Radoslaw W. Maruda

An influence of active additives on the formation of selected indicators of the condition of the X10CrNi18-8 stainless steel surface layer in MQCL conditions

The paper presents the results of the research into the impact of anti-wear added to emulsion mist on the geometrical state of the machined surface of stainless steel after turning. In the research, the following machining conditions were compared: dry machining and cooling with compressed air, emulsion mist, emulsion mist + Crodafos O4A-LQ-(MH) and emulsion mist + Crodafos EHA-LQ-(MH). In the first stage, the influence of modifiers on roughness parameters of the machined surface were established. The aim of the second stage was to submit the machined material to microroentgenospectral analysis. The presence of chemical elements on the machined material surface for the aforementioned conditions of machining was analysed. Research results indicate that the application of cooling with emulsion mist with modifiers reduces the roughness parameters of the machined material even up to 80%. Adequately selected conditions of forming emulsion mist forms border layer, beneficially influencing the cutting conditions.

Influence of cooling conditions on the machining process under MQCL and MQL conditions

Original scientific paper The paper presents the results of investigation of the influence of conditions of forming emulsion and oil mist on the chip shape and surface roughness of X10CrNi18-8 stainless steel during turning. In the tests, the following machining operations have been compared: dry machining, cooling by the MQCL (Minimal Quantity Cooling Lubricat) method, cooling by the MQL (Minimum Quantity Lubricat) method. The tests have been performed in two stages. In the first stage, the influence of the mass flow of the active medium on the chip shape and on the Ra and Rq roughness parameters of the machined surface have been determined. The purpose of stage two was to determine the influence of the MQL and MQCL method on the selected indices of the machining process as compared to dry machining as a function of variable cutting speed. It has been found that, under MQCL and MQL conditions, the area of formation of elemental chips and ones with the shape of short spirals is wider as compared to dry turning. With increased mass flow of emulsion and oil, tangled chip is formed. Cooling by the MQCL and MQL method results in reduction of the selected roughness parameter values by 2 % to 42 % as compared to dry machining.

Structural and Microhardness Changes After Turning of the AISI 1045 Steel for Minimum Quantity Cooling Lubrication

This work presents the cooling effect under minimum quantity cooling lubrication and dry cutting on structural changes and microhardness of the ferritic-pearlitic AISI 1045 steel after turning. Due to the fact that the AISI 1045 steel has a two-phase structure, microhardness tests using the Vickers method were conducted with a load of 0.05 HV separately for ferrite and pearlite grains. The tests showed that cooling of the cutting zone under minimum quantity cooling lubrication (MQCL) condition decreased the depth of the hardened layer compared to dry cutting by approximately 40% for both pearlite and ferrite. Scanning electron microscopy analysis revealed that applying MQCL limits the formation of plastic deformations, among others, by reducing the surface crumple zone by approximately 50% compared to dry cutting. As a result of cooling being applied to the cutting zone using the MQCL method, the average diameter of ferrite grains has been decreased in the entire surface area compared to dry cutting. When using dry cutting, clear structural changes of the surface layer were also observed. This may be the result of sulfide inclusions which have formed, causing microcracks on the edge of the hardened layer and surface deformation visible as notches.

Improving the efficiency of running-in for a bronze–stainless steel friction pair

In this paper, the possibility of the transfer of additives that are in the emulsion mist is shown by the example of the bronze CuSn7Zn4Pb6–stainless steel X10CrNi18-8 friction pair. The additive is first transferred on the processed surface of the part and through it–in the contact zone of the friction pair. It was established that the emulsion mist reduces the roughness of machined stainless steel surface more than three times, and the introduction of additives based on phosphate esters into the emulsion reduces the roughness by 4–4.5 times. Phosphate-based additive remains on the machined surface in significant quantities, even after 30 min working at heavy loads, reducing the instantaneous friction coefficient and the temperature of the friction zone. The mean width of profile elements of the assessed profile of bronze samples decreases by two times and their bearing length ratio decreases by four times. In this case, a decrease in the wear rate of bronze by more than 40% is ensured. This fact indicates the better running-in of the friction pair.

