@’@UNIT TITLE: Welding Technology @’@ Essay Example

7MIG WELDING

USING INFORMATION AND PREPARING FOR WORK

Course: WELDING TECHNOLOGY

Professor: A R Fisher

Metal Inert Gas (MIG)

MIG welding is a process that utilizes heat generated by a DC electric arc to fuse the workpiece in the joint area. It involves a continuous electrode being fed by powered rolls fed into the welding area. The welding electrode is normally melted in the same speed as its being fed and ends up forming the weld pool (Cornu, 2013). The process involves protection of the arc and the welded pool against atmospheric contamination by a shield of non- reactive gas. This kind of welding process was first used in aluminum welding in the 1940s and later adopted in steel welding. Its adoption to steel welding was due to its speedy welding process when compared to other welding processes.

The inert gas applied in this process is acquired through expensive procedures that limited its use in steel welding. However, the process was resolved when a semi-inert gas such as carbon dioxide (CO2) was utilized in place of the inert gas (Eshraghi, 2014). The process’s efficiency is based on a good selection of a perfect package of the gas mixture, flow rate, current and electrode speed. Once the above selection has been made effectively, the required skills are quite minimal. The process has evolved to the extent of being executed by robots in precise welding joints.

Amperage

Two main factors determine the amperage settings of the machine:

  • Material thickness

The guidelines indicate that for every 0.001 inches of material thickness, 1 amp is required. In our case, a material of 1.6mm will be used. Converting the 1.6mm into inches gives 0.0629921 inches. 0.0629921 inches will, therefore, require 62.9921 amps.

  • Wire size

Wire (electrode) thickness will be a commonly used size of 30-130 A: 0.023 in.

The amount of voltage selected will determine the height and width of the bead. The material thickness will also influence the amount of voltage applied in the welding process (Eshraghi, 2014). The suggested voltage for welding the 1.6mm material is approximately 23 volts.

Wire feed speed

Wire feed speed is given in inches per meter. The suggested wire feed speed for this practical is 240- 400 (ipm) because the practical will mostly comprise of 1F/2F and 3F/4F joints (Dong, 2013).

Equipment selection

Indeed, considering the type of welding process to be carried out, the best welding equipment is the Clarke 135TE Turbo MIG Welder. This equipment is mostly preferred because it is easy to set and consists of a turbofan that is responsible for prolonged welding sessions (Dong, 2013). This welding equipment comes with CO2, regulator, earth clump, mild steel wire professional torch assembly, a user guide and a face shield. Besides its capability of withstanding extended welding sessions, the machine is versatile in that it can be used to weld a diversity of surfaces including stainless steel joints.

Safety issues arising from using the machine

  1. Light emanating from the torch can cause injuries to the welder’s eyes. As a precaution, the machine comes with a protective gear to prevent the welder against the direct light.

  2. Another safety concern is the possibility of the machine to knock the welder especially when an electric current is introduced instantaneously. Also, to shield the welder from injuries from such occurrences, the machine is clumped on the ground using the earth clump that comes along with it.

Machine welding technical specifications

No Gas/Gas

CO2 to be used

Min/Max Amps

Mild steel capacity

Welding wire sizes

0.6-0.8 mm

Amps at 60% Duty

Input Voltage

Open circuit Voltage

Power supply

13Amp plug supply

List of consumables required for the welding process:

  1. Contact tips

  2. Wire spool

  3. Ground cable with clamp

  4. Drive roller

  5. Spot weld nozzles.

Work plan

@'@UNIT TITLE:  Welding Technology      @'@

Consumable specifications

Contact tip should be matched with the wire size. Therefore, this is normally done as a way of reducing wandering of the welding electrode inside the tip. The wire should be flexible (not too tight or too loose) to minimize freeze-up and arcing respectively.

The internal diameter of the contact tip should always be smooth and kept free of burrs. Extrusion marks should also be avoided during processing of the contact tips. The presence of this marks the electrode to pick up debris which it then deposits it at the end of the tip or even at the weld puddle.

Right Alloy types

Copper alloy 122 is the standard alloy in use for most contact tips. Nozzles and diffusers are available in different alloy types ranging from copper to nickel coated alloys.

Proper matting between the contact tip and the diffuser

The two surfaces should mate properly to ensure a long lasting life for the two surfaces.

Welding tools and equipment used to produce the welded components

MIG machine (Clarke 135TE Turbo MIG Welder).

This machine was picked on the bases of cost considerations in terms of material and time consumption.

Shielding Gas bottle

Among the shielding bottles, the cheapest is the one that contains pure carbon dioxide. This shielding gas bottle produces a lot of spatter and penetrates deep in steel surfaces thus producing a decent looking bead. A 40 cubic foot in depth is appropriate for simple activities such as in our case.

A pair of pliers is used cutting the welding wire, removing traces of spatter out of the nozzle and is also used in some cases as a hammer.

