ME 111L Lab Unit 3 - Intro (group)

ME 111L Lab Unit 3 - Intro (group) - phase) above the...

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3.) Introduce TTT diagram for isothermal transformation of 4140 steel and state what’s transforming and what the products are. We are isothermally transforming six 4140 tensile specimens and six Charpy V-notch specimens that were all initially austenitized in the furnace at 850 0 C. One tensile specimen and one impact specimen is isothermally transformed at 700 0 C for 2 hours, 660 0 C for 1 hour, 620 0 C for 1.5 hours, 460 0 C for 1 hour, and 360 0 C for 1 hour. The final tensile and impact specimens from the 850 0 C furnace are quenched in oil. During austenitizing of the 12 specimen, the steels were completely transformed to austenite (the
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Unformatted text preview: phase) above the eutectic temperature. Austenite can decompose into pearlite + proeutectoid phase, bainite, or martensite. The 700 C isothermally transformed steel specimens were transformed into coarse pearlite upon rapid cooling. The 660 C specimens transformed into medium pearlite. The 620 C transformed into fine pearlite. The 460 C transformed into upper bainite. The 360 C transformed into lower bainite. And the oil quenched specimens transformed into martensite. References Azom Materials, 2000 <http://www.azom.com/work/pAkmxBcSVBfns037Q0LN_files/image004.gif>...
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This note was uploaded on 02/14/2010 for the course ME 111L taught by Professor Ciulik during the Spring '10 term at University of Texas at Austin.

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