Good Plastic Properties Research Articles

Study of Semi-Solid Magnesium Alloys (With RE Elements) as a Non-Newtonian Fluid Described by Rheological Models

This paper includes the results of high-temperature rheological experiments on semi-solid magnesium alloys and the verification of different models describing the rheological behaviour of semi-solid magnesium alloys. Such information is key from the point of view of designing alloy forming processes in their semi-solid states. Magnesium alloys are a very attractive material, due to their light weight and good plastic properties; on the other hand, this material is very reactive in a liquid (semi-solid) state, which is challenging from a testing and forming perspective. Formulating/finding models for an accurate description of the rheological behaviour of semi-solid magnesium alloys seems to be key from the standpoint of developing and optimising forming processes for semi-solid magnesium alloys.

Microstructure and Properties of Hybrid Laser Arc Welded Joints (Laser Beam-MAG) in Thermo-Mechanical Control Processed S700MC Steel

The article presents the microstructure and properties of joints welded using the Hybrid Laser Arc Welding (HLAW) method laser beam-Metal Active Gas (MAG). The joints were made of 10-mm-thick steel S700MC subjected to the Thermo-Mechanical Control Process (TMCP) and characterised by a high yield point. In addition, the welding process involved the use of solid wire GMn4Ni1.5CrMo having a diameter of 1.2 mm. Non-destructive tests involving the joints made it possible to classify the joints as representing quality level B in accordance with the ISO 12932 standard. Destructive tests of the joints revealed that the joints were characterised by tensile strength similar to that of the base material. The hybrid welding (laser beam-MAG) of steel S700MC enabled the obtainment of good plastic properties of welded joints. In each area of the welded joints, the toughness values satisfied the criteria related to the minimum allowed toughness value. Tests involving the use of a transmission electron microscope and performed in the weld area revealed the decay of the precipitation hardening effect (i.e., the lack of precipitates having a size of several nm) and the presence of coagulated titanium-niobium precipitates having a size of 100 nm, restricting the growth of recrystallised austenite grains, as well as of spherical stable TiO precipitates (200 nm) responsible for the nucleation of ferrite inside austenite grains (significantly improving the plastic properties of joints). The tests demonstrated that it is possible to make welded joints satisfying quality-related requirements referred to in ISO 15614-14.

INVESTIGATIONS OF WELDED CONNECTIONS OF THE BASIC TUBE DESIGN OF DRILLING RISER ABR-G

Background. This article deals with the problem of ensuring the operability of the main pipe structures of the riser. Raiser is one of the main components in the development of oil and gas fields on the shelf and sea. There are different types of risers, which are used depending on technological tasks. The system of the riser is an intermediate link between the offshore platform and the wellhead on the seabed. Raiser isolates the well from the environment, provides a closed circulation of the drilling fluid, serves as a channel for drilling and casing pipes, geophysical equipment, and also manages the blowout device components and connectors through hydraulic and service pipelines laid along the entire length of the riser. The design of the low-pressure riser is the concept of a 21-inch pipe with welded flange connections of the «Vetco» type. Raiser has two hydraulic lines, two lines of jammingthrottling and one booster. A typical material for the construction of the pipe structure of the riser is steel with good plastic properties, however, as the depth of the sea increases, exploration and development of deposits is becoming a matter of the possibility of using titanium and aluminum alloys, as well as composite materials. This is due to the in- crease in weight of equipment as the depth in- creases - a consequence of approaching the weight of the structure to critical strength val- ues. Aims and Objectives The main objective of the research is the analysis of displacement characteristics of oil wells and oil fields. Methods Samples of welded joints were subjected on the tensile machine INSTON 5900 Series. Alloy was analyzed for low-cycle fatigue, on a test machine PSA, 100 kN (Schenck Trebel Corporation). Rezults Based on the results of the conducted studies, it was concluded that the technology of welding manual arc welding does not provide the necessary strength characteristics required for operation of the ADB-G riser. The strength of the welded joint was 0.60-0.61σ from the yield strength of the base metal, while the reference values were 0.98σ.

