Description and Translation of JB/ZQ 4321 Fasteners
JB/ZQ 4321 fasteners, an important industrial standard in China, serve as specialized connecting components widely used in general machinery, electrical equipment, and industrial pipelines. Their core function is to provide reliable detachable joints, effectively transmitting static loads and resisting vibration-induced loosening, while ensuring assembly accuracy and operational safety in medium-load applications. These fasteners facilitate convenient maintenance and component replacement without compromising structural stability.
In terms of materials, JB/ZQ 4321 fasteners are primarily manufactured from medium-carbon steel (e.g., 4.8-grade and 8.8-grade steel conforming to relevant standards) and low-alloy steel, offering appropriate tensile strength and mechanical ductility. For mild corrosion environments, galvanized carbon steel variants are specified, while stainless steel options (e.g., 304) are available for enhanced corrosion resistance requirements.
Surface treatments include zinc plating with chromate passivation to improve rust resistance, phosphating for better lubrication during installation, and black oxide coating for increased wear resistance and aesthetic appearance. These treatments effectively extend service life and optimize compatibility with various operating conditions.
Key characteristics of JB/ZQ 4321 fasteners include standardized metric thread specifications, hexagonal head designs with chamfered edges, and precise dimensional tolerances ensuring interchangeability. Their mechanical attributes feature specified tensile strengths (400-800 MPa depending on grade), suitable yield ratios, and sufficient toughness. Additionally, they exhibit stable clamping performance and good processability, making them a cost-effective choice for general industrial applications and machinery manufacturing.
| Size ① | 14 | 18 | 22 | 25 | 33 | 38 | 42 | 45 | 48 | 51 | 57 | 60 | ||
| d | M6 | M6 | M10 | M10 | M10 | M12 | M12 | M12 | M12 | M12 | M12 | M12 | ||
| a | 33 | 35 | 42 | 44 | 48 | 55 | 57 | 59 | 60 | 62 | 66 | 67 | ||
| R | 8 | 10 | 12 | 14 | 18 | 20 | 22 | 24 | 25 | 27 | 31 | 32 | ||
| b | 22 | 22 | 28 | 28 | 28 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | ||
| n | 22 | 26 | 34 | 38 | 46 | 52 | 56 | 60 | 62 | 66 | 74 | 76 | ||
| L0 | Blank Length | 98 | 108 | 135 | 143 | 160 | 192 | 202 | 210 | 220 | 225 | 240 | 250 | |
| c | 1 | 1 | 1.5 | 1.5 | 1.5 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | ||
| per 1000 units≈kg | 22 | 24 | 83 | 88 | 99 | 171 | 180 | 188 | 196 | 200 | 214 | 223 | ||
| Size ① | 76 | 83 | 89 | 102 | 108 | 114 | 133 | 140 | 159 | 165 | 219 | |||
| d | M12 | M12 | M12 | M16 | M16 | M16 | M16 | M16 | M16 | M16 | M16 | |||
| a | 75 | 78 | 81 | 93 | 96 | 99 | 108 | 112 | 122 | 125 | 152 | |||
| R | 40 | 43 | 46 | 53 | 56 | 59 | 69 | 72 | 82 | 85 | 112 | |||
| b | 32 | 32 | 32 | 38 | 38 | 38 | 38 | 38 | 38 | 38 | 38 | |||
| n | 92 | 98 | 104 | 122 | 128 | 134 | 154 | 160 | 180 | 186 | 240 | |||
| L0 | Blank Length | 289 | 310 | 325 | 365 | 390 | 405 | 450 | 470 | 520 | 538 | 680 | ||
| c | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | |||
| per 1000 units≈kg | 256 | 276 | 290 | 575 | 616 | 640 | 712 | 752 | 822 | 850 | 1075 | |||
| ①,d0：Tube outer diameter | ||||||||||||||
U-bolts sourced from controlled dimensions or drawings for pipe, equipment and support assemblies.
Pipe supports, clamps and equipment fastening where the U-bolt geometry and load requirement are engineered.
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 U-bolt, or attach a controlled drawing. Similar product names do not guarantee dimensional interchangeability.
Specify the required material, property class or grade for the U-bolt. The proposed supply is confirmed against those requirements before quotation.
Confirm rod diameter, inside width, leg length, bend radius, thread, material, grade, finish and accessories. 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 U-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 U-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 U-bolt.
