Measurement Technology of Steel PipeWall Thickness Based on Computer Radiograph

A methodology is proposed for evaluation of steel pipe wall thickness based on the CR imaging system, which is of great significance to the corrosion monitoring of pipelines, in this paper. Through experiments, the relationship between the contrast response characteristics of CR imaging system and the ray energy was studied by using steel step wedge to determine the linear response range of CR imaging system for thickness measurement. Then the digital image quality of three steel pipe samples with different wall thickness was evaluated according to the detection technology level specified in the special equipment standard in order to optimize the exposure parameters. The thickness-gray linear equations measured and fitted under the optimal exposure parameters were used to calculate the wall thickness. Measurement errors were less than 3% for given samples. This paper verifies the feasibility of CR measurement of pipe wall thickness of special equipment, and provides an auxiliary method for pipe wall corrosion monitoring.