Welding Practice Research Articles

An Approach to Best Welding Practice. Part – XXI – Section III – B-I

An Approach to Best Welding Practice. Part – XXI – Section III – B-I

The State of the Art of Underwater Wet Welding Practice: Part 1

Developments in underwater wet welding (UWW) over the past four decades are reviewed, with an emphasis on the research that has been conducted in the last ten years. Shielded metal arc welding with rutile-based coated electrodes was established as the most applied process in the practice of wet welding of structural steels in shallow water. The advancements achieved in previous decades had already led to control of the chemical com-position and microstructure of weld metals. Research and development in consumables formulation have led to control of the amount of hydrogen content and the level of weld porosity in the weld metal. The main focus of research and development in the last decade was on weldability of naval and offshore structural steels and acceptance of welding procedures for Class A weld classification according to American Welding Society D3.6, Under-water Welding Code. Applications of strictly controlled welding techniques, including new postweld heat treatment procedures, allowed for the welding of steels with carbon equivalent values greater than 0.40. Classification societies are meticulously scrutinizing wet welding procedures and wet weld properties in structural steels at depths smaller than 30 m prior to qualifying them as Class A capable. Alternate wet welding processes that have been tested in previous decades — such as friction stir welding, dry local habitat, and gas metal arc welding —have not achieved great success as originally claimed. Al-most all of the new UWW process developments in the last decade have focused on the flux cored arc welding (FCAW) process. Part 1 of this paper covers developments in microstructural optimization and weld metal porosity control for UWW. Part 2 discusses the hydrogen pickup mechanism, weld cooling rate control, design, and qualification of consumables. It ends with a description of the advancements in FCAW applications for UWW.

Evaluation of the Creep Strength of 9Cr-1Mo-V and 1Cr-1Mo-1/4V Castings and Weldments Using Accelerated Creep Testing

Abstract The traditional method to generate creep data requires several long term tests; in some cases upward of 100,000 h. These tests are often time and cost prohibitive to perform. Creep data in literature are limited to commonly available materials in set processing conditions. This speaks very little to the properties for new materials, alternate processing of existing materials, as well as properties for weldments and heat affected zones (HAZ) that occur in the fabrication of large equipment. Due to this, several methods have been developed for accelerated creep testing. The stress relaxation test (SRT) is one such method and is discussed as the means to evaluate two different materials and their weldments used in the manufacturing of steam turbine casings. Cast 9Cr-1Mo-V material from two different foundries as well as their weldments and HAZ were tested at temperatures between 550 °C and 700 °C. The SRT generated data closely match that given in literature. In a nearly identical test program, cast 1Cr1Mo¼V steel showed anomalies in the weld and HAZ behavior. Further investigation showed that the incorrect weld metal was used, and in a second attempt, poor welding practice lead to premature specimen failure due to Type IV cracking. These two case studies illustrate the ability of the SRT method to accurately predict creep properties and its sensitivity to detect variations in properties, which can make it useful for rapid verification of casting suppliers and welding procedures for high temperature applications.

Study of DP590 Microstructure Welded with Resistance Spot Welding Method by Using EBSD Technique

In automotive industries, employing advanced high-strength steels such as dual-phase steels by taking advantage of high dynamic force absorption during car accidents and lightweight is one of the major challenges. In this regard, the effect of resistance spot welding parameters on the above great properties of advanced high-strength DP590 steel has been studied. In this study, the effect of optimized welding (spot resistance welding) on the weld microstructure was evaluated using optical microscopy as well as scanning electron microscope equipped with electron backscatter diffraction analysis (EBSD). Also, hardness profile along with the welding section was determined as mechanical property. The results showed that the welding practice has a significant influenced on the microstructure and microhardness of welded samples. The final microstructure of the nugget consisted of lath martensite, whereas in the HAZ, the microstructure was found to be mixture of coarse and fine martensite. The hardness profile was relevant to the above phase configuration. The phase variations along with different weld region were extensively characterized and discussed using EBSD technique.

