I. Thermal Expansion and Contraction Method
Cast iron is temperature-sensitive. First, use a blowtorch to evenly heat the elbow joint (taking care to avoid other components). When the surface turns slightly red, immediately wrap it with a wet cloth for rapid cooling.The thermal shock will loosen the rust layer, after which the elbow can be separated by gently tapping both sides with a rubber mallet.Wear heat-insulating gloves during operation and ensure good ventilation for high-temperature work.
II. Mechanical Loosening Method
For heavily rusted elbows, first soak the joint with rust remover for 6 hours. Then secure the main pipe with a pipe wrench, place a chain wrench on the elbow, and apply force slowly to rotate it.If it remains immovable, use an angle grinder to cut a 2 mm stress-relief groove on the side of the elbow to release internal stress. Ensure the cutting depth does not exceed 1/3 of the pipe wall thickness.
III. Sectional Cutting Technique
When traditional methods fail, use a portable cutter to make a circumferential cut along the centerline of the elbow, leaving a 5 mm connecting section to avoid damaging the main pipe.After cutting, pry the opening open with a wedge, then finish the remaining part with a hacksaw.Wear safety goggles during cutting and place a debris collection box under the pipeline.
