Experimental studies on fillet weldment joints by artisans in Ghana’s Western Region

Constant progress, demand in the manufacturing of mechanisms parts, and the ability to join parts together is another critical aspect of manufacturing for assemblers. Joining methods plays a significant role and welding must be constantly improved, experimented with, and upgraded due to its increasing use in all aspects of manufacturing. The quality of a weld joint is highly dependent on the process parameter. Welds are examined to ensure that they meet specifications through various experimental processes ranging from computational networks, evolutionary algorithms, non-destructive testing (NDT) and destructive testing (DE) to ascertain the quality of joints. The main objective of the study was to ascertain the quality of welded joints through non-destructive evaluation (NDE). To achieve this goal, an experimental method of four (4) NDE methods were employed to evaluate the quality of weldment joints on a mild steel material joined using manual metal arc welding (MMAW) process in selected fabrication shops in Takoradi-Kokompe, Ghana. Steel specimens were prepared and taken to the artisans to be created into corner joints using the fillet method. The specimens were tested using non-destructive testing techniques. The results on the welded joints were evaluated using the AWS D1.1 code of acceptance for structural steels. The results revealed that all welded joints from fabricators failed to meet the AWS D1.1:2000 acceptance criteria and, thus, had to be rejected. The results implies that through the artisans have worked for many years in the welding trade, their lack of competence and skills in the selection of right input welding parameters contributed to the results. The results implies that, the finished artefacts may look fine but internal structures may contribute to future failure of the fabricated artefacts.


Introduction
With the continuous development and demand for various parts such as automotive, aerospace structures, various machine components, and so on, and the high rate of production of those parts, automation and accuracy are two of the most desired demands that needs to be met to ascertain quality in production (Kim et al., 2015).Joining is a critical manufacturing requirement for assembling operations.Material joining methods are important technologies in many manufacturing industries (Lee, 2011).
Most products, machines, or structures are assembled and fastened from parts to create highly reliable devices, and the joining of these parts may be accomplished through rivets, seaming, clamping, soldering, brazing, welding, and the use of adhesives (Ahmadnia et al., 2015).
Many factors influence those decisions, ranging from production costs to mechanical properties like strength, vibration damping, durability Ahn et al., (2018), Resistance to corrosion or erosion, as well as the ability to correct flaws.The three main types of joining processes are mechanical joining, welding, and adhesive bonding (Rao et al., 2014).Welding techniques include fusion welding, brazing and soldering, and solid -state welding.During fusion welding, the zone being joined melts and solidifies (Varun Kumar et al., 2021).For metals and plastics, melting occurs in both the workpieces and the filler material.Brazing and soldering are methods of joining materials in which melted filler material is added between the joined surfaces (Kah et al., 2013).Solid-state welding does not require the melting of the filler material's base because it only involves plastic deformation and diffusion (Yun et al., 2019;Sekyi-Ansah et al., 2020).Welding technology is now available in all areas of manufacturing, including rail, roads, shipbuilding, large dam construction, and various projects, pipelines, various power plants, and the automobile industry.Welding must be constantly improved, experimented with, and upgraded due to the constant increase in its use in all aspects of manufacturing.Every manufacturing process must be improved and innovated in light of modern technologies and rising product quality demands.When one considers the welding process, one immediately considers the Arc, Spatter, Weld bead, and surface finish (Srivastava and Sharma, 2017) The optimum processing parameter has a significant impact on the quality of welded joints (Cooley et al., 2011).Controlling the input process parameters was a frequent problem for the manufacturer in order to achieve a good, welded joint with the required weld quality.Historically, skilled operators or engineers chose parameters by trial and error, which took time for each new welded product to obtain a welded joint that met the required specifications.The welds are examined to see if they meet the specifications (Liu et al., 2021).Design of experiment (DoE), evolutionary algorithms, and computational networks are commonly used today to develop mathematical relationships between welding process input parameters and weld joint output variables in order to determine the welding input parameters that lead to the desired weld quality (Kolahan and Heidari, 2010).
Non-destructive methods are a significant category with numerous applications for evaluating materials, metals, and engineering material components (Fahr, 2013).The recognition and classification of damages on a welded portion's surface is known as non-destructive evaluation (NDE) or non-destructive testing (NDT) Hung et al. (2013), surface and layout of material without severing or otherwise modifying it (Rausche, 2004).In other words, NDT is the method of assessing and inspecting engineering materials components in order to characterize or find defects and flaws in comparison to some standards without changing the original attributes or causing harm to the object being tested (Brierley et al., 2014;Sekyi-Ansah et al., 2022).The NDT techniques are a reduced method of testing a specimen for individual investigation or for checking the entire material in a quality control system in a manufacturing facility (Dobmann et al., 2010).Work on assessment of local welding *Corresponding author: joseph.sekyi-ansah@ttu.edu.ghartisans has been carried out by researchers.The results of Birir (2015) on plates and pipes welded by local artisans in Kenya, using NDT showed a significant failure in most of the samples collected when tested using radiography and visual testing.In a recent study conducted by Sekyi-Ansah et al. (2023) on exhaust pipes welded by artisans also failed the code of acceptance for ASME B31.3 when tested with NDT.The design, manufacturing and fabrication students' projects are associated with various fabrication processes, including welding.The majority of student projects at Takoradi Technical University (TTU) are created outside of the campus by welding artisans from Takoradi Township.These artifacts are held together by a series of welded joints.The operations of these artifacts are related to vibrations, rotations, and so on.If the welded joints have internal defects during fabrication, deformation is likely to occur within the defected zone.As a result, an assessment of the quality of weldment joint using NDT techniques on the weldment done by artisans at Kokompe in Sekondi-Takoradi Metropolis is required.A variety of NDT methods are used in the testing of materials (Gholizadeh, 2016).Even though similar experimental research using NDT has been conducted by Sekyi-Ansah et al. (2022) on Tee joints on local welding artisans in Kokompe-Takoradi, it did not consider corner fillet joint.Since there is constant increase in the use of welding in all aspects of manufacturing, it must be constantly improved, experimented with, and upgraded.In this that, this study seeks to evaluate the welding quality of welded fillet joints by artisans from some selected fabrication shops at Kokompe in Ghana's Western region.The study's objectives were to use NDT to identify defects in the weldment joint and to determine whether the weldment joint met the the AWS D1.1 code of acceptance.

