The wedge and bulge expansion tests were compared in the assessment of the seam welds strength in a tubular profile extruded at two ram speeds.In the wedge test,the expansion was determined by moving a conical punch i...The wedge and bulge expansion tests were compared in the assessment of the seam welds strength in a tubular profile extruded at two ram speeds.In the wedge test,the expansion was determined by moving a conical punch into the tube until the specimen fracture.In the bulge test,a hydrostatic tensile stress state was applied by expanding the specimen with an internal rubber plug.The two methodologies were compared in terms of load and hoop strain at fracture and by detecting the fracture morphology and location.Then,the effect of a number of design parameters was investigated in order to evaluate the robustness of the standard testing conditions.For both tests,ductile fractures appeared in the seam welds location,but the bulge test was more robust and conservative with respect to the wedge test,showing less scattered data.Thus,the performances of a second die for the tube profile,designed to optimize the seam welds quality,have been successfully assessed by the bulge test and results compared to those achieved by a novel numerical quality index,coming to a final good matching.展开更多
With a grant from the Italian Ministry of the Environment, the National Institute of Health (Istituto Superiore di Sanita) promoted and coordinated some activities aimed at determining the extent and the intensity of ...With a grant from the Italian Ministry of the Environment, the National Institute of Health (Istituto Superiore di Sanita) promoted and coordinated some activities aimed at determining the extent and the intensity of contamination of waters used for human consumption by some chemical agents, and describing causes and modalities of contamination and human health implications. The chemical agents examined were herbicides, nitrates, trihalomethanes, asbestos, manganese and fluoride. In this paper a first nationwide picture of these problems is reported.展开更多
文摘The wedge and bulge expansion tests were compared in the assessment of the seam welds strength in a tubular profile extruded at two ram speeds.In the wedge test,the expansion was determined by moving a conical punch into the tube until the specimen fracture.In the bulge test,a hydrostatic tensile stress state was applied by expanding the specimen with an internal rubber plug.The two methodologies were compared in terms of load and hoop strain at fracture and by detecting the fracture morphology and location.Then,the effect of a number of design parameters was investigated in order to evaluate the robustness of the standard testing conditions.For both tests,ductile fractures appeared in the seam welds location,but the bulge test was more robust and conservative with respect to the wedge test,showing less scattered data.Thus,the performances of a second die for the tube profile,designed to optimize the seam welds quality,have been successfully assessed by the bulge test and results compared to those achieved by a novel numerical quality index,coming to a final good matching.
文摘With a grant from the Italian Ministry of the Environment, the National Institute of Health (Istituto Superiore di Sanita) promoted and coordinated some activities aimed at determining the extent and the intensity of contamination of waters used for human consumption by some chemical agents, and describing causes and modalities of contamination and human health implications. The chemical agents examined were herbicides, nitrates, trihalomethanes, asbestos, manganese and fluoride. In this paper a first nationwide picture of these problems is reported.
