The Microstructure Evolution and Precipitation Behavior within HSLA Steels with Different M/C Atomic Ratios

The microstructure and hardening behavior of HSLA steels with different microalloying element/carbon (M/C) atomic ratios, namely high M/C steel (H-M/C) and low M/C steel (L-M/C), were investigated in the present study. A dual precipitation morphology of nanosized carbides, namely interphase precipitation carbides and random precipitation carbides, was found at the same ferrite grain of both kind of steels, and these precipitates are believed to provide the main strengthening ability within ferrite. Of the two steels with different M/C atomic ratios, the ferrite matrix of H-M/C steel showed a rising trend in micro-hardness with increasing isothermal holding times from 5 min to 60 min at 650°C to 700°C. This higher strengthening ability occurring within ferrite grains after holding at longer times can be ascribed to the higher austenite decomposition rate occurring in the H-M/C atomic ratio steel. Therefore, the hardening mechanisms in both kinds of steel are also discussed in the present study.

SOIL EROSION ASSESMENT IN SOUTHERN EVIA ISLAND USING USLE AND GIS

In the present study the evaluation of soil erosion in Southern Evia Island was carried out. Data related with precipitation, morphology, land cover and lithology were collected. A spatial database was created and the further processing of the collected data was prepared using GIS. The Universal Soil Loss Equation (USLE) was used to predict the spatial distribution of the average annual rate of erosion. Five major factors were used to calculate the soil loss. These are rainfall erositivity (R), soil erodibility (K), slope length and steepness (LS), cropping management (C) and conservation supporting practice (P). Each factor is the numerical estimate of a specific condition that affects the severity of soil erosion. The obtained soil loss values were used to create the erosion risk map. The applied methodology provides a cost effected and rapid estimation of areas that are vulnerable to soil erosion and need immediate attention from soil conservation point of view. Moreover these results can be used to assist land use planning.

Shaping the Microstructure of Cast Iron Automobile Cylinder Liners Aimed at Providing High Service Properties

The paper presents an analysis of factors affecting the wear of cylinder liners. The effect of the graphite precipitation morphology on the cylinder liner wear mechanism is presented. Materials used to cast cylinder liners mounted in a number of engines have been examined for their conformity with requirements set out in applicable Polish industrial standard. A casting for a prototype cylinder liner has been made with a microstructure guaranteeing good service properties of the part.