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Metal Casting Technologies : September 2007
75 WHO'S WHO OF METALS -- ANNUAL 2006/7 The same principle can be implemented to other regions in the iron carbon phase diagram, provided the constants such as a1 and a2 and temperature T have to be changed. Let us consider the other curves and analyze their carbon content variation with pictures. Let us take the region of ferrite and austenite and implement the same method [Fig 5]. In this region carbon content variation constants are a1=0.00076 and a2=0.044, and their starting value is 0.008. These values can be directly substituted in the equation 1 and 2 to find the value of X1 and X2 corresponding to the input and hence the composition can be calculated applying lever rule. Here 0.018 is the carbon content and 810° C is the temperature given as input. Similarly the temperature change for this region is illustrated in Fig. 6. Taking this carbon and temperature as input the corresponding maximum temperature T1 and T2 is calculated using equation 3 and 4. When the input temperature lies within this range then it represents ferrite and austenite region. Apart from these regions, the carbon content variation constants a1 and a2 for other regions are tabulated in Table. 1. In Table 1, constant a2 =0 indicates that carbon content is a constant without variation, and this is due to the absence of right hand side curve in that region. In Fig. 7 a flowchart for the system process is shown to examine how far the expert system operates when the user gives the inputs. Region in the iron carbon phase diagram Carbon content variation constants a1 a2 Region separating austenite and mixture of austenite and cementite 0.0309 0 Region separating liquid and a mixture of liquid and cementite. 0.237 0 Region separating delta ferrite and a mixture of delta ferrite and austenite. 0.01 0.0189 Region separating delta ferrite and a mixture of liquid and delta ferrite. 0.018 0.106 Region separating ferrite and a mixture of austenite and ferrite. 0.00076 0 Table 1. Carbon content variation in various regions Figure 6. Maximum temperature for carbon content as input AVAILABLE NOW! 2032 MOULDING MACHINE ■ 775(w) x 600(h) x 250-600(d)mm Mold Size ■ PLC Retrofit with Open Program & Color Operator Interface ■ Core Setter Unit (right) ■ Machine Inspected, Cleaned, and Painted (exterior) ■ Manuals, Documentation, and Schematics ■ Over $300,000 in Spare Parts (including additional rebuilt main pump) ■ PMC-SBC Cooling Line Available ■ Operational for Inspection ■ Much, Much, More...... Contact for Details C.A. PICARD SURFACE ENGINEERING INC. 689 Sugar Lane, Elyria, Ohio 44035, USA Phone: +001-440-366-5400 Fax: +001-440-366-5404 Email: email@example.com