Description and Translation of GB 5787 Fasteners
GB 5787 fasteners, a crucial standard in Chinese mechanical engineering, function as specialized detachable connectors primarily used in automotive, machinery, and equipment manufacturing. Their core role is to provide secure clamping in applications requiring high-precision jointing, effectively transmitting radial and axial loads while maintaining component stability under dynamic operating conditions. These fasteners facilitate reliable assembly and disassembly, ensuring maintenance efficiency without compromising structural integrity.
In terms of materials, GB 5787 fasteners are predominantly crafted from high-quality carbon steel (e.g., 8.8-grade steel compliant with GB/T 3098.1) and alloy steel, offering excellent tensile strength and mechanical durability. For corrosion-resistant requirements, stainless steel variants (e.g., 304, 316) meeting relevant standards are specified to ensure performance in humid or chemically exposed environments.
Surface treatments include zinc plating with passivation for enhanced corrosion resistance, phosphating to improve lubrication during installation and prevent seizing, and black oxide coating for increased wear resistance. These treatments extend service life while optimizing compatibility with diverse operating conditions.
Key characteristics of GB 5787 fasteners include fine metric thread specifications, precision-engineered hexagonal heads with flange designs for improved load distribution, and strict dimensional tolerances ensuring interchangeability. Their mechanical attributes feature specified tensile strengths (minimum 800 MPa for 8.8 grade), appropriate yield ratios, and sufficient ductility. Additionally, they exhibit stable torque-tension relationships and superior clamping performance, making them indispensable in high-precision mechanical assemblies and industrial applications.
| Thread Size d | M5 | M6 | M8 | M10 | M12 | (M14) | M16 | ||||
| P ① | Pitch | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | |||
| b | L≤125 | 16 | 18 | 22 | 26 | 30 | 34 | 38 | |||
| 125＜L≤200 | - | - | 28 | 32 | 36 | 40 | 44 | ||||
| L＞200 | - | - | - | - | - | 53 | 57 | ||||
| c | min | 1 | 1.1 | 1.2 | 1.5 | 1.8 | 2.1 | 2.4 | |||
| da | Type A | max | 5.7 | 6.8 | 9.2 | 11.2 | 13.7 | 15.7 | 17.7 | ||
| Type B | max | 6.2 | 7.4 | 10 | 12.6 | 15.2 | 17.7 | 20.7 | |||
| dc | max | 11.4 | 13.6 | 17 | 20.8 | 24.7 | 28.6 | 32.8 | |||
| ds | max | 5 | 6 | 8 | 10 | 12 | 14 | 16 | |||
| min | 4.82 | 5.82 | 7.78 | 9.78 | 11.73 | 13.73 | 15.73 | ||||
| du | max | 5.5 | 6.6 | 9 | 11 | 13.5 | 15.5 | 17.5 | |||
| dw | min | 9.4 | 11.6 | 14.9 | 18.7 | 22.6 | 26.4 | 30.6 | |||
| e | min | 7.44 | 8.56 | 10.8 | 14.08 | 16.32 | 19.68 | 22.94 | |||
| f | max | 1.4 | 2 | 2 | 2 | 3 | 3 | 3 | |||
| k | max | 5.6 | 6.8 | 8.5 | 9.7 | 11.9 | 12.9 | 15.1 | |||
| k1 | min | 2.3 | 2.9 | 3.8 | 4.3 | 5.4 | 5.6 | 6.7 | |||
| r1 | min | 0.2 | 0.25 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | |||
| r2 | max | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.9 | 1 | |||
| r3 | min | 0.1 | 0.1 | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | |||
| r4 | Ref. | 3 | 3.4 | 4.3 | 4.3 | 6.4 | 6.4 | 6.4 | |||
| s | max | 7 | 8 | 10 | 13 | 15 | 18 | 21 | |||
| min | 6.64 | 7.64 | 9.64 | 12.57 | 14.57 | 17.57 | 20.48 | ||||
| t | max | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | 0.45 | 0.5 | |||
| min | 0.05 | 0.05 | 0.1 | 0.15 | 0.15 | 0.2 | 0.25 | ||||
| Length of Thread b | - | - | - | - | - | - | - | ||||
| ①,P = pitch of coarse thread. | |||||||||||
Description and Translation of GB 5787 Fasteners
GB 5787 fasteners, a crucial standard in Chinese mechanical engineering, function as specialized detachable connectors primarily used in automotive, machinery, and equipment manufacturing. Their core role is to provide secure clamping in applications requiring high-precision jointing, effectively transmitting radial and axial loads while maintaining component stability under dynamic operating conditions. These fasteners facilitate reliable assembly and disassembly, ensuring maintenance efficiency without compromising structural integrity.
