widos 4900 - Page 22

Ku nst sto ffschwei ß tec hni k
Starting and operating Chapter 5
02.11.11 Working instructions WIDOS 4900 Page 22 of 46
• Move the pipe ends towards one another by means of the valve lever and plane same with a
planing pressure between 1 and 15 bar above the movement pressure.
Planing must be carried out until a revolving cutting has been formed on both sides.
• Open the slide again by means of the valve lever, switch off planer motor, remove planer and
put it into the heat protective box.
• Remove the produced cuttings without contacting the worked surfaces.
• Close slide.
• Check pipe mismatch and gap on the joining pipe ends. According to DVS 2207, the
mismatch on the pipe outer side must not exceed 0.1 x pipe wall thickness, the admissible gap
must not exceed 0.5 mm.
The mismatch compensation is carried out via further tightening or releasing of the
clamping nuts.
In case of a mismatch compensation, planing must be carried out again afterwards.
• The adjustment pressure for the pipe dimension to be welded can be gathered from the table.
Add the movement pressure.
Set the resulting pressure value at the pressure limiter valve and check by actuating the
valve lever.
• Open slide again slightly.
• Take heating up time, maximum change-over time, cooling down time and bead height for the
pipe dimension to be welded from the table.
• Move the heating element, which has been cleaned and brought to nominal temperature, by
means of the handle upwards between the pipes, if necessary wait until the control lamp on
the heating element flashes in regular intervals.
Take care that it lies in the zone of the throat of the tear-off bar (see point 4.3 ).
• Close slide smoothly to the set adjustment pressure.
When the prescribed revolving bead height has been reached, reduce pressure. For this
purpose, move the valve lever to the position „pressure-less“ until the desired heating up
pressure has built up (heating up pressure = approx. 10% of the adjustment pressure).
• The heating up time starts now. Press the stop watch and compare the actual time with the
nominal time taken from the table.
• After expiration of the heating up time, open the slide, remove the heating element as quickly
as possible, put it into the heat protective box and close the slide smoothly.
The maximum time frame for this process is predetermined by the value for the change-
over time taken from the table.
• When the welding pressure has been built up, press the stop-watch and keep the control lever
for approximately 10s on the position „pressure“ so that the hydraulic accumulator can be
filled. During the cooling down period re-adjust pressure, if necessary (the pressure for
cooling down is the same as the set adjustment pressure).
• After expiration of the cooling down period, release pressure, remove the welded parts and
open the slide.