DEPARTMENT OF MECHANICAL ENGINEERING JJ203 (ARC WELDING) NAME
MATRIX NO.
MUHAMMAD ASYRAF BIN RAZALI MUHAMAD TAUFIQ BIN RESDI
06DKM11F1084 06DKM11F11083
LECTURER NAME: PUAN YUSNIZAR BINTI BOHARI ENCIK MUTIMAN MAT
CONTENT
Introduction Objectives Safety precaution Equipment/apparatus Safety clothes Work step Discussion Conclusion Appendix reference
Introduction Arc welding is the fusion of two pieces of metal by an electric arc between the pieces being joined – the work pieces – and an electrode that is guided along the joint between the pieces. The electrode is either a rod that simply carries current between the tip and the work, or a rod or wire that melts and supplies filler metal to the joint. The basic arc welding circuit is an alternating current (AC) or direct current (DC) power source connected by a “work” cable to the work piece and by a “hot” cable to an electrode. When the electrode is positioned close to the work piece, an arc is created across the gap between the metal and the hot cable electrode. An ionized column of gas develops to complete the circuit. Basic Welding Circuit
The arc produces a temperature of about 3600°C at the tip and melts part of the metal being welded and part of the electrode. This produces a pool of molten metal that cools and solidifies behind the electrode as it is moved along the joint. There are two types of electrodes. Consumable electrode tips melt, and molten metal droplets detach and mix into the weld pool. Non-consumable electrodes do not melt. Instead, filler metal is melted into the joint from a separate rod or wire. The strength of the weld is reduced when metals at high temperatures react with oxygen and nitrogen in the air to form oxides and nitrides. Most arc welding processes minimize contact between the molten metal and the air with a shield of gas, vapour or slag. Granular flux, for example, adds deoxidizers that create a shield to protect the molten pool, thus improving the weld.
OBJECTIVE Understand of arc welding in joining process such as make a 90 degree joint Know the problem that occurs on the arc welding process. Type of metal and electrode that are used in arc welding. Know the angles that are used in arc welding process.
SAFETY PRECAUTION Welding is a process involving with electricity and high temperature (heat), so we must take precaution in doing this process to as precaution. The safety are:
1) Wear safety equipment such as head shield, glove and apron (safety jacket) before start welding. 2) Do not watch the ultraviolet rays spatter when welding using eye without a head Shield. 3) Carry Out at a comfortable area and where the is good welding will be done away from the flammable materials. 4) Do not disturb other student that are still work. 5) Do not use tools that we do not recognize.
EQUIPMENT AND APPARATUS Apparatus 1. WELDING MACHINE
Welding is a metal-joining process in which coalescence is obtained by heat and/or pressure. In arch welding, the fusion is obtained by heat produced from an electric arch between the work and the electrode. Generally, there are 2 types of welding machine: A) Alternating Current-AC b) Direct Current-DC
2. ELECTROD HOLDER
It is used to electricity from welding machine to work metal. It is also used to hold the electrode during the welding process. It has a spring as its parts so that it can hold and let go off the electrode easily. Electrode holder must be lightweight, have good rubber coating and easy to handle for quite along time. It has its own size for the amount of electric current that it carries
3.ElECTROD
Welding electrodes are metal wires with baked on chemical coatings. The rod is used to sustain the welding arc and to provide the filler metal required for the joint to be welded. The coating protects the metal from damage, stabilizes the arc, and improves the weld
4.EARTH HOLDER
It is connected to the earth cable and clipped to the work metal or to work table. It has a spring so that is can be easily clipped and unclipped. Without this equipment, welding work will certainly cannot be done
5. CHIPPING HAMMER
It is made from an old punch, chisel or spring metal. Shape like a chisel at one end and has a sharpened end at the other one. Its holder is made from welded soft metal. It is used commonly to break off slag excess stringer from the surface of the work metal
6. WIRE BRUSH
It is used to clean the surface of the stringer bead after the slag is chipped away and to remove dirt from the surface of work metal before welding can be done.
SAFETY CLOTHES GAMBAR RAJAH 1. MASK SHIELD
HURAIAN It is made from inflammable material. In the middle of the shield there is a bright rectangular glass coated with dark colored glass. It is used to protect the user from firebolt and harmful rays during welding work. There are two types of shield, one is the helmet type and the other one is the hand held type. The sizes are No. 10 and No. 11 respectively
2. GLOVES
3. Apron
It must be made from high quality leather. Use to protect your hand from fire-bolt and hot metal welding
It is used to protect the user from the intense heat produced during welding operations. It is made of high quality leather to provide greater comfort for the user
WORK STEPS 1. 2. 3. 4.
Clean the surface of the metal plate with wire brush before welding. Mark the point where you wish to begin your weld on the metal plate Select the appropriate electrode with the type of your work. Adjust the electrical current between the electrodes as suitable for the particular size 80-90 5. Welding on a flat surface and the angle between the electrode and the object of work is between 15-30 degree .
6. the next step, after making notch on both plates, we need to attach both plat at an angle of 90 degrees . 7. Close the plate at 90 degree position
8. Then we have to “Kimpal Paku” at the end of the joint . 9. After that, we welding the joint and the angle between the electrode and the object is between 15- 30 degree .
10. When the welding is complete, clean the surface and the project is completed .
Discussion 1.The north is not uniform or uneven Using the appropriate degrees of inclination. Adjust the voltage
1. The plates are not in a straight position Making a nail at the end of the weld plates Use the support plate to establish the position of the plate to get a straight plate 3. The difference should affect the melting of metals 80-85 = slow molten metal 80-85 = slow molten metal
CONCLUSION At the end of this experiment , We get to know how to do an arc welding and how the process is occur . Beside that, there are also a few tips on handling and welding that we have learn . We also can improve our skills in welding .
APPENDIX
REFERENCE http://www.scribd.com/doc/51718380/ARC-WELDING-REPORT http://www.scribd.com/doc/27715057/Report-Arka http://www.oocities.org/unitenz/notes/arc_welding_1.htm http://www.oocities.org/unitenz/notes/arc_welding_2.htm http://www.scribd.com/doc/27715057/Report-Arka http://www.google.com.my/#sclient=psyab&hl=en&source=hp&q=report+arc+welding+conclusion&psj=1&oq=
