Metal Casting Technologies : MCT DEC 2017 (4TH QRT)
30 www.metals.rala.com.au METAL Casting Technologies 4th Quarter 2017 31 ASIA PACIFIC CASTING TECHNOLOGIES A–D D–J I–Z altair.com altair.com amelt.com amelt.com beckwithmacbro.com.au beckwithmacbro.com.au castingchina-gz.com castingchina-gz.com coolfog.com.au coolfog.com.au imf.it imf.it finitesolutions.com finitesolutions.com magmasoft.com.sg magmasoft.com.sg foundry-eqpt.com foundry-eqpt.com objective3d.com.au objective3d.com.au glucinaalloys.co.nz glucinaalloys.co.nz spectrosource.com.au spectrosource.com.au hitachi-hightech.com/hha hitachi-hightech.com/hha thermofisher.com/oes thermofisher.com/oes julang.com.cn julang.com.cn ajaxtocco.com ajaxtocco.com ask-chemicals.com ask-chemicals.com bruker-elemental.com bruker-elemental.com castingtechnologynz.org castingtechnologynz.org dickinsons.com.au dickinsons.com.au didion.com didion.com inductotherm.com.au inductotherm.com.au foseco.com foseco.com metalsonline.rala.com.au metalsonline.rala.com.au generalkinematics.com generalkinematics.com spectro.com/lab spectro.com/lab hayesmetals.co.nz hayesmetals.co.nz synchroerp.com synchroerp.com huettenes-albertus.com huettenes-albertus.com wesomega.com.au wesomega.com.au WEB SHOWCASE Company Directory/Suppliers WEB SHOWCASE | COMPANY DIRECTORY/SUPPLIERS BacktoBASICS values and converting minutes to seconds the formula can be further simplified to: P = 3,007.2/time in seconds Most permeability metres are equipped with measuring devices for direct reading of permeability number so that calculations are unnecessary. Determination of strength of moulding sand Sand specimens may be subjected to forces under controlled conditions so that measures of various strengths can be made. 1. Compression strength is measured when the specimen is caused to break under a compressive load. 2. Shear strength is measured when the specimen is caused to break under a shearing load. 3. Tensile strength is measured when the specimen is caused to break under tension forces. 4. Transverse strength is measured when the specimen is caused to break under a bending load. Compressive and Shear strengths are most often used for testing of green sands using a standard 2-inch diameter by 2-inch high, three ram sample. See Figure 8. It is important in these and other green sand tests that the test be performed immediately after the specimen is stripped from the tube. 1. Compression strength, usually simply referred to as green strength, is obtained by applying a uniformly increasing load to the specimen until fracture takes place. 2. Shear strength is obtained in much the same way as compressive strength; however, the specimen holding devise is changed so that the load is applied on the upper half of the specimen at one end and on the lower half at the other end. The specimen then ruptures in shear along its longitudinal axis when sufficiently loaded. Tensile and transverse strength are measured on specially prepared specimens of cured or dried core sand mixtures. 1. Tensile strength is measured using a cured “dog-bone” specimen and appropriate attachments on the strength machine. 2. Transverse strength is measured using a cured specimen, typically 25mm by 200mm loaded with appropriate attachments so that the force is at the centre of the span. Mould hardness The hardness of compacted green sand can be measured using a mould hardness tester, which incorporates a spring-loaded ball. See Figure 9. 1. The range of scale is from zero to 100. If no penetration occurs, the hardness is 100, whilst if the ball sinks completely in the sand the reading is taken as zero. 2. Typical mould hardnesses obtained from different green sand moulding machines vary from approximately 80to95.n REFERENCES 1) Principles of Metal Casting – Heine, Loper & Rosenthal – McGraw-Hill Book Company 1967 2) Introduction to Foundry Technology – Ekey & Winter – McGraw-Hill Book Company 1958 FIGURE 8. Sand strength tester. FIGURE 9. Green-hardness tester.
MCT MAR 2018 (1ST QRT)