Flange Head Screws Manufacturer in India | Stainless Hex Flange Screws

Overview

Stainless Hex Flange Screws & Flange Head Screws: Manufacturer & Stockist

A flange head screw carries its own washer. The flange spreads the load, covers oversized and slotted holes, and with serrations resists vibration loosening, all in one part that cannot be dropped or forgotten on the line.

Exotic Alloy manufactures flange head screws in Mumbai, India, for automotive and electrical assemblers, HVAC, solar and enclosure builders and machine makers. We stock across India and supply Kenya, East Africa, the Gulf and Europe. Heads and flanges are cold formed in one piece, with serrations formed in the heading die where specified.

More than one flange

The small ISO 4162 flange suits compact assemblies, the heavy EN 1665 flange takes ordinary hex spanners, the ISO 7053 washer head is made for sheet metal, and the ISO 7380-2 flanged button gives a low, smooth head. For the full hex flange bolt data, see hex flange bolts.

ISO 4162 / EN 1665 ISO 7053 tapping ISO 7380-2 button Plain / serrated A2 / A4 stainless

Flange head screw at a glance

Flange: One piece with the head, plain or serrated
Bearing: At least as wide as an ISO 7089 washer (hex types)
Length: Measured from the bearing face
Threads: Metric machine; ST tapping (ISO 7053)
Stainless: A2-70, A4-70; ISO 3506-4 for tapping screws
Related: Hex flange bolts, button head screws, self drilling screws

ISO 4162 M8 × 25, shown with the serrated flange option, drawn to scale (end views at 65 %). The head height k includes the flange. ISO 4162 uses a 10 mm hexagon for M8, smaller than the 13 mm of an EN 1665 or ISO 4014 head.

Specification

Flange Head Screw Specification

The range we manufacture and supply.

StandardsISO 4162 (small series); EN 1665 (heavy series, formerly DIN 6921); ISO 7053 (formerly DIN 6928); ISO 7380-2

Size rangeISO 4162 M5–M16; EN 1665 M5–M20; ISO 7380-2 M3–M16; ISO 7053 ST2.9–ST8

ThreadMetric coarse 6g, fine to order; tapping screw thread ST (ISO 1478)

FlangePlain or radially serrated; serrated not used with washers

GradesA2-70, A4-70 (ISO 3506-1); stainless tapping screws to ISO 3506-4; steel 8.8 / 10.9; case-hardened tapping screws to ISO 2702

FinishPassivated stainless; zinc plated, zinc flake or zinc-nickel steel

DrivesExternal hex (flange and washer head); hex socket or hexalobular (flanged button)

MarkingMaterial and class on the head (e.g. A2-70) with maker’s mark

CertificationMill certificate; EN 10204 3.1; PMI for stainless

PackingBoxes, bulk cartons and bags for assembly lines

Flange heads

Types of Flange Head Screws

Same idea, four standards: here they are at the same size next to a plain hex head and a washer.

M6-size heads at the same scale (ST6.3 for the tapping screw), from the standard tables; the dashed line is the part surface. Every flange is wider than the 12 mm ISO 7089 washer.

Size	ISO 7089 washer OD mm	ISO 4162 flange d_c max, mm	EN 1665 flange d_c max, mm	ISO 7380-2 flange d_c max, mm	ISO 7380-1 button d_k max, no flange	Spanner ISO 4162 / EN 1665
M5	10	11.4	11.8	11.8	9.5	7 / 8 mm
M6	12	13.6	14.2	13.6	10.5	8 / 10 mm
M8	16	17	18	17.8	14	10 / 13 mm
M10	20	20.8	22.3	21.9	17.5	13 / 16 mm
M12	24	24.7	26.6	26	21	15 / 18 mm
M16	30	32.8	35	34	28	21 / 24 mm

Maximum diameters in mm. ISO 7380-1 is the plain button head without a flange, for comparison.

Dimensions

Flange Head Screw Dimensions

Size	Pitch P	d_c max flange dia.	c min flange edge	k max head height	k′ min wrenching height	s across flats	e min across corners	b l ≤ 125
M5	0.8	11.4	1	5.6	2.8	7	7.44	16
M6	1	13.6	1.1	6.8	3.4	8	8.56	18
M8	1.25	17	1.2	8.5	4.2	10	10.80	22
M10	1.5	20.8	1.5	9.7	5.7	13	14.08	26
M12	1.75	24.7	1.8	11.9	6.1	15	16.32	30
M14	2	28.6	2.1	12.9	7.1	18	19.68	34
M16	2	32.8	2.4	15.1	8.7	21	22.58	38

ISO 4162 hexagon flange screws, small series, mm (fasten.it and AFT Fasteners agree).

