Type Of Filler Material Research Articles

Finite Element Analysis of Residual Stress Level Prediction for TIG Welding Process

Tungsten Inert Gas (TIG) welding process requires high heat input during the process, when the material is cooled down non-uniform distribution of thermal strain causes residual stress which can weaken the material and fatigue life of the material. The residual stress can be measured from method such as x-ray diffraction (XRD), using strain gage of drilled hole and so on. A numerical method of constructing a finite element analysis (FEA) model can be used for predicting the residual stress level of the welding process. This paper uses the TIG welding condition for stainless steel grade 304 that the material provided the highest level of tensile strength, obtained from previous study, as a condition for the FEA model. The residual stress results from the FEA predictive model and the results from XRD were compared. In the FEA model, the workpiece, heat affected zone (HAZ), and filler metal assumed to be the same. The results showed consistent residual profile between the model and the actual measurement from XRD, but there was some discrepancy of the magnitude of residual stress which can due to the type of filler material that was used.

3D finite element analysis and experimental investigations of a new type of timber beam-to-beam connection

A new type of semi-rigid timber beam-to-beam connection and its behavior under bending is presented. This connection consists of four identical steel parts, which are inserted into the timber beams in the tension and compression zone of the connection. These steel parts are easily connected by mounting bolts on the construction site. In order to avoid initial slip, gaps between the timber and the steel parts are filled using two different types of filler materials, namely cement based (CEM) or polyurethane based (PUR) filler. In this study, the connection is modeled by means of the Finite Element (FE) Method and the modeling results are compared to the results of an experimental assessment of the proposed connection under bending. The material model for timber encompasses a Hill criterion in combination with cohesive surface contact in order to depict both, yielding in compression and brittle failure in shear and tension perpendicular to the grain. The experimentally observed decisive failure mode, i.e. shear block failure, could be reproduced by the model. Subsequently, the FE model was used to investigate the effect of using different filler materials, or not considering the filler in the analysis at all. In addition, a particular influence of clamping bolts in the timber on the strength of the connection was revealed. The FE analysis excluding these bolts showed good agreement with the experiments in terms of the strength of the connection, while considering these bolts led to an overestimation of the strength. This is a consequence of the considerable influence of the clamping bolts on stresses perpendicular to the grain in the timber in the block-shear area, and therefore, on shear failure initiation. Using the CEM filler hardly changed the overall behavior of the connection as compared to the analyses without filler material, while the PUR filler leads to a less ductile overall behavior. This is well in line with experimental observations. The application of modeling approaches for timber has proven suitable for the analysis of such a type of timber beam-to-beam connection and, consequently, might be used for further optimization of this connection.

Estimating the Reliability for Asphalt Milling Machines Teeth Manufactured by Claddings Processes

The issues from the last decades related to the crisis of natural resources, raw materials, equipment, energy etc., gave rise to a new concept, namely sustainable development. The theory of sustainable development focuses on the development of quality products to provide trust and confidence, so as reliable. On this line the paper presents an approach on assessing the reliability and non-reliability of the milling teeth for asphalt machines classic manufactured and those manufactured by welding load, which give them self wear protection systems and self-lock at rotation. So in this sense there are presented comparative estimates regarding to the operating lifetime of the four batches of milling teeth for asphalt, 41Cr4 mark steel (EN 10083-1) the classic version and 3 groups of teeth load by weld on their working surface(wear) by different welding methods, namely: WIG - with filler material type tubular wire FILEUR DUR 606B, WIG – filler material with tubular type VT2, 5CrTiD rods, and MIG/MAG (CMT), the tubular wire filler material type FILEUR DUR. So, asphalt milling machines were stripped with 4 groups of teeth in order to track the behaviour during exploitation of each batch. Assuming that the product specifications properly respond customers' requirements, the level of reliability can be measured accurately by the fraction of delivered units that meet the specifications. On this line for estimating the reliability the Monte Carlo simulation method was used, which is suitable for analyzing the products that are designed to provide superior quality.