In terms of materials, GB 5787 fasteners are predominantly crafted from high-quality carbon steel (e.g., 8.8-grade steel compliant with GB/T 3098.1) and alloy steel, offering excellent tensile strength and mechanical durability. For corrosion-resistant requirements, stainless steel variants (e.g., 304, 316) meeting relevant standards are specified to ensure performance in humid or chemically exposed environments.
Surface treatments include zinc plating with passivation for enhanced corrosion resistance, phosphating to improve lubrication during installation and prevent seizing, and black oxide coating for increased wear resistance. These treatments extend service life while optimizing compatibility with diverse operating conditions.
Key characteristics of GB 5787 fasteners include fine metric thread specifications, precision-engineered hexagonal heads with flange designs for improved load distribution, and strict dimensional tolerances ensuring interchangeability. Their mechanical attributes feature specified tensile strengths (minimum 800 MPa for 8.8 grade), appropriate yield ratios, and sufficient ductility. Additionally, they exhibit stable torque-tension relationships and superior clamping performance, making them indispensable in high-precision mechanical assemblies and industrial applications.
| Thread Size d | M5 | M6 | M8 | M10 | M12 | (M14) | M16 | ||||
| P ① | Pitch | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | |||
| b | L≤125 | 16 | 18 | 22 | 26 | 30 | 34 | 38 | |||
| 125＜L≤200 | - | - | 28 | 32 | 36 | 40 | 44 | ||||
| L＞200 | - | - | - | - | - | 53 | 57 | ||||
| c | min | 1 | 1.1 | 1.2 | 1.5 | 1.8 | 2.1 | 2.4 | |||
| da | Type A | max | 5.7 | 6.8 | 9.2 | 11.2 | 13.7 | 15.7 | 17.7 | ||
| Type B | max | 6.2 | 7.4 | 10 | 12.6 | 15.2 | 17.7 | 20.7 | |||
| dc | max | 11.4 | 13.6 | 17 | 20.8 | 24.7 | 28.6 | 32.8 | |||
| ds | max | 5 | 6 | 8 | 10 | 12 | 14 | 16 | |||
| min | 4.82 | 5.82 | 7.78 | 9.78 | 11.73 | 13.73 | 15.73 | ||||
| du | max | 5.5 | 6.6 | 9 | 11 | 13.5 | 15.5 | 17.5 | |||
| dw | min | 9.4 | 11.6 | 14.9 | 18.7 | 22.6 | 26.4 | 30.6 | |||
| e | min | 7.44 | 8.56 | 10.8 | 14.08 | 16.32 | 19.68 | 22.94 | |||
| f | max | 1.4 | 2 | 2 | 2 | 3 | 3 | 3 | |||
| k | max | 5.6 | 6.8 | 8.5 | 9.7 | 11.9 | 12.9 | 15.1 | |||
| k1 | min | 2.3 | 2.9 | 3.8 | 4.3 | 5.4 | 5.6 | 6.7 | |||
| r1 | min | 0.2 | 0.25 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | |||
| r2 | max | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.9 | 1 | |||
| r3 | min | 0.1 | 0.1 | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | |||
| r4 | Ref. | 3 | 3.4 | 4.3 | 4.3 | 6.4 | 6.4 | 6.4 | |||
| s | max | 7 | 8 | 10 | 13 | 15 | 18 | 21 | |||
| min | 6.64 | 7.64 | 9.64 | 12.57 | 14.57 | 17.57 | 20.48 | ||||
| t | max | 0.15 | 0.2 | 0.25 | 0.3 | 0.35 | 0.45 | 0.5 | |||
| min | 0.05 | 0.05 | 0.1 | 0.15 | 0.15 | 0.2 | 0.25 | ||||
| Length of Thread b | - | - | - | - | - | - | - | ||||
| ①,P = pitch of coarse thread. | |||||||||||
