Aluminum Alloy Drill Research Articles

Multiaxial Fatigue of Aluminum Drill Pipes—Experiments and Numerical Analyses

Abstract This article presents an experimental test program and numerical analyses conducted on aluminum alloy drill pipes with two different geometries. Small-scale characterization tests were conducted to determine both the material mechanical properties and the fatigue S–N curves. Full-scale fatigue tests of the components are also presented. A finite element model of the drill pipes, including the tool-joint region, was developed. The model simulates, through different load steps, the tool-joint hot-assembly and the experimental loads to obtain the actual stress distribution during the full-scale tests. Maximum stress amplitude in the aluminum pipes was found to be coincident with the edge of the connector, at the same location where failure was observed in full-scale tests. The study revealed that such pipes present a complex stress state near their connection to the steel tool-joints due to their geometry and the residual stresses induced during the assembly of the steel connectors onto the aluminum pipes. Finally, multi-axial fatigue models were calibrated with the results of the small-scale tests and applied to the stress–strain state obtained numerically. Theoretical predictions were correlated with full-scale fatigue test results.

Parameter optimization of 7050 aluminum alloy drilling based on ABAQUS

For the drilling of 7050-T7450 aluminum alloy commonly used in the aerospace field, this article uses ABAQUS finite element software to establish a drilling simulation model of 7050-T7450 aluminum alloy. A simplified cutting model is created based on the actual cutting model, combined with the Johnson-Cook material constitutive equation, and then the actual drilling process is simulated. At the same time, through the use of orthogonal experiment analysis method, the influence of the four factors of tool diameter, drilling speed, feed rate and tool tip angle on the axial force and moment of twist drill is analyzed. The extremely poor method is used to determine the best cutting combination plan. According to the results of the orthogonal experiment, a multiple linear regression was performed using MATLABLE software, and a drilling model was established to obtain an empirical formula. The accuracy of the empirical formula is verified by comparing the calculation of the empirical formula with the simulation result, and it provides a reference for the actual processing.

Effect of <i>In Situ</i> TiB<sub>2</sub> Particles on the Grain Size and Mechanical Properties of 7075 Aluminum Alloy

Light-weight and high-strength aluminum alloy drill pipes are potential and promising to replace traditional steel drill pipes. In this study, the grain size and mechanical properties of aluminum alloy drilling pipe materials reinforced by in-situ TiB2 particles were studied. The results showed when reinforced by in-situ TiB2 particles the grain size of aluminum alloy materials was refined from 155 m to 57 m and ultimate tensile strength was increased from 590 MPa to 720 MPa. Besides, the results also indicated that the friction coefficient was reduced from 0.99 to 0.50 and thus the abrasion resistance of 7075 aluminum alloy was enhanced by 34 %. This study provided theoretical basis for the application of light-weight and high-strength aluminum alloy drill pipes in directional drilling and ultra-deep wells.

Performance and wear mechanisms of uncoated, TiAlN, and AlTiN-coated carbide tools in high-speed drilling of Al-Si alloy

Owning to the extremely abrasive silicon particles, low melting point of aluminum, and its susceptibility to adhere to the tool, high-speed drilling of aluminum alloys containing high silicon content becomes a challenging operation. Hence, the understanding of the tool wear mechanisms is essential in order to develop and select the efficient tool material. This paper reports on the investigation of performance and wear mechanism of uncoated and TiAlN and AlTiN-coated tools when high-speed drilling of Al-Si (A383) alloy. Drilling tests were conducted at various cutting parameters, while thrust forces were measured using a dynamometer. The wear mechanisms that contributed to the drill failure were assessed by analyzing the worn cutting edge and drill bit cross section; and by employing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Results showed that feed rate has the highest effect on the primary wear stage; and flank wear at the outer cutting edge found to be dominant failure mode for all tools. Moreover, it is found that plastic deformation, diffusion, attrition, abrasion, and fracture are the main operating tool wear mechanisms. The longest tool life was recorded for AlTiN-coated tool, but more adhesion of Al was observed on this tool surface. At the end, TiAlN-coated drill was proposed as the tool with the best performance among the tool materials used in this study.