A Problem-based Learning for Vocational Key Competencies in a Welding Practice of Specialized High Schools

A Problem-based Learning for Vocational Key Competencies in a Welding Practice of Specialized High Schools

Research on Teaching a Welding Implementation Course Assisted by Sustainable Virtual Reality Technology

The purpose of this study is to explore the application of VR (virtual reality) technology to assist the development of VR welding courses in welding practice teaching, and to implement experimental teaching to verify its effectiveness. The preliminary VR welding curriculum structure was developed by this study according to the results of literature review and focus group interviews, the student-based “VR welding course” was developed, and 34 first-year students of the electric welding practice course were taken as the research subjects to implement experimental teaching and case study. The qualitative and quantitative research and analysis results are as follows. (1) The results of the final test of the welding practice of most students are significantly higher than the results of the mid-term test. (2) Most students expressed significant positive affirmation of the learning effect of the VR-assisted welding course. (3) Most students were very significantly positive regarding their learning satisfaction with the VR-assisted welding teaching course. (4) The four major implementation priorities of VR welding courses were planned. This study develops a “teaching mode of a welding implementation course assisted by virtual reality technology”, which can provide students with a safe, low-cost, repeatable, and sustainable welding skills learning environment, and has been positively affirmed by most students. In the future, the results of this study can provide reference for the introduction of virtual-reality-assisted teaching of welding related courses in various universities of science and technology, in order to strengthen teachers’ teaching ability in VR assisted implementation courses and provide students with more diversified learning stimuli.

Development of teaching materials for gas metal arc welding (gmaw) practice courses

In improving the quality of human resources, one of which lies in the quality of quality education. In this case, education has a very important meaning in human life, both in the life of individuals, nations, and countries. Therefore education must be implemented as well as possible so that it is following the objectives that have been planned. The objectives to be achieved from this study are to produce teaching materials for GMAW welding practice materials, produce teaching materials that are suitable for use in GMAW welding practices, and provide an evaluation of the effectiveness of using GMAW welding practice teaching materials after being used in learning. This research method uses the Borg and Gall development research method which is simplified into four steps, namely modified (simplified) into 4 steps consisting of: (1) preliminary study; (2) product development and validation; (3) limited trial; and (4) the final product. The type of research used in this research is the development of teaching materials in the form of practice modules, job sheets, and evaluation sheets in the GMAW welding practice course. Based on the research results, the researcher can conclude that the development of teaching materials for GMAW welding practices has been implemented properly. The revised results from the experts have been applied to the modules made so that the modules can be used properly by students.

The demonstration method using kinesthetic learning style on oxy-acetylene welding practice

This study aims to determine the differences between students’ learning outcomes using kinesthetic learning demonstration learning methods on the oxy-acetylene welding practice subject for welding technique class grade X students at Sayegan 1 Vocational High School. The research method used was an experimental method with quasi-experimental design research as the research type. The results showed differences between the learning outcomes of welding technique class grade X students between before they were given the treatment and after, using the kinesthetic learning style demonstration method. It could be seen in the results of the assessment: the average post-test scores in the two classes are the highest on the aspect of the assessment criteria number 2 for the experimental and control groups with a value of 0.4. The lowest is in criterion number 8, with a value of 0.25 for the experimental group. For the control group, the lowest is on criterion number 4, with a value of 0.11. This was proved by the increase of the average score on assessment criteria before and after the treatment. Thus, the demonstration method’s effect using kinesthetic learning style on oxy-acetylene welding practices of welding technique class grade X students at Sayegan 1 Vocational High School.

Research on Optimization of VR Welding Course Development with ANP and Satisfaction Evaluation

