ASTM A709 Qib 50 steel phaj yog asiab- zog, qis- alloy (HSLA)structural steel feem ntau siv hauv kev tsim choj thiab kev tsim kho dav dav. Nws muab cov khoom siv zog zoo tshaj plaws nrog cov weldability zoo thiab zoo atmospheric corrosion kuj.
Qib no yog tsim los ua kom tau raws li qhov yuav tsum tau ua ntawm kev ua haujlwmASTM A709 / A709M tus qauv, uas npog cov qauv steel phaj siv hauv cov txuas hniav thiab lwm yam kev thauj khoom -cov kabmob.
Nrog tsawg kawg nkaus tawm lub zog ntawm345 MPa (50 ksi), A709 Qib 50 muaj qhov zoo sib npaug ntawm lub zog, durability, thiab tus nqi -kev ua tau zoo, ua rau nws yog ib qho ntawm cov hlau siv dav tshaj plaws.
Tshuaj muaj pes tsawg leeg (% Maximum)
| Element | C | Mn | P | S | Si | Cu | Ni | Cr | V |
|---|---|---|---|---|---|---|---|---|---|
| Hom kab mob | Tsawg dua lossis sib npaug li 0.23 | 0.50–1.35 | Tsawg dua lossis sib npaug li 0.035 | Tsawg dua lossis sib npaug li 0.040 | 0.15–0.50 | 0.20–0.40 | Tsawg dua lossis sib npaug li 0.40 | Tsawg dua lossis sib npaug li 0.40 | Tsawg dua lossis sib npaug li 0.08 |
Mechanical Properties
| Khoom | Metric | Imperial | Kev piav qhia |
|---|---|---|---|
| Yield zog (Min) | 345 MPa rau | 50 ksg | Xyuas kom ntseeg tau lub zog nyob rau hauv hnyav loads |
| Tensile zog | 450-620 MPa | 65-90 hli | Lub peev xwm tensile siab rau kev ruaj ntseg |
| Elongation (Min, 200mm) | 18% | 18% | Muab txaus ductility thiab formability |
| Charpy V-Nov Toughness | Ntau tshaj lossis sib npaug rau 34 J @ -20 degree | Ntau dua lossis sib npaug li 25 ft·lbf @ -4℃F | Haum rau qis-kub choj kev pabcuam |
Daim ntawv thov
ASTM A709 Qib 50 steel phaj tau siv dav hauv ntau qhov kev lag luam uas yuav tsum muaj lub zog siab, zoo toughness, thiab durability.
Cov ntawv thov ib txwm muaj xws li:
Choj Girders thiab Decks:
Siv nyob rau hauv welded los yog bolted choj qauv uas yuav tsum tau txhim khu kev qha load- bearing peev.
A709 Qib 50 daim hlau nrog50 ksi (345 MPa)Yam tsawg kawg nkaus lub zog yog zoo tagnrho rau girders thiab cross beams nyob rau hauv ob qho tib si txoj kev loj thiab railway choj.
Hom phaj thickness ranges los ntawm12mm txog 80mm, txhawb span lengths mus txog100 meters.
Highway Overpasses thiab Viaducts:
Haum rau fabrication ntawm trusses, diaphragms, thiab stiffeners.
Cov hlau muab kev tiv thaiv kev qaug zog siab thiab muaj zog zoo ib yam dhau sijhawm ntev - kev pabcuam, feem ntautshaj 30 xyootsis muaj structural degradation thaum tswj kom zoo.
Nws toughness tso cai rau kev nyab xeeb ua haujlwm nyob rau hauv qhov kub thiab txias raws li qhov tsawg-20 degree.
Structure Frames:
Siv rau hauv cov tsev lag luam loj, siab - cov qauv nce, thiab cov tsev khaws khoom uas yuav tsum muaj kev sib xyaw ua ke ntawm lub zog thiab hloov tau yooj yim.
A709 Gr.50 tuaj yeem txo qhov hnyav tag nrho steel los ntawm10–15%piv nrog cov hlau me me (A36), txo cov khoom siv thiab cov nqi erection.
Feem ntau thicknesses rau cov kev siv no yog6-40 hli.
Crane thiab Hoisting Equipment:
Siv nyob rau hauv load-cov kabmob booms, thav ntawv, thiab lub hauv paus kev txhawb nqa qhov siab tensile zog (txog620 MPa rau) yog qhov tseem ceeb.
Lub phaj tuav cov qauv kev ruaj ntseg nyob rau hauv hnyav cyclic loading thiab dynamic kev nyuaj siab tej yam kev mob, ncua cov khoom lifespan los ntawm20–25%piv nrog cov qauv carbon steels.
Marine thiab Offshore Projects:
Ua tau zoo nyob rau hauv ntsev -laden los yog ntub ib puag ncig, nrog tus nqi corrosion30-40% qis duatshaj li cov qauv hlau.
Feem ntau siv nyob rau hauv ntug dej hiav txwv txuas hniav, offshore platforms, thiab dock cov qauv raug rau tidal tej yam kev mob.
Thaum coated los yog galvanized, kev pab cuam lub neej yuav tshaj50 xyoonrog tsawg kawg repainting xav tau.
