Future Issues Facing Boston: The Assessing Department

Taxpayers\u27 opinions of municipal government often focus on the property tax. Taxpayers are stingy, and they are critical as to whether their money is purchasing competent services. For citizens to have faith that government is democratic, taxes must be equitable — everyone must pay their fair share. For government to function efficiently, tax administration must be efficient in order to support city services. The property tax is a complex, difficult tax to administer; it is vulnerable to misuse. However, there have been recent, dramatic changes to the tax laws. Municipal government in Massachusetts now has the political and legal wherewithall to properly administer the tax. The new administration has a unique opportunity to initiate programs promoting equity and efficiency. This paper discusses three areas where they can act

Comparative Study of the Tempering Behavior of Different Martensitic Steels by Means of In-Situ Diffractometry and Dilatometry

Martensitic steels are tempered to increase the toughness of the metastable martensite, which is brittle in the as-quenched state, and to achieve a more stable microstructure. During the tempering of steels, several particular overlapping effects can arise. Classical dilatometric investigations can only detect effects by monitoring the integral length change of the sample. Additional in-situ diffractometry allowed a differentiation of the individual effects such as transformation of retained austenite and formation of cementite during tempering. Additionally, the lattice parameters of martensite and therefrom the tetragonality was analyzed. Two low-alloy steels with carbon contents of 0.4 and 1.0 wt.% and a high-alloy 5Cr-1Mo-steel with 0.4 wt.% carbon were investigated by dilatometry and in-situ diffractometry. In this paper, microstructural effects during tempering of the investigated steels are discussed by a comparative study of dilatometric and diffractometric experiments. The influence of the chemical composition on the tempering behavior is illustrated by comparing the determined effects of the three steels. The kinetics of tempering is similar for the low-alloy steels and shifted to much higher temperatures for the high-alloy steel. During tempering, the tetragonality of martensite in the steel with 1.0 wt% carbon shifts towards a low carbon behavior, as in the steels with 0.4 wt.% carbon

A multiscale perspective on the kinetics of solid state transformations with application to bainite formation

We give an excerpt of recent developments in the experimentally benchmarked modeling of bainite formation in the press hardening process. As the press hardening process poses a heavily multi-parameter dependent modeling challenge, we focus on three main branches which complement each other. We emphasise the combination of basic sharp interface and phase field models with pragmatically adapted multi phase field models and experimentally parametrized implementations of the Johnson-Mehl-Avrami model. In the basic thermodynamic modeling part, we review fundamental aspects of displacive and diffusional-displacive transformations to predict dominant transformation morphologies. These results provide a link to multi-phase-field implementations which allow to simulate isothermal bainitic transformations, supported by available material data from thermodynamic databases. Excellent agreement with experiments, e.g. scanning electron microscopy for the transformed bainite in the high-carbon steel 100Cr6 shows the value of these model implementations. The further connection to Johnson-Mehl-Avrami models offers to extend the understanding to transformation plasticity for the press hardening steel 22MnB5

Segregations in Steels during Heat Treatment – A Consideration along the Process Chain

Abstract Segregation is an unavoidable phenomenon in continuous or ingot casting of steel for thermodynamic reasons. If costly processes that explicitly reduce segregation are not carried out, the segregations remain until the final product. Therefore, an understanding of the development and effects of segregation along the entire process chain is necessary. The focus in this publication is on the treatment of segregations in low alloy steels. First, the characterisation of segregation is presented. An overview of the formation and development of segregations during primary shaping and forming processes is given. The focus is on segregation-related effects during heat treatment with regard to inhomogeneous microstructure and negative heat treatment results such as distortion or hardening cracks. In a short outlook, the influence of segregation on the component behaviour is described. ◼</jats:p