Apha kulapho ibhetshi yentsimbi idibana khona ngaphezulu kwenkcazo okanye ibakala. Yindlela yokuvumela iivenkile ezinyibilikayo ukuba zivelise isinyithi esingenasici ngokufanelekileyo ngokukhawulela inani leentlobo ezahlukeneyo zetsimbi. Ukubunjwa kweekhemikhali kunye neempawu zomatshini zetsimbi zinokuhlangabezana nebakala elingaphezulu kwelinye ngaphakathi komgangatho ofanayo okanye kwimigangatho emininzi. Oku kukwavumela abaninimasheya ukuba banciphise amanqanaba esitokhwe.

Ngokomzekelo, kuqhelekile ukuba i-1.4401 kunye ne-1.4404 (316 kunye ne-316L) iqinisekiswe kabini - oko kukuthi umxholo wekhabhoni ungaphantsi kwe-0.030%. Intsimbi eqinisekisiweyo kuyo yomibini imigangatho yaseYurophu nase-US nayo ixhaphakile.

Kukho iintlobo ezininzi ezahlukeneyo zokugqitywa komphezulu kwintsimbi engenasici. Ezinye zezi zisuka kwilitye lokusila kodwa ezininzi zisetyenziswa kamva ngexesha lokusetyenzwa, umzekelo, ukupholishwa, ukubrashwa, ukuqhushumba, okukroliweyo kunye nokugqitywa kombala.

Ukubaluleka kokugqitywa kwendawo ekunqumeni ukuxhathisa kwe-corrosion ye-stainless steel surface ayinakugxininiswa. Ukugqitywa komphezulu orhabaxa kunokwehlisa ngokufanelekileyo ukuxhathisa komhlwa ukuya kwinqanaba elisezantsi lentsimbi engatyiwayo.

Iindidi ezahlukeneyo zensimbi engenasici zisetyenziswa kulo lonke ubushushu ukusuka kwi-ambient ukuya kwi-1100 deg C. Ukukhetha ibakala kuxhomekeke kwizinto ezininzi:

Ubushushu obuphezulu bokusebenza
Ixesha kwiqondo lobushushu, ubume bomjikelezo wenkqubo
Uhlobo lomoya, i-oxidising, ukunciphisa, i-sulphidising, i-carburising.
Imfuneko yokomelela

Kwimigangatho yaseYurophu, ulwahlulo lwenziwa phakathi kweentsimbi ezingenasici kunye neentsimbi ezixhathisa ukushisa. Nangona kunjalo, lo mahluko uhlala umnyama kwaye luncedo ukuwaqwalasela njengoluhlu olulodwa lweentsimbi.

Ukunyuka kwezixa zeChromium kunye nesilicon zinika ukuxhathisa okukhulu kwe-oxidation. Ukunyuka kwezixa ze-Nickel kunika ukuxhathisa okukhulu kwe-carburisation.

Iintsimbi ze-Austenitic stainless zisetyenziswa kakhulu kwinkonzo ukuya kuthi ga kwiqondo eliphantsi njengobushushu be-helium engamanzi (-269 deg C). Oku kubangelwe ubukhulu becala kukungabikho kotshintsho olucacileyo ukusuka kwi-ductile ukuya kwi-brittle fracture kuvavanyo lokuqina kwempembelelo.

Ukuqina kulinganiswa ngokuchaphazela isampuli encinci ngehamile ejingayo. Umgama ihamile ejiwulwayo emva kwempembelelo ngumlinganiselo wobulukhuni. Umgama omfutshane, uqina intsimbi njengoko amandla ehamile afunxwa yisampuli. Ukuqina kulinganiswa ngeeJoules (J). Ubuncinci amaxabiso obunzima bucaciswe kwizicelo ezahlukeneyo. Ixabiso eliyi-40 J lithathwa njengelifanelekileyo kwiimeko ezininzi zenkonzo.

Iintsimbi ezinezakhiwo ze-ferritic okanye ze-martensitic zibonisa utshintsho ngokukhawuleza ukusuka kwi-ductile (ekhuselekileyo) ukuya kwi-brittle (engakhuselekanga) i-fracture phezu komlinganiselo omncinci weqondo lokushisa. Nkqu ezi zintsimbi zibalaseleyo zibonisa oku kuziphatha kumaqondo obushushu angaphezu kwe-100 deg C kwaye kwiimeko ezininzi kuphela ngaphantsi kwe-zero.