Size	Pitch P	d_c max flange dia.	c min flange edge	k max head height	s across flats	e min across corners	d_s min shank	b l ≤ 125 / ≤ 200 / > 200
M5	0.8	11.8	1	5.8	8	8.71	4.82	16 / – / –
M6	1	14.2	1.1	6.6	10	10.95	5.82	18 / – / –
M8	1.25	18	1.2	8.1	13	14.26	7.78	22 / 28 / –
M10	1.5	22.3	1.5	10.4	16	17.62	9.78	26 / 32 / –
M12	1.75	26.6	1.8	11.8	18	19.86	11.73	30 / 36 / –
M14	2	30.5	2.1	13.7	21	23.15	13.73	34 / 40 / –
M16	2	35	2.4	15.4	24	26.51	15.73	38 / 44 / 57
M20	2.5	43	3	18.9	30	33.23	19.67	46 / 62 / 65

EN 1665 hexagon flange bolts and screws, heavy series, mm. EN 1665 replaced DIN 6921 and changed the hexagon for M10 to M20.

Size	Thread dia. mm	Pitch P	d_k washer dia. max / min	k head height max / min	c washer thickness min	s across flats	e min
ST2.9	2.9	1.1	6.3 / 5.8	2.8 / 2.5	0.4	4	4.28
ST3.5	3.5	1.3	8.3 / 7.6	3.4 / 3	0.6	5.5	5.96
ST3.9	3.9	1.3	8.3 / 7.6	3.4 / 3	0.6	5.5	5.96
ST4.2	4.2	1.4	8.8 / 8.1	4.1 / 3.6	0.8	7	7.59
ST4.8	4.8	1.6	10.5 / 9.8	4.3 / 3.8	0.9	8	8.71
ST5.5	5.5	1.8	11 / 10	5.4 / 4.8	1	8	8.71
ST6.3	6.3	1.8	13.5 / 12.2	5.9 / 5.3	1	10	10.95
ST8	8	2.1	18 / 16.7	7 / 6.4	1.2	13	14.26

DIN EN ISO 7053:2019 hexagon washer head tapping screws, mm (formerly DIN 6928).

Size	Pitch P	d_c flange dia. max	d_k dome dia. max	k head height max	c flange thickness min	s hex key	t socket depth, min
M3	0.5	6.9	5.2	1.65	0.7	2	1.04
M4	0.7	9.4	7.2	2.2	0.8	2.5	1.3
M5	0.8	11.8	8.8	2.75	1	3	1.56
M6	1	13.6	10	3.3	1.2	4	2.08
M8	1.25	17.8	13.2	4.4	1.5	5	2.6
M10	1.5	21.9	16.5	5.5	2	6	3.1
M12	1.75	26	19.4	6.6	2.4	8	4.16
M16	2	34	26	8.8	2.8	10	5.2

ISO 7380-2 hexagon socket button head screws with collar (flange), mm.

Serrated vs plain

Serrated or Plain Flange?

How serrations lock (schematic). The teeth are shaped to slide on tightening and dig in against loosening.

Situation	Choose	Why
Vibration, bare steel joint	Serrated	Teeth resist turning back
Painted, powder-coated or plated part	Plain	Serrations cut the coating and start corrosion
Aluminium, plastics, thin soft sheet	Plain	Teeth embed too deeply and preload drops
Hardened surface	Plain (plus a locking method)	Teeth cannot bite
Part removed often	Plain	Repeated biting damages the surface

Thin sheet

Flange Head Screws in Thin Sheet: Pull-Through

In thin sheet the head can punch through before the screw breaks. A wider bearing diameter raises that load in proportion.

Size	Hole ISO 273 medium	ISO 7380-1 button no flange, kN	Washer ISO 7089 kN	ISO 4162 flange kN	EN 1665 flange kN
M5	5.5	9.7	10.2	11.6	12.0
M6	6.6	10.7	12.2	13.8	14.5
M8	9	14.3	16.3	17.3	18.3
M10	11	17.8	20.4	21.2	22.7
M12	13.5	21.4	24.4	25.1	27.1
M16	17.5	28.5	30.5	33.4	35.6

Our first estimate for 1.5 mm S235 sheet (R_m 360 MPa): F ≈ π × bearing diameter × thickness × 0.6 R_m (punching shear). Real pull-through also depends on hole size, sheet bending and edge distance; test critical joints.

Calculator

Head Pull-Through & Bearing Calculator

Pick the head and the sheet to compare bearing area and estimated pull-through load, against a plain washer of the same size.

Head & sheet

Head

Size

Sheet material

Sheet, mm

Hole, mm

Hole defaults: ISO 273 medium for machine screws, thread size + 0.5 mm for tapping screws (clearance in the top sheet). Estimate only: F = π d_w t × 0.6 R_m.