This is tools that protect one’s hands from injuries. They are not expensive as they retail from as low as $3 for the simple ones. There are more complex ones that last longer and are more comfortable to the hand that retails at around $ 30.

Welding goggles

These are part of protective gears that are used to protect the welder against flying objects towards the eyes and excessive light from the welding flame. It is an important recommendation during welding activities.

Wire brush

Wire brushes are used for cleaning metallic surfaces. An appropriate brush is very important when considering surfaces to clean (Mondal, 2015). Mild stainless brush, for example, cannot be used to clean stainless or aluminum surfaces because it may end up contaminating the surfaces. It is therefore advisable to get a brush specific for each surface i.e. aluminum wire brush for aluminum surfaces.

Anti-spatter

Aerosol cans and gunky from containers can serve this purpose. The aerosol sprays are used for spraying into the machine nozzle. Anti-spatter can also be applied to the nozzle before the start of the project (Mondal, 2015).

Permanent marker

The permanent marker is necessary for drawing welding boundaries on joint lines. It is important to use a permanent marker with a sharp narrow tip to get narrow lines.

Grinders appear in different sizes out there in the retail shops. For the purposes of this practical, a four-inch grinder is recommended as the job is not so intensive.

W@'@UNIT TITLE:  Welding Technology      @'@                                        1 ork plan

Effects of using incorrect welding parameters

Parameter

Process faults

Effects on safety

Amperage

Wire stubbing (caused by high currents)

If the tip reaches the welder’s body, it may cause burns.

Excess spatter (caused by very high voltage levels)

May cause poorly fixed handles to melt hence body burns may occur

Welding speed

Unstable arc (Caused by imbalanced welding speed. Either too high or too low) may cause poorly welded joints.

The magnetic arc may blow hence causing injury to the welder.

Welding procedure for a Lap joint

  1. The plates to be joined are 1.6mm in thickness and 50 by 150 mm in dimension. The first step is to overlap the plates is such a way that the overlap surface is twice the thickness of the plates i.e. 3.2mm in this case (Kianersi, 2014).

  2. After overlapping the surfaces, the top piece is clamped to ensure that it is maintained in a flat position. The top piece is then pushed to the bottom part.

  3. The two pieces are then grounded on the working table. From this point, the joint are welded together because a complete circuit is now formed.

  4. Before the welding activity commences, safety should be taken into consideration. The gloves and welding goggles are won. The Clarke 135TE Turbo MIG Welder alongside the 0.6-0.8 mm wire is set up for the lap joint welding. Therefore, using a chipping hammer or the pliers, the slag flux is removed, or in some cases, it can be left to fall off by itself. The flux is used to protect the weld while still in the molten form.

Butt Welding Procedure.

  1. Firstly, butt welds are circumferential joints and are the most common joints applied in the fabrication of welded pipe systems (Kianersi, 2014). They are used where high levels of strength are required.

The two curved surfaces are placed back to back with elongated plate surfaces facing away from each other. The faces are then joined using the MIG welder machine alongside the gas shield cylinder and the welding wire (ISO, 2015)

  1. . The right specifications have to be followed as specified earlier in this paper.

Test piece

This is a standardized specimen that represents the real welding components as they will appear at the end of the welding process (ISO, 2015). For this case, the two joints featured will see its surfaces drilled at intervals of 20mm and 15mm at the extreme ends of the welding material. The drilled holes will act as the joining points for the welds during the welding process. The test plates are of 150 by 50 mm.

References

ISO, C., 2015. TR 15608, Welding: Guidelines For A Metallic Materials Grouping System, 2013. Copyright (c).

Mondal, P. and Bose, D., 2015. Optimization Of The Process Parameters For Mig Welding Of Aisi 304 And Is 1079 Using Fuzzy Logic Method. International Research Journal of Engineering and Technology (IRJET), 2(08), pp.483-488.

Dong, P., Li, H., Sun, D., Gong, W. and Liu, J., 2013. Effects of welding speed on the microstructure and hardness in friction stir welding joints of 6005A-T6 aluminum alloy. Materials & Design, 45, pp.524-531.

Kianersi, D., Mostafaei, A. and Amadeh, A.A., 2014. Resistance spot welding joints of AISI 316L austenitic stainless steel sheets: Phase transformations, mechanical properties and microstructure characterizations. Materials & Design, 61, pp.251-263.

Eshraghi, M., Tschopp, M.A., Zaeem, M.A. and Felicelli, S.D., 2014. Effect of resistance spot welding parameters on weld pool properties in a DP600 dual-phase steel: a parametric study using thermomechanically-coupled finite element analysis. Materials & Design, 56, pp.387-397.

Cornu, J., 2013. Advanced Welding Systems: 1 Fundamentals of Fusion Welding Technology. Springer Science & Business Media.