Subject: "semi steel" what is it?

From: [email-masked] (Jim Waggener)
Date: Wed, 18 Sep 1996 21:45:28 GMT

I have several stakes that are marked "semi steel"
what is the composition of this metal?

Jim Waggener
[email-masked]

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From: [email-masked]
Date: 19 Sep 1996 16:19:17 GMT

>what is the composition of this metal?

Obviously the composition is the same as those lathe chucks made from
"semi-steel."  

But - what is it really?  Maybe cheap steel made from old, ground up
semi-tractor-trailer trucks.  Hmm.

Enquiring minds actually *do* want to know...

===========================================================

 1959 BMW R50                                           Jim Rozen              
 1969 BMW R60US                                (JRR0 @ watson.ibm.com)                 
 1975 BMW R75/6    (The "new" one)        

===========================================================

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From: [email-masked] (Mr. Art D. Devonshire)
Date: 22 Sep 1996 02:11:50 GMT

Semi Steel is when steel scrap is used in the production of grey cast 
iron. Art. San diego

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From: [email-masked] (dal wagner)
Date: 20 Sep 1996 16:52:46 GMT

>what is the composition of this metal?
Dal Wagner replies:

Jim
I can assure you it has nothing to do with the trucking industry.

When they roll steel to make structural members they start with ingots
that have "blow holes" or voids distributed through out the material.
When they roll the material, these voids are pressed together or welded.
Steel "deoxidized" in this manner is called "semikilled".
There's nothing special about this material and nothing wrong with it.
Hope you didn't pay a premium price for that "special semi steel".

Regards

Dal Wagner

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From: [email-masked] (Steve Rayner)
Date: Sun, 22 Sep 1996 10:21:42 GMT

>Semi Steel is when steel scrap is used in the production of grey cast 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
In truth, I believe the above describes Malleable Iron, not semi steel.

Semi steel describes several types of Nodular Cast Iron, also known as 
Spheriodal Graphite Iron.  The graphite is in tiny balls, rather than flakes.
The addition of small ammounts of magnesium, or cerium bearing alloys, 
and special processing, create its charactaristics.  It machines like 
cast iron, but its toughness is midway between steel & cast iron.  It is 
often used for lathe chucks, and can be welded or brazed.
-- 
Steve.

**************  BE ALERT, THE WORLD NEEDS MORE LERTS ************************

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From: [email-masked] (MMalone805)
Date: 22 Sep 1996 12:32:39 -0400

Semi Steel is an old term for cast iron that contains a substantial
portion of steel scrap in the charge.

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From: [email-masked]
Date: 23 Sep 1996 02:14:57 GMT

>Hope you didn't pay a premium price for that "special semi steel".

Actually, it was the other Jim (me) who made the comment about 
trucking... don't pin that on Mr. Waggener!

 1959 BMW R50                                           Jim Rozen

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From: Jim Dincau <[email-masked]>
Date: 22 Sep 1996 23:58:12 GMT

> >Semi Steel is when steel scrap is used in the production of grey cast 
Actually malliable iron is grey iron which has had a lengthly (as much
as 10 days) heat treatment to turn the carbon flakes into nodules. The
difference between 'malliable' and 'ductile' ('nodular') iron is
that the latter alloy produces a nodular structure as cast,or so says The
American Machinists Handbook.
Jim

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From: [email-masked] (Kurt Rieder)
Date: 23 Sep 1996 23:05:14 GMT

[email-masked] wrote:
: In <[email-masked]>, [email-masked] (Jim Waggener) writes:
: >I have several stakes that are marked "semi steel"
: >what is the composition of this metal?
: >Jim Waggener
: >[email-masked]

: Obviously the composition is the same as those lathe chucks made from
: "semi-steel."  
: But - what is it really?  Maybe cheap steel made from old, ground up
: semi-tractor-trailer trucks.  Hmm.

"Semi-steel" is a fairly loose term... but cheap or junk it is not.
It's most often used for castings where better tensile and shock are 
wanted.  It's most often melted by electric furnace... so yes, scrap
is the charge.  An outstanding example of its use is for rail car
wheels.  I once had a facinating tour of Griffin Wheel (near O'Hare
airport, NW of Chicago) where semi-steel wheels were pressure cast
into two piece graphite molds.  The wheels were later dye penetrant
inspected.  I would venture to say that quality concerns at this plant 
exceeded what you would find at a foundry where castings for Bridgeport
or South Bend were made.  Far from junk :-}  In regards to composition,
just a guess... over 1%C, under 2%Si, and some Mn and even some other
low alloy content.

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From: [email-masked] (James Wilkins)
Date: 23 Sep 1996 20:28:29 GMT

> Steel "deoxidized" in this manner is called "semikilled".

It may be a mixture of scrap steel and cast iron.