Kev sib raug zoo ntawm thickness thiab mechanical zog hauvS690 qwtsis yog linear; Nws yog tswj hwm los ntawm cov txheej txheem metallurgical tseem ceeb ntawm Quenched & Tempered (Q&T) txheej txheem. Kev nkag siab txog qhov kev sib raug zoo no yog qhov tseem ceeb rau kev tsim qauv zoo thiab muaj txiaj ntsig, vim tias cov khoom tau lees paub ntawm daim ntawv pov thawj zeb tsuas yog siv tau rau qhov tshwj xeeb tuab.
Nov yog kev tshawb fawb ntxaws ntxaws-raws li kev txheeb xyuas ntawm qhov kev sib raug zoo no.
1. Cov Ntsiab Cai Metallurgical Core: Hardenability & Cooling Rate
S690QL tau txais nws cov khoom los ntawm kev kub ceev los ntawm qhov kub austenitizing (~ 900 degree), ua ib qho nyuaj martensitic / bainitic microstructure, uas yog ces tempered rau toughness.
Nyias Phaj: Ua kom txias sai thiab sib npaug thoob plaws hauv nws qhov hla -section. Qhov no ua rau tag nrho martensitic microstructure tom qab quenching, uas tom qab tempering yields siab tshaj plaws lub zog thiab pom toughness.
Thick Plate: Cov tub ntxhais (nruab nrab) txias qeeb qeeb dua qhov chaw thaum quenching. Qhov kev ua kom txias qeeb qeeb no tuaj yeem ua rau tsim cov khoom hloov pauv hloov pauv (xws li ferrite lossis pearlite) hauv cov tub ntxhais, tsim kom dhau los ntawm - cov khoom thickness gradient. Cov txheej txheem tempering kuj dhau los ua tsis zoo.
Qhov tshwm sim: Raws li thickness nce, qhov lav qhov tsawg kawg nkaus cov khoom txo.
2. Quantitative Analysis: Yuav ua li cas cov khoom Degrade nrog Thickness
Tus qauv EN 10025-6 raug lees paub qhov no los ntawm kev sib koom ua pawg phaj tuab thiab muab cov cuab yeej txo qis rau cov pab pawg tuab.
Piv txwv li EN 10025-6 (S690QL):
| Khoom Thickness * t * (mm) | Yield zog ReH (MPa) min | Tensile zog Rm (MPa) | Elongation A (%) min | Impact Zog KV (J) min |
|---|---|---|---|---|
| t Tsawg dua lossis sib npaug li 30 | 690 | 770 - 940 | 14 | 30 J ntawm -40℃(L) / -60℃(L1) |
* 30 | 670 |
770 - 940 |
14 |
Ib yam |
|
* 50 | 650 |
750 - 930 |
14 |
Ib yam |
|
* 100 | 630 |
730 - 910 |
13 |
Ib yam (Note 1) |
|
* 150 | 600 |
710 - 890 |
13 |
Ib yam (Note 1) |
|
*(Note 1: For thicknesses >100mm, cuam tshuam qhov chaw kuaj (nto vs . 1/4 thickness) thiab cov qauv coj los ua qhov tseem ceeb, thiab qhov ntsuas kub yuav raug pom zoo.)*
Cov Lus Qhia Tseem Ceeb:
Yield zog: poob los ntawm ~ 13% thaum tsiv los ntawm Tsawg dua los yog sib npaug li 30mm mus rau 150-250mm phaj (690 → 600 MPa). Tus tsim qauv siv lub npe "690" tus nqi rau 200mm tuab tivthaiv yuav yog 13% overstressed.
Tensile Strength: Qhov ntau hloov mus rau hauv qab tab sis tswj qhov sib tshooj tseem ceeb, qhia tias lub zog tseem ceeb ntawm lub tshuab tseem ua haujlwm tab sis tsis zoo.