Conformal antenna array for millimeter-wave communications: performance evaluation

In this paper, we study the influence of the radius of a cylindrical supporting structure on radiation properties of a conformal millimeter-wave antenna array. Bent antenna array structures on cylindrical surfaces may have important applications in future mobile devices. Small radii may be needed if the antenna is printed on the edges of mobile devices and in items which human beings are wearing, such as wrist watches, bracelets, and rings. The antenna under study consists of four linear series-fed arrays of four patch elements and is operating at 58.8 GHz with linear polarization. The antenna array is fabricated on polytetrafluoroethylene substrate with thickness of 127 µm due to its good plasticity properties, and low losses. Results for both planar and conformal antenna arrays show rather good agreement between simulation and measurements. The results show that conformal antenna structures allow achieving large angular coverage and may allow beam-steering implementations if switches are used to select between different arrays around a cylindrical supporting structure.

Influence of copolymer fraction composition in ultrahigh molecular weight polyethylene blends with ethylene/1‐hexene copolymers on material physical and tensile properties

AbstractThe reactor blends (RBs) with bimodal molecular weight distribution on the base of ultrahigh molecular weight polyethylene (UHMWPE) and low molecular weight random ethylene/1‐hexene copolymers (CEH) were synthesized by two‐step processes including ethylene polymerization followed by ethylene/1‐hexene copolymerization over rac‐(CH3)2Si(Ind)2ZrCl2/methylaluminoxane catalyst. The four series of blends differed in a composition of copolymer fraction that was varied in a wide range (from 3.0 to 37.0 mol % of 1‐hexene). The differential scanning calorimetric study shows the double melting behavior of the net semicrystalline CEHs, which can be attributed to intramolecular heterogeneity in chain branch distribution. The introduction of CEHs leads to the modification of nascent RB crystalline and amorphous phases. Physical and tensile properties as well as melting indexes of the materials depend not only on the percentage of copolymer fraction that varied from 6.9 to 35.8 wt % but also on its composition. The increase of copolymer fraction with high content of 1‐hexene (≥11.0 mol %) in the blends leads to the change of the character of stress–strain curves; the materials behave as elastomers. Controlled regulation of copolymer fraction characteristics in the synthesis yields RBs combining the enough high strength, good plastic properties with enhanced melting indexes as compared with the net UHMWPE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40151.

Technology of welding hard wearing plates

The technology of welding of abrasion-resisting plates with the use of different filler metals designed for providing high wear resistance of the top layer and good plastic properties of the parent material is presented. To this end, we made test joints which were subjected to metallographic examination, mechanical testing, hardness measurements and testing of wear resistance of the type metal–mineral in accordance with ASTM G65-04 standard. In each case, the weld joining the wear resistant layer was made with the use of an XHD 6710 covered electrode. For making the weld joining of the parent material of the abrasion-resisting plate, we applied austenitic and ferritic–perlitic filler materials in the form of covered electrodes and solid wires for gas shielded arc welding. The tests have shown that the XHD 6710 electrode can be used for joining of top layers of abrasion-resisting plates providing their high wear resistance. For interpasses and filler passes, it is recommended to use austenitic filler metals which are characterized by very good plastic properties. Moreover, they reduce the mixing ratio of the weld metal and the material of the abrasion resistant layer.

The Theoretical and Experimental Analyses of the Influence of Single Draft on Properties of Rope Wires / Analiza Teoretyczo-Doświadczalna Wplywu Wielkości Gniotu Pojedynczego Na Własności Drutów Liniarskich

In the paper the influence of the value of a single draft on the properties of rope wires has been assessed. The drawing process of φ5.5 mm wire rod to the final wire of φ2.18 mm was conducted in 6, 11 and 17 drafts, by means of a block drawing machine with the drawing speed of 1.6 m/s. For the wires drawn with the medium single draft: 10.4%, 15.5% and 26.5% the investigation of mechanical-technological properties has been done, in which yield strength, tensile strength, elongation, contraction, number of twists and number of bands were determined. In order to explain the effect of value of a single draft on properties of rope wires, the fatigue strength, roughness and residual stresses of drawn wires have been also determined. In addition, the numerical analysis of the drawing process on the base of Drawing 2D in which distribution of redundant strain, effective strain, longitudinal residual stresses and temperature of drawn wires has been shown. The theoretical-experimental analysis of drawing of rope wires have enabled the evaluation of optimal value of single drafts by which relatively the most advantageous and useful properties of wires can be used. The investigation has shown, that in manufacturing of rope wires small single draft in 10% range should be applied. It allowed to obtain products of good plasticity properties, low deformation inhomogeneity and residual stresses, high bending and fatigue strength. The obtained data investigation can be applied while designing the production process of high carbon steel wires.

