DIN 7603A Copper Sealing Ring (Form A) — T3 Annealed Copper

FULLERKREG DIN 7603A flat sealing rings are manufactured to DIN 7603 Form A standard in T3 annealed copper (Cu-ETP / T3, soft annealed). DIN 7603 Form A is a flat (plain) sealing ring used for pipe flanges (DIN 3850), plug screws (DIN 908), ball-type pipe fittings, and hollow connections (DIN 7001). T3 copper in the soft-annealed condition provides excellent conformability — the copper deforms plastically under bolt load to fill microscopic surface irregularities, creating a reliable metal-to-metal seal without gasket compounds. Copper sealing rings are widely specified in hydraulic systems, pneumatic systems, fuel systems, and high-pressure pipe connections where reliable leak-free sealing is critical.

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Product Highlights

• Standard: DIN 7603 Form A (Flat Sealing Ring)
• Material: T3 Annealed Copper (Cu-ETP, soft annealed)
• Profile: Form A — flat plain ring (no inner or outer bead)
• Size Range: d1 6 – 90 mm (inner diameter)
• Applications: Pipe flanges (DIN 3850), plug screws (DIN 908), pipe fittings, hollow connections (DIN 7001)
• Sealing mechanism: Plastic deformation of soft copper — fills surface irregularities for metal-to-metal seal
• Temperature resistance: Up to +300°C continuous service
• Media compatibility: Oil, fuel, hydraulic fluid, water, compressed air, steam
• RoHS & REACH Compliant

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Dimensional Specifications — DIN 7603 Form A, T3 Copper

All dimensions in millimeters (mm). Per DIN 7603 Form A.

Nominal Size	d1 (ID)	d2 (OD)	b (thickness)
6×10	6.0	10.0	1.5
6.5×10	6.5	10.0	1.5
7×11	7.0	11.0	1.5
8×12	8.0	12.0	1.5
8×13	8.0	13.0	1.5
8×14	8.0	14.0	1.5
9×13	9.0	13.0	1.5
10×13.5	10.0	13.5	1.5
10×14	10.0	14.0	1.5
10×16	10.0	16.0	1.5
11×15	11.0	15.0	1.5
12×16	12.0	16.0	1.5
12×18	12.0	18.0	1.5
12×20	12.0	20.0	1.5
13×17	13.0	17.0	1.5
14×18	14.0	18.0	1.5
14×20	14.0	20.0	1.5
15×19	15.0	19.0	1.5
16×20	16.0	20.0	1.5
16×22	16.0	22.0	1.5
17×21	17.0	21.0	1.5
18×22	18.0	22.0	1.5
18×24	18.0	24.0	1.5
19×23	19.0	23.0	1.5
20×24	20.0	24.0	1.5
20×26	20.0	26.0	1.5
21×25	21.0	25.0	1.5
22×27	22.0	27.0	1.5
22×29	22.0	29.0	1.5
24×29	24.0	29.0	1.5
24×32	24.0	32.0	1.5
26×32	26.0	32.0	1.5
27×32	27.0	32.0	1.5
28×34	28.0	34.0	1.5
29×36	29.0	36.0	2.0
30×36	30.0	36.0	2.0
32×38	32.0	38.0	2.0
33×40	33.0	40.0	2.0
34×40	34.0	40.0	2.0
35×42	35.0	42.0	2.0
36×41	36.0	41.0	2.0
38×44	38.0	44.0	2.0
40×46	40.0	46.0	2.0
40×47	40.0	47.0	2.0
42×48	42.0	48.0	2.0
44×50	44.0	50.0	2.0
45×52	45.0	52.0	2.0
48×55	48.0	55.0	2.0
50×57	50.0	57.0	2.0
52×59	52.0	59.0	2.0
55×62	55.0	62.0	2.0
58×65	58.0	65.0	2.0
60×67	60.0	67.0	2.0
62×70	62.0	70.0	2.0
65×72	65.0	72.0	2.0
68×75	68.0	75.0	2.0
70×78	70.0	78.0	2.0
72×80	72.0	80.0	2.0
75×83	75.0	83.0	2.0
78×86	78.0	86.0	2.0
80×88	80.0	88.0	2.0
85×93	85.0	93.0	2.0
90×100	90.0	100.0	2.0

All dimensions in mm per DIN 7603 Form A. d1 = inner diameter; d2 = outer diameter; b = thickness. Sizes d1 6–28mm: b = 1.5mm. Sizes d1 29–90mm: b = 2.0mm.

