Cracks in seamless aluminum tubes are caused by tensile stress when the profiles are extruded, and transverse tearing of metals with different degrees of surface formation. The main causes of such phenomena are as follows:
1. Due to the frictional force, the metal surface layer is subjected to additional tensile stress, and cracks are generated when the additional tensile stress is greater than the tensile strength of the surface metal.
2. When the extrusion temperature is too high, the tensile strength of the metal surface decreases, and cracks are generated under the action of friction.
3. When the extrusion speed is too fast, the additional tensile stress on the metal surface layer causes the profile to crack.
The solution for cracking of seamless aluminum tubes is only to strictly control the extrusion process parameters to ensure reasonable exit speed and outlet temperature, in order to reduce the cracking of seamless aluminum tubes, which requires the company to strictly control and supervise production. process.