Experimental design
The experiment welded three (3) joint specimens (corner joints) using a manual metal arc welding (MMAW) process with an alternating current machine (AC).For the measurement and analysis tool chosen to assess the quality of the welded joint, the materials samples chosen for the experiment were Ferromagnetic.According to AWS D1.1 and D1.2 code of guideline for welding structural steels, the acceptable thickness of the material should be between 6 mm > T < 20 mm (OSNDT, 2023;Perdhana, 2023).Mild carbon steel material samples with dimensions of 75mm x 50mm x 10mm were chosen for the experiment's specimen joint formation based on the guidelines.The experiments used four non-destructive methods: visual testing (VT), liquid penetrant testing (LPT), magnetic particle testing (MPT), and radiography inspection or testing (RT).Three of the measuring devices (VT, LPT, and MPT) produce results when the discontinuities or flaws are visible and open to the surface, while one (RT) produces results when the discontinuity is visible and open to the surface on both the surface and the subsurface.Based on the material, type of weld, welding current, and voltage, the experiment considered E6013 and E4310 electrodes.

Material properties
Mild steel with a carbon content of 0.16 % to 0.29 % and a relatively high melting point of 1450 °C to 1520 °C was chosen for the analysis.Tables 1 and 2 show the chemical composition and mechanical properties of the selected material sample (Bodude et al., 2020).

Material preparation
To facilitate the cutting of the material samples, a power hacksaw machine Ercole 280 (PS01) with the following specifications was chosen.Weight approx.900 kg, saw blades number: 5, angular cut degrees: +45, saw blade length: 575 mm, motor 380 volt, power: 3 ps, cut range round diameter: 320 mm, strokes per minute number: 6, machine width/depth/height approx.: 1850 x 800 x 1600 mm, a speed of 7 strokes per minute.The material dimensions were 150 mm x 100 mm x 10 mm.

Surface preparation of samples
The obtained samples were taken to the workshop and held in a bench vice with soft jaws to prevent dents on the material surface.Initially, a smooth file with a single cut was used to deburr square corners and remove rust from the surface.After a DESC Blue Emery Clothe Sheet, a surface finish of 230 280 mm (9" 11") Grit P60 (Grade 2) was applied.

Welding procedure of sample material
Figure 1 shows the graphical illustration of the welded sample joint specimen and figure 2 shows how the sample materials

Experimental method and testing flow chart
Figure 3 describes the sample preparation and the methodology flow chart for the experiment conducted on the fillet welded joint to ascertain the desired results.Following the cutting process, six (6) 75 x 50 x 10 mm material samples were chosen to produce corner welded joints.Three (3) welded samples were produced from the six (6) samples chosen.

Measurement processes
For quality and dependability, the welded joint must be inspected and measured.Undercuts, uncertified craters, surface cracks, lack of fusion, flows, and other defects can be detected using visual inspection.The size of the joints, joint width and height, bevel angle, preparation depth and width, including angle, root gap, root face depth, convexity, and leg length were all determined using welded joint meters and welding templates.Four of the six commonly used NDT evaluation methods were used in the experiment: visual, liquid penetrant, magnetic particle, and radiography.

