Socket Flanged Button Screws (ISO 7380-2) - Stainless Steel (A2)

FULLERKREG ISO 7380-2 A2 Stainless Steel Flanged Button Head Socket Cap Screws

FULLERKREG ISO 7380-2 A2 Stainless Steel Flanged Button Head Socket Cap Screws are corrosion-resistant fasteners featuring a low-profile dome-shaped button head with an integrated flange and a hexagon socket drive. Manufactured from A2 (SUS304) austenitic stainless steel with a passivated natural finish, these screws combine the excellent corrosion resistance of 18-8 stainless steel with the engineering advantages of an integrated flange — eliminating the need for a separate washer while providing superior pull-through resistance and a clean, professional appearance. They are the preferred choice for food processing, medical, outdoor, and aesthetic applications where both corrosion resistance and load distribution are required.

Product Specifications

• Standard: ISO 7380-2 (2022)
• Material: A2 Stainless Steel (SUS304 / 18-8)
• Strength Grade: A2-70
• Tensile Strength: Min. 700 MPa
• Proof Load Stress (Rp0.2): Min. 450 MPa
• Hardness: ≤95 HRB (max. 210 HV)
• Head Type: Flanged button head (low-profile dome with integrated flange)
• Surface Treatment: Passivation — natural silver finish (pickling & passivation)
• Thread Type: Metric coarse, full thread
• Thread Tolerance: 6g
• Drive Type: Hexagon socket (Allen key / hex key)
• Sizes Available: M4 – M16

ISO 7380-2 vs ISO 7380-1 — Flanged vs Plain Button Head

Property	ISO 7380-2 Flanged (This Page)	ISO 7380-1 Plain Button Head
Head profile	Low dome + integrated flange	Low dome only
Bearing surface area	Significantly larger (flange)	Standard button head
Washer required?	No — flange acts as integrated washer	Sometimes yes
Pull-through resistance	Superior	Standard
Load distribution	Excellent on thin/soft materials	Good
Assembly efficiency	Faster — one fewer component	Standard
Best for	Thin panels, soft materials, high pull-through risk	General low-profile applications

Material — A2 Stainless Steel (SUS304) Chemical Composition (%)

All values are maximum unless a range is indicated.

Grade	C (max)	Si (max)	Mn (max)	P (max)	S (max)	Cr	Ni
SUS304 (A2)	≤0.08	≤1.00	≤2.00	≤0.045	≤0.030	18.00–20.00	8.00–10.50

Mechanical Properties — A2-70 (ISO 3506-1)

Property	Requirement	Unit
Tensile Strength (Rm)	Min. 700	MPa
Proof Load Stress (Rp0.2)	Min. 450	MPa
Hardness (max)	≤95 HRB / ≤210 HV	HRB / HV
Elongation after fracture (A)	Min. 25	%
Thread Tolerance Class	6g	—
Surface Treatment	Passivation (natural finish)	—

Key Features

• Integrated flange — built-in washer function eliminates need for separate washer, reducing part count and assembly time
• A2 Stainless Steel (SUS304) — excellent corrosion resistance in atmospheric, freshwater, food processing, and mild chemical environments
• Passivated natural finish — clean silver appearance with enhanced oxide layer for superior rust resistance
• Superior pull-through resistance — large flange bearing area prevents pull-through in thin sheet metal, plastic, and composite materials
• Low-profile button head — smooth dome design with clean aesthetic appearance
• Non-magnetic — suitable for applications sensitive to magnetic interference
• Hygienic & food-safe — compliant for food processing, pharmaceutical, and medical equipment use
• RoHS & REACH compliant — no restricted hazardous substances
• ISO 7380-2 (2022) standard — latest revision compliance

Corrosion Resistance Guide — A2 (SUS304)

Environment	A2 (SUS304) Performance	Recommendation
Indoor / dry environments	Excellent	✅ Ideal
Outdoor / atmospheric exposure	Very good	✅ Suitable
Food processing / pharmaceutical	Excellent	✅ Ideal
Freshwater / mild humidity	Very good	✅ Suitable
Mild chemical exposure	Good	✅ Generally suitable
Saltwater / marine (direct)	Limited	⚠️ Consider A4 (SUS316)
Strong acids / chlorides	Poor	❌ Not recommended

