Question

explain answers

Temperature (C 800 [a] What microstructure would be developed by rapidly cooling to 600°C and holding for 50ts0A 5 seconds, followed by rapid cooling to 400'C s and holding for 50 seconds, followed by quenching to room temperature? o ftvg5m600 S07. tortie Euectoid temperature 700 A Z$7.Boinile L5-maikns: 500 400- What microstructure would be developed by rapidly cooling to 400 C and holding for 500 seconds, followed by quenching to room temperature, then heating to 700 C for several days? b) A 300 Mstarth 200 50% MS0% 90% 100- lo0/ Sehurndie S7c fero lay alkr aunti hras o sehuale 10 10 s 10 so Time (sh 10 10 Describe a thermal treatment that would generate a microstructure consisting of 50% bainite and 50 % martensite. Write your answer out here, not on the graph, honesen z to aus enie [cl S0% m Cool to yuoc (ugidy hold er so sec Yunuh at roo kanp Describe a thermal treatment that would generate a microstructure consisting of 100 % tempered martensite.. Write your answer out here, not on the graph. (d)

Answer 1

Aft eooling to and holding at 6oo'c tor 4, appuosimatily 50/ 600 the spuimun has trans formid to rapid temp 50o niarlite (midium). During thu thanformalion tooling To 4so C ho 10 lo A 450c a tart timing tin Ocurs again at 3ero tun lojec ,anniour whil holding at usb'c tor m atuly SOT remauning un readud soy. (or el orighal to bainitu And uhon ooung to room hranform min) toill timturature thu ununuu traufamatn original microstructure hau Jo 251 remauning thal to martinirte Hence paditi, s, bainili and r martnite holdung at ioo'c tor s00ec, Aft coobng to and a foroa lion e austenit to l0o1. martnsit tates thu T00%c several days esult tlace Lat, heating to too snhurodi formalioo the (C) The micro strueture b b martroit and 50. bainit, 50/ hold o 2b-30 JCand thin Cool rapidly to 4ooc

fim furature holdng tor about 20-30ce qunch to toom Ault in 5ol. tran tormation to bainit Unon loolhg to tn purature, amaning so. trauforn to martinsite Yoom Temp 400