Metallurgical Influences Research Articles

Metallurgical influence of separated endodontic instruments on the retrieval capability of katana-sword-like ultrasonic tip under different lubricants: In vitro study

Abstract Introduction: Ultrasonic retrieval is a time-consuming procedure sacrificing considerable amounts of dentin. This study aimed to assess the retrieval capability of katana tip on different alloys under different lubricants regarding dentin thickness and retrieval time. Materials and Methods: Extracted premolars were used to reach 40 samples. The apical 4 mm of X2 ProTaper Next and A1 Neoniti instruments were fractured, and katana tip was utilized for retrieval, using ethylenediaminetetraacetic acid or olive oil as intracanal lubricants. Dentin thickness was assessed using cone-beam computed tomography, and the time of retrieval was recorded. Results: There was no significant difference in the retrieval capability among the groups. Different alloys and lubricants had no significant effect on dentin thickness. However, olive oil significantly reduced the retrieval time. Conclusion: Katana tip proved to be efficient enough to retrieve apically separated instruments in curved canals, with instrument’s metallurgical makeup presenting minimal effect on its capability. Katana tip and high-viscosity lubricants reduced the retrieval time, which might reduce the dentin removal amount.

Influence of machining on the surface integrity of high- and medium-entropy alloys

High- and medium-entropy alloys (HEAs) are a quite new class of materials. They have a high potential for applications from low to high temperatures due to the excellent combination of their structural properties. Concerning their application as components; processing properties, such as machinability, have hardly been investigated so far. Hence, machinability analyses with a focus on the influence of the milling process and its basic parameters (cutting speed, feed per cutting edge) on the resulting surface integrity of specimens from an equiatomic high- (CoCrFeMnNi) and a medium- (CoCrNi) entropy alloy have been carried out. A highly innovative milling process with ultrasonic assistance (USAM) was compared to conventional milling processes. Recent studies have shown that USAM has a high potential to significantly reduce the mechanical load on the tool and workpiece surface during milling. In this study, the basic machining and ultrasonic parameters were systematically varied. After machining, the surface integrity of the alloys was analyzed in terms of topography, defects, subsurface damage, and residual stresses. It was observed that USAM reduces the cutting forces and increases the surface integrity in terms of lower tensile residual stresses and defect density near the surfaces for the CoCrFeMnNi alloy. It was shown that the cutting forces and the metallurgical influence in the sub surface region are reduced by increasing the cutting speed and reducing the feed rate per cutting edge. With the CoCrNi alloy, the tool revealed severe wear. As a result, for this alloy no influence of the parameters on the machinability could be determined.

Metallurgical Effect of Rare-Earth Lanthanum Fluoride and Boride in the Composite Coating of Wires in the Arc Welding of Bainitic-Martensitic and Austenitic Steel

For arc welding of high-strength and cold-resistant steels, the author developed an advanced design of steel wire with a micro-composite coating of a nickel matrix and nanoparticles of LaF3 and LaB6, which improves the metallurgical influence of rare-earth elements (REE) and forms refractory sulphides and oxides of REE, as well as boron nitride. The addition of 0.1–0.3 wt% La in the weld pool leads to an increase in the content of the refractory compounds La2O3, LaO2, and LaS, and to the reduction in the content of the low-melting and brittle oxides and sulphides SiO2, SiO, MnO, MnS, and SiS. The use of steel wire with the composite coating of LaF3 and LaB6 allows for microstructural refinement when welding S960QL bainitic-martensitic steel and X70 API bainitic steel, and increases the impact toughness of the welds by 1.17–1.6 times.

Thermal Transformations of the Nickel Laterite Agglomerate Phases and their Metallurgical Influence

In nickel laterite agglomerates from rotary kiln of RKEF process the phases lizardite and/or chrysotile, clinochlore, quartz and hematite were identified. The product contain SiO2 (32.67%), Fe2O3 (24.68%), MgO (21.81%) and NiO (3.30%) as principal components. When thermal treatment were carried out weight differences can be observed where the adsorbed water removed during drying, without phase changes in temperatures ranging from 60°C to 100°C, indicated influence of mineral assemblage. Phase changes and weight loss was observed in calcination with clear crystalline restructuring of the serpentines and clinochlore at 500°C. Above this temperature new phases are crystallized until 820°C, when is formed forsterite and enstatite, provably trevorite and remaining unchanged quartz. There were identified nickel minerals. The nickel occurs in bearing phases as Mg-Ni ion substitution in the crystal structure. On the analyzed conditions might infer that these new phases formed can affect the pyrometallurgical process of reduction.

