Experimental Analysis of the Austenitic Phase in Steels by the Application of X-Ray Diffractometry

Uniform austenite remaining in the microstructure of the martensitic transformation is called the residual austenite. It is undesirable structure in components, due to its slow decay causes dimensional instability in these components and reducing the hardness. There is a change in volume and it generate internal stress which often appear as cracks. The residual austenite is highly undesirable component in the molded parts, as well as the production of gears and bearing components. The article deals with quantification of residual austenite in steels by using the Average peak method by X-ray diffraction. This method applies four separate peaks to determine the amount of austenite.

Transient Heat and Mass Transfer Flow through Salt Water in an Ocean by Inclined Angle

In the present computational study, the inclined angle effect of unsteady heat and mass transfer flow through salt water in an ocean was studied. The governing equations together with continuity, momentum, salinity and temperature were developed using the boundary layer approximation. Cartesian coordinate system was introduced to interpret the physical model where x-axis chosen along the direction of salt water flow and y-axis is inclined to x-axis. Two angle of inclination was considered such as 90° and 120°. The time dependent governing equations under the initial and boundary conditions were than transformed into the dimensionless form. A numerical solution approach so-called explicit finite difference method (EFDM) was employed to solve the obtained dimensionless equations. Different physical parameter was found in the model such as Prandtl number, Modified Prandtl number, Grashof number, Heat source parameter and Soret number. A stability and convergence analysis was developed in this study to describe the aspects of the finite difference scheme and this analysis is significant due to accuracy of the EFDM approach. The convergence criteria were observed to be in terms of dimensionless parameter as Pr ≥ 0.0128 and Ps ≥ 0.016. The distributions of the temperature and salinity profiles of salt water flow over different time steps were investigated for the effect of different dimensionless parameters and shown graphically.

Non-Destructive Analysis of Basic Surface Characteristics of Titanium Dental Implants Made by Miniature Machining

One of the most best-known characteristic and important requirement of dental implant is made of biomaterials ability to create correct interaction between implant and human body. The most implemented material in manufacturing of dental implants is titanium of different grades of pureness. Since most of the implant surface is in direct contact with bone tissue, shape and integrity of said surface has great influence on the successful osseointegration. Among other characteristics of titanium that predetermine ideal biomaterial, it shows a high mechanical strength making precise machining miniature Increasingly difficult. The article is focused on evaluation of the resulting quality, integrity and characteristics of dental implants surface after machining.

Study of Hard Milling Surfaces Via Nondestructive Magnetic Method

Grinding operations are sometimes replaced with hard turning or milling cycles. Mechanism of chip separation during grinding and the corresponding surface integrity remarkably differs from hard turning or milling. For this reason, this paper deals with application of Barkhausen noise for evaluation of surface anisotropy after hard milling. Experiments were carried out on bearing steel 100CrMn6 hardened on 45, 55, 62 HRC and one series without heat treatment. The analysis contains comparison of RMS values for the different hardness and tool wear after hard milling and also discusses the specific mechanism of BW motion in the case of cyclic magnetization.

Triaxial Measurement Method for Analysis of Residual Stress after High Feed Milling by X-Ray Diffraction

Surface integrity is a broad term which includes various quality factors affecting the functional properties of parts. Residual stress is one of these factors. Machining generates residual stresses in the surface and subsurface layers of the structural elements. X-ray diffractometry is a non-destructive method applicable for the measurement of residual stresses in surface and subsurface layers of components. The article is focused on the non-destructive progressive method of triaxial measurement of residual stress after machining the surface of sample by high feed milling technology. Significance of triaxial measuring is the capability of measuring in different angles so it is possible to acquire stress tensor containing normal and shear stress components acting in the spot of measuring, using a Cartesian coordinate system.

Investigation of Surfaces after Non Conventional Machining

This paper deals with analysis of surface integrity of steel after electro discharge machining (EDM), water jet machining, (WJM) laser beam machining (LBM) and plasma beam machining (PBM). The paper discusses surface integrity expressed in surface roughness, sample precision expressed in perpendicularity deviation as well as stress state. This study also demonstrates influence of the various non-conventional methods on structure transformations and reports about sensitivity of the different non-conventional methods of machining with regard to variable thickness of machined samples.

Non-Destructive Analysis of Surface Integrity on Parts from Austenitic Steel for Nuclear Industry

This article is focused on non-destructive detection method of residual stress and chemical properties of stainless steel. By X-ray diffractometry, there it is possible to determine accurately the values of residual stress and austenite percentage without any damage the sample without any change of its original function. Identification of residual stress and its distribution can improve the prediction of failures or damage incidences due to workload over lifetime of components. It can be also used as one of evaluation parameter of suitability of applied manufacturing technological operations.

The Influence of Selected Parameters on Evaluation of the Geometrical Shape Deviation – Cylindricity in 3D Measuring Machine Workspace

Each part as a final product and its surface is composed of various geometric elements, although at first glance seem as smooth and shiny. During the manufacturing process, there is a number of influences (e.g. selected manufacturing technology, production process, human factors, the strategy of measurement, scanning speed, shape of the measurement contact tip, temperature, or the surface tension and the like), which hinder the production of component with ideally shaped elements. From the economic and design point of view (in accordance with determined GPS standards), there is necessary fast and accurate analyze and evaluate these elements. Presented article deals with the influence of scanning speed and measuring strategy for assessment of shape deviations.

X-Ray Diffraction and its Possibilities and Application to Monitor Functional Properties of Components

This article deals with the issue of residual stress analysis in surface and subsurface layers in parts from progressive or hard-to-machine materials made by precise technologies. Measurements was executed by iXRD diffractometry device designed for residual stress and phase structures detection.

Computing of the Theoretical Value of Roughness Parameter Rz when Turning with Helical Cutting Edge

This article describes process of computing and identifying of the value of roughness parameter Rz deduced from basic kinematic and geometric characteristics of turning technology of machining with tool with helical cutting edge. The final mathematical formula is deduced from graphic sketch of turning process and consequently identified using all the known geometric and kinematic parameters. This formula can be used to theoretic evaluation of geometric and cutting parameters influence on the quality of machined surface determined by roughness characteristic of theoretic parameter Rz.