- Ningbo Zhongli bolts manufacturing Co., Ltd. +86-574-86587617
- tan@nbzyl.com
Leave Your Message
INDUSTRIAL-GRADE FASTENERS FOR STRUCTURAL APPLICATIONS
Global demand for high-strength structural bolts is accelerating. From mega infrastructure projects to precision manufacturing, structural fasteners remain the invisible backbone of industrial progress.
The global structural bolt market is projected to surpass USD 8.5 billion by 2028, driven by rapid urbanization, infrastructure investment in emerging economies, and the global push for renewable energy infrastructure including wind farms and solar mounting systems. Demand from Asia-Pacific, the Middle East, and Africa continues to surge as governments fund large-scale construction programs.
Industry trends are moving decisively toward higher-grade structural bolts — Gr10.9 and Gr12.9 are increasingly specified in steel construction, bridge engineering, and heavy machinery. Advanced heat treatment technologies and precision cold-forging processes now allow manufacturers to achieve superior tensile strength while reducing bolt diameter, saving weight without compromising structural integrity.
Environmental compliance is reshaping the fastener industry. Hot-dip galvanized and zinc-flake coated structural bolts are replacing traditional electroplated finishes in outdoor and marine applications. Manufacturers are investing in closed-loop heat treatment systems and low-emission surface treatment lines to meet increasingly strict European and North American environmental regulations.
Structural bolts are mission-critical components across a vast spectrum of industrial sectors. Explore the key application environments where performance cannot be compromised.
ASTM A325 and A490 structural bolts are the standard specification for steel bridge connections, requiring high preload capacity and proven slip-critical joint performance. Our heavy hex head bolts meet all AISC and RCSC structural connection requirements, ensuring decades of reliable service in dynamic load environments.
Wind tower flange connections demand structural bolts with exceptional fatigue resistance and consistent clamping force. Our EN14399 and DIN6914 high-strength hex bolts, combined with DIN6916 hardened washers, provide the precisely controlled preload essential for turbine tower assembly, nacelle mounting, and foundation anchor bolt systems.
Pressure vessel and pipeline flange connections in petrochemical environments require ASTM A193 B7 stud bolts with 2H heavy hex nuts — engineered for extreme temperature cycling, high-pressure sealing, and corrosive media resistance. Our stud bolt assemblies are tested to ISO898-1 and ISO898-2 mechanical property standards for full traceability.
Heavy-duty industrial machinery — from mining excavators to press machines — relies on Gr12.9 hex socket cap screws and high-strength hex bolts to maintain critical joint integrity under severe vibration and shock loading. Our DIN912 and ISO4762 socket head cap screws deliver the highest available strength class for demanding machine assembly applications.
Pre-engineered steel buildings, industrial warehouses, and high-rise structural steel frames depend on DIN931, DIN933, and ISO4014/ISO4017 hex bolts in grades 8.8 and 10.9. Our bolts are available with zinc-plated, hot-dip galvanized, or black oxide finishes to suit both interior structural and exposed exterior applications.
Rail track fastening systems, ship hull structural connections, and automotive chassis assemblies all specify structural bolts to international standards. Our ANSI B18.2.1 UNC/UNF Gr5 and Gr8 hex bolts serve North American transportation infrastructure, while our metric range covers European and Asian railway and marine structural applications.
Ningbo Zhongli Bolts Manufacturing Co., Ltd., founded in 2003, is a professional manufacturer of high-strength fasteners in different specifications for various models, covering an area of about 10,000 square meters, registered capital of 1,500,000 RMB, with total annual productivity of 8,000 tons per year. The company has set up several sales branches in different provinces in China.
Meanwhile, the company's products are exported to Europe, USA, Middle East, Africa, Southeast Asia and other regions. The company has strong technical ability, complete testing equipment and a variety of fully automatic multi-station cold and hot heading machines, so as to provide you with reliable and high-quality products.
🏆 ISO9001 Certified Quality Management System — Our physical and mechanical test results reach ISO898-1 for bolts and ISO898-2 for nuts. We hold EN 15048, EN 14399, AD2000 and CE Certificates.
Our main products 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 Gr8.8 Gr10.9 Gr12.9, hex socket cap screws DIN912, ISO4762 Gr8.8 Gr10.9 Gr12.9 with surface Black, Zinc plated, Hot dip galvanized. Diameters from M10 to M48, length no limited.
Hex Flange bolts DIN6921 Gr8.8 Gr10.9 with serration, thread rod A193 B7 long sizes and short sizes with 2H nuts, stud bolts. We also can supply hex nuts DIN934, DIN6915, plain washers DIN125, DIN126, DIN6916, spring washers DIN127 with Black, Zinc plated and Hot dip galvanized surface.
Our physical and mechanical test results can reach to ISO898-1 for bolts and ISO898-2 for nuts. Through scientific management, Ningbo Zhongli Bolts Manufacturing Co., Ltd. obtained ISO9001 certificate of Quality Management System. Quality is the most important for us. We have strict production and inspection equipment to support this point.
We hope to establish business relationship with all over the world, and our business can bring in mutual benefits for both parties.
Every structural bolt we manufacture passes through a rigorous, fully controlled production workflow — from certified raw material intake to precision thread rolling, heat treatment, and final inspection before shipment.
Our 10,000 m² manufacturing facility is equipped with fully automatic multi-station cold and hot heading machines, dedicated heat treatment furnaces, and a comprehensive quality laboratory.
WHY CHOOSE ZHONGLI STRUCTURAL BOLTS
A Professional Sales and Technical Team with More Than 20 Years History.
We Have Our Own Testing Equipment and Laboratory, Our 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.
We Have Passed ISO 9001, EN 15048, EN 14399, AD2000 and CE Certificates.
Every structural bolt undergoes comprehensive multi-stage quality inspection before leaving our facility. Our in-house laboratory is equipped with advanced dimensional measurement, mechanical testing, and hardness testing instruments to ensure full compliance with international standards.
We hope to establish business relationships with partners all over the world, and our business can bring mutual benefits for both parties.
EN 15048 CE Certification · EN14399 CE Certification · ISO9001 Certificate
Grasp first-hand information — real feedback from our global partners and customers.
FULL RANGE OF HIGH-STRENGTH FASTENERS
DIN912 Cylindrical Hexagonal Structural Bolt — Socket Head Cap Screws ISO4762
Hexagon Structural Bolts ISO4014 ISO4017 Gr8.8 Gr10.9 Gr12.9 — Industrial Grade
A325 Carbon Steel Hex Structural Bolt — Fine Pitch Thread Industrial Application
A307 Hexagon Head Structural Bolt — Fine & Coarse Thread UNC/UNF Industrial
Stud Bolts A193 B7 — Structural Industrial Threaded Bar Black Finish
Hexagonal Socket Cap Screws Full Series — Structural Industrial Bolt Range
Hex Bolt DIN931 Grade 8.8 Zinc Plated — Metric Carbon Steel Structural Industrial
Zinc Plated High-Strength Hex Structural Bolt Full Series — Industrial Grade
Contact Ningbo Zhongli Bolts — Your trusted industrial structural bolt manufacturer and exporter since 2003. Free samples available. Custom specifications welcome.
About Us Quality Inspection Our Certificates
Send Email
