Common Extrusion Defects and Prevention Methods for Automotive Aluminum Extrusion

In the automotive manufacturing sector, the quality of automotive aluminum extrusion parts is of paramount importance as it directly impacts vehicle performance and safety. For aluminum extrusion parts manufacturers for automotive offering aluminum extrusion services for automotive industry, understanding and preventing common extrusion defects are critical for producing high-quality extruded aluminum parts, such as extruded aluminum chassis components or aluminum extrusion plate products.

1. Crack Defects: Guarding Against "Wounds" in Metal

1.1 Surface Cracks

Surface cracks resemble "wounds" on the metal surface and can significantly affect part quality. They are primarily caused by insufficient material ductility, poor lubrication, or improper mold design, leading to excessive tensile stress on the outer metal layer.

To prevent surface cracks, consider the following measures:

Optimize mold design (e.g., using tapered dies) to reduce stress concentration and ensure smooth metal flow.

Improve lubrication (e.g., through phosphating, soaping, or surface coating) to facilitate metal movement during extrusion.

Control extrusion speed and temperature to prevent rapid material cooling and ensure proper deformation conditions.

Select materials with good ductility to lay a solid foundation for high-quality extrusion.

1.2 Center/Shrink Tail Defects

Center or shrink tail defects occur in the late stages of extrusion due to uneven metal flow, allowing oxides or contaminants to enter the product's interior.

Prevention methods include:

Implementing a holding pressure process or use the decorticated extrusion processto block impurities.

Enhancing billet surface treatment (e.g., mechanical processing) to remove contaminants and oxide layers.

Optimizing extrusion barrel and mold design to minimize residual gases and create a favorable environment for metal flow.

2. Surface Defects: Creating a Smooth "Outer Layer"

2.1 Surface Roughness/Vibration Marks

Uneven or vibrating surfaces affect both the aesthetics and performance of parts. They are mainly caused by improper mold design, equipment vibration, or uneven cooling.

To address these issues:

Improve mold manufacturing precision and adjust support pads to ensure a tight seal.

Ensure stable equipment operation by adjusting extrusion axis speed.

Control cooling uniformity to prevent excessive temperature differences between thick and thin sections.

2.2 Inclusions/Water Stains

Inclusions or water stains result from contaminated billets or residual water/oil on the metal surface.

Prevention involves:

Strengthening billet inspection using ultrasonic testing to detect impurities early.

Ensuring products are dry and clean, and optimizing furnace fuel cleanliness and quenching medium management.

3. Internal Defects: Focusing on "Internal Health" of Metal

3.1 Gas Pores

Gas pores, acting like "bombs" hidden within metal, can weaken part strength. They are caused by residual gas in the extrusion barrel, moisture in cast ingots, or improper shearing of press remnants.

Prevention measures include:

Optimizing cast ingot hydrogen removal processes and improving hot shear surface flatness.

Adjusting extrusion pressure and pre-flow processes to fully exhaust gases.

Avoiding excessive mold oil application or residue.

3.2 Mechanical Property Nonconformity

Parts with subpar mechanical properties are akin to a "weak body" unable to perform adequately. This is often due to insufficient extrusion ratios or improper temperature and speed controls.

To prevent this:

Select an appropriate extrusion ratio (usually ≥10) to provide sufficient "exercise" for the metal.

Precisely control cast ingot heating temperature and extrusion speed to enhance metal performance.

4. Dimensional Deviations: Precision is Key

Dimensional deviations can render parts "ill-fitting" and unusable. They are mainly caused by mold wear, material springback, or process parameter fluctuations.

Prevention involves:

Regularly inspecting and maintaining mold precision.

Conducting process tests to determine optimal temperature-speed parameters.

5. Other Defects: Details Make the Difference

5.1 Wrinkles/Folds

Wrinkles or folds, caused by uneven material flow, affect part appearance and performance. Adjusting mold structure and lubrication conditions can guide metal to flow uniformly and eliminate "wrinkles."

5.2 Coarse Grain Ring

Coarse grain rings can be prevented by controlling extrusion temperature and speed, and properly retaining residual material to ensure a more orderly metal crystallization process.

For automotive aluminum extrusion suppliers in the automotive aluminum extrusion market, every defect can impact the quality of automotive aluminum extrusion parts. Only by deeply understanding and effectively preventing these common defects can high-quality products be manufactured.

Shaoyi Company specializes in custom design and processing services. Whether you need to produce custom aluminum extruded bushings for cars or other automotive aluminum extrusion products, our extensive experience and professional technology can help you prevent various extrusion defects and create high-quality aluminum extrusion parts. Choose Shaoyi for a professional, precise, and reliable aluminum extrusion processing partner.