Impact of heat treatment on microstructure of steel 30X padded with wire G18 8Mn

The practical purpose of padding is to increase mechanical properties, hardness and abrasion resistance of surface layers of structural elements while maintaining good plastic properties of the core, apply corrosion-resistant layers, regenerate and/or repair the surface etc. The article describes the results of macroscopic and microscopic metallographic examination of components made of 30X steel, which is an equivalent of 32HA steel produced in Poland, and surfaced with G18 8Mn filler wire using MAG method. One of components was not heat treated after surfacing while the other after surfacing was subjected to quenching and tempering. The examination was aimed at determining the effect of heat treatment on changes in the structure of surfaced components. The metallographic examination has been conducted using optical microscopy in the area of parent metal of 30X steel as well as in heat affected zone (HAZ) in steel under and in the surfacing weld. HAZ width under the surfacing weld has also been measured. On the basis of the results showed that heat treatment after padding is responsible for the presence of the structure of tempered martensite in the heat affected zone and is responsible for a greater width of the HAZ, if compared with the condition without heat treatment.

The Effect of Time and Temperature Variations during Isothermal Annealing on the Mechanical Properties of High Carbon Bainitic Steel

The industrial development require new materials characterized highest mechanical properties. The conditions of thermo-mechanical treatment proved to highest level of mechanical properties for steels. Another method of making strong materials is to reduce the scale of the microstructure using heat treatment [1]. The paper presents the results of investigation into the effect of time and temperature variations during isothermal annealing on the mechanical properties of high carbon (c.a. 0,8%C) bainitic steel. Chemical composition of that steel (addition Si, Mn, Mo and Cr) obtain high level of tensile strength and good plastic properties. The analyzing of published results of researches of high carbon bainitic steels shown, that transformation of bainite can take between 2 to 60 days within the temperature range 125÷325°C [2,3] Based on results of researches of investigated steel a isothermal annealing in temperature range 200÷300°C were done. The experiments were done for 24, 50 and 100 hours of annealing. After that the mechanical tests were done. A Zwick Z100 testing machine was used for tests. The force and elongation values were recorded. On their basis, the proof stress and tensile strength of the steel tested were determined as a function of annealing temperature. The microstructure were determinated too.

Study on Rheocasting-Rolling of Semi-Solid AZ31B Magnesium Alloy

Analysis on microstructure of semi-solid AZ31B magnesium alloy produced under different technological parameters were done, hot rolling experiments of AZ31B magnesium alloy semi-solid strips were carried out on the rheocasting-rolling machine which was developed by ourselves. The result shows that the strips after the rheocasting-rolling of AZ31B semi-solid magnesium alloy have good plasticity and rolling properties, this offers theory basis for reprocessing of AZ31B.

Enrichment of Anhydrous Milk Fat in Polyunsaturated Fatty Acid Residues from Linseed and Rapeseed Oils through Enzymatic Interesterification

Lipozyme TL IM was used in a solvent-free batch and microaqueous system for enzymatic interesterification of anhydrous milkfat (AMF) with linseed oil (LO) in binary blends and with rapeseed oil (RO) in one ternary blend. The aim was to obtain and characterize physicochemically fats enriched with unsaturated C 18 fatty acids (oleic, linoleic, and, especially, linolenic acids) from natural vegetable oils. Binary blends of AMF/LO 100/0, 90/10, 80/20, 70/30, and 60/40 (w/w) were interesterified. The change in triacylglycerol (TAG) profiles showed that quasi-equilibrium conditions were reached after 4-6 h of reaction. Free fatty acid contents <1%. The decrease in solid fat content and in dropping point temperature obtained with increasing content of LO and interesterification resulted in good plastic properties for the products originating from the blends 70/30 and 60/40. This was confirmed by textural measurements. Melting profiles determined by differential scanning calorimetry showed complete disappearance of low-melting TAGs from LO and the formation of intermediary species with a lower melting temperature. Oxidative stability of the interesterified products was diminished with increasing LO content, resulting in low oxidation induction times. A ternary blend composed of AMF/RO/LO 70/20/10 gave satisfactory rheological and oxidative properties, fulfilling the requirements for a marketable spread and, moreover, offering increased potential health benefits due to the enriched content in polyunsaturated fatty acid residues.

