Zeron 100 12-point flange screws are super duplex stainless steel fasteners (UNS S32760 / Werkstoff 1.4501) with a 12-point internal-drive head + integral flange, the high-torque internal-drive pattern used in aerospace, downhole drilling tools, and high-pressure pump bolting where standard hex or socket-head can't deliver enough torque without cam-out. The 12-point geometry provides 12 wrenching surfaces (vs 6 for hex socket), each engaging a fitted bi-hex socket with minimal driver slip. Pattern follows NAS (National Aerospace Standard) and NASM aerospace specs.
12-point internal drive · Higher torque envelope than hex drive · Aerospace / downhole / high-pressure pump bolting
Used where the bolted joint sees aggressive corrosion + cyclic high preload + tight install clearance: subsea downhole completion-tool bolting, ROV-installable high-pressure connectors, aerospace flange bolting on titanium-housing equipment, offshore high-cycle pump casings, and any joint where standard hex would round under repeated install / removal cycles. We supply SA, FG, FLT, and AFP supply states, FG is most common for the high-torque + sour-service combination.
Hex drive cams out at high torque because the 60° flank angle creates radial spreading force on the socket. SHCS (6-point internal hex) is better but still rounds under repeated heavy makeup. The 12-point bi-hex pattern doubles the wrenching surfaces, each engaging at a smaller flank angle that resists cam-out under torque approaching bolt yield. The integral flange under the head spreads bearing load + eliminates the need for a separate washer in many installs. The combination is the standard internal-drive fastener for high-torque-tension applications where the bolt is in service for years before removal.
NAS 1351 (12-point internal-drive flange screw, aerospace) + NASM 1351 (revised aerospace 12-point) + ISO 4762 (alternative SHCS for non-aerospace) + ASTM A1082 (super duplex material) + ASTM A479 (source bar) + NACE MR0175 (sour-service ≤ 28 HRC) + API 6A / 17D (oil-gas downhole). For non-aerospace heavy industrial use, ASME B18.6.7M (metric flange screws) is the reference.
| Service | Recommended supply state |
|---|---|
| Subsea downhole completion tool bolting | FG (NACE-controlled) |
| ROV-installable high-pressure connectors | FG + AFP coating |
| High-cycle offshore pump casing bolts | FG |
| Aerospace flange bolting (corrosion service) | SA or FG per spec |
| Marine drive coupling bolts | SA |
| High-torque tooling / jig fasteners | FG + AFP |
Send the spec (size + length + thread + supply state + standards / NAS or NASM ref + coating + quantity) to info@torqbolt.com or +91-22-66157017 / WhatsApp.
