Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Monel 400 Foundation Bolts (Holding-Down) - UNS N04400 ASTM F468
Monel 400 foundation bolts, holding-down bolts, hold-down bolts, anchor foundation bolts and equipment anchors in UNS N04400 are the cast-in or grouted bolting that ties a static-equipment baseplate, jetty bollard, offshore topside skid or chemical-plant column foot to its concrete plinth. The threaded upper portion is covered by ASTM F468 Class A (F 468U marking); the embedded geometry - L, J, headed or templated - is set by the project structural drawing per AISC Design Guide 1, BS 7419 or the equipment vendor specification. Bar feedstock is ASTM B164 in the hot-worked annealed condition. Monel® is a registered trademark of Special Metals Corporation; TorqBolt is not authorized by, affiliated with or endorsed by Special Metals.
Foundation Bolt Geometry - L, J, Headed and Templated
Four embedded geometries cover the majority of grouted-foundation applications. ASTM F468 governs alloy and threading on the upper exposed portion; the structural drawing sets the embedded shape.
| Type | Embedded shape | Typical use | Pull-out resistance |
|---|---|---|---|
| L-shaped | 90 degree hook at the lower end | Static equipment, small skids, pump bases | Hook bears against concrete |
| J-shaped | 180 degree curved hook | Light columns, brackets, handrail stanchions | Curve bears against concrete |
| Headed (4.6 / 8.8 equivalent geometry, alloy 400) | Square or hex head at the bottom, sometimes with plate washer | Heavy machinery, vibrating compressors, towers | Head plus plate washer in bearing |
| Templated (sleeve-pocket) | Straight shank inside a corrugated steel sleeve, plate at bottom | High-precision alignment, offshore topside skids | Plate at bottom in tension, sleeve allows lateral adjustment |
Diameter and Length Range
Stocked band M12 to M64 (1/2 in to 2-1/2 in) at 200 mm to 1200 mm embedded length. Above M64 or beyond 1200 mm are indent through ASTM B564 forging stock matched to F468 Heavy Forged Equivalent. Threading on the exposed portion follows ASME B1.1 UNC and UNF or ISO 898 metric coarse, class 2A.
| Diameter | Imperial equivalent | Embedded length range | Exposed projection (typical) | Thread length above plate |
|---|---|---|---|---|
| M12 | 1/2 in | 200 to 400 mm | 75 mm | 50 mm |
| M16 | 5/8 in | 250 to 500 mm | 90 mm | 60 mm |
| M20 | 3/4 in | 300 to 600 mm | 110 mm | 75 mm |
| M24 | 7/8 in | 400 to 750 mm | 130 mm | 90 mm |
| M30 | 1-1/8 in | 500 to 900 mm | 160 mm | 110 mm |
| M36 | 1-3/8 in | 600 to 1000 mm | 180 mm | 125 mm |
| M42 to M64 | 1-5/8 to 2-1/2 in | 750 to 1200 mm | 200 to 250 mm | 150 to 200 mm |
Mechanical Properties per ASTM F468
ASTM F468 sets the mechanical floor on the exposed threaded portion by nominal diameter band, with a hardness ceiling of 25 HRC across the size range (tighter than the NACE MR0175 35 HRC sour-service cap). Source: ASTM F468/F468M-2016 Table 2.
| Marking | Diameter (in) | Tensile (ksi) | Tensile (MPa) | Yield min (ksi) | Yield min (MPa) | Elongation | Hardness |
|---|---|---|---|---|---|---|---|
| F 468U | 0.250 to 0.750 | 80 to 130 | 552 to 896 | 40 | 276 | 20% | 75 HRB to 25 HRC |
| F 468U | 0.875 to 1.500 | 70 to 130 | 483 to 896 | 30 | 207 | 20% | 60 HRB to 25 HRC |
| F 468U4 | 0.875 to 1.500 | 80 to 130 | 552 to 896 | 40 | 276 | 20% | 75 HRB to 25 HRC |
| F 468HF | all | 70 to 120 | 483 to 827 | 30 | 207 | 20% | 60 to 95 HRB |
Class A (UNS N04400, F 468U) is the default; the weldable chemistry permits field repair on the exposed thread without changing the base alloy. Class B (UNS N04405, F 468V) is selected only when free-machining governs.
