Special alloy hex socket countersunk screws
Special alloy countersunk screws in Inconel, Hastelloy and titanium for corrosion-exposed equipment, elevated-temperature service and flush panel assemblies. Metric and inch head patterns use ISO 10642 and ASME B18.3 dimensional references.
- Drive
- Internal hex socket
- Head angle
- 90° metric · 82° inch
- Length basis
- Overall, including head
- Threads
- Metric · UNC · UNF · UNJ
- Materials
- Inconel · Hastelloy · Titanium
EN 10204 3.1 MTC · Heat traceability
Hex socket countersunk screws material selection
Equipment & applications
Positioning & locating
Fasten guide plates and slide covers without a projecting head entering the moving envelope. Matching the countersink angle gives full seating around the conical head.
Packaging machinery
Mount access panels and guide plates flush with packaging-machine surfaces. The recessed drive allows removal from the panel face without a side-access spanner.
Vacuum assemblies
Secure flush internal panels and brackets in vacuum-equipment assemblies. Overall screw length includes the head, so the remaining thread engagement is calculated from the panel thickness.
Countersunk head, socket & seating dimensions
Head angle & seating
90° metric and 82° inch heads need matching countersinks. Head diameter and recess depth control whether the screw sits flush.
Socket & overall length
Specify overall length including the head. Socket size and depth govern key engagement, especially in shallow head sections.
Reduced head loadability
ISO 10642 identifies reduced loadability from the countersunk head and socket geometry. For Inconel 718 or A-286, assess head capacity and seating contact alongside the specified material strength and assembly preload.
Dimension guide
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Product and thread standards
Raw Material Specifications
Other Materials & Specifications
Finished-Screw Specifications
Other Materials & Specifications
Threads · Metric
Threads · Inch
Dimension Reference
Production & heat treatment
CNC · Conical Seats
Bar machining suits samples, short runs and unusual countersink angles. Head diameter, included angle and socket depth are produced together to control flush seating and usable key engagement.
Socket & Thread Finishing
Recess finishing clears burrs that obstruct the hex key. Rolled threads suit repeat sizes; cut threads accommodate special pitches, with overall screw length measured including the countersunk head.
Cold Heading / Hot Forging
Small countersunk heads are commonly cold headed in repeat runs using ductile feedstock. Large conical heads and highly resistant nickel alloys favour hot-forged blanks; the conical seat and socket are subsequently finished to size.
Heat Treatment & Seating Checks
Solution treatment and ageing raise the strength of Inconel 718; annealing recovers ductility in cold-worked Inconel 625. Inspection checks the conical seat, socket depth and head section as well as threads, because material strength alone does not establish countersunk-head capacity.
Testing, MTC 3.1 & material traceability
Material certificate
Inconel 625 · historical coil-wire sample
Laboratory report
Inconel 718 · chemistry, tensile & hardness
Identified packing
Heat and batch records linked to the shipment
Additional inspection requirements +
PMI, third-party inspection and witness testing are available by order. Project inspection plans can include UT/PT and heat-treatment records.
Related fastening options
Prepare your enquiry
- Material
- Grade / UNS · Condition
- Size
- Diameter · Length / height
- Thread
- Pitch / TPI · Form & class
- Quantity
- Pieces per size