Measurement for crystallinity of polyethylene PE100 grade pipe for butt fusion joint
Polyethylene PE100 grade pipe for butt fusion joint for urban gas was used to porduce the cold welding defective joint with typical temperature range,whose crystallinity was measured by X-ray diffractometer to obtain the basis for the cold welding defect safety assessment.The results show that the crystallinity of cold welding joint is closely related to the welding temperature of the joint,and the crystallinity value is the highest at 210℃and 230℃,while the crystallinity value is lower at 130℃and 250℃.When crystallinity increases,the highest peak moves in the direction of increasing diffraction angle.The half-peak width of cold welding defects is more than 1.3° at 130℃and 150℃,and the disorder of molecular chain arrangement is increased.