Performance assessment of vegetable oil-based minimum quantity lubrication (MQL) in drilling

Metalworking fluids are widely used to increase productivity and quality of metal cutting. However, these metalworking fluids possesses the problems in terms of the effect on environment and health of the worker. Hence, various approaches to provide cooling and lubrication are explored such as mist cooling, high-pressure cooling, minimum quantity lubrication (MQL), nano fluids, solid lubricants, etc. In this regards, the present work exhibits the performance evaluation of vegetable-based minimum quantity lubrication (MQL) in drilling of aluminium alloy. This drilling tests have been performed in different cutting environments such as Dry, flood cooling, MQL with castor oil, MQL with sunflower oil with uncoated HSS twist drill. The effect of various drilling parameters have been analysed by measuring surface roughness, axial thrust, and torque produced. The comparison of results indicates effectiveness of the vegetable-based MQL in terms improved surface finish and reduction in axial thrust and torque during drilling.

New Findings in the Field of Thermal Drilling of Aluminum Alloys.

This paper explores the joining of materials by a new progressive method of thermal drilling. Many types of joints are utilized in industrial production, especially in the automotive industry, which requires the joining of different types of materials with different thicknesses. For these needs, it will be appropriate to apply the joining method of thermal drilling technology. The used material, its mechanical properties, and the preparation of the joint by assembly and disassembly operations play an equally important role. By using new friction technologies, we can reduce production time, increase joint quality, offer automation in certain types of operations, save economic costs, and protect the environment. In this contribution, the authors present the results of their scientific research work focused on an investigation, comparison and testing of thermal drilling effects on the behavior of aluminum alloys (AlMgSi). The holes, collars and bushings formed by the drilling method were subjected to visual shape evaluation. Based on the evaluation of the samples, the quality of the evaluated joints was assessed. The best shape and strength properties at higher speeds of the drilling machine were obtained at 3400 rpm. The results of the methods of macroscopy and microscopy investigations, as well as the results of the methods of scanning electron microscope (SEM) and energy dispersive X-ray (EDS), are presented in this contribution.

Operational properties of drill pipes made of coated aluminum alloy 2024

The main aim of this article is to provide for the comprehensive study that has been carried out. We tested the performance characteristics of coated aluminum alloy 2024 under conditions simulating the operation of drill pipes in the oil industry. In the course of our study we experimentally determined electrochemical potential and corrosion rate of the coated aluminum alloy 2024. Moreover, a comparative analysis of adhesion and wear resistance of coatings during the use of the alloy has been carried out. The authors have also studied structures of various coatings and the nature of damage to aluminum alloy drill pipes under operation.

Multi-hole simultaneous drilling of aluminium alloy: A preliminary study and evaluation against one-shot drilling process

Poly-drill heads are used in mass production to increase productivity when a large number of holes are required. In this work, drilling experiments on Al5083 aluminium alloy were carried out using a poly-drill head to measure the thrust force and assess hole quality. Analysis of chip formations and post-machining tool condition were evaluated using optical microscopy. Additional drilling tests were conducted using one-shot drilling and results obtained from the two drilling techniques were evaluated against each other. The results showed that the average thrust forces obtained from poly-drill head were slightly lower than those from one-shot drilling. Improvement in hole quality in terms of surface roughness and reduction in chip length were achieved using the poly-drill head. Furthermore, visual inspection of the tools showed that adhesion and built-up edges on drills used in the poly-drill head were lower as compared to drills used in the one-shot drilling. The contribution of input parameters on the measured outputs was determined using an ANOVA statistical tool.

Investigations into solid lubricant filled textured tools on hole geometry and surface integrity during drilling of aluminium alloy

Generation of holes in aluminium alloy is difficult task for manufacturing industries due to chemical affinity with the drilling tool. This results in creation of build edge that leads to high power consumption and variation in form and surface profile of hole geometry. To overcome this, an attempt has been executed to design a textured pattern over the drill margin and flute surface by fiber laser micro machining process. This laser texture pattern on drill tool act as a source to accommodate more solid lubricant during deep drilling process. A detailed experiment has been conducted to study the influence of solid lubricant filled textured tools on hole geometry and surface integrity and finally compared with dry, blasocut, non-textured coated solid lubricant drill tools. It is inferred that accuracy of the hole is improved in solid lubricant filled textured drill tool over non-textured lubricant, blasocut and dry machining. The continuous, smooth and spiral shaped morphology of the chip with less friction is the indication of improvement in the hole accuracy. Cylindricity error, burr height and surface roughness are observed minimum in texture filled graphite and MoS2 assisted drilling. Good surface finish of 100 nm is achieved at higher cutting speed in graphite filled textured drill tool.

