Experimental optimization of simulated ring rolling operation for heavy rail industry

“Industrially cast AISI 1070 steel wheel pre-forms from Amsted Rail Co. were experimentally hot rolled to simulate the conditions for industrial wheel rolling. Ring rolling of near net shape castings can improve location specific properties by decreasing segregation, closing porosity, and reducing grain size without the use of multiple forging operations in a traditional forging line. As-cast wheel sections were subjected to thermomechanical processing routes using a 2-high rolling mill in a temperature range of 830°C to 1200°C. The goal being to simulate the ring rolling process and optimize benefits of mechanical properties of the as-rolled steel. Charpy V- and U-notch impact tests were conducted at -20ºC and 20ºC, respectively, as a function of thermomechanical processing and notch orientation. Mitigation of cast defects such as inclusions and shrinkage porosity by hot rolling were quantified utilizing scanning electron microscopy and micro-computed X-Ray tomography. Microshrinkage porosity was shown to be virtually eliminated at a 66% reduction. A rolling temperature of 830°C resulted in a 114% increase in KCU at 20°C and 67% increase at -20°C in KCV for L-S impact properties through refinement of prior austenite grain size. Anisotropy related to MnS stringers in the rolling direction were the primary cause for reduction in impact toughness in the T-L orientation although grain texture also likely plays a role. Hot tensile tests performed between 830°C to 1200°C in strain rates of 0.1 to 10 s-1 were utilized to develop a Johnson-Cook Strength model. The experimental parameters determined from the Johnson-Cook model were used as inputs to develop a Finite Element Analysis model of the modified wheel rolling process utilizing FORGE NxT software”--Abstract, page iv

The Effects of Forming Parameters on Conical Ring Rolling Process

The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established. The changing laws of equivalent plastic strain (PEEQ) and temperature distributions with rolling time were investigated. The effects of ring’s outer radius growth rate and rolls sizes on the uniformities of PEEQ and temperature distributions, average rolling force, and average rolling moment were studied. The results indicate that the PEEQ at the inner layer and outer layer of rolled ring are larger than that at the middle layer of ring; the temperatures at the “obtuse angle zone” of ring’s cross-section are higher than those at “acute angle zone”; the temperature at the central part of ring is higher than that at the middle part of ring’s outer surfaces. As the ring’s outer radius growth rate increases at its reasonable value ranges, the uniformities of PEEQ and temperature distributions increase. Finally, the optimal values of the ring’s outer radius growth rate and rolls sizes were obtained

Surface treatments for nickel and nickel-base alloys

Surface treatments of nickel and nickel alloys by diffusion coating, electroplating, explosive hardening, peening, and other method

Armourers and their workshops The tools and techniques of late medieval armour production

This thesis is an interdisciplinary study of medieval armour, with the goal of determining the precise techniques used by medieval armourers in the practice of their craft. The corpus for this research is from the collection of the Royal Armouries, as well as a selection of objects from other museums, with a focus on German and Italian armour between 1400 and 1500. The thesis makes use of a new methodology by which the armour itself is used as a primary source, in essence a text, using the interpretation of tool marks left on its surfaces. Although metallurgical studies have been undertaken on armour, the marks have not been systematically studied in the past and provide a means by which the techniques of the medieval armourer may be identified. The thesis also makes use of inventories, artwork, and experimental hammerwork to more accurately understand the workshop environment. Inventories show the variety of tools required in the workshop, as well as what would have been available to an armourer. Artwork showing armourers engaged in their craft is used to interpret some patterns of tool marks as well as identification of certain tools and techniques. The experimental work undertaken was used to recreate particular types of marks and patterns, demonstrating the relation between tools, processes, and the shapes of armour. The research demonstrates that it is possible, using this method, to reconstruct the ways that armourers worked, something that has been largely conjectural previously. This approach to armour studies has not been attempted before and has allowed for several specific questions to be answered. These include finding differences in working techniques of armourers from different regions, the ability to determine if certain unmarked objects were made by the same armourer, changing methods of construction, and whether a piece is a fake or authentic

Third Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution 1881-\u2782

Annual Report of the Bureau of Ethnology. [2317] Research related to the American Indian; third annual report