Cement-Grouted vs Epoxy-Grouted Installation
Two grout chemistries dominate offshore and chemical-plant foundation-bolt installation. The choice is set by dynamic loading and the surrounding aggressive media; the Monel 400 metallurgy is compatible with both routes.
| Grout class | Examples | Compressive strength (28-day) | Service | Curing |
|---|---|---|---|---|
| Non-shrink cementitious | BASF Masterflow 928, Sika Grout 212 HP, Fosroc Conbextra GP | 60 to 80 MPa | Static equipment: pumps, vessels, towers, skid feet, jetty bollards | 7 to 28 days wet cure |
| Epoxy grout | BASF Masterflow 648CP, ITW Devcon Floquil 60, Sika Sikadur 42 MP | 90 to 120 MPa | Dynamic equipment: reciprocating compressors, vibrating screens, offshore topside skids | 24 to 72 hours full cure |
Pour-back grout fills between baseplate and plinth; pocket grout fills the corrugated sleeve in templated designs. The sleeve isolates the upper alloy 400 bolt from grout chemistry so pretensioning is preserved. Cementitious pour-back with epoxy pocket grout is a common offshore-topside hybrid.
Companion Top Nuts, Washers and Sleeves
A foundation-bolt line item is closed in one alloy at the embedment interface. Sacrificial-anode complexity is removed when top nut, washer and exposed thread share the Monel 400 chemistry of the embedded shank.
| Component | Standard | Alloy 400 designation | Notes |
|---|---|---|---|
| Hex top nut | ASTM F467 | F 467U (Class A) | Default; tightened to drawing torque or hydraulic stretch |
| Heavy hex top nut | ASTM F467 | F 467U | Use on bolts above M36 or where seating load is high |
| DIN 125 plain washer | ISO 7089 / DIN 125 | UNS N04400 sheet from ASTM B127 | Distributes bolt head load on baseplate |
| DIN 6916 structural washer | DIN 6916 | UNS N04400 | Square or round, oversized, used on structural-steel foundations |
| Plate washer (custom) | To drawing | UNS N04400 plate from ASTM B127 | Bottom-of-bolt bearing plate, drilled to suit |
| Corrugated sleeve | To drawing | Carbon steel acceptable (isolated from media) | Templated geometry; allows lateral alignment of base plate |
Applications - Offshore Topside, Jetty Bollards, Brackish Towers
Foundation bolts in alloy 400 are specified where the grade-level environment around the plinth attacks carbon steel and crevice-corrodes 316L inside the bolt-grout annulus. Three application clusters dominate.
Offshore platform topside equipment. Foundation bolts for separators, glycol contactors, gas coolers and pump skids on the topside deck see chronic salt-laden fog plus periodic seawater wash-down. ASTM F468 alloy 400 paired with epoxy pocket grout is the standard call-out on North Sea, West African and Gulf of Mexico platforms. The 25 HRC F468 hardness cap clears NACE MR0175 by 10 HRC where the topside vessel is in sour service per ISO 15156-3.
Jetty bollards and dolphins. Mooring bollard hold-down bolts at fender-pile tops, dolphin caps and jetty deck cleats sit in tidal splash zone. Carbon-steel anchor bolts in this service typically last 3 to 5 years; alloy 400 carries the bollard rating through the design life. Pair with monel 400 anchor bolts on adjacent piles for alloy continuity.
Brackish cooling-tower basins. Foundation bolts at petrochemical sites where make-up water carries chloride 2000 to 6000 ppm or where chlorine dioxide / hypochlorite biocide is dosed continuously. Alloy 400 is unaffected by chloride across the basin pH band 6.5 to 9.0.
Related envelopes: HF acid resistance, HF alkylation, sour-service NACE, seawater corrosion, marine applications.
Frequently Asked Questions
Are foundation bolts and holding-down bolts the same thing? Yes. Foundation bolt, holding-down bolt, hold-down bolt and anchor foundation bolt are interchangeable for the cast-in or grouted bolt that ties a baseplate to a concrete plinth. ASTM F468 covers the threaded upper portion in UNS N04400; embedded geometry is set by the project structural drawing.
Cement grout or epoxy grout? Cementitious for static equipment (pumps, vessels, towers, jetty bollards); epoxy for vibrating compressors and offshore topside skids. Alloy 400 is compatible with both.
Do I need a corrugated sleeve? Templated foundation bolts use a corrugated steel sleeve to permit lateral baseplate alignment after concrete cure. L, J and headed bolts do not need a sleeve.
Mill test certificate? EN 10204 type 3.1 default; type 3.2 (Lloyd's, DNV or BV witness) on indent for offshore topside and nuclear scope.
Can the bolt be field-weld repaired? Class A F 468U is weldable; procedure qualified to ASME IX with alloy 400 filler (ERNiCu-7 / ENiCu-7). Class B F 468V is free-machining and not recommended for welding.
Related Products and Specifications
Monel 400 anchor bolts for general structural anchoring. Monel 400 bolts reference covering all head forms. Monel 400 threaded rod for site-cut anchor production. ASTM F468 specification detail.
Request for Quote
Send diameter, embedded length, exposed projection, geometry (L / J / headed / templated), grout class and quantity to info@torqbolt.com or WhatsApp +91-22-66157017. Ex-Mumbai price and lead time returned within one working day. Domestic India 3 to 7 working days; export through JNPT. Full alloy reference on the main Monel 400 page.
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