The Influence of graphite, MOS2 and Blasocut lubricant on hole and chip geometry during peck drilling of aerospace alloy

Aluminium alloy is predominantly using in aerospace and automobile structure applications due to high strength to weight ratio. In general aluminium alloys are easy to machine due to high stacking fault energy. However chip adhesion and built edge formation on the cutting tool are the major issues reported in literature. To overcome this, a novel attempt has been made by employing peck drilling in dry, blasocut, graphite and molybdenum disulphide [MoS 2 ] condition. A detailed experiment has been conducted by varying drilling process parameters. All the experiments are carried out three times and average values are taken for hole accuracy, circularity error, chip morphology, entry and exit burr on hole. It is inferred that accuracy of the holes are improved in solid lubricant assisted machining over blasocut lubricant and dry machining. Circularity error is observed minimum in graphite and MoS 2 assisted machining. Burr formation is observed in the hole exit for dry peck drilling of aluminium alloy, whereas in graphite and MoS 2 assisted machining there is no burr formation in both entry and exit side of the hole. Long continuous, cone shaped chip morphology with smooth surface during peck drilling is the evidence for improvement of hole accuracy in graphite and MoS 2 assisted drilling

Study on Interface Behavior of SiC/SiO2/Al and SiC/Ni/Al

High-temperature oxidation and electroless nickel plating are two common surface modification processes to improve the wettability of SiC/Al interface. The structure and properties of SiC/SiO2/Al and SiC/Ni/Al interface layers were studied for the preparation of aluminum alloy drill pipe. Two kinds of 6.5%SiC/Al–Cu–Mg–Zn composite ingot were prepared using vacuum melting/casting method, and the added SiC particles in the composites were modified by high-temperature oxidation and electroless nickel plating, respectively. Analysis of structure demonstrates that the interface structures of composites ingot are SiC/SiO2/Al structure and SiC/Ni/Al structure, respectively. For SiC/SiO2/Al interface structure, a smooth and dense SiO2 film is well bonded to SiC and Al by chemical bonding. For SiC/Ni/Al interface structure, there is a very thin Ni film between SiC and Al and the bonding strength between Ni and Al is not so strong. Results of the performance test of the composites indicate that the tensile strength and compressive strength of the composites with SiC/SiO2/Al interface structure, respectively, increase by 7.51% and 24.90%, compared with the composites ingot with SiC/Ni/Al interface structure.

Machinability enhancements of ultrasonic-assisted deep drilling of aluminum alloys

This article presents a new practical approach to gain a better insight into the machinability enhancements of ultrasonic-assisted drilling (UAD) of aluminum alloys where the depth ratio is larger than 10. UAD can provide a depth as up to two times compared to that of conventional drilling (CD). The material removal rate of UAD appeared higher than that of CD by 1.5 times. The total drilling torque was considered to consist of three components: the cutting torque, the rubbing torque and the stick-slip torque. Both rubbing torque and stick-slip torque magnitude in CD were higher several times compared to the cutting torque. In contrast, such components in UAD took a small proportion of the cutting torque. Growing rate of the rubbing torque at deeper holes in UAD was slower than that in CD about 33 times. The effect of ultrasonic assistance on the reduction of chip resistance was found to be more effective at high depth ratio. The new approach gives better insight to understand the effects of ultrasonic assistance in deep drilling and would further develop to apply in similar studies.

