CastingsMining Production Supply

Li Ding

Topics:•Introduction•Background

•Products – Particular Piece

•Project I – Time Project

•Project II – Casting Quenching Analysis

•Questions

IntroductionFounded 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..

Alloy Type Gross Weight

• Martensitic Steel

• Pearlitic Steel

• Martensitic Iron

Every 500 # GW; May combine when having same results

Exceptions!

Duty I – Time Project Cont..

Alloy 120Flask Time 4 hours 5 hours 6 hours

Gross Weight Less Than 1250 lb 1250 lb - 7250 lb Larger Than 7250 lbExceptions

Part # 12762 / GW 2910 lb Box Time 51 hr / Flask Time 6 hr

Easy to crack on the opening

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

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.

High Temp Cycle

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..

• 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)

Time, Temperature, Transformation Curve

Questions ?