PIG IRON

Pig Iron

Pig irons are produced by blast furnaces from iron ore and from ferrous scrap in cupolas or electric furnaces (refined pig irons), or as by-products from other processes such as vanadium or titanium oxide production. These latter pig irons are usually high purity irons most suitable for ductile iron production.

The composition of refined pig irons can be adjusted to comply with customer requirements, including a known residual content or added alloys with a specified range of alloy content.

Typical pig iron compositions, with the exception of high purity irons, are shown in Exhibit M.

Control

Pig iron is ordered to a given specification range and should be accompanied by a supplier’s certificate of composition which should include the major residual contents.

No two batches are the same and unless the operation can withstand a reasonable tolerance in casting compositional range, each batch (which in the case of blast furnace irons may have variations in the batch) should be kept separate. This ideal may not be possible in large melting plants.

Foundries should insist on a certificate of analysis and also carry out analytical checks to ensure a quality material.

Pig iron is an expensive metallic and should be used as a general quality control in the metallic charge, i.e.:

 provide and even out carbon “pick-up” variations

 provide and even out silicon levels

 control phosphorus levels

 ensure a better mixing in cupola operations which have inadequate wells and fore hearth facilities

 as a control for excessive residual element levels and possible gas levels when high steel charges are used.

Return Scrap

The return scrap of each individual foundry should be of a known and generally consistent composition. It should be used to the maximum consistent with obtaining the desired composition of the castings to be manufactured.

Control

Each grade of scrap should be kept separate. Large pieces should be broken to a size suitable for individual furnace requirements.

c) Ferro-Alloys

Ferro alloys are used as additions to ensure control of elements such as silicon and manganese in the standard non or low alloy irons.

The high alloy irons such as Ni hard, Ni resist and high chromium iron, represent a small percentage of the iron foundry industry and require special attention to their choice of alloys and ferro alloys. Ferro silicon	Most common grades in lump form contain 75–80% and 45–50% silicon levels.
Silicon carbide	In lump form containing 55–60% Si and 25–30% C
Ferro manganese	Usually obtained in lump form and contains 75–80% manganese.

The use of larger amounts of ferro silicon in cupolas can result in excessive silicon variations unless suitable mixing volumes are provided in wells, receivers or ladles.

Do not rely too much on the cupola for mixing purposes as it is very possible to obtain a wide variation in silicon content from the well, even with a tap and bott system.

Control

Ferro alloys should be checked that they comply with the foundry’s specification for size, grading and composition.

In particular, ferro silicon should be checked for fines as this is a source of high silicon losses and hence variation in silicon content in melting operations.

Briquettes should be checked for consistency of weight and friability. Instability of briquette can also lead to high silicon losses in the cupola.

In both cases alloy content should be occasionally checked by the foundry or by an independent laboratory.

Accurate weighing of ferro alloy additions on suitable scales is an absolute essential to control silicon and manganese contents. When briquettes are used, ensure the chargers can count!

MELTING PROCESS IN FOUNDRY

Raw Materials

a) Controlling Raw Materials

Raw materials for the manufacture of castings must be selected and controlled to ensure that castings have the mechanical properties and chemical composition desired by the customer and are free from defects.

Amongst the various raw materials input into the foundry, metallic take the lion’s share both in terms of technology and economics.

Metallic Raw Materials

I) Steel scrap

ii) Bought cast iron scrap

iii) Pig iron

iv) Return scrap

Ferro Alloys

Each of these materials should be purchased to:

 range of compositions

 range of quality

 range of physical form.

The selections and quantity requirements of these metallic will depend on the melting method and techniques, the types and grades of irons to be produced, the skill of the operators and possibly local factors such as scrap availability.

b) Ferrous Scrap

Steel scrap has quite deliberately been placed as the number one raw metallic.

Over the last decade technical advances in cupola techniques, electric furnace melting and metallurgical skills have resulted in an increase in the use of steel scrap in foundry melting operations.

The scrap industry has made considerable efforts to ensure that it supplies the qualities of scrap required by the foundry industry. Many scrap merchants have geared their business to local foundries. However, it is up to the individual foundry to:

specify the quality and quantity requirement

 carry out the necessary visual check on every individual load of scrap – remember that visual inspection means checking before and after tipping

 visit the scrap merchant’s yard on a regular basis to ensure continuity of quality and supply.

The scrap merchant’s quality is only as good as his scrap source, plus his processing equipment. The former can change, especially when prime steel is at a premium, resulting in scrap of unknown qualities being introduced into the system.

Bought Cast Iron Scrap

Similar remarks concerning quality control apply to cast iron scrap as to steel scrap.

Categories and approximate ranges of composition for the main types of cast iron scrap are shown in Exhibit L.

The controlling element in bought cast iron scrap is considered to be phosphorus and even relatively medium phosphorus contents of 0.3% or less are detrimental to the production of the higher strength grey irons.

However, with certain specific exceptions, the phosphorus levels of cast iron scraps have reduced considerably over the last 20 to 30 years. In fact, the only commercial way to produce a high phosphorus iron is to add ferro phosphorus.

