1. 2015. 04. 08 ( ) 2015. 04. 09 ( ) 2015 2. , 3. 3 4. 4 5. 2. ( ) 1. 3. SQ CQI-9 6. 1 1 7. (1) / < , 1000N/m2 > , 500N/m2 2 1000N/m2 1 . 2 1 . 2 1 . , . 1.1 8. (2) / 1.1 9. (3) / 1.1 10. (4) / 1.1 AL Mg IN-OUT THRO - 11. ? (stress) = (force) / (unit area) / / ( ) : : (yielding) : : ( ) . / 1.1 12. / 1.1 13. tensile strength : yield strength: / 1.1 14. / / - - - - - , . - (quenching) - (tempering) - (annealing) - (normalizing) . - , , - , 1.1 15. 1 1 16. 1.2 - Fe-C 17. : , (phae), , . . . (transformation) (allotropic transformation) . (transformation point) . 0.01% A2, A3, A4 ( ; transformation point) , A2 , A2 ~ A3 , A3 ~ A4 , A4 . A2 ( ) , . 1.2 - 18. 3 4 . Fe 910 1400 . Fe 910 1400 . 0k . Fe -Fe, -Fe, -Fe . A0, A1, A2, A3 A4 5 . A3 ( ) ---- ( ) at 910 , . A1, A4 . . A3 Ac3, Ar3 . : c : chauffage ( ), r : refroidissement ( ) . A2 , A0 . ( , magnetic transformation) . 1.2 - 19. 1 2 < > ferrite: 0.025% . . . austenite: A3 ~ A4 , cementite , austenite( ) . pearlite: 0.85% 723 ferrite cementite ferrite cementite layer . (eutectoid steel) : pearlite( ) 0.8%C . (hypoeutectoid) : 0.8%C . (hypereeutectoid steel) : 0.8%C , . cementite: 8.68% , Fe3C. C > M > T > S > P > A > F 1.2 - 20. 1 2 < > 1.2 - ferrite austenite pearlite 21. 1 2 < > 1.2 - cementite 22. 1 2 (martensite) BCT . Fe-C . , Fe-C . , . (nartensite transformation) . (Ms) (martensite start temperature) Fe-C . . (Mt) (martensite finish temperature) Fe-C . . 1.2 - 23. (Isothermal Transformation Diagrams) - . - IT : Isothermal Transformation -TTT : Time-Temperature-Transformation . ( - - ) . nose (pearlite) , Nose Nose + + : : B : B : 1.2 - 24. - 2 C , , . - nose . nose = 550 1.2 - 25. 1.2 TTT 26. 1.2 TTT 27. 1. Nose nose . 3. , . , . 2. Nose nose . 4. Ms 200 Ms . 5. , , , 750 2 . 1.2 - 28. (continuous cooling Transformation Diagrams) - . , (continuous cooling Transformation Diagrams) CCT .. 1.2 - CCT 29. < 0.2%C CCT diagram > 1.2 - CCT 30. < > 1.2 - 31. H R C 20 70 1.2 32. 1.2 + Fe3C Coarse pearlite Fine pearlite 33. 1.2 + Fe3C Bainite : cementite in the form of needle type 34. 1.2 martensite martensite : a super saturated solid solution of carbon in iron formed by shear transformation (diffusionless transformation) very hard and brittle phase 35. Critical cooling rate 3 1) Grain size 2) carbon content 3) alloying elements 1.2 - 36. 1.2 - 37. 1.2 38. 1.2 39. 1.3 . . BCC C , BCT . , (0.35) . . , . . 40. 1.3 1) ( ) . . ( ,supersaturated solid solution) , Cu . 2) Cu . , age - hardening . 41. 2 ( )2 ( ) 42. 2-1 _ 2.1 43. < > - - - 1) (0.02%C) 2) , (2.5~4.5%C) 3) (0.02~2.0%C) < > - - - 1) ( ) 2) ( , , ) < > 1) ( , , ) 2) ( , , , ) 3) ( , , ) < > 1) 2) 3) 4) 1. : , , , 2. : , 3. : , , TMCP 4. : , 5. : , 2.1 44. (1) (2) 3 . a) . Steel b) . c) . a) , S (Steel: ) F (Ferro: ) . b) , , , , . P : Plate( ), U : Use( ), W : Wire( . ), T : Tube( ), C : Casting( ), K : Gonggu( ), F : Forging( ) Ex) SAPH A : Automobile P : Press H : Hot SPCC P : Plate C : Cold C : commercial . Ex : 1) , SNC . 2.1 45. c) , ( 3 ) . , . 1 : 1 , A : A A , 430 : 4. 30 2A : 2 A , 400 : : . : 1) SM570Q . 