Corporate commitment to sustainability – is it all hot air? A review of the linkage between executive pay and sustainable performance

Across time, companies are increasingly making public commitments to sustainable development and to reducing their impacts on climate change. Management remuneration plans (MRPs) are a key mechanism to motivate managers to achieve corporate goals. We review the MRPs negotiated with key management personnel in a sample of large Australian carbon-intensive companies. Our results show that, as in past decades, the companies in our sample have MRPs in place that continue to fixate on financial performance. We argue that this provides evidence of a disconnection between the sustainability-related rhetoric of the sample companies, and their ‘real’ organisational priorities.

Formation of ultra-fine ferrite in hot rolled strip: potential mechanisms for grain refinement

A novel single-pass hot strip rolling process has been developed in which ultra-fine (<2 μm) ferrite grains form at the surface of hot rolled strip in two low carbon steels with average austenite grain sizes above 200 μm. Two experiments were performed on strip that had been re-heated to 1250°C for 300 s and air-cooled to the rolling temperatures. The first involved hot rolling a sample of 0.09 wt.%C–1.68Mn–0.22Si–0.27Mo steel (steel A) at 800°C, which was just above the Ar3 of this sample, while the second involved hot rolling a sample of 0.11C–1.68Mn–0.22Si steel (steel B) at 675°C, which is just below the Ar3 temperature of the sample. After air cooling, the surface regions of strip of both steel A and B consisted of ultra-fine ferrite grains which had formed within the large austenite grains, while the central regions consisted of a bainitic microstructure. In the case of steel B, a network of allotriomorphic ferrite delineated the prior-austenite grain boundaries throughout the strip cross-section. Based on results from optical microscopy and scanning/transmission electron microscopy, as well as bulk X-ray texture analysis and microtextural analysis using Electron Back-Scattered Diffraction (EBSD), it is shown that the ultra-fine ferrite most likely forms by a process of rapid intragranular nucleation during, or immediately after, deformation. This process of inducing intragranular nucleation of ferrite by deformation is referred to as strain-induced transformation.

Effect of process variables on formation of dynamic strain induced ultrafine ferrite during hot torsion testing

Ultrafine grain sizes were produced using hot torsion testing of a 0.11C-1.68Mn-0.20Si (wt-%) steel, with ultrafine ferrite (<1 µm) nucleating intragranularly during testing by dynamic strain induced transformation. A systematic study was made of the effect of isothermal deformation temperature, strain level, strain rate, and accelerated cooling during deformation on the formation of ultrafine ferrite by this process. Decreasing the isothermal testing temperature below the Ae₃ temperature led to a greater driving force for ferrite nucleation and thus more extensive nucleation during testing; the formation of Widmanstätten ferrite prior to, or early during, deformation imposed a lower temperature limit. Increasing the strain above that where ferrite first began 0.8 at 675C and a strain rate of 3 s¯¹ increased the intragranular nucleation of ferrite. Strain rate appeared to have little effect on the amount of ferrite formed. However, slower strain rates led to extensive polygonisation of the ferrite formed because more time was available for ferrite recovery. Accelerated cooling during deformation followed by air cooling to room temperature led to a uniform microstructure consisting of very fine ferrite grains and fine spherical carbides located in the grain boundaries regions. Air cooling after isothermal testing led to carbide bands and a larger ferrite grain size.

The production of ultrafine ferrite during hot torsion testing of a 0.11 Wt Pct C steel

Ultrafine ferrite grain sizes were produced in a 0.11C-1.6Mn-0.2Si steel by torsion testing isothermally at 675 °C after air cooling from 1250 °C. The ferrite was observed to form intragranularly beyond a von Mises equivalent tensile strain of approximately 0.7 to 0.8 and the number fraction of intragranular ferrite grains continued to increase as the strain level increased. Ferrite nucleated to form parallel and closely spaced linear arrays or “rafts” of many discrete ultrafine ferrite grains. It is shown that ferrite nucleates during deformation on defects developed within the austenite parallel to the macroscopic shear direction (i.e., dynamic strain-induced transformation). A model austenitic Ni-30Fe alloy was used to study the substructure developed in the austenite under similar test conditions as that used to induce intragranular ferrite in the steel. It is shown that the most prevalent features developed during testing are microbands. It is proposed that high-energy jogged regions surrounding intersecting microbands provide potential sites for ferrite nucleation at lower strains, while at higher strains, the walls of the microbands may also act as nucleation sites.

Solid state recycling of 5083 Al alloy by hot extrusion

The machined chips of 5083 Al alloy were recycled by hot extrusion at 723 K with an extrusion ratio of 44:1 in air. Corrosion and mechanical properties of the recycled specimens have been compared with those of a virgin extrusion which was processed from the ingot block. As a result of salt immersion tests, mass loss of the recycled specimen was not less than twice of that of the virgin extrusion. The deterioration in corrosion properties for the recycled specimen was attributed to the excessive contamination of Fe which promoted galvanic corrosion. As a result of tensile tests, the recycled specimen exhibited a good combination of high strength and high elongation to failure at room temperature. The excellent mechanical properties for the recycled specimen were attributed to the refined microstructure. However, the elongation to failure of the recycled specimen at elevated temperatures more than 573 K was lower than that of the virgin extrusion. The contamination of oxide particles is likely to be responsible for the lower elongation in the solid recycled specimen.

