ATAS Metallurgical Process Control VI Foundry Conclave, Coimbatore 2013-03-02

Metallurgical Process control systems

Basic needs of a foundry Improved customer confidence Low environmental impact Improved financial results Competitive edge High Yield Low direct costs Process stability (Reliability)

The purpose of process control World Class Automate Simplify Control Chaos

Do I have all data needed to control my process? Day 1 C = 3,4 % Si = 2,1 % , 1380°C Rejection rate = 2,0 %. All measured data OK! Day 2 Rejection rate = 12,0 % ?

The purpose of process control You get what you measure If it´s not measured it cannot be improved

Chemical & Thermal Analysis 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. It is the effect that is important to know for process control!

Disadvantages of only using the spectrometer You will not receive any information about …. created compounds oxides, silicates, sulphides etc chemical reactions nucleation or precipitation of graphite the dynamics of solidification

The metallurgical “Fingerprint”

Controlling the process with 6 Basic parameters Liquidus Recalescence Solidus Graphite factor 2 Graphite factor 1 Low eutectic

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

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

Thermal parameters TELow TElow, 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. TElow TElow > 1135°C Primary Carbides FREE TElow ≤ 1135°C PRESENT

Recalescence - R R = f ( Nucleation rate + Eutectic growth )

GRF 1 = f ( under cooling, precipitation speed, amount of graphite) Graphite factor 1 – GRF1 GRF 1 = f ( under cooling, precipitation speed, amount of graphite)

Thermal parameters GRF1 GRF 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 75 < GRF1 < 120 Porosity FREE GRF1 ≤ 75 Porosity GRF1 > 120 Chunky

GRF 2 = f ( Graphite shape & amount ) Graphite factor 2 - GRF2 GRF 2 = f ( Graphite shape & amount )

Thermal parameters GRF2 GRF2 > 55 35 ≤ GRF2 ≤ 55 GRF2 < 35 MICROSRHINKAGE PRESENT 35 ≤ GRF2 ≤ 55 MICROSHRINKAGE FREE GRF2 < 35 DEGENERATED GRAPHITE Thermal parameters

Solidus - TS TS = f ( Segregation, Mg )

Controlling shrinkages T,°C Dendrites Eutecticum S1 S2 S3 t,s Outher sunks Macro Shrinkage Micro shrinkage / Porosity

ATAS can detect problems long before they end up in the casting… Stop Correct Improve …and introduce a system for continuous improvement

First sample – Base iron DB © NovaCast Foundry Solutions 2010

Second sample – Base iron DB Optimal Base iron achieved! © NovaCast Foundry Solutions 2010

Third sample – Uninoculated Final iron DB © NovaCast Foundry Solutions 2010

Fourth sample – Inoculated Final iron DB Optimal Final iron with low Mg- additions! © NovaCast Foundry Solutions 2010

Summary ATAS provides important control of the metallurgical process, helping foundries to better understand the metallurgical implications that are affecting the final product quality © NovaCast Foundry Solutions 2010

Raw Material Selection Chemical Composition Preconditioning Summary With ATAS the foundry can control and adjust vital processing steps such as: Raw Material Selection Chemical Composition Preconditioning Magnesium Treatment Inoculation © NovaCast Foundry Solutions 2010

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

Conclusion Establish a cost effective Charge mix Reduction of Inoculation Reduction of Rejection Rates

Conclusion Improved Machinability Consistent quality, mechanical properties and microstructure

Conclusion Provides Evaluation Provides Statistics Provides Data Management

Tailored solutions 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

…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

ATAS Metallurgical Process Control VI Foundry Conclave, Coimbatore 2013-03-02 THANK YOU