quiz5fall01

# quiz5fall01 - rL ENSC 3313 Fall 2001 Answer any 4 Questions...

This preview shows pages 1–2. Sign up to view the full content.

rL Name ENSC 3313, Fall 2001 QuizS Answer any 4 Questions only, 1 point each The starting material is a 10 rnrn diameter yellow brass (70 Cu -30 Zn) rod of hardness HRB (RB) ~. Required is an ~ diameter rod ofHRB 1Q. Describe an apRroRriate processing sequence. HRB = 70 signifies final processing stage of 20% cold work. Hence, we will need a' do ' given by 0.20 = ~ ~ ~ ~- ~ = d2 o do = 8.94 mm O.8d~ =64, The material is heavily cold worked initially, hence we must soften (anneal) the rod. Thence, hQ! work from 10 mrn diameter to 8.94 mrn diameter, thence cold work 20% 2!: anneal thence cold work to 8.94 mrn diameter, anneal thence cold work 20%. If a particular cold worked brass rod takes 60' to recrystallize at 450°C and 20' to recrystallize at 480°C, then how long should recrystallization take at 500°C? 2 Recrystallization is a diffusion-controlled process. Rate = ! = Ce-B/T t where B, C are constants -B( 1h-1h ) = Ce-B/723 Dividing, Substituting, 3=e 1 60 1 20 = Ce-B/7S3 B = 19,936

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 2

quiz5fall01 - rL ENSC 3313 Fall 2001 Answer any 4 Questions...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online