GB/T 3632 Torsion Shear Bolt | TC Bolt Marine | SINOFASTENER

GB/T 3632 torsion shear bolt — commonly known as TC bolt — a ship hull torsion shear bolt with splined shear-off tip for high-strength structural bolting. M16–M30, 10.9S grade, heat-treated alloy steel. Complete bolt-nut-washer assembly per GB/T 3632. Splined tip fractures at calibrated torque, providing instant visual proof of correct preload without torque wrench verification. Equivalent to heavy hex torsion shear bolt ASTM F1852 (F3125 Grade F1852) in international standards.

What Is a Torsion Shear Bolt and How Does It Work?

Atorsion shear bolt (TC bolt) is a high-strength structural bolt with a distinctive splined tail extending beyond the thread end. During installation, a dedicated electric shear wrench grips both the splined tail and the nut simultaneously. As the wrench applies torque, the splined tail twists against the nut until it reaches the factory-calibrated shear point — at which moment the tail fractures cleanly and falls away.

This is the defining advantage of the GB/T 3632 torsion shear bolt: the sheared spline provides permanent, visual proof that every bolt in the connection has reached its design preload. Unlike conventional hex bolts that require post-installation torque checking with a calibrated wrench, each installed TC bolt carries its own verification — the broken spline is the evidence. For classification society surveyed ship hull torsion shear bolt connections, this eliminates inspection bottlenecks and dramatically accelerates shipyard erection schedules.

Theheavy hex torsion shear bolt head accepts standard heavy hex sockets for rapid pneumatic installation. The bolt-nut-washer assembly is specified as a complete set per GB/T 3632 — individual components from different manufacturers must not be mixed, because the calibrated shear torque depends on the matched friction characteristics of the entire assembly.

Marine Applications

Note: The following applications are based on typical industry practice for GB/T 3632 torsion shear bolts in marine structural connections.

Specifications & Materials

Why Choose sinofastener for Torsion Shear Bolts?

Standards Reference

• GB/T 3632 — Torsion shear type high strength bolt assemblies for steel structures
• GB/T 3633 — High strength large hexagon bolt assemblies for steel structures (non-torsion shear type, complementary standard)
• GB/T 1231 — High strength plain washers for steel structures (matching washer for torsion shear bolt)
• GB/T 3098.1 — Mechanical properties of fasteners (bolts, screws, studs) — property class 10.9
• ASTM F1852 — Tension Control (TC) Structural Bolt Assemblies, Steel, Heat Treated, 120/150 ksi (US equivalent — now consolidated into ASTM F3125 Grade F1852)
• ASTM F3125/F3125M — High Strength Structural Bolts and Assemblies (current superseding standard, F1852 designated as Grade F1852)
• JIS B 1186 — High Strength Hexagon Bolt Assemblies (Japanese standard, includes torsion shear type)

FAQ

What is GB/T 3632 torsion shear bolt and how does it work?

TheGB/T 3632 torsion shear bolt is a high-strength structural bolt with a splined tail that shears off at a calibrated torque during installation. A dedicated electric wrench grips the spline and nut simultaneously — when the torque reaches the design value, the spline fractures, providing instant visual proof that the bolt has achieved correct preload. No post-installation torque wrench verification is needed. This is the primary advantage of the TC bolt system for ship hull torsion shear boltconnections.

What is the difference between torsion shear bolt and regular hex bolt?

Thetorsion shear bolt has a splined shear-off tail for visual torque verification, while a regular hex bolt (like A325 or EN 14399) requires post-installation torque checking with a calibrated wrench. The TC bolt system also requires a complete matched assembly — bolt, nut, and washers from the same batch — whereas regular hex bolts can use any nut of matching grade. For ship hull torsion shear bolt applications under classification society survey, the splined shear-off eliminates inspection delays that regular bolts cannot.

What nut and washer are required with GB/T 3632 torsion shear bolt?

EachGB/T 3632 torsion shear bolt must be used as a complete assembly: (1) bolt per GB/T 3632, (2) 10H grade heavy hex nut per GB/T 3632, and (3) two hardened flat washers per GB/T 1231 (HRC 35–45) — one under the bolt head and one under the nut. The washer, nut, and bolt must come from the same production batch because the calibrated shear torque depends on the matched friction characteristics. Never mix components from different manufacturers or batches.

What is the international equivalent of GB/T 3632 torsion shear bolt?

The direct international equivalent is ASTM F1852 (now designated ASTM F3125 Grade F1852) — the US"Tension Control (TC) Structural Bolt Assembly". Both use the same splined shear-off principle: the spline fractures at calibrated torque for visual verification. ASTM F1852 covers sizes 1/2"–1-1/2"in grades A325 and A490 equivalent. The Japanese standard JIS B 1186 also includes a torsion shear type. In Europe, the equivalent preload-controlled system uses EN 14399 HR (hexagon nut with hardened washer), but the splined shear-off tip is specific to GB/T 3632 and ASTM F1852.