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DIN 7603 Form A vs. Form C vs. Form D

Feature	Form A (This Product)	Form C	Form D
Profile	Flat plain ring	Inner bead (raised inner edge)	Outer bead (raised outer edge)
Sealing area	Full flat face	Inner bead concentrates sealing force	Outer bead concentrates sealing force
Typical use	General pipe fittings, plug screws	Higher pressure, concentrated seal	Higher pressure, concentrated seal
Standard	DIN 7603 Form A	DIN 7603 Form C	DIN 7603 Form D

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Material Properties — T3 Annealed Copper (Cu-ETP)

Property	Value
Material Grade	T3 / Cu-ETP / C11000 (equivalent)
Cu Content	≥99.9%
Condition	Soft annealed (O60 / M20)
Hardness	40–65 HV (soft, highly conformable)
Tensile Strength	200–260 MPa
Elongation	≥30% (excellent ductility)
Max. Service Temperature	+300°C continuous
Thermal Conductivity	~390 W/(m·K)
Electrical Conductivity	~58 MS/m
Media Compatibility	Oil, fuel, hydraulic fluid, water, compressed air, steam
RoHS / REACH	Compliant

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How Copper Sealing Rings Work

• Plastic deformation: Soft annealed T3 copper deforms plastically under bolt clamping load, flowing into microscopic surface irregularities on the mating faces
• Metal-to-metal seal: Creates a reliable leak-free metal-to-metal seal without gasket compounds or sealants
• Re-usability: Copper sealing rings can sometimes be re-annealed (heated to ~600°C and quenched) to restore softness for reuse, though replacement is recommended for critical applications
• Temperature stability: Unlike elastomeric seals, copper maintains sealing performance at elevated temperatures up to +300°C

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Application Scenarios

• Hydraulic systems — plug screws (DIN 908), banjo bolts, hydraulic fittings
• Fuel systems — fuel line connections, injection system fittings
• Pneumatic systems — compressed air connections, valve bodies
• Pipe flanges — DIN 3850 flange connections
• Engine & gearbox — oil drain plugs, coolant connections
• Steam & hot water systems — high-temperature pipe connections up to +300°C
• Industrial machinery — general pipe fitting sealing where metal gaskets are required

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Product Photo Gallery

FULLERKREG DIN 7603A Copper Sealing Ring, T3 Annealed Copper:

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Why Choose FULLERKREG?

• 🏭 Direct manufacturer — factory in China, no middlemen
• 📐 Strict DIN dimensional control — 100% inspection on critical dimensions
• 🌍 Global export experience — serving distributors in Europe, North America, Southeast Asia
• 📦 Flexible MOQ — small trial orders and large bulk shipments both welcome
• 📋 Full documentation — material certs, RoHS declarations available
• ⚡ Fast lead times — standard sizes in stock, ready to ship

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Frequently Asked Questions

Q: What is DIN 7603 Form A?
A: DIN 7603 Form A is a flat plain sealing ring (no bead) used for pipe flanges (DIN 3850), plug screws (DIN 908), and pipe fittings. The flat profile provides full-face sealing through plastic deformation of the soft copper under bolt clamping load.

Q: What is T3 copper?
A: T3 is a Chinese standard designation for electrolytic tough pitch copper (Cu-ETP, ≥99.9% Cu), equivalent to C11000. In the soft-annealed condition, it has hardness 40–65 HV and elongation ≥30%, providing excellent conformability for metal-to-metal sealing.

Q: Can copper sealing rings be reused?
A: Copper sealing rings can sometimes be re-annealed (heated to ~600°C and water-quenched) to restore softness for reuse. However, replacement with new rings is recommended for critical pressure applications to ensure reliable sealing.

Q: What is the maximum temperature for T3 copper sealing rings?
A: T3 annealed copper sealing rings are suitable for continuous service up to +300°C, making them suitable for steam, hot oil, and high-temperature hydraulic applications.

Q: Do you provide material test certificates?
A: Yes. Mill certificates and RoHS declarations available upon request.

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