Structure and properties of aluminium cast composites strengthened by dispersion phases

This paper presents a fragment of research on the use of chemically active and passive composite agglomerates intended for the production of composites reinforced with fine dispersion particles. In particular, some results of strength tests have been presented in order to show the effect of composite agglomerates on selected strength properties (Table 2) and material structure. The systems referred to in Table 1 should be treated as model ones that enable showing the influence of reinforcement on composites in an as-cast state. Based on the results obtained, one can affirm that, from the point of view of strength properties, it is more advantageous to apply complex oxides leading to obtaining composites of high strength properties in a cast state. It is also advantageous to use composite agglomerates to reinforce casting alloys, especially silumins, since this ensures obtaining high strength properties and good plastic properties. The presented systems should be treated as model ones, based on which the influence of the reinforcement on composites in a cast state can be shown.

Carbon foams from coals. A preliminary study

Carbon foams were obtained from a bituminous coal with good plasticity properties by a two-stage thermal process under different pressure and temperature conditions. The first stage was a controlled carbonisation treatment under pressure at 450 and 500 °C. In the second stage the carbonisation product was baked at 1100 °C. The foams produced display a macroporous texture with pressure and temperature determining the mean pore size and the amount of pores. The pressure increase reduces the pore size, while the increasing temperature increases the pore volume.

Warm forming of acid resistant steel wires used for manufacturing of springs

Acid resistant steel wires used for manufacturing of springs are required to show high strength properties, and especially very high fatigue strength while maintaining good plastic properties. The production of such wire is technologically difficult. The objective of the paper is to present the results of extensive laboratory and industrial research concerning the search for new conditions of producing wires used for manufacturing of springs. The self-annealing effect occurring in steel at large values of total deformation as well as forming at elevated temperature (warm forming) were employed in the investigations. The process of drawing final wires of 2.06–1.81 mm diameter range of AISI 302 acid resistant steel was realised according to large number of variants applying various reductions and temperature conditions. The wires obtained were used for manufacturing of different types of springs which afterwards were subjected to mechanical and fatigue testing. Additionally, the springs were subjected to special heat treatment. The results of investigations will allow the development of the new technology of production of acid resistant steel wires to be used for manufacturing of springs showing high life and high fatigue strength.

Stacking Sequence Design of Fiber-Metal Laminate for Maximum Strength

FML (Fiber-Metal Laminate) is a new material combining thinmetal laminate with adhesive fiber prepreg. It has nearly all the advantages of metallic and composite materials, including good plasticity, impact resistance, processibility, light weight and excellent fatigue properties. However, in most FML the fiber prepreg is staked in only one direction, although FML can be designed with a varying stacking sequence angle of fiber prepreg. No work has been published on the optimum design of FML. This paper uses genetic algorithms to study the optimal design of FML under various loading conditions. To analyze FML the finite element method is used based on shear deformation theory. The Tsai-Hill failure criterion and theMiser yield criterion are used as the objective functions of the fiber prepreg and the metal laminate, and the ply orientation angles are the design variables. In the genetic algorithm, tournament selection and the uniform crossovermethod are employed. The elitist model is also used for an effective evolution strategy, and the creeping random search method is adopted so as to approach the solutionwith high accuracy. Optimization results are given for various loading conditions and are compared with CFRP (Carbon Fiber Reinforced Plastic). The results show that FML is better than CFRP in most loading conditions. In particular, FML shows good mechanical performance in point and uniform loading conditions and is more stable to unexpected loading.

The effect of the binder on the manufacture of a 5A zeolite monolith

The effect of the binder on the manufacture, by a paste extrusion process, of a 2 mm square lattice channel zeolite monolith with a 0.98 mm wall thickness and an overall diameter of 20 mm has been studied using a variety of visual and analytical techniques. Crucial factors for manufacturing defect-free 5A zeolite monoliths have been found to be the use of a binder with good plasticity properties, such as Na–bentonite, extrusion conditions, and a well-controlled drying process. Pastes containing different amounts of water and binder were characterised from the relationship between pressure drop and extrudate velocity during flow from a circular barrel into a circular die-land. From the relationship between the extrusion pressure and the extrudate velocity, six extrusion parameters were derived for each paste. A higher extrusion pressure is required when there is either a decreased water content or an increased binder content.

Precipitation Kinetics and Strengthening of a Fe-0.8wt%Cu Alloy.

