Lab IV: Phase Transformations Sample Data

1. Lab IV: Phase Transformations Sample Data *All hardness values are from a previous quarter and should not be expected to match your data exactly, but your numbers should be in the same relative order (hardest to softest) for each material – example: for the Quenched 4340 sample, you shouldn’t expect to get exactly 43 HRC, but that sample should be the hardest of the rest of your 4340 samples

2. Brass 360 Quench Soft 58 HRB Quench and Anneal Soft 58 HRB Slow Cool Soft 58 HRB Slow Cool and Anneal Soft 58 HRB 70% Cu30% Zn 550° C Medium Grain size 30 % Zn All alpha phase Hardness may slighting increase with longer time at high temp. Small increase in grain size Note: With no heat treatment Brass 360 is hard [74 HRB]. Heat treatment brings as received samples through recrystalization and grain growth. Must mean that samples were received cold worked Medium Grains Callister sections 7.10-7.13

3. Quench Soft off-scale low Few, if any precipitates form. Supersaturated alloy solution Quench and Anneal Hardest 70 HRB Optimum large number and small size of precipitates Slow Cool Soft off-scale low Fewer number and larger precipitates - OVERAGED Slow Cool and Anneal Softoff-scale lowEven Fewer number and larger precipitates – even more OVERAGED Aluminum 2024 4.4% Cu1.5% Mg0.6% Mn 4.4% Cu Age at 260*C for 20 min Precipitates and lattice strainimpedes dislocation motion Callister p402

4. Steels Overview Hardness Scale Comparison Callister p159

5. Steel 4340 Quench Hardest 43HRC Martensite Quench and Anneal Hard 40 HRC Tempered Martensite Slow Cool Soft 94 HRB pearlite and proeutectoid ferrite Slow Cool and Anneal Soft 88 HRB tempered pearlite and proeutectoid ferrite 0.40% Cand Cr, Mo, Mn heat to 900*C Austentize 0.40% C Higher Carbon content in 4340 produces more lattice distortion in martentsite phase Quench produces martensite

6. Steel 1018 Quench Hardest 38 HRC Martensite Quench and Anneal Hard 32 HRC Tempered Martensite Slow Cool Soft 90 HRB pearlite and proeutectoid ferrite Slow Cool and Anneal Soft 74 HRB tempered pearlite and proeutectoid ferrite 0.18% Cand Mn 0.18% C Included in back of lab handout – use 1019 to approximate 1018 TTT behavior Quench produces martensite

8. Steel 4340 Isothermal transformation diagram Callister p333

9. Callister p343

10. Brass 360

11. Callister p341