How to Solve the Quality Problem of Hollow Hinge Profile Weld_Hinge Knowledge

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The DQx profile is a type of hollow hinge extruded profile that is commonly used as a connecting structural part for doors, windows, and other applications. However, ensuring the quality of profile welds has been a significant challenge due to the large rotational forces that the hollow parts of the joints are subjected to. Over the past two years, several batches of DQx hollow hinge profiles have been found to have poor weld seams and irregularities, particularly in the middle section. Various factors such as heating time after repair, extrusion temperature and speed, ingot cleaning, and mold design have been analyzed and multiple solutions have been proposed to address this quality issue. By adjusting the extrusion process, strengthening inspection control, and creating new molds, the problem of poor weld seams in DQx hinge profiles has been successfully resolved, offering valuable insights for improving the quality control of weld seams in hollow profiles.

2 Mechanism of weld formation

The tongue-shaped die extrusion method is used to create single-hole or porous hollow profiles with minimal wall thickness unevenness and complex shapes. During the extrusion process, the metal ingot is divided into two or more strands through shunt holes and then reassembled in the welding chamber of the mold under high temperature and pressure. This results in the formation of distinct weld seams in the extruded profile, with the number of seams corresponding to the number of metal strands the ingot is divided into. The presence of a rigid area at the bottom of the bridge in the mold slows down the diffusion and bonding of metal atoms, leading to a reduced tissue density and the formation of weld seams. It is crucial for the metal at the weld seam to be fully diffused and bonded to ensure a solid structure. Incomplete welding or poor bonding can result in delamination and compromised weld quality.

3 Cause analysis of weld failure

3.1 Analysis of mold factors

The cross-sectional dimensions of DQx hollow hinge profiles show asymmetry and uneven wall thickness in the solid part, posing challenges in mold design. The layout and design of the shunt hole and bridge in the mold have been identified as problematic, leading to insufficient metal filling in the welding chamber, inconsistent metal flow rates, and poor welding. The configuration of the mold for the solid part also contributes to uneven metal distribution and unstable metal flow during the extrusion process.

3.2 Factor analysis of process parameters

Factors such as the quality and composition of the ingot, extrusion temperature and speed, and mold cleanliness and condition have been identified as influential in weld quality. Inconsistent ingot temperature, the presence of internal and external defects, and uneven distribution of strengthening and impurity phases can lead to poor welding. Improper extrusion temperature and speed, unclean extrusion barrels, and large gaps between the extrusion cylinder and pressure pads can also adversely affect weld quality.

4 Solving measures for poor welding seam welding

4.1 Optimize mold design

To address the challenges posed by the asymmetrical dimensions and uneven wall thickness of DQx hollow hinge profiles, the center position of the mold bridge and mold core should be carefully considered and adjusted. The layout of the shunt hole and design of the bridge should be optimized to ensure adequate metal filling and uniform metal flow rates. Measures should also be taken to prevent aluminum sticking to the mold surface and affecting profile surface quality.

4.2 Welding and repairing molds

To compensate for manufacturing errors and improve mold flow rates, welding and repairing the mold can be an effective solution. By adjusting the flow rate of the mold, especially in the hollow part, the metal flow can be stabilized, ensuring proper welding in the welding chamber. Preventing excessive stress on the weld seam during tension straightening is also important to maintain weld quality.

4.3 Homogenization treatment of ingot

Homogenizing the casting ingot before extrusion is essential to dissolve strengthening phases and impurities, ensuring consistent distribution of alloy components. This treatment eliminates dendrite segregation and internal stress in the ingot, improving its plasticity and reducing extrusion resistance. Etching and cleaning the ingot surface before extrusion is also necessary to ensure weld quality.

4.4 Extrusion Process Parameters

Optimizing extrusion parameters such as temperature, speed, and elongation rate is crucial for ensuring weld quality. Proper extrusion temperature facilitates metal diffusion and bonding, while excessive speed can increase deformation work and elevate metal temperature. Cleanliness of the extrusion cylinder and proper gap tolerances are also important for weld quality.

5 Effect Verification

Several small-scale test productions were conducted using the optimized mold and process, resulting in a weld quality rate of over 95% and consistent appearance of defective weld profiles. These results confirm the effectiveness of the proposed solutions to address the key issues identified.

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This article has highlighted the challenges associated with weld quality in DQx profile hollow hinge extrusions. By optimizing mold design, implementing welding and repair measures, homogenizing the ingot, and optimizing extrusion process parameters, significant improvements have been achieved in weld quality. The insights gained from this research will contribute to the ongoing efforts to enhance the quality control of weld seams in hollow profiles. AOSITE Hardware, one of the leading manufacturers in the industry, maintains a strong commitment to excellence and has obtained several certifications in recognition of its business capabilities and international competitiveness.