Ritmo BASIC 160 V1, Use And Maintenance Handbook

Page: 16 / 95

2. WELDING GENERAL CRITERIA
ﻠﻟا ﺮﻴﻳﺎﻌﻣ ﺔﻣﺎﻌﻟا مﺎﺤ
2./7
WELDING CYCLES
Following are the welding parameters that the operator must set and control afterwards:
Heating plate temperature, Pressures,
Bead dimension, Length of each phase.
The formulas required to calculate the welding parameters (according to the compound and the welding standards being used)
are illustrated in Chapter 9, as well as the parameters for the most common diameters.
SIMPLE PRESSURE WELDING CYCLE
P
1
: Approach and pre-heating pressure
P
2
: Maximum heating pressure
P
5
: Welding pressure
P
t
: Dragging pressure (pressure required to overcome friction - must be read by the operator on the gearcase manometer)
t
1
,
t
2
, …,
t
6
: Length of Phases
1
,
2
, …,
6
Phase 1 Approach and Pre-heating.
Approach both ends to be welded to the heating plate at the
(P
1
+P
t
)
pressure, and wait until the beads reach the required width (UNI 10520) or height (DVS 2207).
Phase 2 Heating.
Reduce pressure to
P
2
maximum value, sufficient to keep the ends in touch with the heating
plate for the entire
t
2
time.
IMPORTANT!
The ends to be welded MUST NOT detach from the heating plate while the pressure is being reduced. If
that happens, the welding
must absolutely
be repeated.
Phase 3 Removal of heating plate.
Remove the heating plate within the maximum
t
3
time, without damaging the
beads.
Phase 4 Reach of welding pressure.
Get both ends together while gradually increasing the pressure up to
(P
5
+P
t
)
value, during
t
4
time. Prevent an excessive leakage of melted material while performing this
phase.
Phase 5 Welding.
Keep both ends together at the
(P
5
+P
t
)
pressure for the entire
t
5
time.
Phase 6 Cooling.
The joint must not be removed or suffer any sort of mechanical strain for the entire
t
6
time.
Do not use water or compressed air to rush cooling. Protect the joint from rain, wind or excessive sunlight.