DNV A thiab DNV B yog cov qauv siv lub zog shipbuilding steel daim hlau ntawv pov thawj los ntawm Det Norske Veritas (DNV). Raws li cov qib hauv paus hauv DNV cov txheej txheem kev faib tawm, lawv tau siv dav rau cov khoom siv dav dav hauv nkoj hulls thiab marine daim ntaub ntawv uas tsis tshua muaj siab - qhov kub thiab txias tsis yog qhov yuav tsum tau ua. Ob qib muaj qhov tsawg kawg nkaus tawm lub zog ntawm 235 MPa, nrog rau lawv cov kev sib txawv tseem ceeb tau txiav txim siab los ntawm lawv qhov sib txawv ntawm qhov sib txawv toughness specifications.
Qhov txawv tseem ceeb
Qhov sib txawv tseem ceeb yog nyob rau hauv qhov yuav tsum tau ua Charpy V- qhov ntsuas qhov cuam tshuam rau qhov yuav tsum tau ua thiab yog li lawv tsim nyog rau thaj chaw sib txawv. DNV Qib A steel tsis muaj qhov ntsuas qhov yuav tsum tau ua. Nws yog npaj rau siv nyob rau hauv tsis yog - tseem ceeb, theem nrab cov qauv uas qhov kev pheej hmoo ntawm brittle fracture yog suav tias yog tsawg nyob rau hauv ib txwm kev pab cuam. Hauv qhov sib piv, DNV Qib B steel yuav tsum tau ua kom tau raws li qhov kev cuam tshuam lub zog muaj nuj nqis thaum kuaj hauv chav sov (feem ntau yog +20℃). Qhov no tau lees paub qhov tawv tawv ua rau Qib B txhim khu kev qha ntau dua rau cov qauv hull thiab lwm yam tseem ceeb uas yuav raug rau cov khoom hnyav lossis kev ntxhov siab.
Tshuaj muaj pes tsawg leeg
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DNV Ib qho General Strength Chemical Composition |
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Qib |
Cov ntsiab lus Max (%) |
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C |
Si |
Mn |
P |
S |
Al |
N |
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DNV A |
0.21 |
0.05 |
2.5 x C |
0.035 |
0.035 |
- |
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Nb |
V |
Ti |
Cu |
Cr |
Ni |
Mo |
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DNV B General Strength Chemical Composition |
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Qib |
Cov ntsiab lus Max (%) |
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C |
Si |
Mn |
P |
S |
Al |
N |
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DNV B |
0.21 |
0.35 |
0.80 |
0.035 |
0.035 |
- |
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Nb |
V |
Ti |
Cu |
Cr |
Ni |
Mo |
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Mechanical Property
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DNV Cov khoom muaj zog dav dav |
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Qib |
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Mechanical Property |
Charpy V Impact Test |
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Thickness |
Yield |
Tensile |
Elongation |
Qib |
Zog 1 |
Zog 2 |
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DNV A |
mm |
Min Mpa |
Mpa |
Tsawg% |
+20 |
J |
J |
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t Tsawg dua lossis sib npaug li 50 |
235 |
400-520 |
22% |
- |
- |
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50＜t Tsawg dua lossis sib npaug rau 70 |
235 |
400-520 |
22% |
24 |
34 |
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70＜t Tsawg dua lossis sib npaug rau 150 |
235 |
400-520 |
22% |
27 |
41 |
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Lus Cim: Lub Zog 1 yog qhov kev ntsuas cuam tshuam, Lub Zog 2 yog qhov ntev |
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DNV B general zog khoom |
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Qib |
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Mechanical Property |
Charpy V Impact Test |
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Thickness |
Yield |
Tensile |
Elongation |
Qib |
Zog 1 |
Zog 2 |
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DNV B |
mm |
Min Mpa |
Mpa |
Tsawg% |
0 |
J |
J |
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t Tsawg dua lossis sib npaug li 50 |
235 |
400-520 |
22% |
20 |
27 |
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50＜t Tsawg dua lossis sib npaug rau 70 |
235 |
400-520 |
22% |
24 |
34 |
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70＜t Tsawg dua lossis sib npaug rau 150 |
235 |
400-520 |
22% |
27 |
41 |
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Lus Cim: Lub Zog 1 yog qhov kev ntsuas cuam tshuam, Lub Zog 2 yog qhov ntev |
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