Lub siab tsis kam ntawm carbon steel kav tsis yog tus nqi ruaj khov tab sis yog txiav txim los ntawm kev sib xyaw ua ke ntawm cov khoom:
1. Khoom Qib
Cov khoom siv qib yog qhov ntsuas tseem ceeb ntawm kev ua haujlwm siab. Cov pa roj carbon zoo tib yam (piv txwv li, Q235) muaj lub zog tensile ntawm li 375-500 MPa, thaum siab - lub zog carbon steel (xws li, X60) tuaj yeem tshaj 517 MPa (ib API 5L tus qauv). Qhov siab dua cov khoom siv zog, qhov ntau dua nws lub peev xwm-cov kabmob.
2. Phab ntsa Thickness thiab txoj kab uas hla
Raws li tus qauv Barlow (P=2St / D, qhov twg P yog siab tsis kam, S yog tensile lub zog, t yog phab ntsa thickness, thiab D yog txheej kab), nyob rau hauv tib cov ntaub ntawv, nce phab ntsa thickness los ntawm 1 hli tuaj yeem txhim kho lub siab los ntawm li 10-15%. Piv txwv li, DN100 SCH40 carbon steel yeeb nkab (6 hli phab ntsa tuab) muaj kev ua haujlwm siab txog 5.6 MPa, thaum SCH80 (8 hli phab ntsa thickness) tuaj yeem ncav cuag 7.4 MPa (ASTM A106 cov ntaub ntawv).
3. Cov txheej txheem tsim khoom
Seamless kav (piv txwv li, ASTM A106) feem ntau muaj kev kub siab ua haujlwm ntau dua li cov kav dej welded (piv txwv li, ASTM A53) vim qhov tsis muaj vuam seams, uas yog cov ntsiab lus tsis muaj zog.
Standard Specifications thiab Pressure Classifications
Cov txheej txheem thoob ntiaj teb sib txawv muaj kev qhia meej meej rau kev ua haujlwm siab ntawm carbon steel kav:
ASTM A106 Seamless Yeeb Nkab: Qib B muaj siab tshaj plaws ua haujlwm siab ntawm 15.8 MPa ntawm chav tsev kub (12 hli phab ntsa thickness, DN150 mob).
API 5L Kab Yeeb: X42 qib yeeb nkab feem ntau muaj qhov tsim siab ntawm 10-12 MPa hauv cov roj thiab cov pa xa tawm (nrog rau kev nyab xeeb ntawm 0.72).
Suav Standard GB / T 8163: 20 # carbon steel yeeb nkab tso cai rau lub siab ntawm 6.4 MPa ntawm 20℃(5 hli phab ntsa thickness, DN80).
Kev xaiv cov lus pom zoo rau kev siv tswv yim
Safety Factor: Industrial piping feem ntau siv qhov kev nyab xeeb ntawm 1.5-4 npaug ntawm kev tsim siab (tus nqi siab dua rau cov xov xwm flammable). Piv txwv li, chav piping yuav tsum muaj kev tiv thaiv corrosion ntxiv rau ASME B31.1.
Kev kho qhov kub thiab txias: At high temperatures (>200 degree), lub siab tsis kam ntawm cov yeeb nkab carbon steel txo los ntawm 20-30%, thiab cov khoom siv kub yuav tsum tau txiav txim siab.
Corrosive Ib puag ncig: Yog hais tias qhov nruab nrab muaj H₂S lossis CO₂, qaub- cov pa roj carbon resistant (xws li, L245NS) yuav tsum tau siv, los yog cov qauv tsim yuav tsum txo qis dua 30%.