2) STB340-S-H , , 340 N/mm2 (1) (2) 2.1 46. (a) (b) (c) (1) (2) (3) 2.1 47. KS a.SM30C : (0.25~0.35% C) / S45C b.SS41(SS400) : ( 41Kgf/mm2 , 400MPa) c.SC49(SC480) : ( 49Kgf/mm2 , 480MPa) / SC d.SF360 : ( 360MPa) / SF e.SWS500 : ( 500MPa) / SM f.STC1 : (1 ) / SK g.STS1 : ( ), STD : ( ) / SKD h.SKH2 : / SKH 1) - SS (Steel Structual, ) SWS (Steel Welding Structure, ) SMA (Steel Maring Atmosphere, ) SV (Steel Rivet, ) SBB (Steel, B- , Boiler, ) 2) : SMxxC (Steel Machine Carbon, ) ex. SM45C 2.1 48. : SCr (Steel Chromium, ), SCM (Steel Chromium Molybdenum, ,) SNC (Steel Nickel Chromium, ), SNCM (Steel Nickel Chromium Molybdenum, ) SMnC (Steel Manganese Chromium, ), SACM (Steel Aluminium Chromium Molybdenum, ) SGV (Steel General Vessel, ) SBV (Steel Boiler Vessel, ) SQV (Steel Quenching Vessel ) 2.1 49. KS : STC (Steel Tool Carbon, ), SKC (Steel K- Chisel, ) STS (Steel Tool Special, ) STD (Steel Tool Die, ) STF (Steel Tool Forging, ) SKH (Steel K- High Speed, ) : STS (Stainless Steel, ) STB (Steel Stainless Bearing, ) SPS (Spring Steel, ) STR (Stainless Steel for Heat Resisting Steel, ) SUM (Stainless Use Machinability, ) 2.1 50. STS 430 : 3 . - : 3 2xx (Cr-Ni-Mn ) 3xx (Cr-Ni ) Austenite 4xx (Cr ) Ferrite 4xx (Cr ) Martensite 5xx (5% Cr ) 6xx(PH ) - : . . (SUS 304 / SUS 321) ASTM 304 SUS 304 ? 1) ASTM 304 Si 0.75wt% 2) JIS 304(KS 304) Si 1.0wt% . ** ASTM (American Society for Testing & Materials) : (JIS, Japanese Industrial Standards) : 2.1 51. 2.1 52. 2. 1 (DIN) 53. DIN (Deutsche Industries Normen) 54. ( ) 2.2 55. 2.2 ( ) ( ) 56. (SCr420HB) 2.2 (GEN II) 57. (SCM820PRH) 2.2 (GEN III) 58. (SCR422PRH) 2.2 (GEN III) 59. I -2 0.001 ~ 0.008% . . . 2.2 - 60. 2.2 - 61. and . 2.2 - 62. 1 50B12 / 10B21 . _ 100kgf/mm2 - SCM435 ~ 2.2 - 63. 2.2 - , , V, Nb, Ti ( , ) ( , ) Ferrite . 64. 2.2 - 65. 2.2 - 66. 2.2 - 67. App , QR Code Scan (* ) 1) App (Play , QREAL ) 2) QR Code Scan < MTC ( Page ) Display > Android V 1.1.4 IOS V 1.0 QR Scan -1 -2 Mobile 68. 3 3 F/Proof 69. - - - . - . - . Normalizing 3.1 70. ? 1 or 2 (SCM920HVSI, SCM920PRH ) ISO 3.1 71. . . . Normalizing Process detail 1. : 900 ~ 930 ( ) 2. : 2 Hr 3. : 4. : ** Ferritic austenitic . ferritic 1. . 2. HB 100~250 3.1 72. (without ) 73. - - - 920 - : 2Hr (with ) 74. SRA . . Stress Relief Annealing Process detail 1. : 550 ~ 650 ( ) 2. : 1 ~ 2 Hr 3. : 4. : ** : 150 ~ 275 : 250 ~ 500 1. : SRA . 2. : 3. . ( , ) - SRA 600C . ** 3.1 75. . crack. - ? ? Crack 1. , . 2. ? 3. ? 3.1 76. 1. 2. 3. 4. ) 6% Cr 0.77%C 0.5% . Ms . 77. . 3.1 Process detail . RX RX . ( ), ( ) . (H2O) CO2 , O2 RX / . 78. RX ( ) ( Cost) 1. . 2. . - ( 2 ) - 1050 / 1. (20% ?) 2. . 3. . . 1. QT (95% ) 2. (70%) 3. ( ?) 1. QT (5% ) 2. (30% ?) 3. ( ) 4. (70 % ) 79. No 1 1. . 2. . 2 RX GAS (LPG) 1. . 2. , . 3 RX GAS (LNG) 1. 2 . 2. . 100 % 70 % 60 % 80. SQ SQ , 3.2 81. . ( , etc..,) 3.2 82. . . SPC 3.3 83. 3.3 84. F/PROOF . , 3.4 F/Proof - 85. ( ) maintance Maintance 3.4 F/Proof - 86. 3.5 another ERP . 1 . 3000EA 1500EA 1 ? 87. 88. 3.5 1 ~ 8 . .. & 89. 3.5 CP CP : 0.18 CP : 0.60 CP : 0.38 CP 90. 1 (Foil Test) 0.1wt%C, 0,1t 2 Coil Test 0.77wt%C, 0,1 coil 3 Shim Stock Test