Heat shrinkable sleeve are extensively utilized in the anti-corrosion treatment of steel pipes. However, due to a lack of familiarity among customers regarding their performance and operational procedures, various issues frequently arise. To address this, Qingdao Huashida Machinery Co., Ltd. has developed a standardized construction process.
Prior to application, it is essential to thoroughly clean the patching area, removing all debris and rust to achieve the specified steel surface rust grade prior to painting or the rust grade Sa2.5 to Sa3.0 as defined by GB/8923. The polyethylene layer at the lap joint must be ground, followed by bevel treatment with an angle not exceeding 30 degrees. Preheating should then be conducted before proceeding with the construction process. The lap width must be no less than 100mm. Construction will cease if humidity exceeds 85% or during rainy or snowy conditions.
Following construction, a thorough inspection is required to ensure that the appearance is smooth and flat, free from wrinkles, bubbles, carbonization, and that the two bevel corners are tightly adhered to the heat shrinkable sleeve . At joint repair points, each pinhole must be individually inspected using a spark leak detector at a voltage of 15kV. Any detected leakage points necessitate rework. The adhesive force must meet established standards, with peel strength not falling below 50N/cm at 25±5℃.
The quality inspection of anti-corrosion coatings (primers) primarily focuses on leak detection. After the coating has fully cured and cooled to ambient temperature, each joint must be inspected using a spark detector: for standard grade, the voltage is set at 2kV, and for reinforced grade, it is 2.5kV. The test head should move at a speed of approximately 0.2m/s. By utilizing Huashida-certified heat shrinkable sleeve, strictly adhering to construction specifications, and conducting comprehensive welding quality inspections, the anti-corrosion and joint repair effectiveness of pipelines can be ensured.
