A dream of dream

Before this you must read..
Tea with SP
love, home & bhaiyaaaa...

In the cracking sound of rocket cracker, my nokia mobile bipped, confirming a new sms. Its not other than SP.

See the moon, its sad
trying to come out from cloud
wants to have a look of her dearie
desires to share this night with you

See the moon, its sad

dreams to sit with you
thinks to walk on sand
wants to feel the wave striking your heart
wants to have an unending hug

See the moon ..
it wishes you happy happy Diwali.

I was the happiest man on the earth, desperately wanted to hug her & lost in her

all of sudden a cracker fall near by me & bam.....i awakened found no body on beach, moved to my little cave, where i had an endless dream, where no one, no one except me & her... .....& obviously the moon in cloud, trying to catch the glimpse of two duckies.

mold water hardness

In very high heat transfer rate applications, such as continuous caster mold cooling systems, chromate levels should be maintained at 100-150 ppm maximum. Under these extreme conditions, chromate can accumulate at the grain boundaries on the mold, causing enough insulation to create equipment reliability problems.

pH of the water must be maintained below 9.0.Corrosion rate accelerates at pH levels higher than 9.0 for Cu.

Secondary Steel Making Process

Seconadary Steel making process consists of :

Deoxidation 

Desulfurization 

Clean steels 

Dehydrogenation 

Decarburization 

Alloy addition 

Reheating 

Secondary steel making operations
Secondary steel making involves some of the following options. The selection of which are available in any particular steel making shop depends on the types of steel being made and the availability of space within the factory.

*Stirring
*Lance
1. Bottom porous plug
2. Electromagnetic Stirring (EMS)
*Ladle furnace
*Ladle injection
1. Powder
2. Wire
*Degassing
1. Tank Degasser
2. Stream Degasser
3. RH Degasser
4. DH Degasser
*CAS-OB
*AOD

Why deoxidize?

The oxygen content of liquid steel in the ladle at the start of the secondary steel making process is 400-1000 ppm (0.04 - 0.1%).
The solubility of oxygen in liquid steel is 0.16% but in solid steel it is only 0.003%.
Therefore, steps have to be taken to reduce the oxygen content (deoxidize) of the steel before it solidifies in order to prevent blowhole formation during casting and a porous product being created or large quantities of FeO being precipitated. 

Sources of oxygen

 

Reducing oxygen content

The addition of a strong oxide forming element is the most commonly used method of reducing the oxygen content of liquid steel.
Use the Ellingham diagram to help you decide which of the following may be suitable (cheapest) choices for this.

Deoxidation reactions


Aluminum, silicon and manganese are the most common deoxidisers used in steel making The chemical reactions associated with their use are:

Silicon and manganese are often used in conjunction with one another.

 

Effectiveness of deoxidizers

Equilibrium concentrations of dissolved oxygen under different concentrations of manganese, silicon and aluminum

Steel cleanness

There are a variety of sources of inclusions:

* indigenous (small):
1. deoxidation product and MnS
* exogenous (large)
1. reoxidation (reaction with air or slag)
2. entrainment of slag
3. eroded refractories

Inclusions are formed by chemical reactions (deoxidation, reoxidation and precipitation) or by physical conditions (turbulance or wear).

Effect of inclusions on downstream processing and properties and performance


Most inclusions have a detrimental effect on properties. Solid oxides (alumina or certain calcium aluminates) can cause nozzle blockage during continuous casting and disrupt the process and have to be burnt out. Some inclusions can cause cracking and defects, slivers and delamination in rolled products and also fracture during hot/cold forming and wire drawing.