Castings
Mining Production Supply
Li Ding
Topics:
•Introduction
•Background
•Products – Particular Piece
•Project I – Time Project
•Project II – Casting Quenching Analysis
•Questions
Introduction
Founded in year 1976, ME
Elecmetal – Duluth belongs to ME
Global (Chile) which is one of the
largest companies in this industry
all over the world.
Positioning itself closer to its
customer base in iron ore
processing.
The company used the most
advanced technology, the vacuum
molding system (V – Process)
Background
I. Crusher
Large Ore has been dumped into the
system for crushing into relatively
small piece.
One major product – “concaves”
constitute the dark blue “walls” which
will be easily to wear out and need
replace every 6 to 12 month based on
type of mine.
Still to big for refining process and
need further process – mill.
II. Mill
After Crush Process, ore will be sent into the
mill from the FE(Feed End) which mill will
rotated at a certain speed with ore against to
the shell and against each other.
Several mills (usually will be three or four,
mine depend) will be applied.
Crushed ore can not leave the mill until its size
is smaller than the opening on the DE(
Discharger End).
“Grinding Ball” may be added for getting fine
power. Sometimes water will be used for
producing pulp which will help moving
smoothly.
Products
Head Liner
Shell Liner
Grates
Concave
Duty I – Time Project
Vacuum Time:
Vacuum applied on the box after liquid metal has been
poured and help casting approach its designed shape
during the primary solidification. (6 to 20 min)
Flask Time:
Solidification keep on going; Shell of the box Flask has been “locked” to avoid and explosion or
casting swell (6 to 16 hr)
Box Time:
“Flask” has been removed; Hot castings will
covered with sufficient sand and send to cooling
tower for completed cooling down. (40 to 85 hr)
Duty I – Time Project Cont..
• New jobs start to coming towards such that build up a general handbook will be
wise choice to achieve a accurate procedures as soon as possible based on the
pervious database.
• Electronic Database was established 14 years ago which has already contain
more than 2000 data sets. Basically, every individual casting will have it own
technical requirement including pouring temperature and speed, “Times”, heat
treatment recipe, finishing inspections etc..
Gross Weight
Alloy Type
• Martensitic Steel
• Pearlitic Steel
• Martensitic Iron
Exceptions!
Every 500 # GW;
May combine when
having same results
Duty I – Time Project Cont..
Alloy 120
Flask Time
4 hours
5 hours
Gross Weight
Less Than 1250 lb
1250 lb - 7250 lb
Part # 12762 / GW 2910 lb
Box Time 51 hr / Flask Time 6 hr
Easy to crack on the opening
6 hours
Larger Than 7250 lb
Exceptions
Duty II – Casting Quenching Analysis (In Processing)
Castings will cool down completely after moving
through these three time periods. However it will
not be accepted by customer since it can’t pass the
High
Temp
Cycle
inspections, especially it hardness will be significant
lower than desired. Such that we perform an extra
process called heat treatment to make sure the
physical properties of every single casting can meet
the requirements.
Quenching
(Fan Blast)
Low
Temp
Cycle
Duty II – Casting Quenching Analysis Cont..
The high temperature cycle
(austenization) is used to
homogenize the internal
structure of the casting.
1750 ℉ will be a general
high temp cycle temperature.
The transformation point
when the internal structure
transfer to pearlite are
differed by alloy type.
Typically, it’s the same as
carbon steel for our steel
alloy.
Duty II – Casting Quenching Analysis Cont..
Time, Temperature, Transformation Curve
•
The quench cycle (Still
Air Cool, Fan Blast &
SAC and Oil Quenching)
is used to develop the
desired microstructure of
the casting. (Hardness)
•
The low temperature cycle
(temper) is used to relieve
stress and refine the final
microstructure of the
casting. (Under the
transformation point)