Applications

FULLERKREG ISO 7380-2 A2 stainless steel flanged button head socket cap screws are widely used in:

• Food processing and packaging machinery (corrosion resistance + hygienic surface)
• Pharmaceutical and medical device manufacturing
• Thin sheet metal and panel assemblies requiring pull-through resistance
• Plastic and composite material fastening (large flange bearing area)
• Outdoor architectural hardware and signage
• Electronics enclosures and control panels
• Laboratory instruments and scientific equipment
• Consumer products and home appliances
• Any application requiring corrosion-resistant flanged button head screws without a separate washer

Dimensional Specifications — ISO 7380-2 (Unit: mm)

Key dimensions per ISO 7380-2 (2022). The flange diameter (dc) is the critical additional dimension vs. ISO 7380-1.

Thread (d)	Pitch (p)	Head Dia. dk Max.	Head Dia. dk Min.	Flange Dia. dc Max.	Flange Dia. dc Min.	Head Height k Max.	Head Height k Min.	Key Size s	Key Depth t Min.
M4	0.7	7.60	7.36	9.40	9.00	2.20	1.80	2.5	1.05
M5	0.8	9.50	9.22	11.80	11.40	2.75	2.25	3.0	1.35
M6	1.0	10.50	10.22	13.60	13.20	3.30	2.70	4.0	1.60
M8	1.25	14.00	13.57	17.90	17.50	4.40	3.60	5.0	2.20
M10	1.5	17.50	17.05	22.30	21.80	5.50	4.50	6.0	2.75
M12	1.75	21.00	20.48	26.70	26.20	6.60	5.40	8.0	3.30
M16	2.0	28.00	27.48	35.70	35.20	8.80	7.20	10.0	4.40

Frequently Asked Questions

Q: What is the difference between ISO 7380-1 and ISO 7380-2?
ISO 7380-1 is the plain button head socket cap screw with no flange. ISO 7380-2 adds an integrated flange under the button head, which significantly increases the bearing surface area, acts as a built-in washer, and provides superior pull-through resistance.

Q: Do I still need a washer with ISO 7380-2 flanged button head screws?
In most applications, no. The integrated flange provides sufficient bearing area to replace a standard flat washer, reducing part count and assembly time.

Q: Why choose A2 stainless steel for flanged button head screws?
A2 (SUS304) provides excellent corrosion resistance for most indoor, outdoor, food processing, and medical applications. The passivated finish enhances the natural oxide layer for superior rust resistance. For marine or chloride-rich environments, consider A4 (SUS316).

Q: Are A2 stainless steel flanged button head screws magnetic?
A2 stainless steel is generally non-magnetic in the annealed state. Cold working during manufacturing may induce slight magnetism. For strictly non-magnetic applications, please confirm with our technical team.

Q: Can I get material certificates and test reports?
Yes. PPAP reports, material certificates, hardness test reports, and tensile test reports are available upon request for all FULLERKREG products.

Packaging & Availability

• Standard sizes M4 – M16 available in stock
• Bulk carton packaging; small box and custom packaging available
• Material certificates and test reports available on request
• PPAP report available on request
• Custom lengths accepted for large orders

Download Specification

• ISO 7380-2 (2022) — Full Dimensional Specification (PDF)

Quality Assurance

All FULLERKREG ISO 7380-2 A2 stainless steel flanged button head socket cap screws are manufactured under strict quality control procedures including:

• Hardness test (≤95 HRB)
• Tensile strength test (min. 700 MPa)
• Dimensional inspection per ISO 7380-2 (2022), including flange diameter verification
• Chemical composition verification (SUS304)
• Salt spray corrosion test
• PPAP documentation available upon request

For wholesale pricing, bulk orders, material certificates, or technical inquiries, please contact our sales team.