Screw (Allen Bolt)
Metracore Alloys Private Limited manufactures and supplies screw (Allen bolt) fasteners across a broad span of alloy grades: stainless and carbon steel at one end, duplex and nickel alloys in the middle, and titanium at the far end. A buyer who has approved one socket head geometry can reorder it in whatever material the service demands. The Allen bolt, listed in most standards as a socket head cap screw, develops high clamping force through a cylindrical head and an internal hexagonal drive. An Allen key or hex wrench engages that recess, so the fastener installs inside counterbores. Our range runs M1.6 through M64 to DIN 912 and ISO 4762, plus unified inch sizes to ASME B18.3, in stainless steel, alloy steel, carbon steel and special alloys. Industrial machinery, automotive assembly, machine tools and structural steelwork take most of our output. Email your thread sizes, grades and quantities to open a quotation.
What is a Screw (Allen Bolt)?
A screw (Allen bolt) is a threaded fastener whose cylindrical head carries a broached hexagonal recess. Torque enters through six internal flats rather than an external hexagon: that’s the difference from a hex bolt. Head diameter drops to about 1.5 times the shank: an M8 head measures 13 mm and seats in a counterbore. Spanner swing room stops mattering. Six faces at a wide radius carry the high tightening torque a class 12.9 joint needs, and removal remains predictable.
Cold heading starts production: one stroke upsets the head and punches the socket, so grain flow follows the profile. Thread rolling follows, displacing metal into the form instead of cutting it, which lifts fatigue strength at the root and suits precision engineering work. One caution belongs here: a hex socket screw isn’t the right pick where side loads or worn keys round out the socket during frequent field assembly.
Why Choose Metracore Alloys Private Limited?
Metracore Alloys Private Limited is a trusted supplier of socket screws, offering a comprehensive range of materials, including stainless steel, duplex steel, nickel alloys, and titanium, to meet diverse industrial requirements. We supply both standard catalogue sizes and custom-manufactured screws produced to customer drawings with precision cold-heading, rolled threads, and thorough dimensional inspection. To ensure complete quality assurance, we provide EN 10204 3.1 mill test certificates with every batch and support third-party inspection on request. Our direct manufacturing approach enables competitive pricing without unnecessary trading margins, while ready stock of popular metric and inch sizes ensures quick dispatch. Backed by reliable global shipping, we deliver quality fasteners efficiently to customers worldwide.
Screw (Allen Bolt) Specifications
The table sets out our manufacturing envelope, from governing standards to certification.
Product Type
Hex socket head cap screw (Allen bolt), cold-headed and thread-rolled
Material Standards
DIN 912, ISO 4762, ASTM A574, ASTM F835, ISO 898-1, ASME B18.3
Dimensional Standards
Stainless A2 (304) and A4 (316) to ISO 3506-1; carbon steel; alloy steel of the 42CrMo4 type; duplex; super duplex; Inconel; Monel; titanium; brass
Diameter Range
M1.6 to M64 metric; unified inch sizes to ASME B18.3
Length Range
5 mm to 300 mm as standard; longer screws produced to drawing
Head Type
Socket head cap, button head, flat countersunk, low head, shoulder
Inspection Standards
Thread gauging to 6g or class 3A, hardness, tensile and dimensional checks per lot
Certification
EN 10204 3.1 mill test certificate
Types of Screw (Allen Bolt)
We run ten variants, separated by head profile, thread length and material.
Socket Head Cap Screw
Button Head Allen Bolt
Flat Head Allen Screw
Low-Head Socket Screw
Shoulder Allen Bolt
Half Thread Allen Bolt
Full Thread Allen Bolt
Stainless Steel Allen Bolt
High Tensile Allen Bolt
Custom Allen Bolts
Reach out to Metracore Alloys Private Limited for reliableScrew (Allen Bolt)
Technical Details of Screw (Allen Bolt)
Available Materials
| Material Family | Grades We Produce | Why Buyers Specify It |
|---|---|---|
| Stainless Steel | A2 (304), A4 (316) to ISO 3506-1 | Outdoor, food, washdown and mild chemical duty |
| Carbon Steel | Property class 8.8, zinc-plated | General machinery and indoor assembly at lower cost |
| Alloy Steel | 42CrMo4 type, class 12.9 to ASTM A574 | High-preload joints in tooling and hydraulics |
| Duplex Stainless Steel | UNS S31803 / S32205 (2205) | Chloride service needing more strength than A4 |
| Super Duplex Steel | UNS S32750, S32760 | Offshore platforms, brine circuits, desalination plant |
| Inconel | 600 (N06600), 625 (N06625), 718 (N07718) | Hot-bolted joints and sour service in petrochemical plant |
| Monel | 400 (N04400), K500 (N05500) | Seawater immersion and hydrofluoric acid exposure |
| Titanium | Grade 2 (R50400), Grade 5 Ti-6Al-4V (R56400) | Weight-critical aerospace and marine hardware |
| Brass | Free-machining brass | Electrical fittings, instruments and decorative fixings |
Mechanical Properties
Property class, not head shape, sets the load a socket screw carries.
