2. Place one side of the circular tube on the plane to ensure that the nozzle is flush;

3. After measuring the angle of 45 in a section of the circular tube, cut the corresponding part with a hacksaw.

4. The other half of the material was sawed off in this way, so there are two 45 materials.

5. After aligning the two incisions, connect them by welding or crimping.

6. The picture below shows the finished product of 90 elbow.