Fume and gas emission during arc welding: Hazards and recommendation

Welding is the principal industrial process used for joining metals, but at the same time, it’s the significant source of toxic fumes and gases emission. With the advent of new types of welding procedures and consumables, the number of welders exposed to welding fumes is growing constantly in spite of the mechanisation and automation of the process. Having in mind that, in some cases, toxic fumes and gases can be over the respective limits for toxic substances, one of the most important requirements for chosen welding procedure is its harmlessness to the environment. The health aspects associated with welding are complex and the industry is continuing its research to evaluate the effects of the welder’s exposure to typical constituents of welding fumes and gases, as well as its impact on what concerns climatic changes. The aim of this paper is to estimate the influence of the type of filler material on the emission of toxic substances, and to show the potential hazards. In order to determine that effect, microalloyed steel has been welded using two different filler materials (metal cored wire and self-shielded wire). The concentrations of emitted total dust, CO2, CO, SO, Mn, Ni, Al, Cr, Cr(VI), Ca and P were measured. By comparing results for both filler materials, it was established that the special attention must be paid to the high concentration of manganese and CO in metal cored wire, as well as high concentrations of phosphorus and aluminum in self-shielded wire. Also, conducted experimental measurements of emission of certain elements did not show higher toxicity of self-shielded wire compare to metal cored wire, what is in the contrast with previous studies.

The behavior of welded dissimilar metals structures under rotating reversed cyclic bending

A cantilever type rotating bending testing machine was used to test several welded specimens, these consisted of welding of steel ST60 to stainless steel SS304, and welding of steel ST60 to stainless steel SS316, using different filler types of stainless steel SS308, SS309 and SS310. The effect on the heat affected zone (HAZ) was investigated. Fracture surface examinations were also carried out. The numerical analysis adopted the finite element package ABAQUS® to model the welded specimens. Elasto-plastic non-linear analysis was conducted for stress distribution contours. von Mises stresses were obtained as well as crack initiation fatigue life. Both numerical and experimental studies were carried out at four different levels of applied stress from 0.6Sy to 1.2Sy at steps of 0.2Sy. The developed maximum stresses exhibited linear behavior followed by non-linear behavior with further increase of applied stress. The filler type had a pronounced effect on the developed stress such that higher stresses were obtained for filler SS308 and lower stresses for SS309 and for SS310, respectively. The crack initiation fatigue life decreased non-linearly with increasing the applied stress and it was greatly affected by the type of filler material; filler SS310 had higher fatigue life cycles than SS309 while SS308 had the lowest fatigue life cycles. The crack initiation fatigue life (Ni) and failure life (Nf) exponentially decreased with the increase in the applied stress. The experimental and numerical results were in good agreement. The SS310 filler, which has the highest Cr%, Mn% and Ni% is the best filler for welding ST60 to SS304 and also for welding ST60 to SS304, and it is recommended for such welding applications.

Residual Stress Distributions at High Strength Steel Welds Prepared by Low Transformation Temperature (LTT) and Conventional Welding Consumables

Residual stress distributions in fillet welds in 8 mm 900 MPa steel have been mapped perpendicular and parallel to the weld line and also through the thickness in the vicinity of weld toe position. Measurements were carried out on four welds when two of them were performed with conventional and two with the so called LTT (low transformation temperature) filler materials. Both neutron and X-ray diffractions were used for determination of the residual stress distribution. Fatigue properties have also been evaluated for all test welds. Neutron diffraction measurements showed that the stress profiles perpendicular to the weld toe qualitatively did not depend on filler material type although the absolute stress levels differed. Trends were similar for positions 2, 4 and 6 millimetres below the surface for all three stress components; σx (direction perpendicular to the weld), σy (parallel to the weld) and σz (through the thickness). X-ray diffraction showed difference in residual stress level at the weld toe. Lower residual stress levels have been identified for LTT filler material when compared to the conventional consumable compositions. The effect of residual stress is discussed in relation to fatigue properties of all four welds. Remarkable higher fatigue strength has been measured for welds prepared by the LTT filler materials.

Forming fabric weave-scale variations in paper filler content

A series of experiments were conducted on handsheets to investigate small-scale variations in filler concentration on the surface of paper. The surface distribution of two types of filler material was investigated: precipitated calcium carbonate (CaCO3) and kaolin clay (Al2Si2O5(OH)4). The effect of retention aids, dewatering rate, and forming fabric geometry on filler distribution was tested. Local filler concentration was found to be strongly correlated with the relative flow velocity during formation. In samples formed by gravity and vacuum drainage, kaolin displayed a significantly greater variation in local concentration than precipitated calcium carbonate, though the difference was reduced under vacuum drainage conditions. The distribution on the top side of the paper was comparable between the filler types, independent of drainage velocity. Under vacuum drainage, retention aids did not improve filler uniformity on the wire side. However, on the top side of the paper, a moderate reduction in spatial variation was observed. Additionally, on the wire side of samples made with gravity drainage, the addition of retention aids produced a significant improvement in the uniformity of the filler material. These filler distribution trends are believed to be related to variable filler retention as a function of filler type, drainage velocity, and chemical retention aids. Additionally, samples made with an industry forming fabric showed the same distribution trends and an improvement in the uniformity of the filler material.