Hot tensile behavior and deformation mechanism of Mg–5Al–2Ca alloy influenced by SiC particles

Multiple physical and metallurgical influences exerted by SiC particles (SiCp) still make it difficult to understand that how the addition of SiCp affects the hot tensile deformation behavior of Mg matrix alloy. A deformation mechanism analysis method developed in this study is promising to find a reasonable answer on this problem, via the comparison of SiCp/Mg–5Al–2Ca composite (SiCp/AC52) and Mg–5Al–2Ca alloy (AC52). The effects of SiCp on the constitutive description, deformation mechanism, strain hardening and softening behavior are specially investigated based on the microstructure evolutions, true stress-strain behaviors and fracture characteristics of the uniaxial tensile tests under the deformation temperatures of 290–350 °C and strain rates of 8.3 × 10−4-1.67 × 10−2 s−1. The grains exhibit different growth levels during the hot tensile deformation, and it becomes more evident with the decrease in the strain rate and the increase in the temperature. The addition of SiCp restrains grain growth and leads to a refined and homogeneous grain microstructure. The flow stress at low strain rate is increased with the addition of SiCp, while, which is decreased by SiCp when the strain rate over 8.3 × 10−3 s−1. The addition of SiCp leads to the tress exponent value n and the activation energy value Q increasing from 1.56 and 90.33 kJ/mol to 2.94 and 110.77 kJ/mol, respectively. The dominating deformation mechanism is altered corresponding to the strain rate. The addition of SiCp causes the local stress/strain redistribution, restrains the grain boundary sliding and facilitates the dislocation climb creep in the hot tensile deformation. Moreover, such addition stimulates the generation and coalescence of previously-induced small voids or dimples, while inhibits its extension and enlargement. As a result, the fracture morphologies exhibit an intergranular ductile fracture combined with micro-dimple growth and coalescence.

Laboratory Study of a Soil-Cutting Blade Shaping During a Wear in an Abrasive Soil Environment

The authors studied the wear of soil-cutting parts blades samples on a laboratory bench, which allowed simulating conditions close to real soil environment. (Research purpose) To evaluate the possibility of the samples wear modeling in a circular soil bench and to study the structural and metallurgical parameters influence of soil-cutting blades model samples on the intensity of their wear. (Materials and methods) The authors conducted research using soil mass, including quartz sand, moistened clay and crushed stone. (Results and discussion) It was found that with an increase in the base material (steel) hardness, the difference in wear rate between the most and least loaded working parts individual zones decreased. With an increase in the hardness of steel 65G from 20 to 40 units on the Rockwell scale, wear in the most and least loaded zones amounted to 7.5 and 5.5 millimeters, respectively, so it decreased by 13.5 percent. It was determined that an increase in the thickness of the hard alloy promoted the difference approximation between the wear of the maximum and minimum loaded zones. With a thickness of one-millimeter 65G steel, hardened to 40 Rockwell units, the difference in a wear of the respective zones was 4.0 and 4.4 millimeters (1.10 percent), and with a surfacing thickness of 2.5 millimeters - it was 3.5 and 3.7 millimeters (1.057 percent). (Conclusions) The authors proved that with an increase in the base material hardness and an increase in the surfacing thickness, the values of a wear in the zones of the highest and lowest loads came closer due to an increase in the resistance of the less loaded zone compared to the more loaded zone, with the properties of the forming medium being constant.

ГИБРИДНАЯ ЛАЗЕРНО-ДУГОВАЯ СВАРКА ВЫСОКОПРОЧНЫХ ТРУБНЫХ СТАЛЕЙ КЛАССОВ ПРОЧНОСТИ API X80 И X120

The aim of the present work was to investigate the possibilities of hybrid laser arc welding regarding reliable production of longitudinal welds of high strength pipe steels X80 and X120 and to evaluate achievable mechanical properties of laser hybrid welds. The study focused on weld toughness examination in low temperature range up to -60 °C. SЮТЭКЛХО ПТХХОЫ ЦКЭОЫТКХЬ were identified in the context of this task. It could be shown that metal cored electrodes guaranteed sufficient Charpy impact toughness at low temperature for both investigated materials. Modern arc welding technologies such as modified pulsed spray arc were used to promote deeper Penetration of the filler material into the narrow laser welding gap. Edge preparation with a 14 mm deep root face was considered as optimum, because no penetration of the filler material could be detected beyond this depth limit and therefore any metallurgical influences on the weld metal properties through the welding wire could be excluded.

