Allen CSK Bolt

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Precipitation-hardening stainless steel is the speciality around which Metracore Alloys Private Limited has built its fittings production. We manufacture 17-4 PH Stainless Steel Pipe Fittings from grade UNS S17400, a martensitic alloy whose copper and niobium additions respond to a single ageing treatment after solution annealing. Tensile strength reaches 1310 MPa in the H900 condition. Hardness climbs to 40 HRC, yet the grade still resists corrosion in most industrial media. Aerospace programmes, oil and gas operators, petrochemical plants, power stations, marine yards, and chemical processors specify these fittings where mechanical performance decides the selection. On this page you’ll find the product definition, specifications, fitting types, composition limits, mechanical values for both aged conditions, features, applications, available standards, advantages, and the reasons buyers order from us, with FAQs at the end. Our ISO-certified production covers 1/2 NB through 24 NB with EN 10204 3.1 certification on every batch. Share your dimensions and quantities to receive a manufacturing quotation.

What are 17-4 PH Stainless Steel Pipe Fittings?

17-4 PH Stainless Steel Pipe Fittings are pipe connection components made from precipitation-hardening martensitic stainless steel, designated UNS S17400. The alloy contains 15.0 to 17.5% chromium with 3.0 to 5.0% each of nickel and copper. Niobium at 0.15 to 0.45% joins copper in forming fine precipitates during ageing. Those particles lift strength and hardness sharply. Corrosion resistance is better than the 400 series martensitic grades and approaches, but does not match, grade 304 in most environments. SS 17-4 PH Pipe Fittings machine cleanly in the solution-annealed state and weld without special preparation. Strength holds through repeated load cycles, extending service life in pressure equipment. Continuous service above 316°C isn’t recommended; prolonged exposure over-ages the structure and lowers strength.

Why Choose Metracore Alloys Private Limited?

Metracore Alloys Private Limited manufactures every fitting in-house under an ISO-certified quality system, so specification control runs from raw material to final inspection. Custom sizes come off the same production line as catalogue items. Third-party inspection agencies are welcome at any stage, and each consignment carries its EN 10204 3.1 Mill Test Certificate. Pricing stays competitive because we produce rather than resell. Ready stock in popular sizes shortens project schedules, and our despatch team arranges fast global shipping. Send your enquiry with sizes, schedule, and aged condition, and we’ll confirm price and delivery.

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Table of Content

Allen CSK Bolt Specifications

The table sets out our standard DIN 7991 Allen Bolt envelope: standards, grades, threads, sizes, head angle, finishes, classes and certification.

Types of Allen CSK Bolts

Thread length, material, pitch and finish separate the ten variants in our bolt and fastener range.

Reach out to Metracore Alloys Private Limited for reliable Allen CSK Bolts

Technical Details of Allen CSK Bolts

Mechanical Properties

Fastener strength is dictated by its property class rather than head geometry, adhering strictly to ISO 898-1 for carbon steel and ISO 3506-1 for stainless steel.

Property	Class 8.8	Class 10.9	Class 12.9
Tensile Strength	800 MPa min	1040 MPa	1220 MPa
Yield Strength (0.2% Proof Stress)	640 MPa	—	1100 MPa
Hardness	—	320–380 HV	385–435 HV
Proof Load (Proof Stress)	580 MPa	830 MPa	970 MPa
Elongation After Fracture	12% min	—	8%
Torque Capacity	The socket cap’s tightening torque depends on the applied torque, not the thread.

A countersunk socket bolt suits neither thin sheet, where the countersink removes the bearing material, nor joints needing maximum preload from a shallow head.

Available Materials

Nine material families span the range from indoor machinery work to seawater and sour service, each carrying its own grade set.

Stainless Steel

Grades 304, 316 and 316L cover outdoor, food and washdown fixing. Carbon in 316L stays at 0.03% maximum, which stops sensitisation at weld heat-affected zones.

Carbon Steel

Property class 8.8 with plating fits indoor machinery and general assembly. Tensile strength reaches 800 MPa minimum. Plating adds thin corrosion cover, nothing more, so keep these fasteners dry.

Alloy Steel

Quenching and tempering push class 10.9 to 1040 MPa and class 12.9 to 1220 MPa. Both go into high preload joints, finished in black oxide or zinc.

Duplex Stainless Steel

Grade 2205 carries the designations UNS S31803 and S32205. Its 50/50 austenite-ferrite structure roughly doubles the yield strength of 316 and pushes chloride pitting resistance higher.

Super Duplex Stainless Steel

Offshore, brine and seawater exposure calls for UNS S32750 or S32760. PREN values above 40 come from raised chromium, molybdenum and nitrogen, well clear of standard duplex figures.

Titanium

Weight-critical aerospace and marine assemblies run Grade 2 or Grade 5. Ti-6Al-4V reaches roughly 895 MPa tensile against 345 MPa for Grade 2, which stays easier to form.

Inconel

Alloy 625 and Alloy 718 bolt into high-temperature and sour service. Both hold clamping load where carbon steel relaxes, and both resist stress corrosion cracking in H2S.

