© novacast foundry solutions ab metallurgical process control systems

© NovaCast Foundry Solutions AB

Metallurgical Process control systems


Basic needs of a foundry

Process stability

(Reliability)

High Yield Low direct costs

Low environmental

impact

Competitive edge

Improved customer

confidence

Improved financial results


World Class

Chaos

Control

Simplify

Automate

The purpose of process control


Day 1• C = 3,4 % • Si = 2,1 % , 1380°C • Rejection rate = 2,0 %.• All measured data OK!

Day 2• C = 3,4 % • Si = 2,1 % , 1380°C • Rejection rate = 12,0 % • All measured data OK!

?

Do I have all data needed to control my process?


You get what you measure

If it´s not measured it cannot be improved

The purpose of process control


The spectrometer shows the amount in % of different elements in the melt.

The metallurgical key temperatures show the total effect of elements, oxides, silicates, dissolved oxygen, combined oxygen and other gases in the melt.

Chemical & Thermal Analysis

It is the effect that is important to know for process control!


Disadvantages of only using the spectrometer

• created compounds• oxides, silicates, sulphides etc• chemical reactions• nucleation or precipitation of graphite• the dynamics of solidification

You will not receive any information about ….


The metallurgical “Fingerprint”


Controlling the process with 6 Basic parameters


Liquidus - TL


Adjusting CEL with Spectro

If C and Si are within limits then the iron is considered to be OK.

Example:

C = 3.30 - 3.45 Si = 2.0 - 2.2 P = 0.05 - 0.1

CEL = C + Si/4 + P/2. CEL min=3.83 CEL max=4.05

Variation +/- 0.11 Variation in TL = 1168 – 1193 = 25 C

RISK FOR DEFECTS


Low eutectic - TElow

TElow = f ( Nucleation status, Disolved Oxygen & Oxides )

© NovaCast Foundry Solutions AB14

TElow

TElow > 1135°CPrimary Carbides

FREE

TElow ≤ 1135°CPrimary Carbides

PRESENT

Thermal parameters TELowTElow, The low eutectic temperature (a high value is essential). If TElow is too low then the nucleation is too low. Risk for chill in corners and thin sections. Risk for undercooled graphite shapes.


Recalescence - R

R = f ( Nucleation rate + Eutectic growth )


Graphite factor 1 – GRF1

GRF 1 = f ( under cooling, precipitation speed, amount of graphite)


Thermal parameters GRF1GRF 1, Graphite Factor 1 (a medium value is good). If too low it is an indication that the carbon content might be too low especially if R is low or normal. It also indicates that the precipitation of graphite is lower than normal, which might be due to bad nucleation. A low GRF 1 indicates a risk for micro-

shrinkages.

GRF1 > 120 Chunky

GRF1

75 < GRF1 < 120 Porosity FREE

GRF1 ≤ 75 Porosity


Graphite factor 2 - GRF2

GRF 2 = f ( Graphite shape & amount )


GRF2

GRF2 > 55 MICROSRHINKAGE

PRESENT

35 ≤ GRF2 ≤ 55 MICROSHRINKAGE

FREE

GRF2 < 35 DEGENERATED

GRAPHITE

Thermal parameters

GRF2


Solidus - TS

TS = f ( Segregation, Mg )


Micro shrinkage / Porosity

Controlling shrinkages

Macro ShrinkageOuther sunks

S1 S2 S3

t,s

T,°C

DendritesEutecticum


ATAS can detect problems long before they end up in the casting…

…and introduce a system for continuous improvement

© NovaCast Foundry Solutions AB 23.© NovaCast Foundry Solutions 2010

First sample – Base iron DB


Optimal Base iron achieved!

Second sample – Base iron DB


Third sample – Uninoculated Final iron DB


Optimal Final iron with low Mg- additions!

Fourth sample – Inoculated Final iron DB


ATAS provides important control of the metallurgical process, helping foundries to better understand the metallurgical implications that are affecting the final product quality

Summary


With ATAS the foundry can control and adjust vital processing steps such as:

•Raw Material Selection•Chemical Composition•Preconditioning•Magnesium Treatment•Inoculation

Summary


Contains specific parameters for different stages in the process, from Base to Final iron

ATAS Alloy Database


Conclusion

Establish a cost effective Charge mixReduction of InoculationReduction of Rejection Rates


Conclusion

Improved MachinabilityConsistent quality, mechanical properties and microstructure


Conclusion

Provides EvaluationProvides StatisticsProvides Data Management


Process control by ATAS can be tailored to become a part of the everyday process at any foundry, prepared to be connected to demanding networks and complex server systems

Man + Machine + Method

Tailored solutions


•…measures the effect of all elements and compounds• …creates a system for continuous improvement • …ensures stability of the metallurgical process• …essential for Ductile Iron production• …can be profitable within 6 months• …is used by people

© novacast foundry solutions ab metallurgical process control systems

Documents

c risk

spectroif c

c rejection rate

low grf

f graphite shape

low eutectic temperature

f nucleation status

c si4 p2