Elongation: me ntsis txo nyob rau hauv daim hlau tuab heev, qhia tau hais tias ib tug me me poob nyob rau hauv uniform ductility.
Impact Toughness: Qhov tsawg kawg nkaus tus nqi zog (piv txwv li, 30 J) yog khaws cia, tab sis qhov no yog ntsuas ntawm tus qauv 10x10mm coj los ntawm ib qho chaw tshwj xeeb (feem ntau yog 1/4 thickness point). Qhov dhau los ntawm - thickness toughness, tshwj xeeb tshaj yog nyob rau hauv lub centerline, tuaj yeem txo qis vim yog kev sib cais thiab kev hloov pauv microstructural.
3. Mechanisms tsav cov cuab yeej txo ib lub thickness
| Khoom | Thawj Mechanism ntawm Degradation nrog Thickness | Engineering Implication |
|---|---|---|
| Yield & Tensile zog | Txo qis qis qis hauv cov tub ntxhais: Ua rau tsis muaj - martensitic theem (xws li bainite, ferrite) uas muaj zog qis dua. Tsis tas li ntawd, tempering yuav tsis tshua muaj txiaj ntsig hauv cov tub ntxhais yog tias lub phaj tsis ncav cuag qhov kub thiab txias. | Tsim yuav tsum siv tus nqi derated lub zog rau qhov tshwj xeeb thickness. Lub npe "S690" yog kev dag rau cov phaj tuab. |
| Toughness (Fracture Resistance) | 1. Microstructural Coarsening: qeeb qeeb ua rau coarser ua ntej austenite nplej thiab microstructural constituents. 2. Centerline Segregation: impurities (P, S) thiab alloying ntsiab (Mn) cais mus rau nruab nrab - thickness thaum lub sij hawm ingot solidification, tsim ib tug nruam band ntawm tej yam khoom uas nkig. |
Ua rau muaj kev pheej hmoo ntawm nkig tawg pib ntawm lub hauv paus, tshwj xeeb tshaj yog nyob rau hauv -thickness stress. Kev tswj hwm nruj ntawm cov sulfur (Z-cov hlau zoo) thiab tej zaum yuav xav tau kev sim ntxiv (xws li, CTOD kev ntsuam xyuas ntawm qhov tob). |
| Los ntawm -Thickness (Z-kev taw qhia) Properties | Elongated Inclusions: Sulfide thiab oxide inclusions elongate nyob rau hauv cov kev taw qhia dov. Nyob rau hauv daim hlau tuab, qhov no ua rau cov phiaj xwm tsis muaj zog rau qhov luv -transverse (Z) kev taw qhia. | High risk of lamellar tearing under welding-induced shrinkage stresses. For thicknesses >30mm nyob rau hauv welded tsim, qhia S690QL nrog Z-zoo (xws li, Z35) yog yuav tsum tau. |
| Weld HAZ Khoom | Kev Tiv Thaiv Kev Nyuaj Siab & Kev Nyuaj Siab Ntxiv: Cov phaj tuab tsim cov qib siab ntawm triaxial tuav thaum lub sij hawm vuam, xauv rau hauv cov kev ntxhov siab ntau dua thiab ua rau muaj kev kub ntxhov ntau dua. Qhov dav ntawm softened HAZ kuj nce. | Yuav tsum muaj cov txheej txheem vuam nruj dua (siab dua ua ntej- cua sov, tswj kev sib cuam tshuam temp, tejzaum nws yog PWHT). Lub softened HAZ dhau los ua qhov loj dua thiab tseem ceeb tshaj qhov tsis muaj zog txuas. |
4. Kev tshawb fawb-Raws li Kev Tsim Qauv & Cov Lus Qhia Txog Kev Muag Khoom
A. Rau Designers:
Tsis txhob Siv Nominal Qib Strength: Ib txwm tau txais kev lees paub cov cuab yeej cuab tam rau cov tuab tuab ntawm cov qauv lossis daim ntawv pov thawj zeb. Ua kev suav nrog cov nqi derated (piv txwv li, 650 MPa rau t=65mm).
