Polyethylene material has some specification that makes very difficult any kind of inspection based on ultrasonic. The acoustic impedance and sound velocity in this kind of material are near to the materials commonly ...Polyethylene material has some specification that makes very difficult any kind of inspection based on ultrasonic. The acoustic impedance and sound velocity in this kind of material are near to the materials commonly used in ultrasonic wedges. Also this kind of materials are highly attenuative materials for ultrasound. To inspection of polyethylene circumferential but welds and overcome to all the problems mentioned, the especial technique of TOFD （Time of Flight Diffraction） method which employs low frequency probe and concentrate on the inspection area that longitudinal waves turn into transverse waves has been used. The purpose of inspection is determining the exact location of surface and internal welding defects. For this purpose, two separate polyethylene pipes with 10 inch in diameter, 15 mm thickness and also 25 inch diameter, 28 mm thickness, were selected. In total 40 artificial defects which involve 28 side drill holes in deferent depths and 12 surface and sub-surface notches were created. All artificially created defects were detected with very good accuracy. Unlike the conventional TOFD method which have 2 to 3 mm dead zone, by using the above method even surface notch with 0.5 mm has been detected.展开更多
During manufacturing and storage of 3PE pipes,the end PE upwarp is a common phenomenon,and the gap corrosion will be easy to produce under the condition of poor atmosphere environment, which hazard the anti-corrosion ...During manufacturing and storage of 3PE pipes,the end PE upwarp is a common phenomenon,and the gap corrosion will be easy to produce under the condition of poor atmosphere environment, which hazard the anti-corrosion quality of 3PE pipes and difficult to field coating for welded joints. The authors analyze the PE upwarp problem, and based on the analysis results the quality control measures are given for the manufacturing of 3PE pipes.展开更多
介绍了国内外耐热聚乙烯管材PE-RT树脂基本性能、结构特点,借助DSC、GPC、TREE、13C N M R等分析方法,对国内外PE-RT树脂产品结构进行剖析,对比分析这些树脂的微观结构,以及所反映的宏观力学、加工性能。试验结果表明,抚顺石化辛烯共聚...介绍了国内外耐热聚乙烯管材PE-RT树脂基本性能、结构特点,借助DSC、GPC、TREE、13C N M R等分析方法,对国内外PE-RT树脂产品结构进行剖析,对比分析这些树脂的微观结构,以及所反映的宏观力学、加工性能。试验结果表明,抚顺石化辛烯共聚耐热聚乙烯管材树脂DP800与同类产品相比,加工性能及力学性能较好。展开更多
文摘Polyethylene material has some specification that makes very difficult any kind of inspection based on ultrasonic. The acoustic impedance and sound velocity in this kind of material are near to the materials commonly used in ultrasonic wedges. Also this kind of materials are highly attenuative materials for ultrasound. To inspection of polyethylene circumferential but welds and overcome to all the problems mentioned, the especial technique of TOFD （Time of Flight Diffraction） method which employs low frequency probe and concentrate on the inspection area that longitudinal waves turn into transverse waves has been used. The purpose of inspection is determining the exact location of surface and internal welding defects. For this purpose, two separate polyethylene pipes with 10 inch in diameter, 15 mm thickness and also 25 inch diameter, 28 mm thickness, were selected. In total 40 artificial defects which involve 28 side drill holes in deferent depths and 12 surface and sub-surface notches were created. All artificially created defects were detected with very good accuracy. Unlike the conventional TOFD method which have 2 to 3 mm dead zone, by using the above method even surface notch with 0.5 mm has been detected.
文摘During manufacturing and storage of 3PE pipes,the end PE upwarp is a common phenomenon,and the gap corrosion will be easy to produce under the condition of poor atmosphere environment, which hazard the anti-corrosion quality of 3PE pipes and difficult to field coating for welded joints. The authors analyze the PE upwarp problem, and based on the analysis results the quality control measures are given for the manufacturing of 3PE pipes.
文摘介绍了国内外耐热聚乙烯管材PE-RT树脂基本性能、结构特点,借助DSC、GPC、TREE、13C N M R等分析方法,对国内外PE-RT树脂产品结构进行剖析,对比分析这些树脂的微观结构,以及所反映的宏观力学、加工性能。试验结果表明,抚顺石化辛烯共聚耐热聚乙烯管材树脂DP800与同类产品相比,加工性能及力学性能较好。
