Good sales stage: Preparation before homework
1. Anran inspection (of utmost importance)
Personal protective equipment (PPE):
Protective goggles/face shields: Dark colored eye protection lenses (usually 5 # to 7 #) specifically designed for gas cutting are required to prevent strong arc light and splashes from damaging the eyes. It is strictly prohibited to use sunglasses as a substitute.
Protective gloves: heat-resistant leather gloves that protect hands from high-temperature metals and splashes.
Flame retardant work clothes: Wear tight fitting, oil-free work clothes to prevent skin exposure and clothing from catching fire.
Anran shoes: labor protection shoes that are resistant to impact and puncture.
Work environment inspection:
Confirm the location: Flammable and explosive materials (such as oil, wood, gas tanks, etc.) are strictly prohibited from being stored near the operation site.
Firefighting preparation: Confirm that sufficient firefighting equipment, such as fire extinguishers and firefighting sand, is available on site.
Ventilation: Confirm that the work area is well ventilated, especially in enclosed or semi enclosed spaces, to prevent the accumulation of toxic gases and metal dust.
Inspect the workpiece: Remove oil, paint, moisture, and debris from the surface of the workpiece to be cut, especially from sealed containers, which need to be thoroughly cleaned and confirmed to have no explosion risk. The workpiece should be elevated to avoid direct contact with the cement floor (which is prone to explosion).
2. Equipment connection and inspection
Gas cylinder fixation: Separate the oxygen cylinder and acetylene cylinder (or liquefied petroleum gas cylinder) and place them upright, firmly fix them to prevent tipping.
Install flashback preventer: A qualified flashback preventer needs to be installed between the oxygen and gas pressure regulator (pressure reducing valve) and the cutting torch.
Connecting the gas path:
Distinguishing gas paths: Oxygen pipes are blue or black, while gas pipes are red. Confirm the connection is correct and prohibit reverse connection appropriately.
Connection sequence: First connect the tempering preventer, then connect the hose to the cutting torch. The interface needs to be firm, without air leakage or aging cracks.
Check the airtightness:
Slightly open the oxygen and gas cylinder valves and blow off the dust at the interface (do not harm people).
Install the pressure reducer and adjust the screw to a relaxed state (no output pressure).
Then slowly open the bottle valve and check for any air leaks at all joints (soap water can be used for leak detection).
Parameter adjustment:
Gas pressure: Adjust the gas pressure regulator to the appropriate pressure (usually 0.05-0.1 MPa) based on the cutting nozzle model and steel plate thickness.
Oxygen pressure: According to the process requirements, adjust the oxygen pressure reducer to the cutting oxygen pressure (usually much higher than the gas pressure, specific values refer to the cutting nozzle specification table).
Excellent stage: ignition, ignition adjustment, and cutting
3. Ignition operation
Open the torch valve:
Slowly open the acetylene (or gas) valve on the cutting torch counterclockwise for about half a turn.
Then slowly open a small portion of the preheating oxygen valve counterclockwise.
Ignition: Use a one-on-one ignition gun to ignite on the side and rear of the cutting nozzle. It is strictly prohibited to use ordinary lighters or matches to ignite, as it can easily cause finger illness.
Adjust preheating flame:
After ignition, adjust the flame to neutral flame by adjusting the gas valve and preheating oxygen valve.
Neutral flame characteristics: The flame core is a clear bright blue conical shape with distinct contours, and the outer flame is light blue. The flame is stable and does not make a "hissing" sound (peroxide) or emit black smoke (carbonization flame).
4. Preheating and cutting
Preheating: Place the cutting nozzle perpendicular to the surface of the workpiece, with the flame center about 2-5mm away from the workpiece, and align it with the starting point of the cutting line for uniform preheating.
Cutting off:
When the preheating point appears bright red or in a molten state (about 1300 ° C), it indicates that the ignition point of the steel has been reached.
Open the cutting oxygen valve at a constant speed: At this point, press the cutting oxygen handle/valve smoothly and thoroughly with your right thumb or palm.
Hearing the piercing sound of "pu" and seeing sparks and slag spraying out from the bottom of the workpiece indicates that it has been cut through.
5. Normal cutting
Maintain stability: After cutting through, immediately adjust the inclination angle of the cutting torch according to the thickness of the steel plate (when cutting thick plates, it can be tilted backwards by 5 °~10 ° in the direction of movement).
Uniform movement: Move along the cutting line at a uniform speed. If the speed is too fast, it cannot be cut through; If the speed is too slow, the incision will be too wide and the edges will melt severely.
Maintain distance: Throughout the cutting process, keep the distance between the cutting nozzle and the surface of the workpiece basically unchanged (about 3-5mm).
Observing slag: When cutting, observe the direction of the slag (spark beam) spray. If the spark beam tilts back about 15 degrees in the direction of movement, it indicates that the speed is appropriate.
Phase Three: End of Cutting and Closing
6. Shutdown and shutdown sequence
At the end of cutting, the cutting oxygen valve should be closed first, and then the cutting torch should be moved away from the workpiece at a suitable speed.
Closing sequence: Close the gas valve on the cutting torch first, and then close the preheating oxygen valve. This sequence is crucial to prevent tempering and the production of black smoke.
7. Equipment Closing
Close the cylinder valve: After all work is completed, first close the cylinder valves of the oxygen and gas cylinders.
Release pipeline pressure: Open the oxygen and gas valves on the cutting torch again to discharge the residual gas in the pipeline until the pressure gauge returns to zero.
Loosen the pressure regulator: Loosen all adjustment screws of the pressure regulator to prevent the pressure spring from failing.
Wrap the hose: Arrange the cutting torch and hose and hang them on a one-to-one rack.
Key Enron Warning and Common Problems
Tempering treatment: If you hear a "hissing" scream or flames backfire into the cutting torch, this is a sign of tempering! It is necessary to immediately close the cutting oxygen valve, and then close the gas valve at a suitable speed. Tempering is usually caused by overheating, blockage, or improper operation of the cutting nozzle.
Cutting nozzle blockage: If the flame shape is abnormal or the cutting oxygen line is not straight, the cutting nozzle may be blocked. One on one needle should be used for cleaning, and it is strictly prohibited to poke with hard objects such as steel wire.
Poor incision quality:
Cannot cut through: too fast speed, insufficient pressure, insufficient preheating.
Upper edge melting: slow speed, strong preheating flame, too close cutting distance.
There is a lot of slag hanging on the lower edge: the speed is too fast, the oxygen pressure is insufficient, and the cutting nozzle size is too small.