The marriage process; A general look at arc welding

4년 전

Introduction

I once worked in a workshop where I had my engineering internship, there we fixed diesel engine generators. I would like to talk about that but what really caught my attention was the welding of metals. Damn! I would say to myself, what kind of stuff is this thing made of that makes it so strong after weld?. When I got back to school, I decided to ask my lecturers but all they did tell me was its made of flux and some metal. But this answer is not enough to care my curiosity, so I decided to do a research.



welding operation

What is welding?

As I noticed enlightenment for the non-science people is needed I would be taking it slow and in the best simple term, I can use.
Welding is simply joining two or more metal or plastics using high temperature. Welding is usually done at a very high temperature and both metals are melted then fused together using an electrode. This electrode is called welding electrodes. A little pressure may be applied during welding. lastly, arc welding is always done using a welding machine which raises the temperature to a varying temperature depending on the capacity. In arc welding, both welded part have to be connected to the ground clamp of the welding machine for electrical safety.




A small welding machine

Have you ever welded before?

Let me describe my first experience, I usually thought the electrode was just applied to the point where you need the weld and it was so easy till I found out the electrodes become so sticky when you want to raise up the electrode welder. Then I discovered life is not a bed of rose. It was so difficult to raise.
Now, I want you to see welding as a white wedding where both the husband and wife are the metals to be joined together and the electrode is the reverend to join both metals together. lol, I guess its clear enough?
There are different types of welding which are.

  • Oxy-fuel metal welding
  • Shielded-metal arc metal welding
  • Gas tungsten arc metal welding
  • Gas metal arc metal welding
  • Flux cored arc metal welding
  • Submerged arc metal welding
  • Electroslag metal welding
  • Electric resistance metal welding.

The one we used in our workshop was the shielded metal arc welding. But I am not talking about welding in this article, but the main topic is understanding the component and how the electrode filler works.

The welding electrode

The welding electrode is a very important tool in arc welding. Its main job is to conduct current through the metal to be joined and to fuse or hold the two metals together. (i.e. the metal and the workpiece). As a weld is being done, the welding electrode melts to form a molten pool which cools down and solidify to form a joint. The coating of the weld electrode scatters as this operation is being done and gives off vapors that function as a shielding gas and a providing layer of slag whose functions are to protect the weld area from contamination from the atmosphere.




welding electrode

Composition of weld electrode

There are several types of electrodes for different type of welding but Basically, the weld electrodes are made up of two parts which are;

The metal and the flux coating

The metal used in the electrode could vary from cast iron, copper, brass, aluminum, and mild steel. Depending on the type of metal you want to weld different types of electrodes are selected for these purposes.

The flux coating

The flux coating is wrapped around the metal rod and is made up of cellulose(C6H10O5) from plants for flexibility, other compositions are powdered iron and hydrogen.
Potassium and sodium are also used to make flux coating and works as a binding agent. The main function of the flux coating is to help electric current flow evenly during welding.

How to make a good weld?

There are several steps involved in making a good weld, these include;

  1. Prepare the surface by cleaning and marking out the points you want to weld. (i.e. both ends must be smoothened and straightened out as you don’t want a weak joint)
  2. Tack the joint in preparation for the weld. Tacking involves adding little weld across the joint still having spaces. More like a weak joint.
  3. If you are satisfied with the way the tacking positions the joint, then you perform the full weld. But resist the temptation to weld too much so as not to overshoot the joint.
  4. Perform clean up by grinding the joint using the grinding machine.

Conclusion

Welding is being carried out in our daily construction in almost everything as no metal is formed that way in bridges, cars, airplanes, and many more applications. filler electrodes are used in most arc welding process.
Filler electrodes are used for different types of welding depending on the material used and they comprise of mainly flux material and metal.
A good weld must be performed using the steps above a weak weld leads to accidents as you all know engineering is all about safety. Always ensure you have your safety google on while welding to prevent eye damage.
Safety first!!




welding used to form a pipe


References

For more reading on welding

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I can't say it's a topic I've ever thought about much but it was interesting to learn the intricacies. I must say it's a much more complex and thought-through process than I'd assumed.

Thanks, good read :)

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  ·  4년 전

thank you sir.. i look forward to enlightening the steem community about more engineering stuffs.