An Analysis of the Stress Relief Process of Drum Rotors

John Moran

Conduction Heat Transfer

MEAE6630H01

April 13, 2000

Process

• Rotors EB welded into drums

• Drums stress relieved in vacuum furnace

• Heat to 1100 F, hold for 2hrs

• Static cool

• Free convection cool

• Forced convection cool

Approach

• Collect TC data

• 2D MARC finite element model

• Assume a flux function based on known behavior of process and match to TC data

• Draw conclusions

X

Y Z

25

28

133

212

477

490

731

885

1092

1182

X

Y Z

Fixture

TC 19, 20

TC 13, 14

CLWeld Joint 1

Weld Joint 2

Weld Joint 3

Bore (4 plcs)Web (4 plcs)

Comparison of TC Data with Finite Element Solution

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450

Minutes

Control TC

Over Temp TC

TC13

TC14

TC19

TC20

node 25 TC 13,14

node 1182 TC 19,20

Reference Locations vs. Temperature

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450

Time (min.)

edge

weld joint 3

weld joint 2

weld joint 1

top bore

upper middle bore

lower middle bore

bottom bore

Temperature profile after heat up period

Temperature profile after soak period

Temperature profile after radiation cool down period

Temperature profile after free convection cool down period

Temperature profile after forced convection cool down period

Conclusions

• Analysis too crude for quantitative solution but adequate for qualitative solution

• % Power to bottom heaters should be increased to even out heating

• Inner bores have slowest response, TC locations do not reflect max T’s across the part

• Large T’s across inner disks may cause warping, detailed study is warranted