Hybrid laser arc welding of X80 and X120 steel grade

The aim of the present work was to investigate the possibilities of hybrid laser arc welding regarding reliable production of longitudinal welds of high strength pipe steels X80 and X120 and to evaluate achievable mechanical properties of laser hybrid welds. The study focused on weld toughness examination in low temperature range up to −60°C. Suitable filler materials were identified in the context of this task. It could be shown that metal cored electrodes guaranteed sufficient Charpy impact toughness at low temperature for both investigated materials. Modern arc welding technologies such as modified pulsed spray arc were used to promote deeper penetration of the filler material into the narrow laser welding gap. Edge preparation with a 14 mm deep root face was considered as optimum, because no penetration of the filler material could be detected beyond this depth limit, and therefore, any metallurgical influences on the weld metal properties through the welding wire could be excluded.

Metallurgical influence of multi-beam technology on duplex stainless steel welds

The main problem of electron beam welding of duplex stainless steels (DSS) is the degradation of the mechanical properties and the corrosion resistance due to an unfavourable ferrite content in the weld metal. This occurs because of the high cooling rate and the effusion of nitrogen from the weld pool, which is characteristic for this welding process. To guarantee the necessary mechanical and technological properties and the corrosion resistance, the DSS are welded with filler material and afterwards undergo a post-weld heat treatment. The present work shows the results of investigations concerning the development of an electron multi-beam technology for welding the thick-walled components of DSS without a filler material and post-weld heat treatment. The electron multi-beam technique allows the formation of many weld pools at the same time, which might achieve slower cooling rates and influence the austenite–ferrite formation of the DSS welds. Based on the results of previous studies, in which the optimum cooling rate and number of weld pools were determined, different electron multi-beam techniques were developed and applied to produce the bead on plates of these steels. The studies were performed on standard duplex stainless steel of type X2CrNiMoN22-5-3 and on lean duplex stainless steel of type X2CrNiN23-4. The resulting austenite formation, mechanical properties and the corrosion resistance of the electron multi-beam welds were investigated and are presented in this work.

Metallurgical influence on quench distortion of SAE 52100 long cylinders

AbstractQuenching of steel components results in complex and hard-to-predict dimensional and shape changes (distortion). Even the components manufactured from different parts of the same semifinished product may show significantly different distortion behaviours during quenching. The reason is thought to be non-uniform distribution of distortion potential carriers in the final component (i.e. alloying elements, segregations, residual stresses and phases) which are accumulated throughout the whole manufacturing chain. This study focuses on the effects of alloying element distribution and segregation on quench distortion. For this aim, long cylinders of various diameters were machined from 45 mm diameter SAE 52100 steel bars, and marked to define their exact positions in the initial bar. Then the cylinders were austenitised in a vertical furnace under nitrogen atmosphere and quenched in a gas nozzle field. The coordinate measurement results show that dimensional changes deviate significantly with machining ...

Was Yahweh Worshiped in the Aegean?

A comparison of Aegean and biblical sources reveals striking similarities between Dionysus and Yahweh: both are characterized by the same symbols, the same mode of action and the same theophany; both provoked a comparable doubt concerning their divine nature and/or their actual powers; and both had the same subversive effects with regard to the official pantheon. The homology between Yahweh and Dionysus is confirmed by their common vestigial link to copper metallurgy. From Greek literary sources and reflections about the continuous metallurgical influence of Canaan on the Aegean world, it is concluded that during the Bronze Age Dionysus was probably the Aegean counterpart of Yahweh, the mysterious Canaanite god of furnace metallurgy. Further examination suggests that the popularization of the cult of Dionysus in Greece, from the ninth century BCE, underwent a similar process leading in Canaan to the emergence of the Israelite alliance. These findings open new horizons of investigation, both of the ancient Aegean civilization and of the nature of the popular cult of Yahweh in Canaan prior to the monotheistic reform.