Precipitation kinetics and strengthening have been investigated for a Fe-0.8wt%Cu alloy. Microstructure evolution during aging at 500°C has been studied by a combination of Transmission Electron Microscopy and Small-Angle X-ray Scattering to provide information on the nature and location of the precipitates as well as a quantitative estimate of their size and volume fraction. The associated mechanical properties have been studied by hardness and tensile tests. The precipitation kinetics measured in this study are fully compatible with results reported for alloys with higher Cu levels. Nucleation of Cu precipitates is promoted by the presence of dislocations whereas coarsening rates in the later stages of aging appear to be not affected by fast diffusion paths along dislocations The strength of individual precipitates increases with precipitate size based on the analysis of the mechanical test results. However, the strength of the largest precipitates observed remains approximately half of the strength required for the Orowan by-passing mechanism. The Russell-Brown model for modulus strengthening has successfully been applied to the current data. Study of the plastic behavior shows that the maximum initial hardening rate is related to the highest strength of the material. This unusual result may be explained by a dynamic strained-induced phase transformation of the precipitates from the bcc to the 9R structure. Consequently, the hardening potential of Fe-Cu alloys is associated with good plastic properties close to peak strength thereby indicating the excellent potential of copper as hardening element for the development of novel high strength interstitial free IF steels.

Plasticity of the coating mass in the production of welding electrodes

The main factors affecting the quality of the electrode are the quality of the coating mass: plasticity; suitability for heat treatment (susceptibility for swelling, cracks, indentation, etc.); technological properties. Usually, the plasticity is evaluated by two parameters: plastic strength and pressing pressure. As the plastic strength increases and the pressing pressure decreases, the plasticity of the coating mass increases. Of course, the pressing pressure must be stable. Plastic strength (yield limit) is the force required for causing shearing between the layers of the coating mass. It is determined from the maximum immersion of the 'cold' into the pre-pressed mass with constant load. In most cases, the pressing pressure is determined using a procedure in which the coating mass is pressed-out at a given rate through a hole 4 mm in diameter and 20 mm long. However, at high plastic strength and low pressure of discharge of the coating mass through the hole, the layer of the coating on the rod was not concentric. On the basis of the investigations (started at the E O Paton Electric Welding Institute), a special method was developed for eliminating this discrepancy. According to this method, the coating mass is pressed-out not simply through a hole but through a special device modelling the conditions of formation of mass flows in the pressing zone of the electric coating press. Pressure values are continuously recorded during pressing. The variation of pressure during pressing affects most efficiently the nature of formation of mass flows in the pressing zone and makes it possible to evaluate the pressing properties of the coating materials. If there are pulsations of pressure, high quality pressing of the coating mass is not possible. In this article, the author presents a plasticity diagram of coating mass in the 'pressing pressure pp -plastic strength pT ' co-ordinate system (see Figure). The integrity and completeness of the diagram is ensured by the fact that only three parameters are taken into account, so that areas with different plasticity can be defined. If the characteristics of the coating mass are included in region 2 (and even better in region 1), this mass has good plastic properties resulting in concentric deposition on the rod. The plasticity of the coating mass can be regulated by changing the grain composition of the charge, the physicochemical condition of the surface of powders, the properties of liquid glass and the methods of plastification. Unfortunately, the unambiguous relationships of the effect of these factors have not as yet been determined. , MPa

Duplex antiabrasive coatings (Fe-based alloy-tin) produced by impulse plasma deposition

TiN-type antiabrasive coatings are commonly produced by various PVD-CVD methods. It is known that the multilayer coatings are better than monolayer coatings because of the possibility of controlling the stress level, in particular, in interfaces, and as a result in the whole coating. In this paper, phase composition, morphology, anticorrosive (tightness) and antiabrasive properties of the duplex (Fe-based alloy-tin) coatings produced by impulse plasma deposition were examined and compared with the single-layer TiN ones. The very good mechanic and plastic properties of Fe-Ni-Mo-Al-Ti alloys (maraging steel) which were used seem to predestine this alloy as a metallic bond layer in multilayer antiabrasive coatings.

Porous structure of alumina ceramic supports for gas separation membranes, I. Preparation and study of the extrusion masses

The properties of aluminium-containing compounds and the compositions of extrusion pastes have been studied to obtain materials with good plastic properties. To prepare these masses aluminium hydroxide (as binder) and α-alumina powders (as additives) were used. It was shown that there is an optimal correlation between binder and additive for preparation of the extrusion pastes with good plastic properties.