(1) argon arc welder must have a pressure vessel welder qualification certificate, no permit personnel are strictly prohibited to weld.
(2) in order to effectively control the speed of heating of the welded parts, should be used as far as possible to break the arc method of welding, welding wire diameter selected towel 3mm, while welding current should be given strict control, such as towel 12 * 2 instrumentation pipe joints recommended to use 60 ~ 80 amps welding current, the maximum should not exceed 90 amps.
(3) Each welding port welding process should be paused about 3 times, after each pause, to wait for its temperature to drop to about 60", and then continue to weld, in order to save time, can be several welding ports alternately. After breaking the arc and then starting the arc, be sure to pay attention to the quality of the weld at the arc, usually in the arc arc pit back 5-6mm after breaking the arc to start the arc, wait for the molten pool to form, add some appropriate welding wire. Then start the normal welding.
(4) welders in the arc, to be particularly focused, in order to reduce the arc pit cracking, shrinkage of the chances of production, you can extend the current decay time. So that the temperature of the welded parts can slowly drop, and the arc to the wall thickness of the thicker instrument pipe joint side to lead to
(5) after welding, observe the appearance of its weld luster, if no luster and into the gray, indicating that the organization has been over-burned, coarse, such a situation, should be re-pairing, welding. At the same time, should strengthen the inspection of the arc out, found that there are cracks, shrinkage, surface porosity and other defects should be polished processing or welding rework.
(6) Instrument tube and aluminium tube and aluminium container, aluminium tube on the joint before welding shall be welded samples (with the same instrument tube and joint) to test its strength and welding performance, and get the supervision and the owner and other parties to confirm before the next step can be carried out.
When welding instrumentation tubes, Dear Air Separation ensures the safety of small air separation unit and large air separation unit by working strictly in accordance with its performance.
