensional and geometrical tolerances shall comply with GB/T 3103.1 for product grade C
| - Unspecified dimensional and geometrical tolerances shall comply with GB/T 3103.1 for product grade C
|
Hot-dip galvanizing | - ① No more than two hot-dip galvanizing cycles are permitted;
② After galvanizing, externally threaded components shall be centrifuged or subjected to a zinc-removal process to remove excess zinc from the threads; ③ Suitable material selection, heat treatment or other measures shall be used to achieve the required ductility in the finished bolts.
| - ① No more than two hot-dip galvanizing cycles are permitted;
② After galvanizing, externally threaded components shall be centrifuged or subjected to a zinc-removal process to remove excess zinc from the threads; ③ Suitable material selection, heat treatment or other measures shall be used to achieve the required ductility in the finished bolts.
| - ① Before hot-dip galvanizing, use a mechanical (physical )) method to remove rust. During hot-dip galvanizing, the manufacturer shall take effective measures to prevent hydrogen embrittlement;
② After galvanizing, externally threaded components shall be centrifuged or subjected to a zinc-removal process to remove excess zinc from the threads;
③ Repeated hot-dip galvanizing is not permitted.
| - ① Before hot-dip galvanizing, remove rust by mechanical (physical) means. During galvanizing, the manufacturer shall take effective measures to prevent hydrogen embrittlement;
② After galvanizing, externally threaded components shall be centrifuged or subjected to a zinc-removal process to remove excess zinc from the threads;
③ Repeated hot-dip galvanizing is not permitted.
| - ① Before hot-dip galvanizing, remove rust by mechanical (physical) means. During galvanizing, the manufacturer shall take effective measures to prevent hydrogen embrittlement;
② After galvanizing, externally threaded components shall be centrifuged or subjected to a zinc-removal process to remove excess zinc from the threads;
③ Repeated hot-dip galvanizing is not permitted.
|
| a Free-cutting steel may be used for these property classes. Maximum contents are 0.34% sulfur, 0.11% phosphorus and 0.35% lead. b The material for these property classes shall have sufficient hardenability to achieve approximately 90% martensite at the core of the threaded cross-section after quenching and before tempering. Account shall also be taken of the effect of the hot-dip galvanizing temperature on mechanical properties. c These alloy steels shall contain at least one of the following elements at the stated minimum content: 0.30% chromium, 0.30% nickel, 0.20% molybdenum or 0.10% vanadium. When two, three or four elements are used in combination, their total content shall be at least 70% of the sum of their individual minimum contents. d These alloy steels shall contain at least two of the following elements at the stated minimum contents: 0.30% chromium, 0.30% nickel, 0.20% molybdenum and 0.10% vanadium. When three or four elements are used in combination, their total content shall be at least 70% of the sum of their individual minimum contents. |