Metallurgical aspects of rock bolt stress corrosion cracking

This paper reports on the metallurgical influence on rock bolt stress corrosion cracking for a range of: (1) existing rock bolt steels and (2) commercial steels. Rock bolt steels 1355, MAC and MA840B displayed SCC when loaded at 0.019 MPa s −1 in the sulphate pH 2.1 solutions at the free corrosion potential. They had comparable threshold stresses and comparable stress corrosion crack velocities. Rock bolts steel 5152CW10D had the best SCC resistance of the rock bolt steels tested. Cold work increased the resistance of 5152 to SCC. The five commercial steels 1008, X65, X70, 4140 and 4145H were subjected to the linearly increasing stress test (LIST) in the dilute pH 2.1 sulphate solution at their free corrosion potential and at increasingly negative applied potential values to −1500 mV. The increasingly negative applied potential increases the aggressivity of SCC conditions because of increasing hydrogen liberated at the specimen surface. The steels 1008, X65, X70 and 4145H resisted SCC for all applied potentials including −1500 mV.

An evaluation of steels subjected to rock bolt SCC conditions

In order to understand the metallurgical influences on rock bolt stress corrosion cracking (SCC), an evaluation has been carried out of a range of steels subjected to the conditions previously identified as producing laboratory SCC similar to that observed for rock bolts in service. The approach has been to use the linearly increasing stress test for samples exposed to a dilute pH 2.1-sulphate solution, as per our prior studies. SCC was evaluated from the decrease in tensile strength, ductility and fractography as revealed by scanning electron microscopy observation. A range of SCC susceptibilities was observed.

Metallurgical influence on distortion of the case-hardening steel 20MnCr5

In literature, only few works are published that make statements on influences between material properties and distortion. There are some investigations on the influence of carbides and their distribution in the structure. Other authors report on a distinct influence of the texture on distortion. However, the operational sequences during solidification as well as the following deforming processes affect the homogeneity of the chemical composition. Local fluctuations of the chemical composition lead to locally different phase transformations. As a result there will be differences in the structure and therefore inhomogeneous distortion. The hardenability could be suitable as an integrating parameter to describe the effect of the alloying elements as well as their homogeneity in distribution in the structure on distortion. Additionally, the preheating treatment of the material as well as the carburizing process can influence the size alteration and the deformation. Therefore, in this work steel of the quality 20MnCr5 with different hardenability grades were varied concerning their preheating treatment conditions. Three conditions were adjusted: annealing to a specific structure, pre-aging and the condition after cooling from the hot rolling heat. The extend of distortion was evaluated by measurements on a coordinate measuring apparatus before and after hardening. Metallurgische Beeinflussung des Verzugs beim Einsatzstahl 20MnCr5 In der Literatur finden sich zurzeit nur wenige Arbeiten, die sich mit der Beeinflussung des Verzuges durch die Materialeigenschaften beschäftigen. Einige beschäftigen sich mit dem Einfluss von Carbiden und deren Verteilung im Gefüge, andere mit dem Einfluss von Texturen. Allerdings beeinflussen die Vorgänge während der Erstarrung sowie jene während der Umformprozesse die Homogenität der chemischen Zusammensetzung. Schwankungen der lokalen chemischen Zusammensetzung führen wiederum zu lokal unterschiedlich ablaufenden Phasenumwandlungen. Daraus resultieren unterschiedliche Gefüge, die ungleichmäßigen Verzug hervorrufen. Die Härtbarkeit könnte ein geeigneter Parameter sein, um als integrierender Faktor den Einfluss der Legierungselemente zusammen mit deren Verteilung im Gefüge zu bewerten. Darüber hinaus kann der Vorwärmebehandlungszustand sowie die Aufkohlung die Maß- und Formänderungen des Bauteils beeinflussen. Daher wurden drei Vorwärmebehandlungszustände eingestellt: BG-Glühen, Vorvergüten und der Zustand nach Abkühlung aus der Walzhitze. Der Verzug wurde anhand von Messungen auf einem Koordinatenmessgerät vor und nach dem Blindhärten bewertet.

