 In order to apply to the thermal power plant & incineration facilities throughout the local and overseas, The POSCO newly developed the sulfate & corrosion-resistant steel(So-called ANCOR).The ANCOR shows an excellent characteristic in terms of corrosion-resistant in sulfate solution when compared with an existing STS type material. Moreover it solves the corrosion problem which may arise from desulfurization facilities in the thermal power plant. The localization of welding consumables was demanded according to the development of ANCOR steel. |
| Advanced environmentally-friendly steel
with sulphuric acid Corrosion Resistance
steel
The new material from POSCO, the specification of their own which has an excellence in high concentration of sulphuric acid dew-point corrosion Sulphuric acid & corrosion resistance
: 10 times more compared to STS steels,
1.5 times compared to weather proof
steels Currently applied to 3rd & 4th of Youngheung thermal power plant in domestic |
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Amount of corrosion according to sulphuric acid concentration and temperature |
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| Corrosion characteristics of sulphuric acid resistant : General steel < STS < Weather proof steel < Sulphuric acid & corrosion resistant steel
Sulphuric acid corrosion resistant : To strengthen its characteristics, Cu & Co are added.
The steel added with Cu : Cu shows 3 times higher of its sulphuric acid resistant characteristics when compared to the steel without Cu.
Cu-Co : Co is mixed together with Cu, which exceptionally improves the characteristics of sulphuric acid & corrosion resistance |
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| The speed of corrosion according to the temperature and sulphuric acid concentration |
| ASTM G31-72 : Standard Practice for Laboratory Immersion Corrosion Testing of Metals To maintain 50% of sulphuric acid solution at 70? for 3-6 hours To measure the amount of corrosion after depositing the testing sample
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Equipment for testing the corrosion |
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Category
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Standard (The required mechanical properties)
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A condition for evaluation
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The assurance for high-temperature steel
(Type A) |
The assurance for sulphuric acid corrosion resistance
(Type B) |
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Mechanical properties (butt) |
Sulphuric acid & corrosion resistance
|
After corrosion, WM thickness
 Thickness of base metal |
70?, 50% To deposit sulphuric acid solution for 6 hrs
|
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T.S in high temp. (Mpa)
|
400
( ruptured base metal )
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- |
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T.S in normal temp
(Mpa) |
550
( ruptured base metal )
|
420
( ruptured base metal )
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Temp
: 25? |
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Impact value
(J,FCAW) |
60 |
60 |
WM, FL, FL+1 (0?) |
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Actual welding: 2 sets (Total welding line 600mm)
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FCAW |
|
SC-71ACR |
 |
WM |
FL |
FL+1 |
FL+3 |
??
|
|
SC- 71ACR |
 |
 |
 |
 |
 |
| Test standard: ASTM G31 (Laboratory Immersion Corrosion Testing of Metals) Test condition: Immersion in 50%, 70oC liquid acid during 6hours
Shape of test material |
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weld zone corrosion test metal Surface/Lateral |
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SC- 71ACR |
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Test material |
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SC-71ACR |
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Base metal
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Test standard : JIS Z3121 (Methods of tensile test for butt welded joints) Test material (Average 2EA): 1A/1 T.S (Mpa) / El. %, Breakage position
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SC-71ACR |
440 / 30.4%, breakage of base metal
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T.S (Mpa) / El. %, Breakage position
|
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FCAW
|
A |
407.9 / 32.8%,
Breakage of base metal |
B |
416.6 / 37.8%,
Breakage of base metal
|
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C |
412.2 / 33.6%,
Breakage of base metal
|
|
Solid
|
D |
423.9 / 34.7%,
Breakage of base metal
|
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Test standard: JIS Z3128 (Methods of impact test for welded joint) Test material (Average 3ea) / Test temperature: sub-size Charpy test material (5mmt) / 0oC|
Classification
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Monoacid |
SC-71ACR
|
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A
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B
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WM |
40.01 |
49.86 |
69.05 |
WM |
27.36 |
50.69 |
60.4 |
WM |
38.4 |
46.13 |
69.05 |
FL |
81.9 |
60.4 |
90.95 |
FL |
87.76 |
78.32 |
89.58 |
FL |
56.15 |
71.68 |
89.12 |
FL+1 |
87.31 |
87.76 |
81.9 |
FL+1 |
91.41 |
87.76 |
83.69 |
FL+1 |
86.86 |
91.86 |
86.41 |