Estimate

17.3

kN estimated pull-through

Bearing diameter:17 mm

Bearing area:163 mm²

With ISO 7089 washer:16.3 kN

Materials

Flange Head Screw Materials & Grades

Screw	Steel	Stainless	Note
ISO 4162 / EN 1665	8.8, 10.9 (ISO 898-1)	A2-70, A4-70 (ISO 3506-1)	Full-strength hex heads
ISO 7380-2	Heat-treated alloy steel	A2 / A4	Reduced loadability head
ISO 7053	Case-hardened steel (ISO 2702)	A2 / A4 tapping screws (ISO 3506-4)	Forms its own thread in sheet

Stainless A2

304

The grade in the photo; indoor and mild outdoor.

304 304L

Stainless A4

316

Coastal, solar and washdown use.

316 316L

Carbon & boron steel

8.8 · 10.9

Quenched and tempered machine screws.

1035 15B35H

Case-hardening steel

Tapping screws

Hard case to form threads in sheet.

1018 1022

Manufacturing

How Our Flange Head Screws Are Made

1

Wire

Stainless, carbon or case-hardening wire, certified by heat.

2

Heading

Head and flange formed together; serrations pressed in the die.

3

Trimming

Hexagon trimmed; button heads keep their formed socket.

4

Thread rolling

Metric or ST tapping threads rolled.

5

Heat treatment

Quench and temper (8.8 / 10.9) or case hardening (tapping).

6

Finishing

Passivation for stainless; zinc or zinc flake for steel.

Applications

Where Our Flange Head Screws Are Used

Automotive

Brackets, heat shields and body parts with serrated flange screws.

HVAC & ducting

Hex washer head tapping screws in sheet metal.

Solar mounting

A4 flange screws on rails and clamps.

Electrical enclosures

Panels, cabinets and switchgear.

Machinery guards

Flanged button heads on covers and guards.

Food equipment

Plain-flange stainless screws on cleanable surfaces.

Quality & testing

Flange Head Screw Inspection & Certification

Check	Method	Applied to
Flange diameter & thickness	Callipers: d_c, c	Every lot
Hexagon & head height	Callipers: s, e, k	Every lot
Serrations	Visual and profile check	Serrated lots
Thread	Ring gauges / tapping test plate	Every lot
Mechanical	ISO 898-1, ISO 3506, ISO 2702 tests	Every heat-treatment or material lot
Material	PMI	Stainless lots

Every shipment includes

Mill certificate with heat number
Dimensional report
Lot number on every box

On request

EN 10204 3.1 certificate
Drive and torsion tests for tapping screws
Salt spray test for coated lots

FAQ

Flange Head Screw Questions, Answered

A flange head screw has a round, washer-like flange formed in one piece under its head. The flange spreads the clamp load over a larger area, covers oversized holes and replaces a separate washer. Common types are hex flange screws (ISO 4162, EN 1665), hexagon washer head tapping screws (ISO 7053) and flanged button head socket screws (ISO 7380-2).

For most assemblies, yes: one part instead of two, nothing to drop or forget, and a flange at least as large as an ISO 7089 washer. For M8, for example, the ISO 4162 flange is 17 mm and the EN 1665 flange 18 mm, against 16 mm for the washer. A separate hardened or large washer is still the better choice for very soft materials or oversized slots.

Choose serrated where vibration could loosen the screw: the radial teeth bite into the joint surface and resist turning back. Choose plain where the surface must not be marked, is painted or coated, is softer than the screw would allow, or is hardened so that the teeth cannot grip.

It is better not to. The serrations cut through paint and coatings, which starts corrosion and lets the joint lose preload as the coating creeps. On soft materials such as aluminium or plastics the teeth embed too deeply. Use a plain flange there, and never put a washer under a serrated flange.

It is a sheet metal screw with a hex head and an integral washer, made to ISO 7053 (formerly DIN 6928) in sizes ST2.9 to ST8. It forms its own thread in a pilot hole in sheet metal. The hex is 7 mm across flats for ST4.2, 8 mm for ST4.8 and ST5.5, and 10 mm for ST6.3.

It depends on the series. ISO 4162 small series flange screws have smaller hexagons: 10 mm for M8, 13 mm for M10 and 15 mm for M12. EN 1665 heavy series screws use the ISO 4014 hexagon: 13 mm for M8, 16 mm for M10 and 18 mm for M12.

No. ISO 7380-2 flanged button head screws are classed as having reduced loadability: the low head cannot carry the full load of the property class marked on it. Use them for covers, guards and panels, and use ISO 4762 socket cap screws or hex flange screws where the joint carries high tension.

Machine-thread flange screws are usually made in A2-70 (304) and A4-70 (316) to ISO 3506-1. Stainless tapping screws such as ISO 7053 hexagon washer head screws are covered by ISO 3506-4. Use A4 near the sea, in chemical plants and in washdown areas.