Static Restoration Research Articles

Static recrystallization and restoration after hot deformation of Type 304 stainless steel

AbstractSpecimens of Type 304 stainless steel have been deformed in torsion at temperatures of 950–1150°C and annealed for different times before quenching or continuing the deformation. The kinetics of static recrystallization and the recrystallized grain size have been determined by quantitative metallography. Increasing strain and decreasing original grain size both reduce recrystallization time and recrystallized grain size. Increasing strain rate and decreasing temperature of deformation have a similar, but smaller effect. Annealing temperature also strongly influences recrystallization time (activation energy 425 kJ mol−1), but not recrystallized grain size. The effects of all the experimental variables are described in terms of simple parametric relationships. The kinetics of static restoration have been determined both from hardness tests on quenched specimens and from interrupted torsion tests. The extent of restoration is related in a non-linear manner to fraction recrystallized. This arises par...

The Use Of Nondestructive Tests On Historic TimberStructures

Non destructive and partially destructive diagnosis of buildings is, currently, a very important question in the field of Civil Engineering for two main reasons. First there is the need to know, with a fairly high degree of accuracy, about the mechanical characteristics of the materials in situ in order both to draw up the structural profile of a construction and to proceed in the most correct way towards drawing up a project for the static restoration of existing structures. The second reason lies in the more general need to formulate a realistic model either of functioning of the whole structure or of one part of it, starting from the information the construction itself offers in its current state, under specific testing conditions. At the present state of knowledge, the conservation and restoration of ancient timber structures has raised a series of problems that have not received sufficient attention at both methodological and technical level. In particular they regard: the assessment of the real efficacy (and/or reliability) of the use of new diagnostic methods to evaluate the conservation status of the material, the forecast of the structural functionality of both their overall behaviour and that of the individual elements, the judgment of the durability of works performed using innovative type techniques. The paper present a series of non destructive techniques carried out on the XVIII-XIX century wooden floors of Venetian houses, either in original state and restored or replaced, and with the addition of one or two series of planks of wood. Transactions on the Built Environment vol 26, © 1997 WIT Press, www.witpress.com, ISSN 1743-3509