The purpose of this study is to explore the ability indices of VR (virtual reality) technology when it is applied to assist the teaching of a welding practice course, develop a VR welding course as the basis of course planning and teaching design, and implement experimental teaching to verify its effectiveness. On the basis of a literature review and focus group interviews, initial ability indices of a VR welding course were proposed. Then, 15 experts from VR- and welding-related specialties were invited to form a consulting team to determine “the ability indices of the VR welding course” according to the results of a Fuzzy Delphi expert questionnaire. Moreover, the results of an ANP (Analytic Network Process) expert questionnaire were used to understand the relative importance of the ability indices of the VR welding course, as well as the relative feasibility of VR-assisted welding teaching, in order to develop a “VR welding course”, in which 34 first-grade students of the welding practice course were taken as the research objects during the implementation of experimental teaching. The qualitative research and analysis results are as follows: (1) the VR welding course includes 8 ability indices and 30 evaluation indices; (2) the item with the highest feasibility in VR-assisted welding teaching is “welding construction”, followed by “map reading and drawing”; (3) best feasibility of VR technology “Interaction” in assisting welding teaching; (4) the relative importance of the ability indices of the VR welding course is the greatest for “welding construction”, followed by “welding inspection”; (5) the VR welding course students express significant positive responses to the learning of ability indices and ability demonstration; (6) the majority of students express significant positive learning satisfaction with VR-assisted welding course teaching. This study puts forward a set of rigorous models for the construction of ability indices for a VR course and course development. It can provide a reference for introducing VR-assisted teaching to related welding courses that are run by universities of science and technology in Taiwan. Furthermore, such VR courses can offer students a safe, diversified, and efficient learning environment.

The development of tungsten inert gas welding practical manual for vocational high school

This study aims to develop a product in the form of a tungsten inert gas (TIG) welding practice manual for Class XII students and find out the level of the eligibility. This research is a type of Research and Development (R&D) research. The stages of this research include problem identification, data collection, product design, design validation, design revision, limited trial, product revision I, large group trial, product revision 2, product ready to use. Data collection techniques are done using a questionnaire. The data obtained were analyzed using quantitative descriptive analysis techniques. The results of this study are in the form of a TIG welding practice manual for class XII students. The feasibility level of the TIG welding practice manual is known through the validation process carried out by 4 expert validators. The feasibility test was conducted on 30 students. The average feasibility value obtained from experts as well as the feasibility test on students was 84.81% and included in the very feasible category.

The development of job sheet practice shield metal arc welding assisted augmented reality

The purpose of this research is measuring the feasibility of a job sheet of shielded arc metal welding practice assisted augmented reality. This research used the method of research and development studies (R&D). The research was conducted on 32 students of class X at vocational high school Muhammadiyah 1 Salam. Data collection techniques were conducted using a questionnaire. The questionnaire was validated by an evaluation of the expert. The instrument test included 30 respondents outside the research sample. Data analysis technique performed with quantitative descriptive analysis technique percentage. The result of this research is in form of a job sheet practice welding SMAW using augmented reality.

Preliminary Study on Teaching Reform of Automatic Welding Practice Based on K5 Teaching Method

With the continuous development of automation technology, the teaching of automation technology in colleges and universities currently plays an important role. For example, in the process of automated welding practice, students are required to complete the practical hands-on ability of automated welding technology through the orderly teaching, and master the relevant theories of automated welding technology.

An Approach to Best Welding Practice:Part – XIV

An Approach to Best Welding Practice:Part – XIV

Evaluasi Kualitas Hasil Praktek Las Busur Guna Menunjang Kerja Di Kapal

Penelitian terhadap benda hasil praktek taruna, pada umumnya dilakukan secara visual, termasuk hasil praktek las busur taruna Jurusan Teknika Akademi Maritim Yogyakarta, karena metode tersebut yang dianggap paling praktis, akan tetapi metode tersebut belum bisa mengungkap kualitas hasil praktek, terutama berhubungan dengan sifat mekanis dan deposit logam. Sehubungan dengan hal tersebut, penelitian ini untuk mengetahui kualitas hasil praktek las busur,dengan melakukan pengujian tarik dan pengujian makro. Penelitian ini merupakan penelitian deskriptif dengan populasi penelitian 40 benda hasil praktek las busur taruna, dan sampel penelitian 50 % dari populasi. Kelulusan pengujian tarik, ditentukan dengan membandingkan data tegangan Tarik. Minimum bahan dasar dan bahan las. Sedangkan kelulusan uji makro ditentukan dengan ada tidaknya cacat di dalam deposit logam. Jumlah kelulusan dari kedua pengujian tersebut diprosentasekan. Dalam penelitian ini taruna dapat melakukan pengelasan sambungan I dengan hasil memenuhi syarat kelulusan uji tarik berjumlah 12 taruna atau ( 60% ), sedangkan taruna yang dapat melakukan pengelasan sambungan I dan T dengan hasil memenuhi syarat kelulusan uji makro, adalah untuk sambungan I sebanyak 16 buah (70%), sedangkan sambungan T sebesar 65 %.

