Bellow quality appraisal

Corrugated pipe, also known as metal hose, is a tubular part made of metal thin-walled materials. Its main feature is its ability to bend and deflect to a certain extent. Due to its good mechanical properties and chemical stability, corrugated pipes are widely used in industry, construction, automobile and chemical industries.
corrugated pipes can have different materials and appearances. The most common one is stainless steel corrugated pipes. Others include copper corrugated pipes, aluminum corrugated pipes, titanium corrugated pipes and other different materials.
Zhongke Testing and Appraisal Institute can provide quality appraisal services for stainless steel corrugated pipes, copper corrugated pipes, aluminum corrugated pipes and other corrugated pipes, and make accurate appraisals in terms of product design analysis, product load analysis and product quality analysis.

1. Classification by material
Common materials include stainless steel bellows, copper bellows, aluminum bellows and plastic bellows, etc.
2. Classification by shape
(1) Corrugated pipes are divided into round and square.
(2) is divided into single-layer corrugated pipes and double-layered corrugated pipes according to different corrugated structures.
(3) According to the thickness of the pipe wall, it can be divided into thin-walled corrugated pipes and thick-walled corrugated pipes.
3. Classification by use
(1) Metal corrugated pipe: mainly used in gas, water supply, chemical industry, HVAC and air conditioning and other fields.
(2) Plastic corrugated pipe: mostly used in electronics, automobiles, communications, home appliances and other fields.

GB/T 19647-2005 Plastic single-wall corrugated pipe for farmland drainage
GB/T 39754-2021 Hot-coated steel plate and steel strip for corrugated pipe
GB/T 38215-2019 Hot-rolled steel strip for structural corrugated pipe
GB/T 12777-2019 General technical conditions for metal bellows expansion joints
GB/T 35990-2018 Metal bellows expansion joints for pressure pipes
GB/T 30092-2013 Metal bellows compensators for high-voltage combined electrical appliances
GB/T 35979-2018 Technical specifications for the selection, installation, use and maintenance of metal bellows expansion joints
GB/T 19472.1-2019 Polyethylene (PE) structural wall piping system for underground use Part 1: Polyethylene double-wall corrugated pipe
GB/T 35451.1-2017 Polypropylene (PP) structural wall piping system for underground drainage and sewage Part 1: Polypropylene double-wall corrugated pipe
GB/T 18477.1-2007 Rigid polyvinyl chloride (PVC-U) structural wall piping system for underground drainage Part 1: Double-wall corrugated pipe
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A construction company purchased a batch of rigid-band reinforced polyethylene spiral corrugated pipes from a material company. The ring stiffness requirement is greater than or equal to 12.5KN/㎡. After the construction was completed, the pipelines collapsed one after another. The construction company believed that the collapse was caused by problems with the quality of the pipelines, so they appealed to the court.
Our company was entrusted by the court to undertake the quality analysis of the "bellows" involved in this case.
appraisal analysis results: The
quality analysis expert group discussed and comprehensively technical analyzed the relevant information, on-site investigation and inspection, and inspection and testing data of the "corrugated pipe" involved in the case, and made the following quality analysis opinions:
The minimum anti-corrosion layer thickness of the pipe fitting involved in the case does not meet the requirements of "CJ/T 225-2011 Steel Strip Reinforced Polyethylene (PE) Spiral Corrugated Pipe for Buried Drainage". It is not excluded that some pipe fittings have a ring stiffness of 10KN/㎡. There is a direct causal relationship between pipe fittings with ring stiffness less than 12.5KN/㎡ and pipe collapse.