ASTM A302 Grades C and D are manganese-molybdenum (Mn-Mo) alloy steels for boilers and pressure vessels, differing mainly in their nickel content and heat treatment requirements, with Grade D typically having higher nickel for improved properties, both offering excellent strength for high-temperature applications, though Grade C (Mn-Mo-Ni) is often specifically alloyed with nickel for better notch toughness. Both grades aim for similar strength levels (tensile 550-690 MPa, yield >345 MPa) men gen konpozisyon chimik diferan ak espesifikasyon aplikasyon, espesyalman konsènan nikèl ak tretman chalè.
Konpozisyon chimik ASTM A302 Klas C
ASTMA302 Klas CKonpozisyon chimik | |||||||
Klas | Eleman Max (%) | ||||||
C | Si | Mn | P | S | Al | N | |
A302 Klas C | 0.20-0.25 | 0.13–0.45 | 1.07-1.62 | 0,035 | 0,035 |
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Nb | V | Ti | Cu | Kr | Ni | Mo | |
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| 0.37-0.73 | 0.41–0.64 | |
Konpozisyon chimik ASTM A302 Klas D
ASTMA302 Klas DKonpozisyon chimik | |||||||
Klas | Eleman Max (%) | ||||||
C | Si | Mn | P | S | Al | N | |
A302 Klas D | 0.20-0.25 | 0.13–0.45 | 1.07-1.62 | 0,035 | 0.035 |
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Nb | V | Ti | Cu | Kr | Ni | Mo | |
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| 0.67-1.03 | 0.41–0.64 | |
Pwopriyete mekanik ASTM A302 Klas C
Klas |
| ASTM A302 Klas CPwopriyete mekanik | ||
Epesè | Sede | Tensile | Elongasyon | |
A302 Klas C | mm | Min Mpa | Mpa | % min |
6-50 | 345 | 550-690 | 20% | |
50-200 | 345 | 550-690 | 17% | |
Pwopriyete mekanik ASTM A302 Klas D
Klas |
| ASTM A302 Klas DPwopriyete mekanik | ||
Epesè | Sede | Tensile | Elongasyon | |
A302 Klas D | mm | Min Mpa | Mpa | % min |
6-50 | 345 | 550-690 | 20% | |
50-200 | 345 | 550-690 | 17% | |
Diferans kle ak resanblans
Konpozisyon: Tou de se Mn-Mo asye, men Klas C souvan enkòpore Nikèl (Mn-Mo{-Ni), pandan ke Klas D gen ladan tou Nikèl, jeneralman ak pi gwo konsantrasyon pou severite amelyore.
Pwopriyete mekanik: Yo pataje menm jan fòs, ak fòs rupture nan 550-690 MPa ak fòs sede minimòm alantou 345 MPa.
Aplikasyon: Yo itilize nan aplikasyon kritik tankou chodyè soude, tank depo, ak echanjeur chalè nan pwojè lwil oliv ak gaz.
Tretman Chalè: Plak ki gen plis pase 50mm epè yo dwe nòmalman nòmalize, epi yo ka aplike tretman siplemantè tankou PWHT (Post-Weld Heat Treatment) oswa HIC (Hydrogen Induced Cracking).
Klas C (Mn-Mo-Ni)
Alyaj: Manganèz-Molybdène-Nikèl.
Benefis: Nikèl amelyore severite, sa ki fè li apwopriye pou anviwonman tanperati ki wo -.
Klas D (Mn-Mo-Ni)
Alyaj: Manganèz-Molybdène-Nikèl.
Karakteristik kle: Gen yon kontni nikèl ki pi wo konpare ak Klas C, amelyore pwopriyete mekanik li yo ak severite.
