Scientia Sinica

300 280 260 240 220 200 #180 160 140 120 100 80 60 40

0.004

(j-O) wonsuy yeurajuy

Fig. 7.

0.004

(j-O) wonsuy [eurs}U]

Fig. 8.

0.003

0.002 yo

0.003 0.002

0.001

\ ~

0.001

0 1.7 1.8 1.9

Internal friction in (martensi

5 | a i At I ,

a 1

Temperature (°C)

oat an,

x > Se eee ann eee ™.. == a, I

2. a a °

es) lesen a ap * CEE ©

2.0 Dil PP) 2.3 2.4 2.5 2.6 2G, 2.8 DO umanStO Buln 2 3.3 3.4 1000/T —> ;

ling-rod specimen, containing 0.25% C after dif

rent heat treatments, Curve I, quenched into 10°% brine from 930°C

structure); curve II, after tempering at 280°C; curve III, measurements with lowering temperature after the completion of curve

II; curve IV, measurements taken by raising the temperature after the completion of curve II; curve V, measurements taken by lowering the temperature after the completion of curve IV. Frequency of vibration; Curves I-II-III, 2 cycles per second; curves 1V-V, 0.46 cycle per second.

1.7 1.8 19

Internal friction in a

300 280 260 240 220 200 180 160 140 120 100 80 60. 40

Temperature (°C)

20 gt a2 23 24) as ale 27 28 °29 30 Bil 32 33° (3.4 1000/1 —

carbon steel specimen containing 0.25% C after different heat treatments. Curve I,quenched into 10°% brine from 930°C

(martensitic structure); curve II, after tempering at 280°C; curve III, measurements with lowering temperature after the completion of curve II.

No. 1 KE, MA: INTERNAL FRICTION ASSOCIATED WITH TEMPERING OF MARTENSITE 27