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. | |||||||||||
Hexagon flange bolts sourced for applications that require an integrated bearing surface under the head.
Machinery, automotive-related assemblies and equipment connections, subject to the approved specification.
Suitability must be approved against the customer drawing, joint design and service conditions. Product-specific numbers are not published until confirmed by Shuojia and the selected manufacturing partner.
Drawing- and sample-based requests are reviewed with qualified manufacturing partners. State any required material certificate, dimensional report, thread-gauge result, hardness record, coating-thickness report or third-party inspection before quotation.
State the complete standard designation and revision for the Hexagon Flange Bolt, or attach a controlled drawing. Similar product names do not guarantee dimensional interchangeability.
Specify the required material, property class or grade for the Hexagon Flange Bolt. The proposed supply is confirmed against those requirements before quotation.
Confirm flange diameter, serrated or plain face, thread, property class, finish and tightening requirement. Add any tolerances or mating-part details that control fit or function.
State the service environment, coating system, colour, thickness and corrosion-test requirement. Shuojia will confirm the available Hexagon Flange Bolt sourcing route against the RFQ.
Request the exact records needed, such as material certificates, dimensional results, thread-gauge checks, hardness results or coating-thickness reports. Availability is confirmed in the quotation.
They depend on the final Hexagon Flange Bolt specification, quantity, tooling, finish, inspection and packing. The written quotation confirms all three before an order is placed.
Send the standard or drawing, material and grade, dimensions, finish, quantity, packing, documentation, destination and required delivery date for the Hexagon Flange Bolt.