The research of technological and environmental conditions during low-energetic gas-shielded metal arc welding of aluminium alloys

In this paper, two trends of research conducted at the Welding Institute have been presented, namely the study of material and technological welding conditions of different aluminium alloys using CMT and ColdArc methods and the influence of selected technological parameters on emission rate to the working environment. The properties of welded joints as well as the application fields of modern low-energy welding devices for joining thin aluminium sheets have been discussed. The relationships between the welding method, base and filler material type, and emission rate have also been presented.

Impact of hydrated lime on the durability of SMA mixtures: laboratory and field evaluation

The work presented in this paper describes the research activities of the task group ‘Properties of filler aggregates’ with respect to the durability of Stone Mastic Asphalt (SMA) mixtures, which was conducted recently at the Belgian Road Research Centre. The main objective of this study comprises the effect of hydrated lime on the durability of SMA mixtures. The methodology developed in this study includes in an initial phase the design in the laboratory of a ‘critical’ SMA10 mixture. Such a ‘critical’ SMA10 mixture was considered to be characterised by a high water sensitivity and, therefore, a low durability. During this process, attention was paid to both the SMA composition as well as to the compaction energy applied in order to provide suitable test samples. Subsequently, by making use of such a ‘critical’ SMA10 mixture, the effect of the filler nature on the durability of the SMA mixtures was established; in particular both the modification by as well as the optimal content of hydrated lime was studied. Additionally, the possible effect of hydrated lime on the workability of latter SMA mixtures was investigated. Finally, the results obtained in the laboratory were complemented by a field study and a monitoring campaign. This survey comprises the evaluation of the impact of hydrated lime on the compactibility and the water sensitivity on test sections as well as a yearly follow up of the performance of a series of SMA10 mixtures varying in the type of filler material used.

Implants into fresh extraction site: A literature review, case immediate placement report

Immediate implants are positioned in the course of surgical extraction of the tooth to be replaced. The percentage success of such procedures varies among authors from 92.7-98.0%. The main indication of immediate implantation is the replacement of teeth with pathologies not amenable to treatment. Its advantages with respect to delayed implantation include reduced postextraction alveolar bone resorption, a shortening of rehabilitation treatment time, and avoidance of a second surgical intervention. The inconveniences in turn comprise a general requirement for membrane-guided bone regeneration techniques, with the associated risk of exposure and infection, and the need for mucogingival grafts to seal the socket space and/or cover the membranes. The surgical requirements for immediate implantation include extraction with the least trauma possible, preservation of the extraction socket walls and thorough alveolar curettage to eliminate all pathological material. Primary stability is an essential requirement, and is achieved with an implant exceeding the alveolar apex by 3-5 mm, or by placing an implant of greater diameter than the remnant alveolus. Esthetic emergence in the anterior zone is achieved by 1-3 mm subcrest implantation. Regarding guided regeneration of alveolar bone, the literature lacks consensus on the use of membranes and type of filler material required. While primary wound closure is desirable, some authors do not consider it to be of great relevance.

Effect of Filler Materials on Texture Development in Bi0.5(Na0.85K0.15)0.5TiO3 Ceramics

Textured Bi0.5(Na0.85K0.15)TiO3 (BNKT) ceramics were prepared by reactive-templated grain growth method with platelike Bi4Ti3O12 grains as reactive templates. A mixture of raw materials or a pre-reacted BNKT powder was added as filler to control the amount of template grains. This work focused on the effect of filler material type on the chemical reaction and compositional homogeneity. The mixture of raw materials gave a faster reaction rate than did the pre-reacted BNKT powder. The slower reaction with the pre-reacted BNKT powder resulted in the formation of a liquid phase and a retarded texture development.