Control

As with steel scrap loads, a visual inspection of each individual load is essential, and again check before and after tipping, including the bottom of the transport vehicle.

Attention must be paid to possible sources of contamination such as: gas works scrap		high sulphur
enamelled scrap	–	lead, boron and antimony
petrol engine scrap	–	lead, aluminium, etc, plus the possibility of small quantities of chromium

The vast majority of cast iron borings originates from low phosphorus sources and as such are a useful, relatively low cost raw material for many iron foundries.

It can be briquetted, packed in canisters and used in cupola operations. Commercial success depends on the quality of briquette or canning operations as there can be serious losses in the melting operation.

The coreless induction furnace is an ideal melting unit providing the borings are dry and relatively free from rust and foreign matter.  Briquetted cast iron borings should be free from corroded lumps and excessive cutting fluids.

A RETREAT A HEAD

Here’s to Blaine and Jean Harker, those lovable two,

with joy so contagious and counseling so true.

A mourner in grief is a magnet to Jean,

since few are the pains she’s not suffered or seen.

At the parties they give there is greatness of table,

and every last diner eats more than he’s able.

Jean’s food pantry likewise, for the hungry and poor,

was much like her heart—a wide open door.

Their lives are committed to lifting the fallen,

through talkin’ and workin’ and sweatin’ and bawlin’.

An unspoken concern here is needful of saying—

for Jean’s own self-healing we are fervently praying.

While Blaine may have yet to get milk from a cow,

in spite of the Amish folks showing him how,

he’s mastered the art of infectious laughter

that shatters the silence from floor-joist to rafter.

They’ve moved to the country near Old Shipshewana,

but they can’t quite move in yet, as much as they wanna—

while waiting for lodgers to kindly dislodge

they have set up their home in a large upper garage.

We honor the Harkers today, Blaine and Jean,

and the Power behind them, so strong yet unseen.

May God bless their home, the retreat of their dreams,

granting laughter which heals, and the grace which redeems

FLOWER IN VASE

This budding daffodil contains

A universe in birth:

Each molecule a galaxy,

Each quark a tiny earth.

And what we call our universe,

All matter, time, and space,

May be a single atom of

A macrocosmic vase.

Thus up and down the scale of size

Throughout Infinity,

Both “small” and “large” are limitless

And join Eternity.

Great men have puzzled over God

To place Him in their plan,

As Primal Cause, or Sourceless Source,

Or vast Omniscient Man.

But God can never be confined

Within a man-made phrase;

He hides behind unnumbered veils

Impossible to raise.

And yet we see His evidence

In every time and place—

Behind each seed and universe,

Within each flower and vase.

Inside our inmost soul of souls,

If we can meditate,

We find a spark of light divine

And feel it radiate.

While nowhere, and yet everywhere,

Our God resides within;

Though still and small, His guiding voice

Transcends life’s noisy din.

To hear His voice and understand,

Then fearlessly obey,

Is that which mystics, martyrs, saints,

And wise men call “The Way.”

Consider every universe

And every point in space

As God in God in God in God,

As vase in flower in vase.

DOWN DOWN IN THE TAO

Down, Down in the Tao

A Grand Unnameable

inaudibly speaks

from endless here,

else could speak we not

nor be.

Feathers, we,

on a deep bird

unseen between

two night skies,

flying because

feathers can.

Listening are we, with

our universe held to one ear,

to keeps-playing scuffles

between Isn’t and Is, boisterous

in their muffled playroom.

To dance is the rule

in our This-That school

excepting that sleep

too is a rule

and quite more deep.

End of the world?

Peace after that?

Perhaps—but from within

the Night of All Nights

some eventually tickled

divine sleeper may

dreamingly laugh aloud,

stirring breathing into the mist

and back soon will be we,

guns, and daily newspapers.

Call this if you wish

“The Little Laugh Theory”

although nameable is the Is

no more than is the Isn’t,

down, down in the Tao

TREAT CHILDREN INDIVIDUALLY NOT EQUALLY

Treat children individually, not equally

Parents sometimes believe that the best way to avoid arguments

and unhappiness among their children is to give equally to each

child. New clothing for a child often is matched with something new for

the siblings too. Spending time with one child often means trying to

spend an equal amount of time with the other.

This practice of attempting to give equally to all the children only

encourages comparisons by the children who often feel cheated. No

matter how hard you try to make things the same portions of favorite food, time spent, or gifts given children are bound to find some way that you’re not being fair.Children feel special and valued

when you give to each according to individual need. Instead of telling

children that you love them equally, privately point out their special

qualities that have nothing to do with others in the family. (“I love

spending time with you” or “You’re the only one like you in the whole

world and I love you.”)?

A HIDDNEN SKY

There is a sky

below the ground.

I saw it today

through puddle windows

along my street.

Big sycamore leaves

were floating in it

like balloons becalmed.

Trees were towering

downly up

beneath my feet.

If streets contain a sky,do you and I?