Safety Precautions Of Welding And Its Effects On Health

Electric arc welding is one which utilizes electricity to produce heat to join two metals. Safety is main criterion during every welding operation. Welding process is very hazardous. It needs protection of face, body and also weld area. During welding process, ultraviolet, infrared radiation, dust & fumes are produced which is very harmful for any exposed human being. This research contains overview of hazards and harmful effects on health and safety precautions during welding.

The content is adapted from numerous research papers. This paper involves the people which can affect by electric welding. This profession is very hazardous and limited people have knowledge about this is conclusion of this paper. It is essential to take protection during welding. This review paper describes that welding is very hazardous process. Workers do not have knowledge about hazards during welding operations (1).

Demands are increasing on companies day by day for high quality and consistent products. Main challenge is to maintain quality and consistency of product in manufacturing process. The main aim is quality management of products in manufacturing process for obtaining objective, automatic inspection and analysis technique must be used. Defects that can be present in welding i.e. crack, distortion, incomplete penetration, porosity, under cutting, overlapping and poor fusion.

Welding defects can greatly affects welding quality and performance. Author discuss a method to analyze defects. Non destructive testing is employed to test a material for surface and internal flaws. without affecting its property. Ultrasonic testing, die penetrant test, magnetic particle inspection methods are used for inspection of defects. Identified defects are analyzed by using one of the seven quality tool cause and effect diagram.

Cause and effect diagram is a tool that helps to identify, sort and display possible causes of a specific problem. Cause and effect diagram has basic seven quality tools i.e. flow chart, control chart, scatter diagram, histogram, Pareto chart, Check sheet and Cause and effect diagram.

These are following observations are made after applying cause and effect diagram:

• Major defect is due to unskilled worker.
• Pareto chart states that spatter, lack of fusion and crack are major defects (2).

The objective of this paper to discuss the advancement in orbital welding. This paper draws special attention to problem faced during orbital welding and its solutions. This process is used to weld pipes/tubes. Author also discussed history of orbital welding, basic concepts of orbital welding and problem faced during welding process. The solution of the problem faced during this welding process are also suggested in this paper. There is very much importance of orbital welding technology in welding field. Orbital welding is used in different application like Boiler tube, nuclear piping, Tube/pipe fittings etc. This paper is an overview of orbital welding process (3).

Welding is used in the automotive industries for joining variety of vehicle parts and it is employed in fabrication and repairing of metal products in every industry. The welding technology which are generally used in vehicle industries i.e. Resistance spot welding, Metal Inert gas welding (MIG), Tungsten inert gas welding (TIG), Laser beam welding (LBW) and Plasma Arc welding (PAW). An advance welding process for automotive industries has been developed for reduction in vehicle weight and increase in fuel efficiency. The advanced technique i.e. magnetic pulse welding (MPW) process is employed for developing light-weight weld parts is also presented. In this paper, latest welding technique i.e. medium frequency welding (MFW) employed in automobile industries is also described.

Magnetic pulse welding helps to make car more fuel efficient and meet the requirement of alternate fuel powered vehicles. The following points are observed i.e.

• The automotive industries focused on developing lighter with strong and fuel efficient vehicles.
• Magnetic pulse welding is advantageous for manufacturing lighter and energy efficient cars.
• Medium frequency welding is used to produce new geometries for automobile transmissions (4).

This paper draws special attention on advancement of robotic functioning and its utilization with various metal joining application. Robots are extensively used in industries to minimize the involvement of human in production and automating the process. For this scenario, robots are programmed to perform critical operations such as welding and material handling.

In this paper various welding techniques are discussed. The layout of robotic cell and parameter for robot selection also discussed in this in brief (5).

Electrogas Arc Welding is used for vertical position welding. EGW is used for welding of sheer stakes and hatch side coamings of container ships. However, in ordinary welding process for ultra thick steel plates, defect such as the lack of fusion are likely to occur.

For solving this issue, author introduced a new concept i.e. Two electrode Vibratory electrogas Arc welding. This technique is used for extra heavy sectioned steel plates. Results obtained after using two electrode VEGA welding process are:

• Stabilized penetration of weld metal
• Improved welding efficiency
• Reduction of shielding gas(6)

Electro gas Welding is used for vertical position welding and employed for welding of sheer stakes and hatch side coamings of cargo vessel. In ordinary welding process for ultra thick steel plates, defect such as the lack of fusion are likely to occur.

For solving this issue, author introduced a new concept i.e. Two electrode Vibratory electrogas Arc welding. This technique is used for extra heavy sectioned steel plates. Results obtained after using two electrode VEGA welding process are:

• Stabilized penetration of weld metal
• Improved welding efficiency
• Reduction of shielding gas(6)

Plasma arc welding is a process which can be employed for almost any existing metals. The several process parameters such as plasma gas flow rate, torch height front weld width, back weld width etc. plays a vital role for prediction of weld geometry. Predictions for weld geometry, several heat transfer models have been developed.