Studies on effective thermal conductivity of particle-reinforced polymeric flexible mould material composites

Due to poor thermal conductivity of conventional flexible polymeric mould materials, the solidification of (wax/plastic) patterns in soft tooling (ST) process takes a longer time. This problem can be solved by increasing the effective thermal conductivity of mould materials through (high thermal conductive) particle reinforcement. Therefore in this study, the equivalent thermal conductivities (ETCs) of particle-reinforced polymeric mould materials, namely silicone rubber and polyurethane are experimentally observed using hot disc technique. Findings show that not only the amount of filler content and type of filler material, but also particle size has significant influence on the effective thermal conductivity of polymer and it starts increasing drastically at 20–30 per cent volume fraction of filler content. To predict the cooling time in ST process, it is important to have an appropriate model of ETC. In this study, a new method is proposed based on a genetic algorithm fuzzy (GA-fuzzy) approach to model the effective thermal conductivity of a two-phase particle-reinforced polymer composites (PCs). The effectiveness of the model is extensively tested in comparison with various empirical expressions reported in literature based on the experimental measurements. It has been found that the model based on GA-fuzzy approach not only outperforms the existing models, but also possesses a generic one applicable to a wide range of two-phase particle-reinforced PCs.

Permittivity of modified polyimide layers on LTCC

In this work, the permittivity of a tailored compound material was investigated consisting of a polyimide matrix in which hollow glass microspheres with a mean diameter of 30 μm are implemented as filler material. Choosing this approach the dielectric constant compared to that of the pure polyimide material is further decreased due to the enclosed air targeted to improve the high-frequency performance of patch antennas operated in the GHz range. Furthermore, the thickness of one single layer can be increased substantially from a maximum of about 10 μm for pure polyimide films to values above 80 μm by simply adding this type of filler material to the liquid polyimide precursor so that cavities in LTCC (low temperature co-fired ceramics) substrates can be filled more reliable. Two different variations of this compound material with filler to polymer ratios of 1:7.5 and 1:10 are realized. Basically, the film thickness depends on the spin coating speed and the microsphere content, respectively. The high initial surface roughness can be decreased to an average value of about 3 μm by applying additional layers of pure polyimide on top enabling thin film technology. The dielectric constant of the complete substrate comprising the LTCC and the compound material is measured using a ring resonator in microstrip configuration. From the resonances occurring in the transmission S-parameter | S 21| spectrum between 1 and 10 GHz, the relative dielectric constant can be determined. Using 820 μm thick LTCC substrates the permittivity can be reduced from originally ε r = 7.8–6.6. By applying numerical calculations, a reduced permittivity of the pure polymer film from ε r = 3.3 to about 2.9 can be determined when adding the glass microspheres.

Characterization of microstructures and mechanical properties of Inconel 617/310 stainless steel dissimilar welds

Abstract The microstructure and mechanical properties of Inconel 617/310 austenitic stainless steel dissimilar welds were investigated in this work. Three types of filler materials, Inconel 617, Inconel 82 and 310 austenitic stainless steels were used to obtain dissimilar joint using the gas tungsten arc welding process. Microstructural observations showed that there was no evidence of any possible cracking in the weldments achieved by the nickel-base filler materials. The welds produced by 617 and 310 filler materials displayed the highest and the lowest ultimate tensile strength and total elongation, respectively. The impact test results indicated that all specimens exhibited ductile fracture. Among the fillers, Inconel 617 exhibited superlative fracture toughness (205 J). The mechanical properties of the Inconel 617 filler material were much better than those of other fillers.

Principal component analysis for multiple quality characteristics optimization of metal inert gas welding aluminum foam plate

Principal component analysis (PCA) coupled with Taguchi methods are employed in the study for multiple quality characteristics optimization of metal inert gas (MIG) arc welding aluminum foam plates. The quality characteristics investigated are the micro-hardness and the bending strength of the weldments. Eight control factors selected are the type of filler material, MIG current, welding speed, MIG gas flow rate, workpiece gap, MIG arcing angle, groove angle, and electrode extension length. It is shown by the experimental results that the optimal parameter combination of the MIG welding process is A 2 (filler material: Type No. 5356), B 3 (MIG current: 100 A), C 1 (welding speed: 80 mm/min), D (MIG gas flow rate: 13 L/min), E 2 (workpiece gap: 1.7 mm), F 3 (MIG arcing angle: 50°), G 3 (groove angle: 20°), and H 1 (electrode extension length: 15 mm). Moreover, it is ascertained from the analysis of variance (ANOVA) results that B (MIG current), C (welding speed), and E (workpiece gap) are the most important control factors in the process design, and thus strict control must be applied to the three factors. The experimental results likewise show that the optimal process design could indeed improve the multiple quality characteristic values of the MIG-welded aluminum foam plates.