Topographic inspection as a method of weld joint diagnostic

The paper demonstrates a topographic inspection in the specific context of three kinds of inspection methods of austenitic stainless steel welds. Visual and metrological inspection was analysed during tungsten inert gas (TIG) welding tests, showing the non-destructive techniques: X-ray, computed tomography, and surface profilometry. The article is a response to the lack of information, especially in the area of non-destructive techniques suitable for wide practical application. The Paper presents advantages and drawbacks of the analysed diagnostic methods and a classification of conventional and specific welded joint flaws. The most important defect in practical applications determining reliability of a welded joint is cracks. This kind of diagnostic is based on the obtained information about anisotropic and inhomogeneous volume under consideration in the heat-affected zone of a weld.

Research on emulsion mist generation in the conditions of minimum quantity cooling lubrication (MQCL)

The paper presents the effect of emulsion mist generation parameters and the distance of the nozzle from the contact zone of the cutting wedge with the workpiece on the diameter and number of droplets supplied into the cutting zone. The conditions of emulsion mist generation, in which all the droplets supplied to the cutting zone in a given time, are evaporated in this time. An analysis of heat flow in the MQCL method was presented and it was proved that the air flow and the distance of the nozzle from the cutting zone have the most significant effect on the diameter of droplets.

EFFECT OF ANTI-WEAR ADDITIVE ON CUTTING TOOL AND SURFACE LAYER OF WORKPIECE STATE UNDER MQCL CONDITIONS

The work presents the results of investigation of the influence of anti-wear additive Crodafos EHA-LQ-(MH) added to the emulsion mist on the condition of machined surface of 1.4310 stainless steel after turning. The investigation included the comparison of the following cutting conditions: dry machining, cooling by the MQCL method and cooling by the MQCL method with Crodafos EHA-LQ-(MH). In the paper, the influence of the Anti-Wear (AW) additive on the roughness parameter Ra of the machined surface for various cutting speeds, vc, and mass flow of the emulsion E has been shown. It was found that the MQCL+AW method decreases the Ra parameter values by 14 % to 35 % in comparison with dry cutting and by 17 % in comparison with MQCL method.The machined material and the rake face of the cutting wedge have been subjected to micro X-ray spectroanalysis. Chemical analysis of the cutting wedge and the surface layer of the machined material has been performed. The results show that water dropletts in MQCL method are very good transport facility for active compounds of AW additive that consequently form the dry-film lubricant on the machined surface.

Influence of Technological Cutting Parameters on Surface Texture of Austenitic Stainless Steel

The paper presents the contribution in engineering of surfaces particularly in surface texture of Austenitic Stainless Steels. The objective of the investigation was to determine the surface texture of austenitic stainless steel after turning with coated carbide tool point. The investigation included geometrical parameters of Surface Integrity for different technological cutting parameters in dry turning process of austenitic stainless steel. The article presents the surface roughness parameters with the roughness profiles (irregular slopes). The percentage of isotropic surfaces and Bearing Area of Primary Model. Analyses were performed for variable cutting parameters. An Infinite Focus Measurement Machine (IFM) was used for the surface texture analysis. The study was performed within a production facility during the machining of electric motor parts and deep-well pumps.

Dynamic Programming Approach in the Optimization of Tool Life in Turning Process of Duplex Stainless Steel DSS

The paper presents the application of dynamic programming for optimization of cutting parameters of Duplex Stainless Steels (DSS). In this work, modified Dijkstras optimization algorithm is used in order to obtain the optimal values of the technological cutting parameters with coated carbide tool point. ANOVA analysis was performed to determine the significance of machining parameters. The results at optimum cutting condition are predicted using estimated values. The study was performed within a production facility during the machining of electric motor parts and deep-well pumps.

Taguchi design of experiment versus dynamic programming approach in the optimization of turning process

The paper examines the influence of cutting parameters, namely cutting speed and feed rate on the tool life in machining process of cylindrical billets made from a Duplex Stainless Steel (DSS). Two optimization methods is presents, one based on the Taguchi design of the experiment with orthogonal array L9 and signal-to-noise ratio (S/N) and the second based on the dynamic programming approach with modified Dijkstras algorithm have been used to find optimal levels of the control parameters. ANOVA was performed to determine the significance of the input variables. A predictive mathematical model has been developed through a regression analysis to study the response. The results at optimum cutting conditions are predicted using estimated values. Finally, the features, the merits and the limitations of the presented optimization approaches were discussed.