Q1: Dab tsi yog tus nqi lag luam sib txawv ntawm Q420 thiab Q390 kav dej?
Q420 is 10-15% more expensive than Q390 (the price difference in 2023 will be approximately 700-1000 yuan/ton). Thick-walled pipes command a higher premium (+20%). Imported resources (such as German S460N) are 1.6 times more expensive than domestically produced pipes. Custom pipes for special sizes (e.g., Φ1500mm and above) have a 35% price fluctuation. Bulk purchases (>50 tons) tau txais 5-8% luv nqi.
Q2: Cov dej num twg xav tau kev siv Q420 cov yeeb nkab steel?
GB 50017 stipulates that Q420 must be used for ultra-long-span steel structures (spans >80m). GB 50936 yuav tsum Q420D / e rau cov leeg tub ntxhais ntawm cov tsev loj-siab. Cua fais txheej qauv iec 61400 qhia meej Q420e rau cov yees dhau 100m. API RP 2A, Lub Offshore platform specification, qhia Q420 rau cov hmoov tsaj deepwitwater. Hla 10092, tus qauv tsheb ciav hlau, yuav tsum Q420 rau cov teeb tseem ceeb ntawm ntev-ntev-spear tsheb ciav hlau siab ceev.
Q3: Yuav ua li cas txheeb xyuas qhov kev tsim nyog ntawm Q420 cov yeeb nkab steel muag khoom?
Xyuas cov hlau zeb lab cov ntawv tso cai tsim khoom (GB / T 1591 daim ntawv pov thawj). Txheeb xyuas qhov ua tau zoo ntawm cov phiaj xwm zoo sib xws hauv peb lub xyoos dhau los (xws li cua lub zog thiab cov haujlwm hauv lub choj). Kev coj ua cov kev rov ua haujlwm ntawm -20℃cuam tshuam lub zog (Q420D ntau dua los yog sib npaug ntawm 34J). Kev coj ua ntawm-chaw soj ntsuam kev tshuaj xyuas cov khoom siv cov khoom siv ntau lawm (quenching thiab tempering kub kho cov kab). Txheeb xyuas cov txheej txheem kev sib cav kom zoo (lub sijhawm teb tsawg dua lossis sib luag rau 24 teev).
Q4: Yuav ua li cas xaiv ntawm Q420 thiab ntau dua-zog-zog cov hlau (xws li Q460)?
Q460 is 1.5 times more expensive than Q420, so upgrades are not recommended unless necessary. Consider Q460 when structural weight reduction is >20%. Vuam nyuaj: Q460 yuav tsum muaj qhov kub siab dua (+50 degree). Q420 tuaj yeem siv los hloov Q460 nrog cov qauv tsim tau zoo (piv txwv li, nce ntxiv phab ntsa thickness). Tham tus txheej txheem kws ua lag luam rau kev xaiv cov kabmob tseem ceeb.
Q5: Cov ntaub ntawv sib txig li cas rau Q420 hauv cov phiaj xwm thoob ntiaj teb?
European Txuj Ci: S460N (EN 10025), S460ML (thiab 10149). American Txuj Ci: ASTM A572 GR.65 (nrog kev cuam tshuam ntxiv). Japanese Txuj Ci: SM570 (JIS G3106). Tus Qauv Lavxias: 17G1C (GOST 19281). Daim ntawv cog lus kev cog lus yuav tsum tau kos npe kom meej qhov tsis sib xws thaum hloov cov ntawv hlau.
