The document discusses types of stresses that occur in materials, including tension/compression stress, shear stress, and torsion stress. It also discusses residual stress, which remains in a structure after manufacturing processes that involve mechanical or thermal effects. Residual stress can cause distortion in components and premature failure. Common manufacturing techniques like shot peening and surface grinding induce compressive residual stresses that increase fatigue strength, while chrome plating induces tensile residual stresses that decrease fatigue strength.

1. SISTIM TEGANGAN & RESIDUAL STRESS
DEPARTEMEN METALURGI MATERIALS
FAKULTAS TEKNIK UNIVERSITAS INDONESIADr. Ir. Winarto, M.Sc.

2. Jenis Tegangan yang Umum
Secara umum jenis tegangan dibagi menjadi 3 bagian :
1. Tegangan tarik / tekan (tension / compression stress)
2. Tegangan geser (shear stress)
3. Tegangan puntir (torsion stress)
•Static
•Dynamic

3. Tension –Torsion -Compression

4. Shear vs. Cleavage

5. SEM Image of Ductile Fracture

8. Cleavage facets

9. Ductile vs. Brittle

10. Tension stress

11. Schematics of typical tensile test fractures

12. Tension

13. Compression

14. HasilUjiKuatTekanPasta Geopolimer

15. HasilUjiKuatTekanBetonGeopolimer

16. Buckling of Cold-Formed Steel Columns

18. Shear Stress Failure

19. Torsion

20. Torsion

21. TORSION FAILURE
Ductile Fracture
Brittle Fracture

22. Torsion Fracture

23. Perpatahan Pada Komponen Mesin
Drive Pinion
Axle Shaft

24. Stress –Strain Diagram

25. Diagram -for Steels

26. Diagram -for Cast Iron

27. Modulus vs. Temperature

28. Effect Surface on Fatigue

29. Stress Concentration on Plate(tension)

30. Stress Concentration on Rods(torsion)

31. Stress Concentration on Plate(compression)

32. Stress Concentration on Plate(bending)

33. Stress Concentration on Hollow Rod

34. Wear on Rollers

35. Shear on plates

36. Stress on Boiler

37. Fatigue on Rods

38. Fatigue on Plates

39. Initial Fracture vs Stress

40. Initial Fracture vs Stress

41. RESIDUAL STRESS
Residualstressadalahstressyangtinggaldidalamstruktursebagaihasildariperlakuanmekanisatauthermalataukeduanya.
Residualstressdapatmenyebabkan2efekutamayaitu:
-Distorsipadakomponen
-Menyebabkankerusakanprematurepadakomponen
Distorsiakibatpanastimbuldaerahyangterkontraksitidakseragammenyebabkanshrinkage(susut)dibagiantertentu.

42. Residual Stress

43. The Cause of Residual Stress

44. Fig. Effect of surface residual stress on the endurance limit of selected steel. All samples were water quenched except as shown, and all specimen dimensions are given in inches. Source: Ref 23, 24

45. Compression at the surface
Surface working: shot peening, surface rolling, lapping, and so on
Rod or wire drawing with shallow penetration(a)
Rolling with shallow penetration(a)
Swaging with shallow penetration(a)
Tube sinking of the inner surface
Coining around holes
Plastic bending of the stretched side
Grinding under gentle conditions
Hammer peening
Quenching without phase transformation
Direct-hardening steel (not through-hardened)
Case-hardening steel
Induction and flame hardening
Prestressing
Ion exchange
Tension at the surface
Rod or wire drawing with deep penetration
Rolling with deep penetration
Swaging with deep penetration
Tube sinking of the outer surface
Plastic bending of the shortened side
Grinding: normal practice and abusive conditions
Direct-hardening steel (through-hardened)(b)
Decarburization of steel surface
Weldment (last portion to reach room temperature)
Machining: turning, milling
Built-up surface of shaft
Electrical discharge machining
Flame cutting
Table. Summary of compressive and tensile residual stresses at the surface of the parts created by the common manufacturing processes (Source: Ref 22)
(a)Shallow penetration refers to 1% reduction in area or thickness; deep penetration refers to 1%.
(b)Depends on the efficiency of quenching medium.

46. Thermal Effect

47. Metal
Modulus of elasticity
Coefficient ofexpansion
Thermal conductivity
GPa
psi ×106
10-6/K
10-6/°F
W m-1k-1
Btu in./ft2· h · °F
Pure iron (ferrite)
206
30
12
7
80
555
Austenitic steel
200
29
18
10
15
100
Aluminum
71
10
23
13
201
1400
Copper
117
17
17
9
385
2670
Titanium
125
18
9
5
23
160
Table 5 Relevant physical properties in the development of thermal stresses (Ref 29).

48. Steel
Heat treatment
Residual stress (longitudinal)
MPa
ksi
832M13 (type)
Carburized at 970 °C (1780 °F) to 1 mm (0.04 in.) case with 0.8% surface C
Direct-quenched
280
40.5
Direct-quenched, -80 °C (-110 °F) subzero treatment
340
49.0
Direct-quenched, -90 °C (-130 °F) subzero treatment, tempered
200
29.0
805A20
Carburized and quenched
240-340(a)
35.0-49.0
805A20
Carburized to 1.1-1.5 mm (0.043-0.06 in.) case at 920 °C (1690 °F), direct oil quench, no temper
190-230
27.5-33.5
805A17
400
58
805A17
Carburized to 1.1-1.5 mm (0.043-0.06 in.) case at 920 °C (1690 °F), direct oil quench, tempered 150 °C (300 °F)
150-200
22-29
897M39
Nitrided to case depth of about 0.5 mm (0.02 in.)
400-600
58.0-87.0
905M39
800-1000
116.0-145.0
Cold-rolled steel
Induction hardened, untempered
1000
145.0
Induction hardened, tempered 200 °C (390 °F)
650
94.0
Induction hardened, tempered 300 °C (570 °F)
350
51
Induction hardened, tempered 400 °C (750 °F)
170
24.5
(a)
Immediately subsurface, that is, 0.05 mm (0.002 in.).
Source: Ref 29
Table 6 A compiled summary of the maximum residual stresses in surface heat-treated steels

49. Fig. 10(a) The transverse shrinkage occurring in butt weldments. (b) Longitudinal residual stress patterns in the weldment and surrounding regions. This also shows longitudinal shrinkage in a butt weld. Source: Ref 47

50. Shoot Peenning

51. Schematic of Residual Stress

52. Home Work
1.Jelaskan jenis-jenis Tegangan yang terjadi pada material
2.Jelaskan dengan gambar distribusi tegangan pada pelat (plates) dan batangan (rods) akibat tegangan tarik bila stress konsentrasinya (a) tidak ada, (b) dipermukaan, (c) di bagian tengah
3.Gambarkan terjadinya residual stressdan efek-nya pada material.
4.Jelaskan penyebab dari tegangan sisa (residual stress)
5.Jelaskan mengapa shoot peeningdan penghalusan permukaan menyebabkan kekuatan fatiknya menjadi tinggi sedangkan chrom-plating menyebabkan kekuatan fatik turun. Uraikan dengan gambar skematis