- Ningbo Zhongli bolts manufacturing Co., Ltd. +86-574-86587617
- tan@nbzyl.com
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Precision-engineered frame bolts designed for demanding structural applications — from steel frameworks to heavy industrial assemblies.
A frame bolt for structural fixing is a high-strength threaded fastener specifically engineered to join, anchor, and secure structural steel members, concrete frameworks, and heavy-duty assemblies. Unlike standard bolts, structural frame bolts must withstand extreme tensile loads, shear forces, vibration, and environmental stress over the full service life of a building or industrial installation.
The most widely recognized standards for structural fixing bolts include ASTM A325, ASTM A490, DIN 6914, EN 14399, and ISO 4014/4017. These standards define the mechanical properties — yield strength, tensile strength, proof load, and hardness — that must be met to qualify a bolt for structural use.
Frame bolts are available in multiple configurations: hex head bolts, heavy hex bolts, stud bolts, and anchor bolts. Each configuration serves a distinct structural role, whether connecting beam-to-column joints, anchoring base plates, or securing curtain wall systems to primary steel frames.
The structural fastener industry continues to expand driven by global infrastructure investment, green construction, and industrial modernization.
Technological advancements, stricter building codes, and sustainability mandates are reshaping how structural fixing bolts are designed, specified, and deployed worldwide.
Rapid urbanization in Asia, the Middle East, and Africa is driving unprecedented demand for Grade 10.9 and 12.9 structural frame bolts capable of handling multi-story steel frame loads exceeding 1,000 kN.
Low-carbon steel production and hot-dip galvanized coatings are becoming the standard for structural bolts used in green-certified buildings, reducing lifecycle environmental impact by up to 40%.
Leading manufacturers are integrating AI-powered vision systems and automated torque verification into production lines, ensuring dimensional accuracy and mechanical consistency at scale.
New chromium-molybdenum alloys and micro-alloyed steels are enabling frame bolts with higher strength-to-weight ratios, supporting lighter structural designs without compromising safety margins.
Convergence between ASTM, ISO, DIN, and EN standards is simplifying international procurement, enabling structural engineers to specify a single bolt type for multi-country projects.
Advances in zinc-nickel, Dacromet, and mechanical zinc plating technologies are extending service life of structural frame bolts in marine, coastal, and chemically aggressive environments.
From skyscraper steel frames to offshore platforms, structural frame bolts are the invisible backbone of modern built environments.
Heavy hex bolts ASTM A325 and A490 are the primary fasteners for beam-to-column connections in commercial and industrial steel frame buildings. Slip-critical connections require precise installation torque to develop full clamping force across faying surfaces.
Long-span bridges use high-tensile stud bolts and anchor bolt assemblies to transfer dynamic live loads into foundation systems. Grade B7 ASTM A193 bolts are preferred for their superior fatigue resistance under cyclic loading.
Pressure vessel flanges, pipe racks, and equipment skids in oil refineries and chemical plants rely on ASTM A193 B7 stud bolts with 2H heavy hex nuts to maintain joint integrity under extreme temperature and pressure cycles.
Pre-tensioned M48 and larger frame bolts secure tower flange segments in wind turbines. These bolts must maintain clamp load over decades of wind-induced vibration, requiring Grade 10.9 or higher with friction-type connections.
Stainless and zinc-plated hex bolts anchor curtain wall mullion systems to primary structural steel. Thermal movement and wind pressure demand fasteners with precisely controlled elongation characteristics.
In earthquake-prone regions, moment-resisting frame connections use fully threaded high-strength bolts with controlled tightening to provide ductile energy dissipation during seismic events, meeting AISC 341 seismic provisions.
Founded in 2003, Ningbo Zhongli Bolts Manufacturing Co., Ltd. is a professional manufacturer of high-strength fasteners in different specifications for various models, covering an area of about 10,000 square meters, with a registered capital of 1,500,000 RMB and a total annual productivity of 8,000 tons per year.
The company has established several sales branches across different provinces in China. Its products are exported to Europe, USA, the Middle East, Africa, Southeast Asia, and other regions worldwide. With strong technical capabilities, complete testing equipment, and a variety of fully automatic multi-station cold and hot heading machines, Zhongli delivers reliable, high-quality structural fixing bolts to global customers.
Our ZYL brand fasteners include structural hex bolts ASTM A325 Type 1, A490, hex head bolts DIN931, DIN933, EN14399, DIN6914, ISO4014, ISO4017 Gr8.8 Gr10.9 Gr12.9, ANSI B18.2.1 UNC and UNF Gr5, Gr8, fine pitch hex bolts DIN960, DIN961, hex socket cap screws DIN912, ISO4762, hex flange bolts DIN6921, thread rod A193 B7 with 2H nuts, and stud bolts. Diameters from M10 to M48, length unlimited.
We also supply hex nuts DIN934, DIN6915, plain washers DIN125, DIN126, DIN6916, and spring washers DIN127 with Black, Zinc plated, and Hot dip galvanized surface finishes.
Through scientific management, Ningbo Zhongli obtained ISO9001 Certificate of Quality Management System. Our physical and mechanical test results meet ISO898-1 for bolts and ISO898-2 for nuts. We hope to establish business relationships worldwide for mutual benefit.
Read More About UsEvery frame bolt for structural fixing undergoes a rigorous 8-stage manufacturing process to ensure dimensional accuracy and mechanical performance.
Our state-of-the-art manufacturing facility is equipped with advanced cold forging, heat treatment, and precision inspection equipment.
Why global engineers and procurement specialists choose Zhongli frame bolts for structural fixing projects.
A Professional Sales and Technical Team with More Than 20 Years History.
We Have Our Own Testing Equipment and Laboratory. Products Have Initial Inspection, Patrol Inspection, and Final Inspection.
Our Factory Has Its Own Cold Forged, Hot Forged, and Heat Treatment Equipment.
Standard Fasteners in Stock. Non-standard Fasteners Can Be Customized to Your Specification.
We Have Passed ISO 9001, EN 15048, EN 14399, AD2000 and CE Certificates.
We hope to establish business relationships with partners all over the world, and our business can bring mutual benefits for both parties.
Every structural frame bolt produced at Zhongli undergoes a comprehensive multi-stage inspection protocol to ensure compliance with international standards and customer specifications.
EN 15048 CE Certification | EN14399 CE Certification | ISO9001 Certificate
Grasp first-hand information — what our global partners say about Zhongli structural frame bolts.
Contact our expert team today — fast reply via email tan@nbzyl.com or WhatsApp/WeChat: +86 152 5786 1940
Explore our full range of high-strength structural fasteners — all manufactured to international standards and available for global export.
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