Threading Process Research Articles

Experimental investigation and numerical simulation of swaging process of tubes for oil country tubular goods

AbstractPremium integrated seamless pipes made from high strength low alloy steels are used to produce oil country tubular goods. Operational requirements of these pipes in petroleum industry lead to an adequate tube end connection with better mechanical strength and sealing properties. Therefore a cold swaging process or calibration of pipe end is necessary for the mechanical threading process of the tube. Applications of typical calibration mandrels result in heavy wear due to higher swaging loads and the optimal necessary geometry of end tube could not be achieved. In this study, a new mandrel geometry with a finished surface was developed to modify the pipe end profile and reduce the wear tool. The investigated pipe made from P110- pipe steel was plastically preformed using a cold swaging process. Experimental measurements of the pipe end geometry after swaging process resulted an increase of the inner tube diameter of approximately 4.9% and an outer tube diameter of 3.7% respectively. Furthermore, a rather constant tube wall thickness was also observed. An Abaqus plug-in was developed to characterize the swaging process of pipe ends. The influence of friction between tool and pipe surfaces on the final geometry of pipe ends and residual stresses in pipe ends due to preforming were numerically predicted. The new designed swaging process resulted a better final pipe end geometry and low tool wear during the preforming of pipe end. The presented plug-in in this work could be used for tool optimization and characterization of swaging process of pipes in oil and gas industries.

Investigation of Thrust Force, Torque and Chip Formation in Tapping Threading by Finite Element Method

Threading with taps is a method frequently used in machining. Since this process takes place in a closed area due to its nature, some difficulties are encountered. In this study, the results of a previous experimental work were compared with the results of a simulation program. In the experimental work, the tapping process were performed by using M10 taps with three different geometries for the drilled holes on AISI 1050 material. Tapping operations were carried out with uncoated and TiN coated HSS tools. For the simulatin program, the 3D CAD models of the tested taps were created by reverse engineering method and then imported into a simulation program, called Third Wave AdvantEdge program. The CAD models were evaluated by Third Wave AdvantEdge program based the finite element method. The thrust force, torque, chip formation occurring during the threading process were examined. It was concluded that the simulation and the experimental results were quite compatible.

Microstructural and fatigue characterization of 316L stainless steel subjected to flow drilling and tapping: comparison with machined threads

Despite extensive research on the plastic deformation of materials to enhance their fatigue resistance, the influence of the flow tapping process on the fatigue resistance of drilled and tapped bars remains poorly understood. Herein, the fatigue performance of flow-drilled (friction-drilled) and flow-tapped 316L stainless steel bars was experimentally analyzed and compared with that of conventional material-shearing-based drilling and tapping operations. The effect of flow processes on the material properties was evaluated via microhardness tests and microstructural analyses. The results indicated that the hardness near the holes produced via flow forming was 62 % higher than that of the base metal. Moreover, grain refinement and plastic deformation were observed beneath the thread surfaces. Metallographic observations revealed the occurrence of craters and folds at the crest of the flow-formed threads. Following the ASTM F382-17 standard, four-point bending fatigue tests were performed at three stress amplitudes with a stress ratio of 0.1. No noteworthy differences were observed when the maximum bending moments applied were at 75 % and 60 % of the bending moment at yield. However, when the maximum bending moment applied was limited to 50 % of the bending moment at yield, the average fatigue life of the specimens with machined threads was longer than that of their flow-formed counterparts. Fractographic observations were used to identify the crack initiation regions and elucidate the underlying fracture mechanisms. For both types of specimens, failure originated at the crest of the first thread, beneath the surface of the maximum tensile stress. The flow-processed specimens exhibited secondary cracks at the root of the threads, where grain refinement also occurred. This study provides robust empirical evidence that using flow-forming processes to thread 316L stainless steel does not systematically improve the fatigue resistance of the material surrounding the holes. Furthermore, by optimizing the flow process and eliminating discontinuities, the threading process proposed herein could help improve the fatigue resistance of orthopedic implants.