Air pressure and wind velocity - modelling ember attack within the urban-rural interface

As population change places pressure on expanding regional and metropolitan urban boundaries, so the threat of bushfire at the rural/urban interface increases. This paper presents a range of 2D and 3D 1:40 and full scale modelling investigations. Various relationships are explored between the urban and rural interface with respect to: air pressure; changes in wind pattern; vectorial velocity; and the deposition of hot ash and firebrand deposits around single story building forms, both as standalone and within an orthogonal array and cul-de-sac relationships.

Sensitivity of the final properties of tailored hot stamping components to the process and material parameters

The final mechanical properties of hot stamped components are affected by many process and material parameters due to the multidisciplinary nature of this thermal-mechanical-metallurgical process. The phase transformation, which depends on the temperature field and history, determines the final microstructure and consequently the final mechanical properties. Tailored hot stamping parts - where the cooling rates are locally chosen to achieve structures with graded properties - has been increasingly adopted in the automotive industry. In this case, the robustness of final part properties is more critical than in the conventional hot stamping parts, where the part is fully quenched. In this study, a wide range of input parameters in a generalized hot stamping model have been investigated, examining the effect on the temperature history and resulting final material properties. A generic thermo-mechanical finite element model of hot stamping was created and a modified phase transformation model, based on Scheil's additive principle, has been applied. The comparison between modeling and experiments shows that the modified phase transformation model coupled with the incubation time provides higher accuracy on the simulation of transformation kinetics history. The robustness of four conditions relevant to tailored hot stamping was investigated: heated tooling (with low and high tool conductance), air cooling, and conventional hot stamping. The results show the high robustness of the conventional hot stamping compared to tailored hot stamping, with respect to the stamped component's final material properties (i.e. phase fraction and hardness). Furthermore, tailored hot stamping showed higher robustness when low conductivity tools are used relative to high conductivity tools.

Numerical modeling of vertical earth pipe cooling system for hot and humid subtropical climate

Energy crisis is one of the major problems facing the progress of human society. There are several energy-efficient technologies that can be applied to save energy and make a sustainable environment. Passive air cooling of earth pipe cooling technology is one of them to reduce the energy consumption for hot and humid subtropical climates. The technology works with a long buried pipe with one end for intake air and the other end for providing air cooled by soil to the desired space such as residential, agricultural, or industrial buildings. It can be an attractive economical alternative to conventional cooling since there are no compressors or any customary mechanical unit. This chapter reports the performance of a vertical earth pipe cooling system for a hot and humid subtropical climatic zone in Queensland, Australia. A series of buried pipes were installed in vertical arrangement in order to increase earth pipe cooling performance. To measure the performance of the system, a numerical model was developed and simulated using the CFD software Fluent in ANSYS 15.0. Data were collected from two modeled rooms built from two shipping containers and installed at the Sustainable Precinct at Central Queensland University, Rockhampton, Australia. The impact of air temperature and velocity on room cooling performance has also been assessed. A temperature reduction of 1.82 °C was observed in the room connected to the vertical earth pipe cooling system, which will save the energy cost for thermal cooling in buildings.

Understanding temperature and contact pressure in hot stamped channels

This paper investigates the temperature and contact pressure conditions in hot stamped channels of boron steel. Hot stamping has been used for many years to produce high strength structural auto-motive components. The high tensile strengths achievable by hot stamping is beneficial where the intrusion during a vehicle crash is not desirable – e.g. for the vehicle occupant compartment. How-ever, the high blank temperatures and high temperature cycling causes a large amount of wear in the tooling. These conditions have led to high tool failures and die maintenance costs. Thus, un-derstanding the main causes of wear behaviour in the hot stamping process is of high interest to hot stampers.
To this aim, a generic 2D thermo-mechanical finite element model of a hat-shaped crash formed hot stamped component was developed (based on the authors previous hot stamp model), and a modified phase transformation model based on Scheil’s additive principle has been applied. The model was created in the finite element software ABAQUS Standard V6.13, including convection and radiation when the component was transferred from furnace to the tool as well as the air-cooling process. A USDFLD subroutine was used to model the phase transformation and a HET-VAL subroutine was used to model the latent heat. Contact heat conductance was a function of the pressure.
The authors have used techniques from their previous work on tool wear estimation for cold stamping to estimate the contact pressure on the tooling, and the amount of sliding that occurs over the tooling, and the corresponding tooling temperature. This data provides a unique data set to understand the wear on the tooling, and will eventually lead to a model for estimating tooling life.

Integrated model of horizontal earth pipe cooling system for a hot humid climate

Energy efficiency of a building has become a major requirement since the building sector produces 40%-50% of the global greenhouse gas emissions. This can be achieved by improving building’s performance through energy savings, by adopting energy efficient technologies and reducing CO2 emissions. There exist several technologies with less or no environmental impact that can be used to reduce energy consumption of the buildings. Earth pipe cooling system is one of them, which works with a long buried pipe with one end for intake air and the other end for providing air cooled by soil to the building. It is an approach for cooling a room in a passive process without using any habitual mechanical unit. The paper investigates the thermal performance of a horizontal earth pipe cooling system in a hot and humid subtropical climatic zone in Queensland, Australia. An integrated numerical model for the horizontal earth pipe cooling system and the room (or building) was developed using ANSYS Fluent to measure the thermal performance of the system. The impact of air temperature, soil temperature, air velocity and relative humidity on room cooling performance has also been assessed. As the soil temperature was below the outdoor minimum temperature during the peak warming hours of the day, it worked as an effective heat sink to cool the room. Both experimental and numerical results showed a temperature reduction of 1.11oC in the room utilizing horizontal earth pipe cooling system which will assist to save the energy cost in the buildings.