1. The aluminum bar is bent, twisted and wavy.
Due to unreasonable die hole design, too fast extrusion speed, improper lubrication of die hole, improper guide path or guide path not installed, etc.
2. Bubbling and peeling.
Due to the poor wear of the inner diameter of the extrusion cylinder, the gap between the extrusion pad and the cylinder is too large; Oil and sewage adhered to the extrusion cylinder and the extrusion pad; There are air holes, sand holes and oil stains on the surface of the ingot, and the surface of the ingot is too rough; The temperature of extrusion cylinder and ingot is too high, and the filling speed is too fast; The die is smeared during extrusion.
3. Extrusion crack.
As the temperature of the extruded billet is too high, the extrusion speed is too fast, the billet treatment is uneven, the mold design is unreasonable, and the flow difference between the center and the edge is too large.
4. Pits or pitted surfaces.
The extrusion speed is too fast or uneven due to the high temperature of cylinder and billet; The working belt of the die is adhered to metal and not smooth; The hardness of the die worktable belt is insufficient or the inner width of the working belt is insufficient; The ingot is too long.
3. Scratches and ridges.
Defects or corners due to die work; The empty die knife is sharp and not smooth; There are foreign matters on the workbench, which is not clean; Hard inclusions in the ingot plug the die hole.
4. The size is unqualified.
Due to die design error or manufacturing defect; Improper mold repair; The billet temperature rise is too high and the extrusion speed changes too much during extrusion; The calculation of billet length is not accurate, and the dimension length is not enough.
5. Stratification
6. There is oil stain and dust on the surface of steel ingot; The surface quality of steel ingot is poor and the segregation lump is large; There are residues on the mold surface; There are reasons such as stratification and bubble in the ingot itself.
7. Tailing
Because the extrusion residue is too short, the extrusion gasket is painted or not clean, the steel ingot surface is not clean, and the product cutting length is not enough, the extrusion speed suddenly increases at the end of extrusion.
5. The performance is unqualified.
Because the extrusion temperature is too low, the profile cannot reach the quenching temperature; The artificial prescription system is inappropriate; The instrument is out of control, and the furnace temperature is too high or too low; The ingot structure is uneven, and the cooling air volume is insufficient.
6. Extrude the cross grain.
Due to unreasonable design of aluminum bar die, unequal length of working belts at the same part, improper control of extrusion speed, and unstable operation of the extruder.