PVD coating strategies: Developing a combination of AlCrN and AlTiSiN for enhanced surface performance during threading of super duplex stainless steel

Super duplex stainless steel (SDSS) is one of the difficult-to-machine materials due to its high tendency to work-harden and low thermal conductivity. According to recent findings, PVD hard coatings based on Al, Cr, and Ti are recommended for SDSS machining. In this work, three different PVD coating systems were applied for the threading process of SDSS. Monolayer Al50Cr50N, Al60Cr40N, and multilayer Al60Cr40N/Al50Ti45Si5N were deposited on cemented carbide inserts. This paper highlighted the effect of alloying and coating architecture design on the cutting tools' mechanical properties, tribological characteristics, and wear performance. A novel balanced combination of AlCrN/AlTiSiN multilayer coating with a Si content of 5 at. % was proposed, and it exhibited improved adhesion, beneficial mechanical properties, and superior cutting tool life. Furthermore, tribological characteristics under extreme environments were analyzed through a heavy-load, high-temperature tribometer, as well as XPS and AES measurements. The surface integrity of workpiece material machined by various coatings was also examined through microstructure, microhardness, and residual stress measurements. The depth profiles of residual stress reveal that the machining process significantly impacts the outcome, influenced by the tribological properties of the coatings. Specifically, the AlCrN/AlTiSiN coating exhibits a minimal effect on the surface. These investigations enhance the comprehension of the mechanisms that cause material mechanical surface transformation in threading operations, contributing to a deeper understanding of machining processes.

Development of a machining strategy to manufacture SiSiC nuts by EDM

Today, the high-precision manufacturing of small cavities in difficult-to-machine materials is still a challenge, even more so if they need to be threaded. The machining time, the wear suffered by the electrodes and the surface finish are determining factors in the efficiency of the threading process. However, there is scant literature on this subject so there is a need to study the process and the parameters involved. Thus, this study presents a novel machining strategy for the manufacture of nuts using die-sinking electrical discharge machining (EDM). Moreover, the novelty of this strategy is that it is carried out in a single stage and with a conventional EDM generator. To do so, a design of experiments (DOE) methodology has been followed. First, the optimal machining conditions are determined by studying the influence of EDM parameters on operation variables and mathematical models are developed using multiple linear regression. These models allow the behavior of the response variables under study to be predicted. Finally, this machining strategy developed from the previous experimental results is validated in the manufacturing process of a final part, specifically a square nut. It can be concluded that the mathematical model is good enough to predict the experimental results. Thus, the new method presented and described in this present study allowed a nut to be obtained with a real arithmetic mean deviation of the roughness profile (Ra) value of 1.27 μm whereas the predicted value from the model was 1.28 μm. To do so, the machining conditions selected were: 4 A (current intensity), 5 µs (pulse time) and 0.4 (duty cycle), which also gave a material removal rate (MRR) value of 0.5370 mm3/min. The machining strategy proposed here may be used for future research works related to the manufacturing of mechanical joints made of conductive ceramic materials.

Cover Feature: Inclusion Complex Formation with Tetra‐PEGylated Tetraphenylporphyrin and Face‐to‐Face Cyclodextrin Dimer through Unprecedented Molecular Threading (Chem. Eur. J. 32/2023)

Molecules putting on sleeveless shirts: Porphyrins with four sufficiently long PEG chains can form 1:1 supramolecular inclusion complexes with a 3,3’-linked cyclodextrin dimer in water through a molecular threading process. This phenomenon is similar to the action of putting on a sleeveless shirt, don't you think? More information can be found in the Research Article by Q. Mao and H. Kitagishi (DOI: 10.1002/chem.202300408). Artwork by Nobuyuki Goto (art director) and Ryoko Sekimoto (illustrator) from PEACE PiECE.

Energy consumption, mechanical and metallographic properties of cryogenically treated tool steels

Abstract This article examines energy consumption, microstructure, mechanical properties, and the change in the wear amount during the machining of GGG-42 cast iron material with two types of guide cutting tool produced by powder metallurgy and casting method The tap. tool samples used as cutting tool material were first subjected to the traditional hardening process and then to two different cryogenic treatments (24–16 h) at −90°C. The internal structures of the guide samples obtained from conventional heat treatment and cryogenic treatment were examined with an optical microscope and Scanning Electron Microscope. The hardness changes were checked with Vickers measurement method. The wear amount forming after the threading process was measured with CLEMEX program in a light microscope. In addition, by measuring the current amount drawn during the machining of the cast iron with guide cutter tools, instantaneous power consumption during cutting and power consumption during chip removal were calculated. The application of heat treatment and cryogenic process increased the hardness of the guides. Moreover, the power consumption during the chip removal was also seen to increase. This can be commented that cutting tools produced with powder metallurgy perform better than the cutting tools produced via casting and 30% energy saving.