Using a supperficially treated 2024 aluminum alloy drill pipe to delay failure during dynamic loading

For many years, a critical factor while drilling deep wells in Algeria oil fields has been the fatigue loads in drill strings used in high tortuosity sections. One solution is the use of drill pipes made of alternative lighter materials instead of conventional steel. A thorough study of superficially (ST) treated 2024 aluminum alloy joined to steel drill pipes in crooked well trajectories is presented in this article. This work discusses several limiting loads exerted on the drill pipes that affect the drilling operation such as axial, twisting and bending forces, which lead to combined cyclic loads. This study is aimed to determine whether it is possible to extend the drilling operation by joining ST 2024 aluminum alloy drill pipes into the drilling string, without losing drilling stability or reliability. It is established that the ST 2024 aluminum alloy drill pipe exerts significant influence on the allowable combined load, but affects to a larger extent the critical load at which loss of drilling string stability occurs, along with improved resistance to wear and corrosion, even at high temperature.

Cutting Environment Impact on the Aluminium Alloy Machining

Abstract The paper is focused on the experiment where the effects of the cutting environment and feed of drilling on the bores roughness and cylindricity were evaluated. Dry drilling of aluminium alloys (without using cutting fluids) is an environmentally friendly machining process but also an extremely difficult task, which is due to the tendency of aluminium to adhere to the drills made of conventional materials such as high-speed steel; and therefore three cutting environments (namely two different emulsions and compressed air) were used in the experiment. The article demonstrates multicriterial optimization of input factors (cutting environment, feed) for two defined target functions: roughness and cylindricity). The measured values were subjected to mathematico–statistical Analysis of Variance (ANOVA). ANOVA was used for examining the effects of machining parameters and their contribution to the surface roughness and bores cylindricity. The optimal cutting parameters were evaluated for “Smaller-the-Better” quality characteristics of both output responses, as can be seen in our article published previously. Based on the ANOVA, we determined that cutting environment exhibited higher percentage of contribution on bores quality than feed of machining. The results show 77.37 % impact of cutting environment and 8.13 % impact of feed on quality of machined bores.

Study on Drilling Parameters Optimization of Aluminum Alloy-Steel Hybrid Drill Pipe

With the increasing number of wells with complex operating conditions, the requirements for oil exploration equipment and technology are higher than ever before. Aluminum alloy drill pipe gradually receives good graces because of its light weight, high strength to mass ratio and strong corrosion resistance. This paper calculates different drillstring combinations according to the same horizontal well. It is found that the hook load and total friction resistance of the aluminum alloy-steel drillstring combination are smallest in the horizontal well, and aluminum alloy-steel drillstring combination is the optimal design. This paper studies the dynamic characteristics of aluminum alloy drill pipe by nonlinear finite element method. The simulation results show that rotation speed has a great influence on the trajectory of the aluminum alloy drill string in the vertical section.When the rotation speed is large, the centrifugal force makes the drill string move close to the wall, and the wear of the drill string is intensified. Besides, The moving range of the rotating drill string in the stable inclined section is close to the lower right part of the wellbore. When the WOB is constant, the range and amplitude of the lateral vibration of the drill string in the X and Y directions become larger as the rotational speed increases.

INVESTIGATE THE BUSHING SHAPE IN MOULD SUPPORTED THERMAL FRICTION DRILLING

Although bushing height and wall thickness are crucial issues, cracks and petal formation on bushings affect these outcomes adversely in thermal friction drilling operations. Therefore, in this paper, bushing shapes were investigated both in traditional and mould supported thermal friction drilling of A7075-T651 aluminum alloy, 4 mm in thickness, at 2000 rpm spindle speed and 25 mm/min feed rate. The proportion of the volume cavities (VBC) of the moulds to the volume of the total evacuated material (VE) selected between 16 % and 32 %. Moreover, the gap sizes between the tool and tool proceeding cavity (CDT) were selected at 0.2 mm, 0.3 mm, and 0.4 mm. In conclusion cracks and petal formation were substantially eliminated, bushing height and wall thickness values were able to select, depending on requirements, also homogenous bushing wall thickness for threading, in moulds supporting thermal friction drilling operations.

