Inconel 625 Stud Bolts
ASTM F468 / F468MASTM B446 Gr.1 / Gr.2
Sour-service review · NACE MR0175 / ISO 15156
Inconel 625 stud bolts pair a solid-solution nickel-chromium-molybdenum alloy with double-ended closure for subsea, marine, and wet-process flange joints that need controlled tensioning. The alloy resists pitting, crevice attack, and chloride stress-corrosion cracking.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Grade 1 · Annealed / Grade 2 · Solution annealed
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Raw Material Specifications
Finished-Stud Specifications
Threads · Metric
Threads · Inch
Dimension Reference
Heat Treatment
Annealed or solution annealedFor B446 stock, Grade 1 is annealed and Grade 2 is solution annealed; the higher-temperature solution treatment supports creep resistance rather than age hardening.
What we can make in Inconel 625
Stud forms & dimension guideFully threaded
Two nuts clamp the flange or cover; usable thread length spans the assembled grip.
Double-end
A plain centre spans the grip, with a threaded portion at each end for the nuts.
Tap-end
One end engages a tapped casing; the exposed end accepts the cover nut.
- Diameter range
- M4–M100 · ¼″–4″
- Thread systems
- Metric · UNC · UNF · 8UN · UNJ
- Stud configurations
- Full thread · double-end · tap-end · stepped shanks
- Machining
- CNC-turned lengths, shoulders, chamfers and unequal threaded ends
- Thread production
- Rolled or cut threads, with specified pitch and tolerance class
- 625 delivery condition
- Annealed · solution annealed
- Flange bolting sets
- 1 stud + 2 heavy hex nuts · optional 2 washers per set
Where 625 fits — and what matters
Subsea & topside piping joints
Inconel 625 Stud BoltsOffshore flange studs are exposed where seawater, spray and deposits reach the nut faces and projecting threads. Inconel 625 brings chloride pitting and crevice-corrosion resistance to those loaded fastening surfaces. The stud-and-nut arrangement also lets crews replace nuts and service the flange without a bolt head occupying one side.
Connection requirements
- Piping flange rating, gasket type, and required preload
- Stud diameter, overall length, and nut engagement at each end
- Seawater exposure, access constraints, and heat-number certification
Marine valve bonnets
Inconel 625 Stud Bolts625 studs are useful on marine bonnets where seawater remains around the cover recesses and projecting threads. Their localized-corrosion resistance addresses those sheltered fastening surfaces. With tapped-stud bonnets, suitable corrosion-resistant nuts can be removed for servicing while the studs stay in the valve body.
Connection requirements
- Bonnet joint thickness, gasket type, and required preload
- Stud diameter, overall length, and tensioning clearance at each end
- Chloride exposure, and heat-number certification
Flue-gas desulfurization (FGD) ducts
Inconel 625 Stud BoltsFGD inspection covers and duct joints can expose studs to wet chloride deposits and acidic condensate. Inconel 625 helps resist localized attack on the shank and threads. Studs also support repeatable cover positioning during cleaning and inspection, with removable nuts accessible outside the duct.
Connection requirements
- Duct joint thickness, gasket type, and required preload
- Stud diameter, overall length, and nut engagement at each end
- Chloride and acid exposure, and heat-number certification
Same stud. Different material priorities.
Full 625 material dataInconel 718 Stud Bolts
Inconel 718 studs carry high tensile loads in turbine casings and hot valve bonnets where the hole pattern limits fastener size. Precipitation hardening supplies strength, and removable nuts provide service access. Sour-gas connections additionally require the prescribed heat-treatment and hardness condition.
Hastelloy C-276 Stud Bolts
Hastelloy C-276 studs suit repeatedly opened reactor, scrubber and acid-exchanger covers exposed to corrosive deposits or process leakage. The alloy protects the loaded stud surfaces in compatible mixed chemical media. Removable nuts provide access while body-mounted studs can remain installed.
Monel K-500 Stud Bolts
Monel K-500 studs suit marine bonnets and pump casings that need stronger nickel-copper bolting within an existing hole pattern. Body-mounted studs can remain in place during servicing. Cathodically protected subsea assemblies require a specific review of the K-500 condition and sustained loading.
From drawing to documented delivery
- 01Drawing & BOMEngineering review
- 02Sample lotOptional · typically ~20 days
- 03Production & testingTypically 25–35 days
- 04Documents & dispatchHeat-linked records and packing
Our engineers check before quoting
625 condition & acceptance
We align B446 Grade 1 / Grade 2 feedstock with the finished-stud specification and required mechanical tests.
Length datum & mating threads
We check the flange size, class and facing, length datum, nut engagement and any extra projection needed for tensioning tools. Stud and nut pitch and thread class are matched.
Nut grade & assembly finish
We check the nut specification, engagement and any coating or lubricant against the assembly requirements.
Inspection & witness points
We include the required MTC, PMI, hardness and third-party witness scope in the quotation.
Matching Kit
Flange Stud Bolt Kits
Build your 625 stud enquiry
Questions about 625 studs
B446 Grade 1 or Grade 2 for 625 studs?
Grade 1 uses an annealed condition, typically selected for service at or below 593°C (1100°F). Grade 2 receives solution annealing for higher-temperature duties requiring creep and rupture performance. Our engineering review aligns the selected bar condition with the finished-stud properties and tests on your order.
Does a B446 certificate cover the finished stud?
B446 covers rod and bar. Finished-stud requirements can follow F468/F468M or the project specification. We connect the incoming heat certificate to the manufactured batch and its dimensional, thread and specified mechanical inspection records.
625 or 2507 for seawater flange studs?
625 is a nickel alloy; 2507 is a high-strength super-duplex stainless steel. The comparison depends on seawater temperature, crevices, cathodic protection and required preload. Neither alloy name alone establishes suitability for the complete connection.
Which nuts and washers go with 625 studs?
We supply matching Inconel 625 nuts, including heavy hex patterns, and washers as required by the assembly. The quotation identifies the nut specification, thread class and quantity per stud. Coating or lubricant selection is checked with the tightening procedure to manage galling.
Can you supply 625 studs for sour service?
We review 625 in the specified condition against the project’s ISO 15156 / NACE MR0175 requirements, hardness limits and service environment. The agreed material and inspection requirements are included in the quotation.
References, sample documents & photo credits
Catalogue photographs show product form. The historical 625 certificate covers the original coil-wire heat. Shipment records correspond to the supplied order and inspection scope. Typical quantities and schedules depend on size, material availability and processing; the quotation confirms the order.