Inclusion Complex Formation with Tetra-PEGylated Tetraphenylporphyrin and Face-to-Face Cyclodextrin Dimer through Unprecedented Molecular Threading.

Herein, a host-guest inclusion complex formation between tetra-PEGylated tetraphenylporphyrin with a per-O-methylated cyclodextrin (CD) dimer through the molecular threading process that is physically unexpected to occur is described. Although the molecular size of the PEGylated porphyrin is much greater than that of the CD dimer, the sandwich-type porphyrin/CD dimer 1 : 1 inclusion complex was spontaneously formed in water. The ferrous porphyrin complex binds O2 reversibly in aqueous solution, which functions as an artificial O2 carrier in vivo. Pharmacokinetic study using rats revealed that the inclusion complex showed a long circulation in blood in contrast to the complex without PEG. We further demonstrate the unique host-guest exchange reaction from the PEGylated porphyrin/CD monomer 1/2 inclusion complex to the 1/1 complex with the CD dimer through the complete dissociation process of the CD monomers.

Calix[6]arene-Based [3]Rotaxanes as Prototypes for the Template Synthesis of Molecular Capsules.

In this work, the ability of several bis-viologen axles to thread a series of heteroditopic tris(N-phenylureido)calix[6]arene wheels to give interwoven supramolecular complexes to the [3]pseudorotaxane type was studied. The unidirectionality of the threading process inside these nonsymmetric wheels allows the formation of highly preorganised [3]pseudorotaxane and [3]rotaxane species in which the macrocycles phenylureido moieties, functionalised with either ester, carboxylic, or hydroxymethyl groups, are facing each other. As verified by NMR and semiempirical computational studies, these latter compounds possess the correct spatial arrangement of their subcomponents, which could lead, in principle, upon proper bridging reaction, to the realisation of upper-to-upper molecular capsules that are based on calix[6]arene derivatives.

Threading holder based on axial metal cylinder pins to reduce tap risk during reversion instant

Internal thread profiles are used widely in manufacturing processes with the aim of assembling/disassembling different components during maintenance activities from the aeronautics sector until common industrial parts. The threading process is one of the last operations carried out to obtain those components, and consequently, it is an operation of high added value. Threading is a complex operation that must carefully synchronize the rotation with the feed movements to avoid tool breakage during the instant of tapping reversion stage. In order to avoid this risk, several toolholders were developed present in the literature but deficiencies in terms of stability and productivity. Therefore, in this work, a new toolholder is proposed in which the common springs used to mitigate the lack of perfect synchronization between rotation and feed movements are replaced by elastic metal pins achieving a torsional compliance toolholder. The results show that the use of the proposed toolholder implies not only a productivity increase but also a surface integrity improvement as well as a stress reduction that the cutting tap is subjected and thus, achieving a substantial improvement in the current tapping processes. In particular, the use of the proposed toolholder implied a 75% reduction of the maximum stress achieved in the reversal instant, improving 20% tool life with an increase of 30% cutting speed. Therefore, the use of the proposed toolholder implies a substantial improvement in the current tapping processes.

Increasing Production Capacity of Oil Country Tubular Goods Pipe Using Oee Methods

The effectiveness of production equipment is very important to pay attention to maintain competition, coupling pipe threading process there has been an imbalance in the threading process time resulting in decreased output due to the number of rejected products which is decreasing in production capacity. To overcome the problem, the data was processed using mixed methods with a sequential explanatory approach, and the overall equipment effectiveness measurement method to analyze the calculation of availability, performance, and quality rate. To determine the root cause of the problem using fishbone diagram analysis and six big losses. The results of the study stated that the overall equipment effectiveness was below the world-class standard, which was below 85% with a difference of 49.74% being the factor causing the failure to achieve the coupling pipe production capacity. The low overall equipment effectiveness is influenced by the engine performance which is a total average of 42.61%, due to failed products and reworked products and the breakdown time for 460 minutes impacting in losses on the engine productivity. These findings pursue the company to monitor, and implement the overall machine effectiveness system to optimize the capacity production.