Analysis tools
The NDT analysis tools are chosen based on the type of joint and flaw to be detected.For the experiment, four different methods for evaluating samples were used, and the tools for each test method were also different.

Visual testing
Visual inspection (VT) is the detection of surface imperfections with the naked eye.VT is normally applied without the use of any additional equipment, but its effectiveness and scope can be improved by using aids such as a magnifying glass.To be able to recognize problems, VT requires good vision, good lighting, and experience.After the welded samples C1, C2 and C3 were collected, physical observations were made on the sample for conformance with the acceptance criteria, and visual testing tools were used to measure the defect and the results compared with standard.

Liquid penetrant testing
Additional testing with liquid penetrants produced more concrete results.A water-soluble visible penetrant was used in the experiment.For liquid penetrant testing, ABRO products were chosen.ARDOX 907 PB 400ml water washable red dye penetrant; ARDOX 9PR5 400ml penetrant remover/solvent cleaner; ARDOX 9D1B 400ml non-aqueous developer.The surface of the pre-cleaned welded samples was sprayed with ARDOX 907 PB penetrant.The penetrant was allowed to sit on the surface for five (5) minutes.The penetrant was then sprayed with an ARDOX 9D1B non-aqueous developer for a maximum of ten (10) minutes to aid in the detection of flaws.A visual inspection is performed to determine flaws.Finally, ARDOX 5319 remover was used to clean the welded samples.

Magnetic particle inspection
Magnetic particle inspection can detect surface and subsurface flaws up to 6mm in depth.The magnetic dye pigment ARDOX 8903W white contrast paint was chosen.To able to obtain both a longitudinal and circular magnetic field, an alternating current (AC) and direct current (DC) yoke was used to generate the magnetic field for the experiment.For creating subsurface and surface flaws, half-wave direct current (HWDC) is the most effective.The following was the test procedure: Magnetic media (magnetic dye pigment) was applied to the welded samples, magnetic particles were introduced by the yokes, and magnetic particle indication was visually interpreted.

Radiography testing
The study used x-ray radiation with a current of 5 mA and a voltage source of 250 kVA because it poses a lower radiation risk than gamma rays.The density and thickness of the material dictated an x-ray exposure time of 0.4 minutes with a geometrical unsharpness of 0.51.In addition, a focal spot size of 22 was chosen with a 600 mm source to film distance.The ASME SEC V specification was chosen, with a single weld single image technique (SWSI).A KODAK AA 400 film with a lead screen size of 100 125 mm and a density range of 1.8 -4 was chosen.Moreover, an ASTM 1A06 penetrometer was used in the development of the X-ray film at a developing time of 5 minutes at 20 °C.On a wire-type image quality indicator, film sensitivity is 2 % (IQI).

Welding code acceptance criteria
The investigational specimen was steel, and the study's defect acceptance criteria were the AWS code for structural steels.This code specifies the specifications for welded steel structure fabrication and erection.This code applies to steels with a thickness of 1/8 inch (3.2mm) or greater.When specified in a contract, the majority of the provisions in this code are mandatory.
The code parts used are AWS D1.1/D1.M 2010 clause 6, inspection for VT, MPI, and DPI, and AWS D1.1:2000.Inspections are carried out in accordance with structural steel code 6.0 (part C) and 6.12 for radiographic inspection.

Results and Discussion
Data presentation for tee joint Table 3 displays Tee joint visual inspection results for visual inspection.The result indicates that all the three welded speci- showed defects for analysis under the acceptance code.Also, C1 joint, both parts showed a lack of fusion, slags, and surface depression.Joint C2, had both faces showing overlaps, undercut, and surface depression.Finally, joint C3 had faces recording under fill, undercut, and depressions.In comparison with the acceptance criteria code adopted, all three tees welded joints were unacceptable per the welding standard code and must be rejected.

Data presentation for corner joint
Table 3 and Figure 4 portrays the results obtained from the visual inspection of the corner welded joint.From the table, the various welded specimen joints were labelled with specific numbers to differentiate each joint for easy presentation of results after performing the NDT inspection.From the table, all three specimens inspected visually showed a significant defect; thus, C1 showed a lack of fusion, slags, surface depression, overlap, and root undercut.Again, C2 showed undercut, slags, overlap, lack of fusion, and spatters.Furthermore, C3 also showed spatters, lack of fusion, and slags as a defect.However, these defects were compared with the acceptance criteria adopted for the study, and per analysis under the code for acceptance, all three corner joints visually inspected must be rejected.This is an indication that the three welded corner joints visually inspected falls below acceptance and are not standard.