Metallurgical and Surface Influence on the Corrosion Resistance of Ni-Cr-Mo Alloys According to ASTM G 28

Abstract The influence of surface condition, chemical composition, and microstructure of Ni-Cr-Mo alloys has been investigated using the ASTM G 28 standard for intergranular corrosion testing. Experiments were carried out mainly using the Ni-based alloys C-22 (UNS N06022) and C-276 (UNS N10276). Repeatabilities of both testing procedures of ASTM G 28, Method A and B, were found to be in most cases ≤3%. A finer surface finish yields lower corrosion rates. The corrosion rate of electropolished specimens is about 5% to 20% lower than for ground specimens. Sandblasted and pickled specimens show a 1.3 to 4 times higher corrosion rate than ground specimens because of the crevice corrosion at laminations and crevices. Method B yields a better differentiation between specimens with different surface finishes than Method A because of the less-aggressive test conditions. In addition to the ratio Cr/(Mo+W), which has already been found to be an indicator of corrosion resistance of these materials, the elements Mo an...

A Prototype laser forming system

A non-contact laser forming (LF) demonstrator system was developed to demonstrate the process on a large primitive shape. The research that led to this development is described in this article. A fundamental study was carried out which examined the effects of laser-forming parameters on tokens of an aluminium and a titanium alloy. Energy, geometrical and metallurgical influences were investigated and are summarised here. Results of the study showed that LF of these aerospace materials is possible using a large operating envelope of laser-processing parameters. A range of metallurgical effects resulted on the titanium alloy and these are traced here. Depending on how the energy input was supplied to the plate surface, various geometrical effects resulted. These effects are discussed. Using the knowledge gathered from the fundamental study, a prototype LF system was built. The components of the system and the forming of a primitive shape on it are discussed. Conclusions from the study indicate that the future work lies in the development of the demonstrator for primitive 3-D shapes and the integration of a knowledge-based system.

Understanding and Modelling the Mechanical and Corrosion Properties of 6056 for Aerospace Applications

Alloys of the Al-Mg-Si-Cu series like AA6056 are good candidates for welded fuselage panels. The first part of the paper recalls the main metallurgical influences on final properties (mechanical strength, damage tolerance and intergranular corrosion resistance). Starting from these principles, the properties of AA6056 type alloys were rationalised using metallurgical modelling. Clear relationships between measured properties and metallurgical calculations are found. An illustration of such an approach is given, leading to an optimised version of AA6056.

The influence of internal stresses on the fracture toughness of α/β titanium alloys

The influence of internal stresses on fracture toughness was investigated in α/β titanium alloys. It was shown that the direct linkage of K IC to various microstructural parameters was not so conclusive, since the different parameters act simultaneously on fracture toughness. On the contrary, the metallurgical parameters change the plastic strain incompatibilities inside the material. Thus X, which is a macroscopic measurement of these incompatibilities, is the relevant parameter to account for the different metallurgical influences on toughness. The influence on X of the α-phase percentage, aspect ratio, and the secondary α-phase percentage was determined, and it was established that low internal stresses could provide high fracture toughness. The present work also showed the ability of a modified Gurson-Tvergaard (GT) model to calculate the experimental K IC value.

Laser beam welding with filler metal

Laser beam welding generally does without the use of filler metal, in contrast to conventional welding processes. The use of filler metal in laser beam welding or in the combined GMA (gas-metal-arc)-laser beam - hybrid welding process widens the field of application for laser beam welding. The main advantages worthy of mention include, primarily, a greater weld gap bridging ability and a metallurgical influence on the weld metal. Based on the current state of knowledge, this article gives a few examples of different materials and material combinations the limited weldability of which is broadened when filler metal is used with laser beam welding. Listed as examples are low-alloy steels with partly elevated carbon contents, duplex steels, and the material combinations of steel/cast iron and austenite-ferrite joints. Besides laser beam welding with filler metal wire, examples of the combined GMA-laser hybrid welding process are also described.

Metallurgical influences on the fatigue strength of an induction hardened micralloy steel : Burnett, M.E., Mussolff, C.F., Michal, G.M. and Rivas, A.L. Fundamentals and Applications of Microalloying Forging Steels (1996) 455–469 Fundamentals and Applications of Microalloying Forging Steels, Golden (8–10 July 1996)

Metallurgical influences on the fatigue strength of an induction hardened micralloy steel : Burnett, M.E., Mussolff, C.F., Michal, G.M. and Rivas, A.L. Fundamentals and Applications of Microalloying Forging Steels (1996) 455–469 Fundamentals and Applications of Microalloying Forging Steels, Golden (8–10 July 1996)