Improving Corrosion Resistance and Corrosive Wear Resistance of Aluminum Alloy Drill Pipe by Surface Nanocrystallization and Micro-arc Oxidation

To improve the corrosion and wear resistance performance of aluminum alloy drill pipes in geological and petroleum drilling applications, a strengthening coating was prepared on the surface of the 2618 aluminum alloy by combining treatment with ultrasonic cold forging technology (UCFT) and micro-arc oxidation (MAO). The effects of the strengthening coating on the corrosion and wear resistance of the aluminum alloy were evaluated by electrochemical and tribological tests. The results demonstrated that the corrosion and wear resistance of the aluminum alloy were improved by the UCFT and MAO technologies, especially the salt corrosion resistance. The corrosion morphology of the strengthening coating primarily included pitting, micro-cracks and NaCl attachment. In addition, the UCFT + MAO composite coating exhibited the best wear performance. The wear rate of the UCFT + MAO composite coating was lower than that of the aluminum alloy by 94%. The results provided support for this excellent surface treatment technology for the corrosion and wear resistance of aluminum alloy drill pipes, and they also present a feasible evaluation method for drill pipes.

Effect of Extrusion Texture on Mechanical and Electrochemical Properties of Aluminum Alloy Drill Pipe

Aiming at the special service environment of aluminum alloy drill pipe, in this paper, the influence of extrusion texture on the mechanical and electrochemical properties of aluminum alloy drill pipe was studied. And the macroscopic textures of longitudinal profile and cross section of aluminum alloy drill pipe were tested, and the tensile, compressive and impact mechanical properties were tested, followed by immersion and electrochemical testing. The results show that the texture which 2A12T4 aluminum alloy drill pipe contains is <001> and <111> along the extrusion direction and <223>, <101> in the transverse direction. The test results of mechanical properties show that the extruded texture will affects the mechanical properties of material. When the cross section and longitudinal profile samples of 2A12T4 were soaked in 3.5% NaCl solution at 25°C, 60°C and 90°C, their corrosion resistance are different. The pits of transverse specimens exhibit a dispersed distribution and that of longitudinal specimens are distributed along the extrusion direction.

An experimental investigation on hole exit geometric error in orbital drilling process

As an alternative to conventional drilling, orbital drilling has been applied to drilling difficult-to-machine materials, while unfavorable geometric error usually occurs at hole exit in orbital drilling of small-diameter holes. This drawback has prevented the wide application of this novelty process for drilling small-diameter holes. In order to minimize the geometric error in orbital drilling, this paper experimentally studied the geometric error by Taguchi and response surface methodologies. The formation mechanism of the geometric error was firstly revealed theoretically. Moreover, the influence of process parameters (tool slenderness index, spindle speed, tangential feed per tooth and axial feed per tooth) on the geometric error in orbital drilling of aluminum alloy was investigated by Taguchi methodology. The ANOVA analysis led to the following optimal combination of drilling parameters: tool slenderness index (50), spindle speed (8000 rpm), tangential feed per tooth (120 μm/rev) and axial feed per tooth (3 μm/rev). In addition, a second-order response model for the geometric error with respect to the drilling parameters was developed by the response surface methodology. Conformation tests were conducted and the results showed that the established model can be used for prediction of the hole exit geometric error in orbital drilling process.

Effect of aging processes on corrosion behavior and stress corrosion sensitivity of pre‐stretched 7075 aluminum alloy

In this work, the microstructures, corrosion behavior, and sensitivity to stress corrosion cracking (SCC) of pre‐stretched 7075 aluminum alloy drill pipes with 2.5–3% tensile plastic deformation in a 3.5% sodium chloride solution are studied. The alloy samples are separately subjected to single‐stage aging, two‐stage aging, and three‐stage aging. The polarization curves of the samples all demonstrate passivation characteristics after the different aging treatments. Single‐stage aging of the sample results in poor corrosion resistance and high SCC sensitivity with continuously distributed grain boundaries. After two‐stage aging, the sample exhibits improved corrosion resistance and SCC sensitivity, with intermittently distributed grain boundaries. Three‐stage aging imparts the alloy with remarkable corrosion resistance and significantly reduced SCC sensitivity, with intermittently distributed grain boundaries. Thus, the three‐stage sample is considered to be the best choice for aluminum alloy drill pipes intended for applications involving heat‐treatment.