Thickness yog ib qho Kev Tsim Nyog: Xav txog kev sib cais cov tswv cuab tuab rau hauv ob daim hlau nyias welded los yog bolted ua ke. Qhov nce hauv cov khoom siv zog (los ntawm 650 rov qab mus rau 690 MPa) tuaj yeem tshaj tus nqi ntawm qhov txuas ntxiv.
Prioritize Toughness for Thick Sections: For fracture-critical applications (e.g., offshore nodes, heavy crane booms), specify the highest subgrade (S690QL1 for -60°C) and consider additional fracture mechanics testing (CTOD) for thicknesses >50 hli.
B. Rau Fabricators & Procurement:
Mandate Z-Quality for Welded Thick Plates: For any plate >30mm uas yuav welded, tshwj xeeb tshaj yog nyob rau hauv T-cov pob qij txha los yog kaum pob qij txha, S690QL1 Z35 yuav tsum yog lub neej ntawd specification. Qhov no ua kom muaj qhov tsawg kawg nkaus 35% txo ntawm thaj chaw hauv los ntawm -thickness tensile test thiab ultra- tsis muaj sulfur.
Request Additional Testing: For very thick plates (>100mm), nws yog qhov yuav tsum tau thov ntxiv Charpy cov kev ntsuam xyuas ntawm 1/2 thickness (centerline) kom paub meej tias toughness uniformity.
Nkag siab Mill's Capability: Lub peev xwm xa cov khoom sib xws hauv cov phaj tuab S690QL txawv ntawm zeb. Nug txog lawv qhov system quenching (siab- dav hlau dej siab vs. da dej) thiab tempering furnace uniformity.
5. Summary: Qhov Thickness -Kev Ua Lag Luam Ua Lag Luam-Off Curve
Kev sib raug zoo tuaj yeem pom tau raws li cov txheej txheem ntawm kev poob qis:
Strength vs. Thickness: Ib qho kev poob qis heev uas maj mam flattens. Qhov tseem ceeb tshaj plaws derating tshwm sim hauv thawj 50 hli.
Toughness (Uniformity) vs. Thickness: Ib qho kev nkhaus ntau dua. Nto toughness tseem siab, tab sis nruab nrab toughness yuav poob precipitously yog tias kev sib cais tsis zoo thiab phaj tuab heev.
Fabrication Risk vs. Thickness: Ib qho exponentially rising curve. Kev pheej hmoo ntawm lamellar tearing, distortion, vuam tawg, thiab residual stresses escalates sai nrog tuab.
Xaus
Rau S690QL, thickness yog thawj qhov kev txiav txim siab ntawm nws cov khoom xa tuaj. Qhov nominal "690" yog qhov kev xav siab tshaj plaws tsuas yog ua tiav hauv cov ntu nyias.
Ua tiav engineering nrog tuab S690QL yuav tsum muaj ob lub tswv yim:
Metallurgical Realism: Txais thiab tsim nrog cov khoom derated uas tau teev tseg los ntawm tus qauv rau pawg tuab.
Proactive Mitigation: Qhia kom paub cov qib kev ua tau zoo (Z-zoo, QL1 subgrade) thiab npaj rau kev tsim kho thiab tshuaj xyuas ntau dua los tiv thaiv cov kev pheej hmoo uas tshwm sim los ntawm tuab.
Tsis quav ntsej txog qhov kev sib raug zoo no yog ib txoj hauv kev ncaj qha mus rau overestimation ntawm lub peev xwm thiab underestimation ntawm kev pheej hmoo, tshwj xeeb tshaj yog cov kev pheej hmoo ntawm brittle fracture originating los ntawm lub hauv paus ntawm ib tug tuab, muaj zog heev tivthaiv. Cov khoom ua tau zoo ntawm cov lus dab neeg yog nruj me ntsis raws li nws tus ntoo khaub lig- seem seem.