Aluminum Welding Wire ER4043 VS ER5356,Which One Should You Choose?

Aluminum Welding Wire ER4043 VS ER5356

1. Chemical Composition & Color (The Biggest Difference)

• ER4043: This is a Silicon (Si) alloy wire (~5%). Silicon lowers the melting point and greatly improves weld puddle fluidity. However, when the welded part is anodized, the silicon particles do not anodize, resulting in a dark gray, smutty-looking finish that does not match the parent metal.

• ER5356: This is a Magnesium (Mg) alloy wire (~5%). Magnesium increases solid solution strength. When anodized, it retains a color much closer to the base metal (a light, off-white matte finish), making it the preferred choice for cosmetic parts that will be anodized.

2. Mechanical Properties

• ER4043: Produces a weld that is softer and has lower tensile and shear strength than ER5356. It is not recommended for applications requiring high strength or where the weld will be subjected to prolonged elevated temperatures (over 150°F / 65°C) as it can lose strength.

• ER5356: Produces a stronger, harder weld deposit with higher shear strength. It maintains its strength better at room temperatures and is the standard choice for structural applications.

3. Welding Performance

• ER4043: Its superior fluidity makes it easier to weld with, especially for beginners or on thin materials. It wets out beautifully and is excellent for bridging gaps. It is also highly resistant to hot cracking, making it ideal for welding crack-sensitive alloys like 6061.

• ER5356: It has a stiffer puddle and can be slightly more challenging to weld with. It produces a brighter, cleaner-looking weld bead (before anodizing) with a smoother surface profile.

4. Common Applications

• Use ER4043 for:

• Welding 6xxx series alloys (e.g., 6061, 6063) - very common.

• Welding cast aluminum alloys (e.g., A356, 319).

• Applications where appearance of the raw weld is important.

• High-temperature applications (e.g., cylinder heads, heat exchangers).

• Where maximum crack resistance is critical.

• Use ER5356 for:

• Welding 5xxx series alloys (e.g., 5052, 5083, 5086) - this is a must.

• Any structure where high strength is required (e.g., frames, chassis, platforms).

• Marine and automotive applications due to its strength and corrosion resistance.

• Parts that will be anodized for a finished appearance.

• Welding a mix of 5xxx and 6xxx series metals.

Summary: Which One Should You Choose?

• Choose ER4043 if you are welding 6xxx series or cast aluminum, need superior crack resistance, are working on high-temperature parts, or are not concerned about anodized color matching.

• Choose ER5356 if you are welding 5xxx series aluminum, need the strongest weld possible, your part will be anodized, or the application is for marine or structural purposes.