3-1/4" Diameter Forged Steel Bar Ring

We focus on three core customer needs: consistent preload under clamping force, long term fatigue life under cyclic loads, and durable corrosion resistance in harsh environments. Our bolts are made from premium alloy steel, processed through precision heat treatment and multi step machining, with strict ISO certified quality control. Every batch is tested before shipment.

We mainly supply Grade 10.9 and Grade 12.9 high strength bolts, and can also provide Grade 8.8 or other grades on request. According to ISO 898 Part 1, Grade 10.9 bolts have a tensile strength of ~1000 MPa and yield strength ~900 MPa; Grade 12.9 bolts reach over 1200 MPa tensile strength. More importantly, we tightly control the torque coefficient of each batch - the mean torque coefficient of a batch is kept between 0.110 and 0.150 with very low standard deviation. This means you get highly con

Yes, and we focus on active rather than passive loosening prevention. We offer factory pre applied threadlocker (anaerobic adhesive) as an option. It wicks into the microscopic gaps between threads and cures, bonding the bolt and nut together. In vibration tests, our pre coated bolts retain >80% of residual torque after 100,000 high frequency cycles - while traditional spring washers retain less than 30% under the same conditions. We can also supply lock nuts, wedge locking washers, or other ant

Grade 10.9 bolts have a minimum yield strength of ~900 MPa, Grade 12.9 ~1080 MPa. We cover thread sizes from M6 to M64 and can produce custom dimensions per your drawing. Grade 10.9 is widely used in heavy machinery, bridge joints, wind turbine tower bolts - places subject to wind loads and long term vibration. Grade 12.9 is preferred in high end equipment, aerospace, precision mechanical structures, and other ultra high strength applications. Tell us your joint requirements, and we will match t

We manufacture to GB/T 3098.1 (ISO 898 Part 1), GB/T 1231, GB/T 3632, and equivalent international standards. Our factory is ISO 9001 certified and equipped with tensile testers, torque testers, hardness testers, salt spray chambers, metallurgical microscopes, and more. Every batch undergoes incoming material inspection, in process heat treatment control, and final 100% verification of tensile strength, yield strength, hardness, wedge load, proof load, torque coefficient, and salt spray corrosio