FATIGUE ANALYSIS OF A RACK TOOL TO INCREASE MILLING PRODUCTIVITY

In recent years, the automotive industry has had remarkable technological growth. Organizations strive to have in their processes more advanced technologies that allow them to create a competitive advantage over others within the same field. The spline rolling and the threading process have evolved in line with the significant demand for quality products from major automakers in the automotive industry. Product consumers of the automotive industry demand quality at low prices, which results in the need to maximize resources for auto-parts manufacturing. In this work, an improvement in the performance of a spline forming rack from 5,000 to 25,000 pieces is reported. A conceptual design of such rack was developed in which the geometry of the tooth was modified; then, employing a finite element analysis, using ANSYS Version R19.2., the average fatigue life of 25,000 cycles was obtained. Finite element results were validated by on-site experimental tests using the Digital Image Correlation (DIC) technique. Finally, the tooling was manufactured and put into operation, reaching 32,785 rolled parts; with this performance, the initial goal of at least 25,000 parts was surpassed. Subsequently, three forming racks were fabricated, from which an average yield of 30,269 rolled parts was obtained. Keywords: Fatigue, Digital Image Correlation technique (DIC), Finite element analysis, Rolling process.

Inside Cover: Active Mechanical Threading by a Molecular Motor (Angew. Chem. Int. Ed. 19/2022)

A molecular motor setup allowing to harness the trajectory of directional motor rotation for an active mechanical threading process is presented by Henry Dube et al. in their Research Article (DOI: 10.1002/anie.202201882). The motor is embedded into a macrocycle and its indane-based rotor fragment then serves as “revolving door” in the light-driven–rotation. In this way a process akin to macroscopic threading of a needle is miniaturized to the molecular level offering a first entry point to mechanical molecular knitting or weaving processes.

The influence of the value of the front angle and the angle of inclination of the cutting edge on the radial force when threading with taps

The purpose and normalization of the accuracy of the geometric parameters of the cutting part of the tool is directly related to the indicators of functional and parametric reliability of taps. The comparison of the taps test results showed that reducing the range of scatter of geometric parameters of the tool of the cutting part of taps makes the threading process more stable (leads to a significant reduction in the resistance dispersion, to a decrease in the number of breakdowns, and a decrease in the coefficients of variation of resistance and wear) and reduces the breakdown of the flank of the thread being cut. In this paper, the dependences of the change in the magnitude of the radial force on the elementary cutting profiles of the tap on the error of the spacing angle between the cutting teeth due to angular displacements of the main cutting blade owing to the presence of the front angle and the angle of inclination of the cutting edge are obtained. The obtained patterns of changes in the radial force on the cutting teeth of the tap can be used when considering alternative options for assigning the angle λ based on the criterion of minimum (limitation) of cutting forces during processing. A change in the front angle in the range of known recommended values does not significantly affect the nature of the change and the amount of radial force on the cutting teeth of the tap, as well as does not affect the one-sided direction of the radial force vector, characteristic of taps with a uniform spacing angle. The error of the spacing angle between the cutting teeth of the tap, due to the presence of the angle of inclination of the cutting edge λ, leads to an increase in the radial force and a change in the nature of the load on the cutting teeth of the tool. The obtained patterns of changes in the radial force on the cutting teeth of the tap can be used when considering alternative options for assigning the angle λ based on the criterion of minimum (limitation) of cutting forces during processing.

Inclusion complexes of triblock L35 copolymer and hydroxyl propyl cyclodextrins: a physico-chemical study

Polypseudorotaxanes based on triblock L35 copolymer and hydroxyl propyl-modified cyclodextrins (HP-α-CD and HP-β-CD) have been characterized. Their physico-chemical properties have been correlated to the threading process.

Use of Advanced Control Techniques With Virtual Rolling to Improve Threading of the Tandem Cold Mill

The threading of the tandem cold metal rolling mill is a significant function in the control of this process. During the threading process it is important to reduce the excursions in the strip thicknesses and tensions. Additionally, in most cases it is desired by the operational personnel to control the individual mill stand speeds such that, as the head of the strip moves between two adjacent stands, its speed between the two stands is held at the strip speed at the exit of the last stand just before acceleration to run speed. Moreover, it is desired that disturbances in the thickness and the resistance to deformation in the incoming strip are successfully handled by the controller. In this article, we propose a method of improved control for this process that considers all of these requirements. The effectiveness of this method is shown by simulation using data from operating mills.

