The concentric reducer in transfer oil line and some of the bends in the front of radiation section of cylindrical furnace in furfural equipment in a refinery suffered localized corrosion.

Standard system for reducers commonly used at home and abroad was introduced, thirty(30) safety incident cases caused by reducer failure were analyzed from aspects of fitting, welding, erosion, breakage, stress corrosion etc.

Detailed siress analysis was carried out for a section of the pipeline including an eccentric reducer on which long cracks appeared twice.

The tapered pipe in air-cooling accessory line of a certain ammonia synthetic tower was cracked.

Based on statistics analysis of an invalid tapered pipe with finite element software Pro/MECHANICA,the stress distribution diagram was obtained and cause of tapered pipe failure was found.

This paper mainly introduces the ultrasonic detecting method against longitudinal cracks on 60 mm×6 mm reducing pipe installed in boiler water wall, including probe selection, adjusting of detecting sensitivity, identification of defect waves, and etc.

The formula of circumferential membrane stress of bend reducer under internal pressure has infer according to its two characteristics in structure,one of which is that the radius of cross section of loop should change with the meridian bending angle,and the other is that it is a conical shell.

Based on modem acoustic theory,the data of different diameters pipe temperament by ZHU Zaiyu and the revised data by YANG Yinliu are analyzed and calculated.

The introduction on the technique of the reducing HDPE pipe insertion method for remediation of on-line old pipes;