Monel

Seawater handling and hydrofluoric acid equipment take Alloy 400 or K-500. Age hardening lifts K-500 to around 790 MPa tensile, roughly double what Alloy 400 delivers.

Brass

Free-machining brass suits decorative, electrical and light-load fixing. Threads cut clean and conductivity stays high. Tensile strength sits near 340 MPa, far below any steel class listed above.

Key Features

Engineers frequently specify this head geometry for its reliable performance in demanding applications. The following eight characteristics highlight why it remains the standard choice for high-precision, flush-fit assemblies.

Flush Surface Installation: the head sinks level, leaving nothing to catch.
High Clamping Force: class 12.9 develops full preload with no added height.
Internal Hex Drive: six flats give positive engagement without cam-out.
Vibration Resistance: the wedged 90-degree seat resists lateral movement.
Mechanical Strength: a Flat Head Allen Bolt matches a cap screw’s shank.
Corrosion-Resistant Options: 316, duplex, titanium and Monel outlast plated steel.
Precision Machining: gauged cone angles and socket depths stop rocking.
Long Service Life: a protected socket keeps shape, so removal doesn’t round the key.

Standards & Quality Assurance

Purchase orders quote the standards below. ISO 10642 now carries the metric hexagon socket countersunk head screw, while DIN 7991 stays on older drawings for the same 90-degree head. An ISO 10642 Countersunk Screw and its DIN equivalent interchange freely. ASTM A574, ASTM F835 and ASME B18.3 apply to inch-series work; ISO 898-1 defines property classes.

The following checks must be evaluated before packaging:

Thread Gauge Inspection: go and no-go gauges confirm 6g or 2A fit.
Tensile Testing: sample bolts go to failure against the ordered class.
Hardness Testing: Vickers or Rockwell readings verify the heat treatment band.
Dimensional Inspection: gauges cover head diameter, angle, socket size and length.
Coating Thickness Testing: plating readings stay inside the countersink allowance.
Visual Examination: inspectors reject burred sockets, cracked heads and damaged threads.

Advantages of Allen CSK Bolts

Replacing traditional protruding fasteners with countersunk socket bolts delivers eight key engineering advantages, significantly enhancing overall assembly performance, flush surface finishes, mechanical reliability, and space efficiency across demanding industrial applications.

Flush Finish: the assembled surface stays smooth on visible panels.
High-Strength Fastening: class 12.9 preload arrives with no height penalty.
Space-Constrained Assemblies: the bolt fits where a hex head has no clearance.
Easy Installation and Removal: one Allen key reaches a recess no spanner enters.
Corrosion-Resistant Alloys: stainless, duplex, titanium and nickel alloys extend life.
Sustained Preload: the wedge seat holds position under vibration.
Low Maintenance: a seated head collects less dirt and moisture.
Standard and Custom Sizes: stock covers M3 to M20; specials the rest.

Manufacturing Process of Allen CSK Bolts

Allen CSK Bolts Application

We supply countersunk socket bolts across eight key industries, meeting specific mechanical and operational demands tailored to each sector’s unique environment.

Exporter, Manufacturer & Supplier of Allen CSK Bolts in various material and sizes.

FAQs

What is an Allen CSK Bolt?

An Allen CSK Bolt is a countersunk-head screw driven by an internal hexagon socket, sitting flush in a matching 90-degree recess.

What is the difference between an Allen CSK Bolt and a Socket Head Cap Screw?

Head shape is the difference, and it changes what the bolt can do. A cap screw stands above the surface and takes a larger key: M10 uses 8 mm against 6 mm here. The bigger socket accepts more torque. Choose flush seating or peak preload accordingly.

Which materials are available for Allen CSK Bolts?

Stainless steel in 304, 316 and 316L covers most orders, with carbon and alloy steel alongside. Duplex, titanium, Inconel and Monel handle the rest.

What standards are followed for Allen CSK Bolts?

Metric sizes follow ISO 10642. DIN 7991 appears on legacy prints, while ASTM A574 and ASME B18.3 cover the inch series, and ISO 898-1 sets property classes.

What sizes of Allen CSK Bolts do you manufacture?

Standard production covers M3 through M20, in lengths from 6 mm to 100 mm. Inch sizes run in UNC and UNF.

Are custom Allen CSK Bolts available?

Yes, custom production runs beside catalogue sizes. Send your project, and we’ll quote lengths, threads, finishes or materials.

Which industries commonly use Allen CSK Bolts?

These are the eight industries where Allen CSK bolts are commonly used: automotive, aerospace, machine tools, automation, electronics, furniture, construction equipment and precision engineering.

Do you provide Mill Test Certificates and third-party inspection?

Yes, every consignment ships with an EN 10204 3.1 mill test certificate covering the heat. Nominated inspectors can witness testing before despatch.

Are stainless steel Allen CSK Bolts suitable for corrosive environments?

Yes, grade 316 handles chloride exposure better than 304, thanks to its molybdenum content. A4-70 material adds 700 MPa minimum tensile strength. Beyond that, seawater immersion and sour service call for duplex, super duplex or Monel.

Do you export Allen CSK Bolts worldwide?

Yes, consignments move worldwide through our domestic and international distribution network. Export cartons carry heat numbers, size marks, and the full test documentation set.