1.1

(Heat treatment) . , () . :a-

b- .

c- .1.2

1.2.1

. (1)

a- , (1-b) , . . 150 1250 b- () () . . . (2) .

1.2.2

a-

.

. , . 250 1600 . 600 3000 . (3)

b-

, (4-a), , (4-b), (4-c). () (1371 - 37.8 ) . .

1.2.3

, , , , .

a-

() . .

b-

, . .c -

.

d-

, .

1.3

, . (1) , . (1)

(steel colours at various temperature with their related processes)

1.4 () (% 0.35) , . , . (5) .1.4.1

((Carbon Content

((Hardening Temperature Range

% 0.80 0.65% 0.95 0.80% 1.1 0.95 % 1.1

(1550 1450) F C (843 - 788)

(1460 1410) F C (739 - 766)

(1450 1400) F C (788 - 760)

(1430 1380) F C (777 - 749)

(2) . 27.8 55.6 .1.4.2

:

a- C (871 - 715) .b- c- . . , . .1.5 . , ( ) .:

:

a- .b- (3) .c- . (3)

FC

Scribers

Center punches

Cold chisels

Screwdrivers

450 430

470

510 480

530230 220

243

265 255

270

1.6 () (annealing) .1.6.1 :

a- .

b- .

c- .1.6.2

:a- (56 - 28) (A3) , (6).

b- . , (25 mm) .c- (28) C (A 1).

d- .

1.6.3 . (A1) . , .1.7 (normalizing) , .:

:

a- (56)C ( A3), .(8)

b- .c- .1.8

. .:

a- , (A1) , (9)

b- .

c- .

1.9 (Case hardening) , () , (10)

a- , (915 - 745) (5.11). . ( 4 6 ) . . .

b-

, . , .c-

. . . .1.10 . .a - . (12)

b-

() . (), (13) . .

1.11 a-

1- () : . 420 300 , ( ) . O2- : 450 540 , . , 4 5 (TB)b- 600 . .c- () .

colours

A3 : Upper critical temperature

A1: Lower critical temperature

(8) (Normalising)

A3 : Upper critical temperature

A1: Lower critical temperature

(7) (Annealing)

A3 : Upper critical temperature

A1: Lower critical temperature

(9) (thermal stress relieving)

(1) ((Heating furnaces

UNION ENGINEERING GROUP

Egyptian Welding Academy

TECHNICAL CENTER

(2)

(3) (optical pyrometer)

a- b- c-

(4) Temperature indicating products))

Celsius / Fahrenheit

Processes

1370 2500

1315 2400

1259 2300

648 1200

1204 2200

1036 1900

1149 2100

1093 2000

981 1800

926 1700

871 1600

760 1400

815 1500

538 1000

704 1300

593 1100

426 800

371 700

315 600

260 500

204 400

93 200

149 300

482 900

38 100

18 0

High speed steel hardening

11931343c

(2150 - 2450 F)

Welding

Alloy tool steel hardening

815 - 1065 C

(1500 - 1950 F)

Carbon Tool Steel Hardening

732 - 843 C

(1350 - 1550 F)

High Speed steel Tempering

815 - 1065 C

(1500 - 1950 F)

Carbon Tool steel Tempering

149 - 565 C

(300 - 1050 F)

Heat Colours

Temper

Colours

White

Yellow White

Yellow

Orange Red

Light Cherry Red

Cherry Red

Dark Red

Very Dark Red

Black Red

In dull light or Darkness

Pale Blue 310 C ( 590 F)

Violet 285 C ( 545 F)

Purple 274 C ( 525 F)

Yellowish Brown 310 C ( 590 F)

Dark Straw 241 C ( 465 F)

Light Straw 218 C ( 425 F)

(5) (Iron Carbon Diagram)

1- (Hardened outer case or shell)

2- (Interior remains relatively soft and tough)

(10) (Case hardening)

(11) (Part packed in container of carbonaceous material)

(12)

1 - (Induced eddy current)

2- (Magnetic Field)

3- (Heat produced by eddy current)

(13)

(Heating surface of steel shaft with high frequency induction coil