Dye penetrant inspection
Table 4 and Figure 5 describes the results obtained from the dye penetrant test conducted on three corner joints.C1, C2, and C3 which represents the codes given to the various specimen.The test results in table 4 shows clearly that all the results obtained indicate a rejection of the weldment joints defects which were lack of fusion, undercuts, and under fill per the code for acceptance.There is a clear indication that the corner weldment joint analysis with the dye penetrant test and assessed with the AWS D1.1/D1.M 2010 clause 6 of structural steel code of acceptance does not meet the standard of welding processes

Magnetic particle inspection
Table 5 and figure 6 presents the results of a magnetic particle inspection test performed on three butt welded joints in an experiment to determine the quality of their welded joints.From the results obtained and analysed with AWS D1.1/D1.M 2010 clause 6 of structural steel code for acceptance for the welded parts, all the welded specimens failed the acceptance criteria and had to be rejected for further corrections, because of lack of fusion, undercuts and cracks showed as defects as displayed.

Radiography inspection
Table 6 and Figure 7 show the results for three specimens of corner joints tested with radiography inspection, the three specimens C1, C2, and C3 all recorded flaws such as lack of fusion, undercuts, and slag inclusions at specified distances measured from a reference on the weldment.After careful examination of the defects and compared with the acceptance criteria of AWS code for structural steels, all the welded specimen was rejected based on the acceptance criteria.C) and 6.12 radiographic inspection were used to compare flaws such as lack of fusion, undercuts, slag inclusions, and porosities to the code chosen for analysis.Overall, due to defects exceeding the AWS D1.1:2000 structural steel code 6.0 inspection (part C) and 6.12 radiographic inspection acceptance code, all welded samples collected and tested must be rejected.

Determining whether the weldment joint specimen meets the acceptance specifications
According to the assessment criteria code AWS D1.1/D1.M 2010 clause 6 used for VT, MPI, and DPI and AWS D1.1:2000 Structural steel code 6.0 inspection (part C) and 6.12 radiographic inspection, the welded joints specimen from the various shops failed after the assessment of the various welded joints in the course of conducting the research practical.Thus, it was discovered from the welding of the specimen at the various selected workshops that majority of welders do not keep their welding electrodes in ovens as required by welding processes.In accordance with the material and electrode to be used, the artisans do not adjust the current and voltage.The material to be welded determines the choice of electrode and insufficient ability.

Conclusions
The study objective is to use NDT to evaluate weldment joint quality in selected fabrication shops in STMA-Kokompe.Three major themes guided the research.The first theme examines weldment joint quality using selected NDT techniques, the second theme compares test results to an AWS code of acceptance, and the third theme investigates the impact of joint type on weldment quality.According to the research findings, the experimental method used produced the required results for the specimen tested.All three (3) samples tested had significant flaws or discontinuities in the artisans' weldment.Accepted welded parts were minor indications that had no direct impact on the welding part.The AWS structural code flaw indications that were less than acceptable included: a lack of fusion; undercuts; slag inclusion; rounded indications; linear indications; and porosities.These discontinuities, if not detected and corrected, cause internal stress and machine component failure.The following are the flaws in courses, according to the research: Inadequate storage of welding consumables, improper current and voltage regulation to suit the specified material, a lack of understanding of the material and electrode selection criteria inadequate skill sets.Furthermore, the study revealed that most of the artisans' work produced at the chosen shops does not meet the AWS structural steel code of acceptance standards.Furthermore, it is evidence that the students' work at these Kokompe fabrication shops may have similar flaws if tests are conducted on them based on the results obtained.

Figure 2 Figure 1 Figure 3
Figure 2 The (a) preparation process before welding, and (b) sample aligned for welding a b

Figure 6
Figure 6 Magnetic particle inspection on (a) C2 and (b) C1

Figure 5
Sample with (a) dye penetrant applied and (b) results after developer applied

Table 3
Visual inspection results of corner joint Keys: C1-Corner joint specimen 1, C2-Corner joint specimen 2, C3 -Corner joint specimen 3 mens and both parts labelled A (front side) and B (backside)

Table 4
Dye penetrant inspection results of the Corner joint The selected NDT techniques discovered a total of rejected and accepted defects, as shown in Table7.NDT was performed using VT, MPI, DPI, and RT.Three of the techniques are only capable of detecting surface defects, while the fourth can detect subsurface defects.Nil for VT and MPI, 1 and 3 for DPI and RT, respectively.The steel specimen chosen for the experiment was classified as structural steel by the code used to analyse the defects.According to AWS D1.1/D1.M 2010 clause 6, majority of defects discovered during VT, MPI, and DPI testing must be rejected based on the code.Undercuts, under fills, lack of fusion, and lack of penetration, porosities, surface depressions, and rounded and linear indications that were roughly above the

Table 5
Magnetic particle inspection results of the Corner joint

Table 6
Radiography inspection results of the Corner joint https//doi.org/10.56049/jghie.v24i1.144JGhIE code's acceptance value were discovered during the test.The ASME section V and AWS D1.1:2000 acceptance codes were used once more.Code 6.0 structural steel (part