| Mechanical Properties | Class |
| Tensile Strength | Class 12.9 alloy steel reaches a minimum of 1220 MPa to ISO 898-1. |
| Yield Strength | 0.2% proof stress runs 640 MPa at class 8.8 and 1100 MPa at 12.9. |
| Hardness | ISO 898-1 sets 320 to 380 HV at class 10.9 and 385 to 435 HV at 12.9. |
| Proof Load | At 970 MPa proof stress, an M12 class 12.9 screw holds near 81 kN. |
| Elongation | Minimum elongation reaches 12% at class 8.8 and 8% at 12.9. |
| Torque Capacity | Six flats at a large radius let an M10 drive on an 8 mm key. |
Features
Eight characteristics dominate socket screw enquiries.
- High Clamping Force: Class 12.9 preload carries joint load through friction.
- Internal Hex Drive: A hex key reaches the recess without side clearance.
- Vibration Resistance: Preload holds the joint above its slip threshold.
- High Tensile Strength: Quenched and tempered alloy steel delivers 1220 MPa minimum.
- Corrosion-Resistant Options: Stainless, duplex, nickel, and titanium replace plated steel.
- Precision Machining: Ground shoulders and gauged threads hold jig tolerances.
- Long Service Life: Rolled threads resist fatigue cracking at the root.
- Reliable Fastening Performance: Batch-consistent geometry moves trial torque figures into production.
Standards & Quality Assurance
DIN 912 and ISO 4762 govern cap screw dimensions, and ASTM F835 governs the button and countersunk types; ASME B18.3 governs inch sizes. ISO 898-1 and ASTM A574 set mechanical requirements. An EN 10204 3.1 mill test certificate travels with every consignment.
Six checks precede despatch from the works:
- Thread Gauge Inspection: Ring gauges verify a 6G or class 3A thread fit.
- Tensile Testing: Samples are pulled to destruction against the declared class minimum.
- Hardness Testing: Vickers or Rockwell readings verify heat treatment response.
- Dimensional Inspection: Head height, socket size, length, and diameter go under gauge.
- Coating Thickness Testing: A magnetic gauge reads plating against the ISO 4042 class.
- Visual Examination: The final check catches burred sockets, cracked heads, and thread damage.
Advantages of Screw (Allen Bolt)
Socket screws outperform external-drive bolting in eight ways, most of them traceable to head geometry.
- High-Strength Fastening: Class 12.9 carries preload beyond any 8.8 hex bolt.
- Compact Head Design: An M8 head spans 13 mm, entering pockets a spanner cannot reach.
- Easy Tightening: One hex key set covers a whole assembly.
- Durability: Heat-treated alloy steel resists head rounding from spanner use.
- Corrosion-Resistant Alloys: Nickel alloys, titanium and duplex extend life in chloride service.
- Precision Assemblies: Ground shoulders and tight tolerances suit jig work.
- Low Maintenance: A correctly preloaded screw holds torque, so retightening drops away.
- Long Operational Life: Rolled threads and controlled hardness survive repeated strip-downs.
Manufacturing Process of Screw (Allen Bolt)
Industrial Applications
Eight sectors buy socket screws in volume, each for a different reason.
Products
Exporter, Manufacturer & Supplier of Screw (Allen Bolt) in various material and sizes.
FAQs
What is a screw (Allen bolt)?
Allen bolts are screws with a hexagonal socket broached into a cylindrical head, driven by an Allen key.
What is the difference between an Allen bolt and a hex bolt?
The drive sits inside the head, not outside it. Head diameter shrinks, and the fastener needs no wrench clearance.
Which materials are available for Allen Bolts?
Production covers carbon steel, alloy steel, stainless, duplex, super duplex, Inconel, Monel, titanium, and brass.
What standards are followed for screws (Allen bolts)?
Cap screw dimensions follow ISO 4762; ASTM F835 covers button and countersunk heads; ASME B18.3 covers the inch series. Mechanical properties come from ISO 898-1 and A574.
What sizes of Allen bolts do you supply?
Metric production spans M1.6 to M64, with standard lengths from 5 mm to 300 mm.
Are custom Allen bolts available?
We produce custom Allen bolts to the drawing. Send yours, and we’ll quote lengths, sockets, threads or coatings.
Which industries commonly use Allen Bolts?
Industrial machinery, automotive plants and heavy engineering take the largest volumes, with aerospace and oil and gas behind.
Do you provide mill test certificates and third-party inspections?
Every order ships with an EN 10204 3.1 certificate, and a customer-nominated agency can inspect before despatch.
Are stainless steel Allen bolts suitable for corrosive environments?
A2 (304) suits outdoor and washdown service. A4 (316) carries 2 to 3% molybdenum for chloride exposure. Duplex or nickel grades take over where brine attacks standard stainless.
Do you export screws (Allen bolts) worldwide?
Our distribution network reaches buyers in domestic and overseas markets, and every shipment leaves with export packaging plus full test records.