Improvement of the Welding Process for Fillet Air Test for the Biggest Taiwan Shipyard

During ship block construction, watertight bulkheads weld of every cabin of ships need to undergo stress testing according to the tanks’ test plan. Every incomplete bulkhead cannot be sprayed in order to protect them after sandblasting; this seriously affects the process of construction. Therefore, the issue of this study is to maintain the integrity of the painting quality and reduce the destruction of the paint, ship-building personnel seek how best to complete the block operation. The aim of this project is to improve the recent watertight bulkheads fillet air test operations in the construction stage using TRIZ (theory of inventive problem solving), promote the ground painting session integrity of every ship, improve the tanks’ test plan in the dock, and reduce the time spent on dismantling operations and the painting operation. Through the TRIZ, this study proposed lots of improvements, some of which are: the watertight cabins can finish the tanks test plan completely, and the integrity of the ground painting can be promoted to reduce the range of cabin test in the dock and reduce watertight bulkheads’ dismantling time. Moreover, because of the considerate reduction of the destruction of the coating, the painting operation is of good quality. The results demonstrate that the TRIZ successfully controls the production quality during construction, reduces working time, and promotes full efficiency. This study saved more than US$1 million of the outsourcing fee.

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Comparative study of welding deformation of a stiffened panel under various welding procedures

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405417712550 ◽

2017 ◽

Vol 233 (1) ◽

pp. 182-191 ◽

Cited By ~ 1

Author(s):

Zhen Chen ◽

Qi Yu ◽

Yu Luo ◽

R Ajit Shenoi

Keyword(s):

Large Scale ◽

Welding Process ◽

Production Quality ◽

Welding Distortion ◽

Stiffened Panel ◽

Welding Deformation ◽

Large Scale Structures ◽

Improve Production Quality ◽

Scale Structures ◽

Welding Procedure

The welding distortions of large-scale structures are extraordinary complicated. If an effective tool of predicting welding distortion is available, then marine design and manufacturing engineers can use this to improve production quality and reduce costs. This article focuses on the comparative studies of welding procedure of a stiffened panel. An efficient thermal elasto-plastic finite element method–based procedure is developed to predict the welding deformation and residual stress of structures. A combined shell/solid model is adopted to enhance modeling and calculation efficiency. The welding process of a stiffened panel is simulated. Three welding procedures of simultaneous, successive and bidirectional welding are studied. The results show that welding distortion can be well controlled by adjusting the welding procedure.

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The Effects of Transient Temperature around Welds on Mechanical Properties of A36 Steel Plate

Journal of Energy Mechanical Material and Manufacturing Engineering ◽

10.22219/jemmme.v1i1.4479 ◽

2017 ◽

Vol 1 (1) ◽

Author(s):

Mohammad Jufri

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Steel Plate ◽

Welding Process ◽

Hardness Test ◽

Production Quality ◽

Transient Temperature ◽

Body Parts ◽

A36 Steel ◽

Thermal Tensioning

There are various ways for welding experts to improve their production quality, and one of which is by designing a particular type of welding tool. Besides aiming to replace the function of operator’s body parts, the tool is also able to control buckling distortions, crack propagations, and stress voltage, as well as to save an additional work, which is the heat treatment after welding process. The best method to control buckling distortions from the thin plate is by applying pre-heating and thermal tensioning. Thermal tensioning is the characterization by heat application during welding process. Transient thermal tensioning is a supporting tool around the weld which is given periodical heat by following the movement of arc welding. The purpose of this research was to minimize distortions and maximize the performance (mechanical properties) of welding joints shaped due to the transient temperature application during the welding process. The method employed in this research was experiment by using A36 steel plate with transient temperature variation of 100, 200, and 300oC, with velocity of 8 mm/s and heater (toutch) distance of 4, 6, and 8 cm. In this research, the researcher conducted tensile-strength test according to the JIS G 3101 standard and hardness test around weld, HAZ (Heat Affected Zone), and parent metal.The findings showed that the change of transient temperature and heater distance affected the mechanical properties (hardness and tensile strength) of A36 steel. The highest level of hardness was obtained in the temperature of 200°C and heater distance of 6 cm, which was as much as 404 VHN. The highest level of tensile strength was obtained in the temperature of 200°C and heater distance variation of 8 cm with yield stress of 302 Mpa and maximum tensile strength of as much as 491 Mpa.

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Development of Ship-Building Assembly System for Ship’s Blocks Using 3D Measurements System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.635-637.621 ◽

2014 ◽

Vol 635-637 ◽

pp. 621-624

Author(s):

Dong Myung Lee ◽

Soo Young Kim ◽

Byung Young Moon

Keyword(s):

Production Efficiency ◽

3D Visualization ◽

Virtual Assembly ◽

Thin Plates ◽

Assembly System ◽

Deformation Analysis ◽

Measurement Information ◽

3D Measurement ◽

Ship Building ◽

Block Construction

Most of Shipyards have adopted block construction method. In spite of efficiency, this method has been reported lots of problems. Overlap or gap between blocks, such problems are mainly caused by deformation of blocks. The ship’s block is built by thin plates which are processed by cutting and welding, etc. Deformation of block comes from process of plates by cutting and welding in the stage of block assembly. In the stage of block erection, overlapping or gap occurs between block’s parts which are caused by deformation of blocks. So, block accuracy management is the key point to production efficiency of shipyards. In this study suggests a 3D measurement based Virtual Assembly System (VAS) to solve those problems. This study specified principle function of VAS and implemented to check validity of principle function. Principle function of VAS is analysis of block’s deformation between design and measurement information and performs block erection process with measurement information in virtual assembly space. According to these principle functions, VAS has been implemented with ACIS for 3D geometric modelling kernel and HOOPS for 3D visualization library. Block deformation analysis and virtual block erection has been performed with two ship block to check validity of VAS.

