1.Vim li cas phosphorus (P) cov ntsiab lus yuav tsum nruj me ntsis tswj? Yuav ua li cas rau txim loj?
Mechanism: Phosphorus atoms muaj cov khoom siv muaj zog ua kom muaj zog hauv cov hlau, txhim kho nws lub zog. Txawm li cas los xij, lawv muaj zog sib cais ntawm cov ciam teb, txo cov qoob loo ciam teb lub zog thiab ua rau muaj kev poob qis hauv cov hlau plasticity thiab toughness.
Cov tsos mob tshwj xeeb: Qhov kev txo qis hauv qhov tawv no tshwj xeeb tshaj yog thaum qhov kub thiab txias, ua rau cov hlau nkig thiab ua rau tawg tawg, ib qho tshwm sim hu ua "txias brittleness."
Kev cuam tshuam rau Stamping: Rau cov khoom uas xav tau txias stamping, muaj phosphorus txo cov khoom txias ua haujlwm. Vim tias stamping yuav tsum muaj cov yas deformation zoo, lub brittleness tshwm sim los ntawm phosphorus ua rau cov khoom tawg yooj yim dua thaum lub sij hawm deformation, tshwj xeeb tshaj yog nyob rau hauv qis kub los yog nyob rau hauv complex deformation.
Quantitative Effects: Kev tshawb fawb qhia tau tias rau cov pa roj carbon tsawg - carbon steel, thaum cov ntsiab lus phosphorus tshaj 0.15%, qhov elongation (plasticity Performance index) ntawm cov khoom pib poob qis heev. Yog li ntawd, phosphorus cov ntsiab lus ntawm txias - dov coils siv rau kev sib sib zog nqus nqus yog feem ntau nruj me ntsis txwv rau qis dua 0.035%.
2.Vim li cas cov ntsiab lus ntawm sulfur (S) yuav tsum tau tswj nruj me ntsis? Yuav ua li cas rau txim loj?
Mechanism: Sulfur yuav luag insoluble hauv hlau, tab sis nws ua ke nrog hlau los ua hlau sulfide (FeS). FeS thiab hlau tsim ib qho qis- melting- taw tes (kwv yees li 985 degree) eutectic qauv.
Cov Lus Qhia Tshwj Xeeb: Kub ua haujlwm kub (xws li kub dov thiab forging) ntawm cov hlau feem ntau yog siab tshaj 1150 ~ 1200 degree. Thaum cov hlau tau rhuab mus rau qhov ntsuas kub no, qhov qis - melting- taw tes FeS faib ntawm cov ciam teb nplej melts ua ntej, cuam tshuam lub zog sib txuas ntawm cov nplej, yog li ua rau cov hlau tawg thaum ua haujlwm; qhov no yog hu ua "kub brittleness."
Kev cuam tshuam rau Stamping: Txawm hais tias cov txheej txheem txias dov nws tus kheej tsis cuam tshuam nrog qhov kub thiab txias, kub -rolled coils yog cov khoom siv raw rau txias dov. Yog tias microcracks tsim nyob rau hauv qhov kub- dov coil vim muaj cov ntsiab lus sulfur siab, cov teeb meem no yuav txuas ntxiv thiab nthuav dav thaum lub sij hawm txias dov, thaum kawg ua rau porosity, tev, los yog stamping tawg nyob rau hauv cov khoom txias tiav - dov.
3.Yuav ua li cas puas muaj phosphorus thiab sulfur ua rau lub sab hauv zoo ntawm txias- dov coils?
Sulfur ua rau delamination tsis xws luag: Qhov no yog ib qho ntawm feem raug mob tshwm sim los ntawm leej faj. Sulfur nyob rau hauv cov hlau muaj xws li sulfides (xws li MnS) thiab yog elongated raws lub dov kev taw qhia thaum dov, tsim banded los yog lamellar qauv. Cov banded sulfides cuam tshuam qhov txuas ntxiv ntawm cov hlau matrix, ua raws li cov txheej txheem ntawm "diaphragms" embedded hauv cov hlau. Thaum lub sij hawm ua tom ntej los yog nyob rau hauv kev ntxhov siab, cov banded inclusions yooj yim tawg, tsim delamination defects. Cov kev tshawb fawb qhia tias txo cov sulfur cov ntsiab lus hauv cov hlau kom qis dua 0.02% tuaj yeem tiv thaiv delamination zoo.
Phosphorus induces stress corrosion cracking: Phosphorus segregation at grain ciam teb dhau los ua "txoj kev nquag" rau kev tawg tawm. Tib lub sijhawm, phosphorus txhawb nqa cov txheej txheem anodic dissolution ntawm cov hlau hauv qee yam corrosive media (xws li cov tshuaj nitrate), cuam tshuam kev tsim cov yeeb yaj kiab passivation, yog li ua rau cov hlau tsis zoo rau kev ntxhov siab corrosion cracking.
4.Dab tsi cuam tshuam dab tsi ua rau phosphorus thiab sulfur muaj nyob rau tom qab ua haujlwm txias- dov coils (xws li vuam thiab kev kho saum npoo)?
Deterioration ntawm Weldability:
Phosphorus: Ua kom txias brittleness nyiam ntawm weld hlau, ua rau nkig tawg ntawm qhov sib koom tes thaum txias los yog kev pab cuam ntawm qhov kub thiab txias.
Sulfur: Txo cov ductility ntawm weld hlau thiab ua rau nws yooj yim rau kub tawg (solidification cracking) thaum lub sij hawm vuam vim hais tias sulfur segregation txo cov solidification kub ntau yam ntawm weld hlau, ua rau nws yooj yim rau tawg nyob rau hauv lub tom ntej theem ntawm solidification.
Kev cuam tshuam rau Kev Kho Nto Zoo:
Ob leeg sulfur thiab phosphorus yog cov khoom sib cais heev. Thaum kho cua sov (xws li annealing), lawv tuaj yeem khaws cia rau saum npoo ntawm daim hlau. Cov deposits saum npoo no tuaj yeem cuam tshuam rau cov tshuaj kho mob tom ntej, xws li ua rau cov crystallization tsis zoo thiab ua rau tsis zoo ntawm cov phosphating zaj duab xis (ib qho ua ntej- txheej hauv qab), thaum kawg txo qhov kev tiv thaiv corrosion tag nrho tom qab txheej.
5.Dab tsi yog cov qauv tswj rau phosphorus thiab sulfur nyob rau hauv cov mob khaub thuas- dov qib qib?High-zoo txias-rolled coils siv rau stamping muaj phosphorus thiab sulfur cov ntsiab lus qis dua qhov siab tshaj qhov txwv rau cov hlau zoo tib yam. Qhov no yog qhov tseeb los xyuas kom meej tias cov khoom muaj zoo plasticity, toughness, thiab sab hauv zoo, yog li kom tsis txhob muaj kev puas tsuaj xws li tawg thiab delamination thaum ua tom ntej xws li stamping.