Chirality Transfer in a Calixarene-Based Directional Pseudorotaxane Complex

Hexamethoxycalix[6]arene 3 forms a directional pseudorotaxane complex with the chiral axle (S)-(α-methyl-benzyl)benzylammonium 2+. Between the two (endo-chiral)-2+@3 and (exo-chiral)-2+@3 pseudorotaxane stereoisomers, the former is preferentially formed. This result confirms the validity of the “endo-α-methyl-benzyl rule”, previously reported by us. DFT calculations suggest that C-H … π interactions between the methyl group of 2+ and the calixarene aromatic rings, determine the stereoselectivity of the threading process toward the “endo-α-methyl-benzyl preference”. An amplification of optical rotation is observed upon formation of the pseudorotaxane complex (endo-chiral)-2+@3 with respect to free axle 2+. Thus, the specifical rotation of the 1:1 mixture of chiral 2+·B(ArF)4− salt and achiral 3 was augmented upon formation of the pseudorotaxane and DFT calculations were used to rationalize this result.

Analysis of Micro-Machining Process for External Thread of Micro Round Tube.

This study aims to analyze the stainless steel micro round tube external threading process for the influence of different outer threading pitches (0.25 mm, 0.4 mm) and outer diameters (Ø1.9, Ø1.94, Ø2). This study also analyzes the effects of different friction factors (0.1, 0.3, 0.5, 0.7, and 0.9) and different tube thicknesses (0.4, 0.45, 0.5, 0.55, and 0.6 mm) on the threading process. This study considers size effect to use corrected material parameters for the microtube to conduct the finite element analysis by DEFORM-3D software. The goal is to understand stainless steel (SUS304) micro round tube threading and the difference by using macro material parameter analysis. The historic forming data from the simulation and experiment of threading processing are presented, and the corresponding stress/strain distribution and thread shape are also calculated. The experiment results are compared to the simulation results to verify the reliability of this analysis method. The result shows that the torque/stress/strain obtained by the modified model is always lower than by Swift’s model. It means that the size effect can be considered to apply on the forming process and provided proper torque to form the external thread of the micro round tube, e.g., the maximum torque of the round die for M2 × 0.25 occurs over the fourth stroke. For the influence of the outer diameter of the micro round tube, the larger diameter induces the larger maximum torque on the round die for M2 × 0.4, but for the smaller pitch of M2 × 0.25, the larger maximum torque is not influenced by the diameter of the tube. When the pitch of the round die is increased, the torque, stress and strain are also increased relatively. As the friction factor and torque between the round die and tube increase, the stress and strain become lower. Changing the tube thickness will not significantly change the torque, the stress, and the strain. These results guide the simulation and experiment of optimized micro round tube threading development and design to reduce cost and increase product quality.

Improvement of thread turning process using micro-hole textured solid-lubricant embedded tools

In this paper, the thread turning of aluminum 7075-T6 alloy is studied using micro-hole textured solid-lubricant embedded carbide inserts. The primary focus of this work is to enhance the performance of the thread turning process for producing high quality threaded parts. To achieve this, micro-holes were generated by laser micro-machining on the rake face of tools and then, MoS2 and CNT (carbon nanotube) solid-lubricants were embedded into micro-holes. The effects of micro-holes and solid-lubrication on the performance of the thread turning process were examined using traditional tool ( T0), micro-hole textured tool ( T1), micro-hole textured MoS2 embedded tool ( T2), and micro-hole textured CNT embedded tool ( T3). In this study, cutting forces, chip-tool contact length, built-up edge (BUE), surface roughness, and operating cost were investigated. The influence of micro-hole generation on the mechanical strength of cutting inserts was evaluated using the finite element method. The results showed that the fabrication of the micro-holes on the rake surface of cutting inserts has no significant effect on the mechanical strength of the tools. The comparisons of our method with traditional tools demonstrated that the cutting performance improved in the threading process. Our results reveal that the main cutting force, radial thrust force, surface roughness, built-up edge, and chip-tool contact length reduced 37.1%, 40.9%, 37.9%, 58.3%, and 38.2%, respectively, as T3 tools are applied in this process. A cost analysis, based on estimated tooling costs, showed that the T3 tool can yield an 18% reduction in overall operating cost.

Calix[6]arene-based Brønsted acids for molecular recognition and catalysis.

We report the synthesis of a versatile trifluoromethylsulfonamide calix[6]arene derivative with Brønsted acid features which can influence both molecular recognition and catalytic application. Indeed, in low polarity media, the trifluoromethyl-containing supramolecular wheel is able to respond to the complexation with charged species as a function of its selective ion-pair recognition. In parallel, the enhanced acidity is the key to promote Michael additions of indoles to nitroalkenes under pseudo-physiological reaction conditions (H2O, 37 °C).