4343 aluminiumlegering

What Is 4343 Aluminum Alloy?

4343 aluminum alloy (UNS A94343) is a 4000-series aluminum-silicon alloy containing 6.8–8.2% silicon. It is not a structural alloy; its primary purpose is as a brazing filler or cladding layer in heat exchanger stock. When heated above the liquidus of the 4343 layer, the silicon-rich surface melts and flows into the joint, producing a strong, leak-tight brazed assembly without separate filler wire.

The most common commercial form is 4343 clad aluminum brazing sheet — a sandwich of core alloy (typically 3003 or 3005) with a thin 4343 cladding on one or both sides. Linsy supplies 4343 brazing sheet, strip, and coil in tempers O and H14, with custom thickness, width, and cladding ratio available on request.

Available 4343 Aluminum Products

Linsy supplies 4343 aluminum in the following forms for brazing and heat exchanger applications. Cladding ratio, thickness, and width can be tailored to your brazing specification.

4343 Aluminum Brazing Sheet & Clad Strip

Formulier	Bekleding	Temper	Dikte (mm)	Breedte (mm)	Lengte (mm)
4343/3003/4343 Brazing Sheet	4343 both sides	O, H14	0.3 – 6.0	500 – 1600	500 – 6000
4343/3003 Clad Sheet	4343 one side	O, H14	0.3 – 6.0	500 – 1600	500 – 6000
4343 Strip / Coil	4343 or clad	O, H14	0.1 – 3.0	20 – 1600	Coil

4343 Aluminum Brazing Wire / Rod

Formulier	Temper	Diameter (mm)	Lengte
4343 Brazing Wire	O	0.8 – 5.0	Coil / spool
4343 Brazing Rod	O	1.6 – 6.0	500 – 1000 mm stick

4343 Specifications & Equivalent Designations

Standaard	Benaming
UNS	A94343
NL	EN AW-4343 / AlSi7.5
ISO	AlSi7.5
AA	4343
ASTM	B209 (clad sheet), B221 (clad extrusion)

Chemical Composition of 4343 Aluminum

Element	Inhoud (%)
Si	6.8 – 8.2
Fe	0.80 max
Cu	0,25 max
Mn	0,10 max
Mg	0,05 max
Cr	0,05 max
Zn	0,10 max
Ti	0,05 max
Overige (per stuk)	0,05 max
Overige (totaal)	0,15 max
Al	Rest

Mechanical Properties of 4343 Aluminum

Eigendom	Value (Typical, O Temper)
Treksterkte (Ultieme)	120 – 150 MPa
Yield Strength (0.2% offset)	45 – 80 MPa
Rek bij breuk	15 – 25%
Afschuifsterkte	85 – 105 MPa

Values are typical for 4343-O clad sheet. Actual values depend on cladding ratio and core alloy. Request MTC for certified values.

Gids voor het kiezen van de juiste temperatuur

Temper	Toestand	When to Use
O	Annealed (softest)	Forming before brazing; maximum formability, lowest strength. Preferred for complex radiator fins and folds.
H14	Strain-hardened, half-hard	Flatness-critical parts that will not be heavily formed before brazing. Less formable than O; suitable for flat heat exchanger plates.

Key Characteristics of 4343 Aluminum

Brazeability & Flowability

4343 is specifically designed for aluminum brazing. The 6.8–8.2% silicon content lowers the melting range to approximately 577–610°C, allowing it to melt and flow as a liquid phase during furnace or torch brazing while the core alloy remains solid. The molten 4343 wets and capillaries into joints, producing clean, strong brazed assemblies without separate filler.

Cladding Configuration

4343 is most effective as a cladding layer on a stronger core (commonly 3003, 3005, or 6061). Typical cladding ratio is 5–15% per side. Linsy supplies standard 4343/3003/4343 (both sides) and 4343/3003 (one side) configurations. Custom cladding ratios are available on request.

Corrosion Considerations

The 4343 cladding layer contains no significant magnesium or copper and is anodic to many core alloys, providing sacrificial protection to the core in many environments. However, 4343 is not intended for marine or seawater service — for those applications, specify 5000-series alloys. 4343 is optimized for heat exchanger environments (coolant, ambient air, moderate humidity).

