touchdown joints gen.

[A_Ander]

Пожалуйста, помогите перевести
touchdown joints; touchdown section
Контекст:
Critical (touchdown) joints – buried defects;
Critical welds include at least those welds in the section that is characterized as the “touchdown zone”;
non-critical welds are made using different welding procedures than the procedures used for critical welds, for example, in a riser with a clad welded touchdown section, and carbon steel upper section
Заранее большое спасибо!

[s_khrytch]

скорее всего, какая-то опорная зона или опорный элемент