An Approach to Best Welding Practice:Part – XI

AN APPROACH TO BEST WELDING PRACTICE Part – XI is particularly focused on the Safety Aspects regarding Electric Shock especially for Fusion Welding Processes to obtain the best possible Accident free shop floor operation.

An Approach to Best Welding Practice : Part – X

“AN APPROACH TO BEST WELDING PRACTICE, Part – X” is the Tenth Detail Part of “AN APPROACH TO BEST WELDING PRACTICE” which was written as a General and Overall approach to the subject matter.

An Approach to Best Welding Practice:Part-IX

“AN APPROACH TO BEST WELDING PRACTICE, Part-IX” is the Ninth Detail Part of “AN APPROACH TO BEST WELDING PRACTICE” which was written as a General and Overall approach to the subject matter.

About weldability and welding of Al alloys: case study and problem solving

Purpose: Among many disciplines within engineering, welding is probably one of the most inexact – rather more of an art than a science. As weldment is meant the complete joint comprising the weld metal, heat affected zones (HAZ) and the adjacent parent metal and should have the same properties as the parent metal. This paper aims provides a basic understanding of the metallurgical principles involved in how aluminium alloys achieve their strength and how welding can affect these properties. The most important and applied welding processes to Al alloys are here shortly introduced, as well as the preparation of parent metals prior to welding and good welding practice to avoid and/or keep under control defects and failures. Some case studies with possible failures will be introduced together with actions and suggestions to solve the observed problems. Design/methodology/approach: Two sheets of the EN AW 5454 (AlMg3Mn) alloy were weld with resistance welding process and after a mechanical processing of lamination was observed the presence of the defect. The microstructure of the defect as well as the welded part were evaluated with stereomicroscope (LEICA MS5), optical microscope (LEICA MEF4M), and with SEM analysis (LEO 1540 VP equipped with an energy dispersive X-ray spectroscope Oxford Link Pentafet). Findings: The well welded part was analysed with optical microscopy and electronic microscopy resulting with the attended mechanical properties. Micro-hardness indentations on the joint demonstrated the good mechanical properties of the joint while with the microscopic observations were identified the orientation and presence of precipitates typical of this alloy. In the defect, microscopically observations showed the presence of oxide inclusions. Research limitations/implications: There are a number of problems associated with the welding of aluminium and its alloys that make it difficult to achieve this ideal. The features and defects that may contribute to the loss of properties comprise the following: gas porosity, oxide inclusions and oxide filming, solidification (hot) cracking or hot tearing, reduced strength in the weld and HAZ, lack of fusion, reduced corrosion resistance and reduced electrical resistance. Originality/value: This case study illustrated clearly the importance of the cleaning on the surfaces to obtain a well welded joint ensuring the desired mechanical properties.

An Approach to Best Welding Practice:Part–VIII

“AN APPROACH TO BEST WELDING PRACTICE, Part – VIII.” is the Eighth Detail Part of “AN APPROACH TO BEST WELDING PRACTICE” which was written as a General and Overall approach to the subject matter.

Innovación en construcciones soldadas a partir del conocimiento de su propósito

Este artículo es resultado de la observación pedagógica realizada por el autor como instructor de soldadura del CIDT, Centro Industrial y del Desarrollo Tecnológico, Barrancabermeja. Con las prácticas cotidianas del ambiente de aprendizaje, descubrió que aún con la enseñanza de las más modernas técnicas y conocimientos necesarios, sus aprendices dudaban para realizar una buena soldadura. Se cuestionó si acaso, mostrarles el qué y el cómo se efectuaba el acto de soldar no era suficiente. Diseñó entonces una manera de descubrir esa razón invisible que detenía a sus aprendices y este trabajo muestra lo que encontró: cuando se sabe el para qué se suelda, los aprendices obtienen claridad y seguridad en sus acciones y se abre la mente a la innovación.