The wide range of application of PAW is discussed in this paper. The keyhole mode of PAW is used in industries due to deep penetration characteristics. This paper contains literature review of various theoretical and experimental studies by different researchers over the years. Plasma Arc Welding (PAW) also compared with other welding process based on existing literature content (8).

The purpose of this paper is to design parameter for shielded metal arc welding to produce no leak in welding object during the process. To achieve this pupose, an effort has been carried out to select predominant parameters i.e. welding current, welding speed, root gap and position of electrode. On the selected parameters, trails has been conducted according to Taguchi method and fixed the levels for parameters. Further the range is split into 3 levels based on no. of factors and levels, L9 (3^4) OA is selected. Experiments are conducted on no. of factors. Leak proof joints can be produced in few specific conditions according to results(9)

An experiment is carried out to find the result of predominant parameters like current, arc voltage, welding speed and heat input rate on the size of heat affected zone during manual metal arc welding. For this research, the outcome of various welding parameters on weldability of mild steel specimen having dimensions 125mmX75mmX5mm welded by MMAW for single V- Butt joint were investigated.

It has been observed from this experiment that increase in amount of heat input, increases width of heat affected zone also when welding speed increase, the width of heat affected zone width decreases . If welding speed controlled properly than it becomes important parameter for controlling HAZ (10).

Author discussed about quality of weld in submerged arc welding and quality of weld in submerged arc welding is mainly affected by independent variables like welding current, arc current, welding speed and electrode stick out.

Author discussed about quality improvement of weld in submerged arc welding. Quality of weld is influenced by independent variables i.e. welding current, arc current, welding speed and electrode stick out.

In this paper, predominant parameters are optimized by using Taguchi method. I8 orthogonal array is used for experiment. Taguchi approach is statistical technique to optimize the parameter and upgrade the characteristics of components that are manufactured.

Taguchi method involves identification of proper control factors to obtain the optimum results of the process. Orthogonal array (OA) is used to conduct a set of experiment. Orthogonal array represents a matrix of nos., each row represents the levels and each column represents a specific factor. Optimum values were evaluated by Taguchi method. The optimal parameters for smaller bead thickness and higher bead hardness are obtained at arc weld current at low level (12.186 A), In this paper, an attempt is made to review and summarize the important research work done on Gas Tungsten Arc welding of stainless steel in the past by various researchers. The material on which most of the work done is austenitic stainless steel. Research work done on TIG of stainless steel can be grouped broadly into three categories i.e. Characterization of weld, Dissimilar metal welding, Parameter optimization. Major area on which research work have been in characterization of weld, dissimilar metal welding, parameter optimization, process modeling , failure analysis and automation of TIG welding process. This paper is aimed at, to give a brief idea about research work in past, draw special attention to important conclusions and results.

Important results from experiment is given below:

• Low heat input should be preferred when welding AISI 304 stainless steel.
• Bowing distortion increases with increases with increase in current due to widening of the bead width and decreases with increase in joint penetration.
• The yield strength of dissimilar metals made by EBW is higher as compared to Gas Tungsten Arc Welding and Friction Resistance welding (12).

Robotic gas metal arc welding (GMAW) is the most significant method in production industries. The main objective of this research is to study how welding control factors affect the joining process. For this purpose, butt joint is employed in this research to recognize suitable variables for welding voltage, welding current and welding speed. Researcher uses low carbon steel A1008 as base metal and AWS ER 70S-6 as filler material. Joint was tested to identify main characteristics of the weld for Hardness and tensile strength. Test was conducted on joint for identify the main properties of weld i.e. Hardness and tensile strength (13).

In submerged Arc welding, arc is surrounded by a blanket of fusible flux. Flux is used for refine the metal and protects weld material from oxidation /unwanted particles. Flux plays a vital role in cost estimation because it is used in large quantity. In this research paper, main emphasis is on flux and factor which affects its consumption. Experiment is carried out by using Design Expert Software. For obtaining this object, Response surface methodology technique is applied. This technique represents the relationship between true mean response and input variable like welding current, arc voltage, welding speed and distance between tip of nozzle & workpiece. The significance of this research to study how input parameters affects flux consumption(14).

JFE Group presented a paper to produce light weight car body. In order to achieve this, steel should have high tensile strength and good weld ability. Thick plates are used in order to manufacture container ship, cylinder vessel etc.. This paper summaries the current development in welding. JFE group presented four types of welding i.e. Unmanned Robot welding system, Narrow Gap Welding of heavy plates, Field Girth welding of gas pipelines and rail welding technology(15).