Common Applications of 4343 Aluminum

• Automotive heat exchangers: radiators, heater cores, charge air coolers, oil coolers
• HVAC & refrigeration: evaporators, condensers, brazed plate heat exchangers
• Industrial brazed assemblies: cooling plates, power electronics cold plates, battery thermal management
• Brazing wire / rod: repair and fabrication of aluminum heat exchanger components

Processing & Brazing Notes

• Brazing temperature: Typical vacuum or controlled-atmosphere brazing at 595–610°C. Oxide dispersal (e.g., Mg vapor in vacuum brazing) may be required depending on furnace type.
• Vormen: 4343-O clad sheet is readily formable. Minimum bend radius depends on total thickness and cladding ratio; consult Linsy technical support for forming limits.
• Not weldable as a structural joint: 4343 is a brazing filler, not a structural welding alloy. Do not use 4343 as a load-bearing welded assembly base metal.
• Surface cleanliness: Brazing performance is sensitive to surface contamination. Parts must be cleaned of oil, grease, and excessive oxide before brazing.
• Anodiseren: Not recommended. The silicon-rich surface does not produce a uniform anodic coating. If corrosion protection is required, specify a different clad configuration.

Kwaliteitsdocumenten en inspectie

• MTC (Material Test Certificate) report supplied with every order.
• SGS third-party test reports available on request.
• Cladding ratio and thickness tolerance confirmed by ultrasonic or chemical spot check.
• RoHS and REACH compliance declarations available.

Why Choose Linsy for 4343 Aluminum

• ISO 9001, ISO 14001, and ISO 45001 certified production.
• Custom cladding ratio, thickness, and width tailored to your brazing specification.
• MTC with every order; SGS test reports available on request.
• Lead time: 10–60 days depending on specification and order volume.
• Low minimum order quantity for brazing sheet and strip.

4343 Aluminum FAQ

What is 4343 aluminum used for?

4343 is used as a brazing cladding layer on heat exchanger stock. It melts during the brazing cycle and joins the assembly without separate filler wire. The most common application is automotive radiators and HVAC heat exchangers.

What tempers does Linsy supply for 4343?

Linsy supplies 4343 clad sheet and strip in tempers O (annealed, best formability) and H14 (half-hard, for flatness-critical parts). O temper is the standard for most brazing applications because the part is formed before brazing.

What cladding ratios are available?

Standard cladding ratio is 10% 4343 per side (for 4343/3003/4343). Linsy also supplies 5%, 12%, and 15% by request. One-side cladding (4343/3003) is available for applications where only one surface requires brazing.

Is 4343 suitable for marine environments?

No. 4343 is not a marine-grade alloy. For seawater or coastal environments, use 5000-series aluminum alloys (5052, 5083, 5086). 4343 is intended for heat exchanger and brazed assembly applications in non-marine environments.

Can 4343 be welded?

4343 is not intended as a structural welding alloy. It is a brazing filler material. If you need to weld aluminum heat exchanger components, consult Linsy technical support for the correct filler wire grade (typically 4043 or 5356 depending on the base alloy).

What core alloys can be clad with 4343?

The most common cores are 3003, 3005, and 6061. 3003 is the standard choice for automotive heat exchangers. 6061 core is used when higher strength is required. Linsy can supply 4343 clad on other core alloys on request.

Veelgestelde vragen over bestellingen in het algemeen

Wat is de minimale bestelhoeveelheid (MOQ)?

MOQ depends on specification. Standard 4343/3003/4343 brazing sheet typically starts from 500 kg. Custom cladding ratio or non-standard thickness may require higher MOQ. Contact Linsy sales for a quote.

What quality documents are supplied?

Every order includes an MTC (Material Test Certificate). SGS third-party testing is available on request at additional cost. RoHS and REACH compliance declarations are available on request.

Wat is de gebruikelijke levertijd?

Lead time is 10–60 days depending on specification, order volume, and current production schedule. Custom cladding ratios or non-standard dimensions may require longer lead time. Your order confirmation will specify the committed delivery date.

Can Linsy supply custom sizes?

Yes. Linsy supplies 4343 brazing sheet and strip in custom thickness, width, cladding ratio, and coil/ sheet length. Provide your drawing or specification for a customized quote.