Ngokuchaseneyo iintsimbi ze-austenitic zibonisa kuphela ukuwa kancinci kwixabiso lokuqina kwempembelelo kwaye zisengaphezulu kwe-100 J kwi -196 deg C.

Enye into echaphazela ukhetho lwentsimbi kwiqondo lokushisa eliphantsi kukukwazi ukuchasana nokuguqulwa kwe-austenite ukuya kwi-martensite.

Ngokuqhelekileyo kuthiwa "insimbi engenasici ayinamagnetic". Oku akuyonyani ngokungqongqo kwaye imeko yokwenyani inzima ngakumbi. Iqondo lempendulo yamagnetic okanye ukunyanzeliswa kwamagnetic kuphuma kwi-microstructure yentsimbi. Isixhobo esingenamagnetic ngokupheleleyo sinobuchwephesha obune-1. Izakhiwo ze-Austenitic azikho-magnetic ngokupheleleyo kwaye ngoko i-100% yentsimbi ye-austenitic stainless iya kuba ne-permeability ye-1. Kwinkqubo oku akufezeki. Kuhlala kukho inani elincinci le-ferrite kunye / okanye i-martensite kwintsimbi kwaye ngoko amaxabiso okunyamezela ahlala engaphezulu kwe-1. Amaxabiso aqhelekileyo kwi-standard austenitic stainless steels ingaba ngomyalelo we-1.05 - 1.1.

Kunokwenzeka ukuba umbane wamagnetic weentsimbi ze-austenitic utshintshwe ngexesha lokucubungula. Ngokomzekelo, umsebenzi obandayo kunye ne-welding inomthwalo wokwandisa inani le-martensite kunye ne-ferrite ngokulandelanayo kwintsimbi. Umzekelo oqhelekileyo ukwisinki yentsimbi engenastainless steel apho i-drainless flat inempendulo encinci yemagnethi ngelixa isitya esicinezelweyo sinempendulo ephezulu ngenxa yokwenziwa kwe-martensite ngakumbi kwiikona.

Ngokwezinto eziphathekayo, i-austenitic stainless steels isetyenziselwa izicelo "ezingezona magnetic", umzekelo imaging resonance magnetic (MRI). Kwezi meko, kuye kufuneke ukuba kuvunyelwane ngeyona ndawo iphezulu yemagnethi phakathi komthengi kunye nomthengisi. Inokuba ngaphantsi njenge-1.004.

Iintsimbi zeMartensitic, i-ferritic, i-duplex kunye nemvula ezenza lukhuni ziyimagnethi.

Intsimbi engatyiwa idla ngokuhlulwa ibe ziindidi ezi-5:

I-1.Ferritic - Ezi zinsimbi zisekelwe kwi-Chromium kunye nexabiso elincinci leCarbon ngokuqhelekileyo lingaphantsi kwe-0.10%. Ezi ntsimbi zine-microstructure efanayo kwikhabhoni kunye neentsimbi eziphantsi. Ngokuqhelekileyo zilinganiselwe ekusebenziseni kumacandelo amancinci ngenxa yokunqongophala kokuqina kwi-welds. Nangona kunjalo, apho ukuwelda kungafunekiyo banikezela ngoluhlu olubanzi lwezicelo. Abanakuqiniswa ngonyango lobushushu. Iintsimbi eziphakamileyo zeChromium ezinezongezo zeMolybdenum zinokusetyenziswa kwiimeko ezinobundlongondlongo ezifana namanzi olwandle. Iintsimbi zeFerritic nazo zikhethwa ngenxa yokuchasana noxinzelelo lwe-corrosion cracking. Ayinabumbeko njengeentsimbi ze-austenitic ezingenasici. Zimagnetic.
2.Austenitic - Ezi zintsimbi zezona ziqhelekileyo. I-microstructure yabo ivela ekongezweni kwe-nickel, i-Manganese kunye ne-Nitrogen. Sisakhiwo esifanayo njengoko senzeka kwiintsimbi eziqhelekileyo kumaqondo obushushu aphezulu kakhulu. Olu lwakhiwo lunika ezi zintsimbi indibaniselwano yeempawu zokuweldability kunye nokwakheka. Ukumelana nokubola kunokongezwa ngokudibanisa iChromium, iMolybdenum kunye neNitrogen. Azinakuqiniswa lunyango lobushushu kodwa zinepropathi eluncedo yokukwazi ukusebenza nzima ukuya kumanqanaba aphezulu ngelixa zigcina inqanaba eliluncedo lokudumba kunye nokuqina. Iintsimbi eziqhelekileyo ze-austenitic zisengozini yoxinzelelo lwe-corrosion cracking. Iintsimbi eziphezulu ze-nickel austenitic ziye zanda ukuchasana noxinzelelo lwe-corrosion cracking. Ngokuqhelekileyo azikho i-magnetic kodwa zihlala zibonisa impendulo yemagnethi ngokuxhomekeke kukwakheka kunye nomsebenzi wokuqina kwentsimbi.
I-3.Martensitic - Ezi zintsimbi zifana neentsimbi ze-ferritic ekubeni zisekelwe kwi-Chromium kodwa zinemigangatho yeCarbon ephezulu ukuya kwi-1%. Oku kuvumela ukuba baqiniswe kwaye bahlanjululwe kakhulu njengekhabhoni kunye neentsimbi eziphantsi kwe-alloy. Zisetyenziswa apho amandla aphezulu kunye nokumelana nokugqwala okuphakathi kuyadingeka. Zixhaphake kakhulu kwiimveliso ezinde kunephepha kunye nefomu yepleyiti. Ngokuqhelekileyo baphantsi kwe-weldability kunye nokwakheka. Zimagnetic.
I-4.Duplex - Ezi zinsimbi zine-microstructure malunga ne-50% ye-ferritic kunye ne-50% ye-austenitic. Oku kubanika amandla aphezulu ngaphezu kweentsimbi ze-ferritic okanye i-austenitic. Ziyakwazi ukumelana noxinzelelo lwe-corrosion cracking. Iintsimbi ezibizwa ngokuba yi "lean duplex" ziyilwe ukuba zibe nokuxhathisa umhlwa okunokuthelekiseka kwiintsimbi eziqhelekileyo ze austenitic kodwa zinamandla ongeziweyo kunye nokumelana noxinzelelo lokuqhekeka komhlwa. Iintsimbi "ze-Superduplex" ziye zaqinisa amandla kunye nokuchasana nazo zonke iindlela zokubola xa kuthelekiswa neentsimbi eziqhelekileyo ze-austenitic. Ziyakwazi ukuwelda kodwa zifuna ukhathalelo ekukhetheni izinto ezityiwayo ze-welding kunye negalelo lobushushu. Banokwakheka okuphakathi. Zimagnetic kodwa azikho kakhulu njenge-ferritic, martensitic kunye ne-PH ngenxa ye-50% yesigaba se-austenitic.
I-5.Ukuqina kwe-Precipitation (PH) - Ezi zinsimbi zinokuhlakulela amandla aphezulu kakhulu ngokongeza izinto ezifana neCopper, i-Niobium kunye ne-Aluminium kwintsimbi. Ngonyango olufanelekileyo "lokuguga", iinqununu ezintle kakhulu zenza kwi-matrix yensimbi enika amandla. Ezi ntsimbi zinokwenziwa ngoomatshini bemilo entsonkothileyo efuna unyamezelo olulungileyo phambi konyango lokugqibela lokwaluphala njengoko kukho ukugqwetheka okuncinci kunyango lokugqibela. Oku kuchasene nokuqina okuqhelekileyo kunye nokufudumala kwiintsimbi ze-martensitic apho ukuphazamiseka kuyingxaki enkulu. Ukuxhatshazwa kwe-Corrosion kuthelekiswa neentsimbi eziqhelekileyo ze-austenitic ezifana ne-1.4301 (304).

 Ezona ntlobo zixhaphakileyo zokubola kwintsimbi engatyiwa zezi:

I-Pitting corrosion - Umaleko wokwenziwa kwintsimbi engatyiwayo unokuhlaselwa ziintlobo ezithile zeekhemikhali. I-chloride ion Cl- yeyona ixhaphakileyo kwezi kwaye ifumaneka kwizinto zemihla ngemihla ezifana netyuwa kunye nebleach. I-pitting corrosion iyaphetshwa ngokuqinisekisa ukuba insimbi engenasici ayidibani ixesha elide kunye neekhemikhali ezinobungozi okanye ngokukhetha ibakala lentsimbi ekwazi ukumelana nokuhlaselwa. I-pitting corrosion resistance inokuhlolwa ngokusebenzisa i-Pitting Resistance Equivalent Number ebalwa kumxholo we-alloy.
I-Crevice corrosion - Intsimbi engatyiwayo ifuna unikezelo lweoksijini ukuqinisekisa ukuba umaleko we-passive unokubumba phezu komhlaba. Kwiimingxuma ezixinene kakhulu, akusoloko kusenzeka ukuba ioksijini ikwazi ukufikelela kumphezulu wentsimbi engenasici ngaloo ndlela ibangela ukuba ibe sesichengeni sokuhlaselwa. I-Crevice corrosion ithintelwa ngokuvala iintanda nge-sealant eguquguqukayo okanye ngokusebenzisa ibakala elixhathisayo lokutya.
I-Corrosion ngokubanzi - Ngokuqhelekileyo, insimbi engagqwali ayidleki ngokufanayo njengoko kwenza i-carbon eqhelekileyo kunye neentsimbi zealloy. Nangona kunjalo, ngezinye iikhemikhali, ngokukodwa i-acids, i-passive layer ingahlaselwa ngokufanayo ngokuxhomekeke kugxininiso kunye nobushushu kwaye ilahleko yesinyithi isasazwa phezu kwendawo yonke yentsimbi. I-Hydrochloric acid kunye ne-sulfuric acid kwezinye iindawo zinobundlongondlongo kwintsimbi engatyiwayo.
I-Stress corrosion cracking (SCC) - Olu luhlobo olunqabileyo lokutya olufuna indibaniselwano ethile yoxinzelelo lwe-tensile, ubushushu kunye neentlobo ezidlayo, ezihlala i-ion ye-chloride, ukuze yenzeke. Usetyenziso oluqhelekileyo apho i-SCC inokwenzeka khona ngamatanki amanzi ashushu kunye namadama okuqubha. Olunye uhlobo olubizwa ngokuba yi-sulphide stress corrosion cracking (SSCC) ludibene ne-hydrogen sulphide kwi-oyile kunye negesi yokuhlola kunye nemveliso.
I-Intergranular corrosion - Le ngoku luhlobo olunqabileyo lokutya. Ukuba inqanaba leCarbon kwintsimbi liphezulu kakhulu, iChromium inokudibanisa neCarbon ukwenza iChromium Carbide. Oku kwenzeka kumaqondo okushisa phakathi kwe-450-850 deg C. Le nkqubo ikwabizwa ngokuba yi-sensitization kwaye ngokuqhelekileyo iyenzeka ngexesha le-welding. I-Chromium ekhoyo ukwenza umaleko wokwenziwa iyancipha ngokusebenzayo kwaye ukuhlwa kuyenzeka. Iyaphetshwa ngokukhetha ibakala eliphantsi lekhabhoni elibizwa ngokuba ngamabakala 'L' okanye ngokusebenzisa intsimbi eneTitanium okanye iNiobium edityaniswa ngokukhethekileyo neCarbon.
I-galvanic corrosion - Ukuba iintsimbi ezimbini ezingafaniyo zidibene kunye kunye ne-electrolyte umz. amanzi okanye enye isisombululo, kunokwenzeka ukuba kumiswe iseli yegalvanic. Oku kufana nebhetri kwaye kunokukhawulezisa ukubola kwentsimbi 'engabekekanga'. Inokuphetshwa ngokuhlula iintsimbi kunye ne-insulator engeyiyo-metallic efana nerabha.

Nangona insimbi engenasici ixhathisa kakhulu kwi-corrosion kune-carbon eqhelekileyo okanye i-alloy steels, kwezinye iimeko inokugqwala. 'Ayinabala' hayi 'ibala-ayinakwenzeka'. Kwiindawo eziqhelekileyo zomoya okanye ezisekwe emanzini, intsimbi estainless ayizukonakala njengoko kubonisiwe ziiyunithi ze-sink yasekhaya, i-cutlery, iisoupani kunye neendawo zokusebenza.

Kukho umbono obanjwe ngokubanzi wokuba insimbi engenasici yafunyanwa ngo-1913 nguSheffield metallurgist uHarry Brearley. Wayezama ngeentlobo ezahlukeneyo zentsimbi yezixhobo kwaye waqaphela ukuba i-13% yensimbi yeChromium ayizange idle emva kweenyanga eziliqela.