Shaping in the Hamburg method involves pushing the charge pipe off a specially formed pin located inside the pipe. The pin has a circular cross-section along its entire length. It starts out straight and turns curved at the end. By using a feed pipe with a suitably smaller diameter for shaping, excess material from the inner bend can be evenly distributed around the entire circumference of the bend, thus ensuring a constant wall thickness around the entire circumference. The process is carried out hot, ensuring appropriate heating parameters, appropriate design parameters of the mandrel and properly calibrated material flow control. This combination of factors allows you to obtain pipe elbows with geometric parameters that are unattainable with other plastic forming methods.

Sections of steel pipe cut into appropriate lengths are placed on the press bar. After turning on the heater, the press slider with the pushing sleeve is activated. The heated section is gradually pressed onto the deforming section of the pin. Gradual bending occurs with a simultaneous increase in diameter. The shaped elbow falls onto the roller table and is carried further. The process is carried out continuously until the last section of the pipe is pressed onto the shaping section of the mandrel. The press slide is then retracted. You can apply a new batch of feed pipes and continue the process.

Basic stages of the technological process in the production of butt elbows using the Hamburg method:
– control of dimensions, quality and marking of feed pipes;
– cutting pipes into sections ensuring the appropriate bending angle of the finished elbows;
– hot deformation of pipes;
– cooling and quality control;
– surface cleaning;
– cutting and chamfering ends;
– protection against corrosion.

Older technological lines use gas heating. The newest ones use induction heating (high power, efficiency, high heating rate, repeatability).

The quality of elbows produced by this method is primarily influenced by: the quality of the surface of the charging pipes, the shape of the mandrel, the thermal parameters of the process, the elbow pushing speed and the appropriate direction of heating.

Elbow defects are usually related to inadequate quality of feed pipes or failure to comply with hot forming technology.