ARC WELDING
Definition
• ARC Welding process has the advantage of being relative simple only requiring a power supply, power cables and electrode holder.
• It is commonly used in construction and jobbing shops.
• The basic arc-welding circuit fitted with is connected by a work cable to the work piece and by an electrode cable to an electrode holder, which takes the electrode and when contact is made to the work piece the circuit is complete.
• An arc is created across the gap and the electrode tip touches the work piece and is withdrawn, yet still remains in close contact.
• The arc produces a tempeture of about 6500 deg F at the tip. This heat melts both the base metal and the electrode, producing a pool of molten metal. The result is a fusion bond.
• Ensure that your job is well guarded so others do not receive a flash from the welding, also slag from the chipping hammer
Tool
The tools required:
• Helmet.
• Earth Clamp.
• Electrode Holder.
• Chipping Hammer.
• Wire Brush
Safety Notes
Before starting actual arc welding you should be fully aware of the dangers involved. The high temperature arc and hot metal can cause severe burns. In addition the electric arc itself provides an additional safety hazard.
When welding with the electric arc, there is added danger that the small globules or droplets of molten metal may leave the arc and fly in all directions.. They present a personal burn hazard plus a fire hazard if they fall in inflammable material.
Other dangers associated with electric arc welding are: Electric shock, Burns, Radiant energy, Gases and fumes, Radiant energy, Combustible material, Fire.
To prevent all of those dangers we must :
A. Electric shock
- Make sure machine is properly grounded.
- Never permit “live” parts of the electric welder to touch bare skin or wet clothing.
- Do not cool electrode holders by emersion in water.
- Turn off power supply when welder is not in use.
- Do not stand on wet areas while welding.
- Wear leather gloves.
- Make sure cable are covered and in good condition.
- Make certain that electrode holders are properly insulated.
B. Burns
- Protect eyes and face from flying particles of slag by use of safety glasses or face shield.
- Wear adequate protective clothing.
- Always wear leather gloves.
- Wear high top shoes.
- Keep collar, shirt pockets, etc buttoned.
- Do not touch the electrode or metal where welding has taken place.
- Handle hot metal with pliers or tongs.
- Keep electrode stubs properly disposed of.
C. Radiant Energy
- Use a welding helmet with the correct shade lens in good condition.
- Wear suitable clothing—do not leave bare skin exposed to the rays of the arc.
- Do not strike the arc without covering the face and eyes. Give warning to others before striking the arc.
- Avoid looking directly at the arc where others are welding without proper eye protection.
D. Gases and Fumes
- Work only in well-ventilated areas.
- Use great care when working on metals covered with lead or zinc.
- If working in a confined area use respirator or other approved breathing devices.
E. Combustible Materials
- Keep shop clean in areas where welding is to be done.
- Do not weld near combustible materials of any kind.
- Never weld on covered containers which may have held combustible materials without first taking adequate safety precautions. For example, fill them with water, steam clean or fill with an inert gas.
F. Fire
- Be familiar with location and types of fire extinguishers.
- Report any unsafe conditions that might start a fire.
- Do not weld near inflammable materials.
- Do not weld on containers that have held inflammable materials.
- Do not weld near electrical fittings or lines.
Filed under: Welding