Microstructural evolutions in dissimilar welds between AISI 310 austenitic stainless steel and Inconel 657

This investigation has been performed to characterize dissimilar metal welds between type 310 austenitic stainless steel (SS) and Inconel 657 superalloy. The welds were produced using four types of filler materials: Inconel 82, Inconel A, Inconel 617, and type 310 SS. The weldments were characterized in detail using optical metallography and scanning electron microscopy. It can be concluded that Inconel A weld metal does not promote severe hot cracking. Continuous NbC precipitates in the Inconel 82 weld metal can sensitize the weld metal to solidification cracking. The presence of high amounts of Mo in Inconel 617 weld metal led to the formation of brittle phases. In addition, continuous precipitates were observed in the 310 SS weld metal, which can lead to poor resistance of the weld metal to hot cracking. In the aged condition, Inconel 82 and Inconel A exhibited good thermal stability, whereas Inconel 617 and type 310 SS exhibited poor thermal stability. Also, after subjecting the heat-affected zone and interface between Inconel weld metal and base metals to aging treatment, unmixed zone of Inconel 657 base metal side has disappeared. Elimination of this region can be attributed to high-temperature interdiffusion of alloying elements. Finally, it is found that Inconel A and Inconel 82 weld metals are the best choices for the dissimilar welds performed here, respectively.

Effect of the electrode to work angle, filler diameter and shielding gas type on weld geometry of HQ130 steel joints produced by robotic GMAW

GMAW (Gas Metal Arc Welding) is an arc welding process which is widely used in industry to join the metals. We investigated the effect of varying welding parameters on the bead geometry in robotic GMA welds of HQ130 steel having 5 mm thickness. The chosen parameters for this study were the electrode to work angle (∅), filler diameter (d) and shielding gas type (S.G). Different samples obtained by employing electrode to work angle of 65°, 75° and 85°, filler diameter of 0.8, 1, 1.2 mm. The main recommended gases for this filler material type were Ar, He and CO 2 gas. Having finished the welding process, the depths of penetration were measured for specimens and the relationship between parameters and penetration of weld were studied. The results clearly illustrated that increasing of electrode to work angle increased the depth of penetration while increasing in filler diameter resulted in decreasing the weld penetration. In addition, the highest penetration was observed for CO 2 shielding gas.

Energy Absorption Capacity of Composite Beams

Local buckling may occur in the compression flange of rectangular hollow-section beams under cyclic repeated loading arising from earthquakes. Once a local mechanism forms, residual strength rapidly reduces within a few cycles. This is true even for compact sections under static bending. This paper aims to study the experimental behaviour and ultimate moment capacity of unfilled and concrete-filled rectangular hollow sections subjected to cyclic reversible loading. Two types of filler material were used - normal mix concrete and fly ash concrete. The effect of filler materials, section slenderness, loaddeflection response, moment-strain behaviour, first cycle peak load, ductility, stiffness degradation and energy absorption of concrete –filled RHS beams are studied.

Fabrication and physicochemical properties of particulate-reinforced precursor-derived Si-C-N ceramics

The present investigation reports the application of four different types of filler materials (Al2O3, Y2O3, SiC and Si3N4) for the preparation of particulate-reinforced composites (PRC) by precursor impregnation and pyrolysis (PIP) method. In the oxide filler systems, deterioration by crack formation was observed during repeated processing cycles. The large difference of the coefficient of thermal expansion between the oxide fillers and Si-C-N matrix is considered as the reasons for the deterioration. The PRC made with SiC filler showed the highest values of relative density, strength, Young's modulus, hardness, and fracture toughness among the four types of PRC. The SiC-based PRC also offered the highest thermal mass stability and creep resistance.

Dissimilar welding of AISI 310 austenitic stainless steel to nickel-based alloy Inconel 657

The current work was carried out to characterize welding of AISI 310 austenitic stainless steel to Inconel 657 nickel–chromium superalloy. The welds were produced using four types of filler materials; the nickel-based corresponding to Inconel 82, Inconel A, Inconel 617 and 310 austenitic stainless steels. This paper describes the selection of welding consumables for the joint. The comparative evaluation was based on hot-cracking tests (Varestraint test) and estimation of mechanical properties. According to Varestraint tests, Inconel A showed the least susceptibility to hot cracking. In tension tests, all weldments failed in the weaker parent metals (i.e., Inconel 657). Moreover, Inconel A weldment had the highest strength and total elongation. On the other hand, the weld metals failed by ductile fracture except Inconel 617, which exhibited mixed fracture mode. At last, it was concluded that Inconel A filler material offered the best compromise for the joint between Inconel 657 and 310 stainless steel.