Introduction of copper tube welding technology

Copper tube is not uncommon in real life, but our understanding of it may only stay in use, and we know little about the previous welding process or method. therefore

A, copper pipe welding process

Tool preparation: welding torch, acetylene cylinder, oxygen cylinder and nitrogen cylinder. Step: Check whether the oxygen and acetylene bottles are sufficient. Welding shall be carried out according to the drawing requirements. When welding the solenoid valve, remove the coil of the solenoid valve to prevent damage, and pay attention to its flow direction. When welding other parts, such as liquid reflector, expansion valve, check valve, etc. Attention should be paid to thermal damage when welding. If necessary, the detachable parts can be removed, and the welded valve body can be wrapped with wet cotton cloth. When welding, low-speed nitrogen should be introduced into the welded pipe to prevent oxidation. After welding, cool and use dry nitrogen to remove oxides and welding slag in the pipe.

Second, the copper pipe welding method

Strictly follow the steps when welding, otherwise the welding quality will be affected.

1, preparation and piping

1. 1, check whether the amount in the oxygen and acetylene cylinders is enough.

1.2, check the drawing requirements to ensure that all parts are complete and functional.

1.3, ensure that the optical path of the pipeline is horizontal and vertical, and pay attention to the directionality of each valve.

1.4, according to the size and pipe diameter required by the drawing, measure the corresponding length with a tape measure, and mark the position with a line number for many times.

1.5. After the thicker copper tube is fixed, remove it with a knife to ensure that the incision is flush and not deformed.

1.6. File off the cutting edge with a file and clean it with a rag. Material flow and welding quality.

1.7. Except for copper welding, all pipe fittings should be cleaned with gauze or stainless steel wire brush before welding to expose the bright metal surface. (All internal surfaces shall be cleaned and metal chips and sand shall be removed. )

1.8. Insert the copper pipes to be welded overlapping each other (pay attention to the dimensions) and align them with the center of the circle.

1.9. See table for the insertion depth and clearance between copper pipe joint and copper pipe. (The insertion depth is approximately equal to the pipe diameter)

Step 2 protect

2. 1, when welding, low-speed nitrogen should be introduced into the welded pipe emulsion to prevent oxidation.

2.2. Acetylene gas should pass through the non-oxidation welding generator to prevent the outer surface of the welded object from being oxidized.

Step 3 weld

3. 1, when welding, the welding parts must be preheated. Heat the welded joint of copper tube with flame. When the copper tube is heated to purple, the flame is removed, and the solder is leaned against the joint, so that the solder melts and flows into the welded copper piece. The heating temperature can be reflected by the color, and the dark red color is about 600 degrees Celsius. Deep red: about 700 degrees Celsius; Orange: 1000 degrees Celsius.

3.2, welding, gas welding flame shall not directly heat covered electrode.

3.3. For the parts that are easily deformed and damaged under high temperature conditions, corresponding protective measures should be taken. Such as angle valves, evaporators, condensers, etc. , should be wrapped in wet gauze at the joint before welding. For solenoid valves, expansion valves, liquid reflectors and four-way valves, the detachable ones must be disassembled and welded, and the above measures are also taken.

3.4 During welding and post-welding annealing of copper tubes, the annealing temperature shall not be lower than 300 degrees Celsius.

3.5 After welding, cool with dry nitrogen to remove oxides and welding slag in the pipe.

In addition to preparing complete materials, such as welding torch, acetylene bottle and oxygen bottle, we should also refer to reasonable steps, such as checking whether the amount in oxygen bottle and acetylene bottle is enough, which are representative operations. Besides, it is not enough to pay attention to welding, because the later maintenance is equally important. Only by integrating all aspects of knowledge can we give full play to the maximum value of customs clearance and avoid the trouble caused by damaged service life.