Zeron 100 socket head cap screws (SHCS, also called Allen-head cap screws) are super duplex stainless steel fasteners (UNS S32760 / Werkstoff 1.4501) with an internal hex drive in a cylindrical head per ASME B18.3 (inch) or ISO 4762 (metric). The internal hex drive lets the bolt seat into a counterbore so the head sits flush with or below the joint surface, the standard call for tight-clearance equipment housings, instrument panels, machined-block flanges, and any installation where an external hex head wouldn't fit. The cylindrical head pattern develops more proof load per bolt than an equivalent-diameter hex bolt because the smaller bearing-face area delivers higher local clamp pressure for the same applied torque.
Internal hex drive · Higher tensile head profile than external hex · PREN ≥ 40 · Hardness ≤ 28 HRC
Use SHCS for: subsea instrument-housing fasteners, ROV interface bolts, equipment-block flange closures, valve-actuator bracket fasteners, hydraulic-block gland bolts, and machinery-frame fasteners on offshore deck modules. The internal-hex drive needs a fitted Allen key or hex-bit for installation, this is acceptable in most service envelopes but check that the drive socket seats fully before torquing (a partially-engaged hex socket cams out under torque and rounds the drive surface).
ASME B18.3 (inch SHCS pattern) or ISO 4762 / DIN 912 (metric SHCS) + ASTM A1082 (mechanical envelope) + ASTM A479 (source bar) + ASME B1.1 / ISO 965 thread tolerance + NACE MR0175 (sour service ≤ 28 HRC) + NORSOK M-650 + M-630 MDS 055 (North Sea super duplex).
| Series | Diameter | Drive size | Length range |
|---|---|---|---|
| UNC inch | #0 to 1-1/2 inch | 0.05 in to 1-1/8 in hex | 1/4 to 12 inch |
| UNF inch | 1/4 to 1-1/2 inch | 3/16 in to 1-1/8 in hex | 1/2 to 12 inch |
| Metric coarse | M3 to M48 | 2.5 to 36 mm hex | 6 to 300 mm |
| Metric fine | M6 to M48 | 5 to 36 mm hex | 10 to 300 mm |
| Service | Recommended supply state |
|---|---|
| Subsea instrument-housing fasteners | FLT (cold-water Charpy reserve) |
| ROV interface bolts | FLT |
| Hydraulic-block gland bolts | FG (high preload) |
| Machinery-frame fasteners on offshore decks | SA |
| Valve-actuator bracket fasteners | SA or FG by load |
| Equipment-block flange closures (counterbored) | FG |
| Repeated-makeup precision-fit equipment | AFP-coated FG |
Send the spec to info@torqbolt.com or +91-22-66157017 / WhatsApp.
