All about Steel

Dear all,

Hi. There seems to be some confusion created by the video taken was shown in class. In the video, pig iron snapped at a force of 6 tons, while steel snapped at a force of 8 tons. What do these show?

Actually, we are measuring tensile strength, i.e. the maximum load in tension a material will withstand before fracturing, or the ability of a material to resist being pulled apart by opposing forces. Hence, I would infer that this property is related to brittleness.

From our notes on alloys (Para 5), it was said that 'brittleness increase as the carbon content increases'. This is exactly what is shown in the example above.

To clarify the terms used on metal, here's quite a good resource:
http://www.arcraftplasma.com/metalchar.htm

Actually, if you are seriously interested in finding out more about strength of steel, you could read this article. Basically, it seems to suggest that strength of steel depends not only on carbon content, but also a variety of other factors.

http://www.key-to-steel.com/default.aspx?ID=CheckArticle&NM=11

To find out more about the other factors, here's a link:
http://www.matter.org.uk/steelmatter/metallurgy/6_1.html

Lastly, there is this interesting article that is highly related to our study on Metal extraction and steel making. In summary, MIT is suggesting to make steel through electrolysis. But why are we not doing it? What are the benefits and disadvantages?

http://web.mit.edu/newsoffice/1996/steelmaking.html


Steel wire. Taken from http://en.wikipedia.org/wiki/Steel

Revision for CCT: Redox

Guys, here's a website that will help you revise your REDOX:

http://www.chemguide.co.uk/inorganic/redoxmenu.html

These are the things you must be able to do after going through the website:

- Define Redox in terms of electron transfer and changes in oxidation state.
- Identify O.S. of a particular ELEMENT in a substance, e.g. What is Cl's O.S. in HOCl?
- Identify a redox reaction, the reducing agent and oxidising agent.
- Write half equations.
- Combine half equations to get ionic equations.

A whole list of practice problems can be found in this website:

http://www.chemtutor.com/redox.htm#osp


A pictorial representation of REDOX. Taken from http://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookEnzym.html

Reactivity Series

Yoz, everybody,

Let's recap what we have learnt this week:

1. The reactivity series ranks the reactivity of various metals [More reactive at the top]. (Remember to come up with your own acronym)

2. The more reactive metals are able to DISPLACE the less reactive ones from their oxides or their salt solutions.

To help you visualise what happens at the atomic level during displacement of metals from the salt solution, go to the following website:
http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/redox/home.html

For additional notes, you could go to this website:
http://www.wpbschoolhouse.btinternet.co.uk/page03/Reactivity.htm

Lastly, remember to plan your experiment (i.e. SPA) before coming for lab next lesson. You would only have 10 mins to complete the experimentation.

Enjoy!


The Promethean Flame (aka Thermit Reaction)
[Thanks to Jon Chiam]