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Analysis of Cracks in the 15MnNbR Spherical Tanks

Volume 1: Codes and Standards ◽

10.1115/pvp2012-78259 ◽

2012 ◽

Author(s):

Weihua Wang ◽

Xiang Li ◽

Guanghai Li ◽

Yiliang Zhang ◽

Zhen Wang

Keyword(s):

Heat Treatment ◽

Residual Stress ◽

Fusion Zone ◽

Stress Testing ◽

Welding Process ◽

Post Weld Heat Treatment ◽

Lower Pole ◽

Hardness Testing ◽

Hydrocarbon Reservoir ◽

Process Controlling

15MnNbR Spherical tanks in a lighter hydrocarbon reservoir were tested by internal MT. Almost whole circle crack located at fusion zone of the weld connecting equator plate and the lower pole plate was found. The cracks are parallel to the weld and the deepest depth is 10 mm. Through hardness testing, metallographic testing and residual stress testing, etc, the causes of cracks were analyzed. The analysis shows that strong assembly, poor welding process controlling and poor effect of post weld heat treatment are the main causes for formation of the cracks.

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Wear of the Tungsten Electrode at the TIG Arc-Spot Welding of Dissimilar Metals

Materials Science Forum ◽

10.4028/www.scientific.net/msf.473-474.73 ◽

2005 ◽

Vol 473-474 ◽

pp. 73-78

Author(s):

János Dobránszky ◽

Szabolcs Bella ◽

Imre Kientzl

Keyword(s):

Spot Welding ◽

Welding Process ◽

Production Quality ◽

Tig Welding ◽

Quality Level ◽

Arc Length ◽

Tungsten Electrode ◽

Aisi 304 ◽

Very High

Micro-TIG welding experiments have been used for the welding of the contacts of special lamps. Since the welded materials were different, the welded joint was a heterogeneous bound. For the joints a 0.6 mm Ni-Mn alloy or 0.4 mm Mo wire were inserted onto the hole of AISI 304 type austenitic stainless steel sheet, with a wall thickness of 0.35 mm. The micro-TIG welding was completed with a welding machine of which control characteristics corresponded to all the requirements necessary for TIG arc-spot welding. The goal of the experiments was to find the optimum regarding the quality of the lamps’ welded joints that correspond with the needed production quality level. The problems that occurred throughout the welding process were due to the very high melting point of the Mo. Also, using optical microscopy and scanning electron microscopy have performed a proper testing in parallel with the experiments. The details, revealed that the geometry of the joint and the resistance depend very much of the arc length, shielding gas velocity and especially of the tip geometry of the tungsten electrode and its wearing. Regarding to the electrode’s wearing, there have been determined the tip angle, the tapering and the effect of the electrode’s material composition. The latter parameter was investigated for unalloyed, thorium-oxide, cerium-oxide and lanthanum- oxide alloyed electrodes.

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Analisa Perhitungan Pekerjaan Reparasi Kapal Dengan Metode Critical Path Method (CPM)

SPECTA Journal of Technology ◽

10.35718/specta.v4i1.172 ◽

2020 ◽

Vol 4 (1) ◽

pp. 84-91

Author(s):

Alamsyah bin Muh. Saleh Alam Muhammad

Keyword(s):

Critical Path ◽

Technical Analysis ◽

Working Time ◽

Critical Path Method ◽

Repair Work ◽

Ship Building ◽

Table Method ◽

Ship Repair

Meranti Nusa Bahari carries out two types of businesses, firstly ship repair and secondly ship building services. Technical analysis of ship repair work using a simple table method. The purpose of this research is to find out how long the ship repairs. The method used is CPM (Critical Path Method). The results of this research are technical analysis of work using a simple table that is able to repair one unit of ship within 22 working days and 20 ships in a year. While the analysis with CPM method found 18 working days per unit of ship and 25 units of ships in a year. There has been a decrease in working time per ship unit of 4 working days which can be used to work on other vessels, with an increase in the number of vessels of 4~5 ships in a year where there is an increase in repair productivity by 20%.

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Menentukan Intensitas Radiasi UV yang Diterima Pekerja Pengelasan dengan Titik Area Mata, Siku, dan Betis

Progressive Physics Journal ◽

10.30872/ppj.v2i1.736 ◽

2021 ◽

Vol 2 (1) ◽

pp. 1

Author(s):

Muliana Dai ◽

Kadek Subagiada ◽

Adrianus Inu Natalisanto

Keyword(s):

Environmental Conditions ◽

Radiation Intensity ◽

Welding Process ◽

Working Time ◽

Measured Radiation

The aim of this study is to measure the UV intensity received by the welders during working time and compare the results of measured radiation intensity which is obtained with the NAB in Regulation of the Minister of Manpower No. 05 of 2018 that is 0,0008 mW/cm2. The reason for using this NAB is for compare value while welding process with the value were allowed from Regulation of the Minister of Manpower. This study has been done in some workshops using the UV Meter and focused on the welders’ eye, elbow and calf area with 10 repetitions in each area. The results for eye area were 0.0749 mW/cm2, for elbow area were 0.0843 mW/cm2and for calf area were 0.0934 mW/cm2and all the results obtained exceed the NAB. The high value is caused by the environmental conditions is open and also affected by indeterminate sunlight, the risks received the welders in watery eye and headache because of the welder are disobey in using PPE while welding process.

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