Q: Ua hoʻomaka mākou e hana i kekahi mau hana e pono ai e hana mua i kekahi mau ʻāpana o ka pae 304 stainless steel, i hoʻopili ʻia iā ia iho a me ke kila palupalu.
A: He nīnau maikaʻi kēia. ʻAe, hiki iā mākou ke kōkua iā ʻoe e hoʻomaopopo i ke ʻano o ka helu ferrite haʻahaʻa a pehea e pale ai.
ʻO ka mea mua, e nānā kākou i ka wehewehe ʻana o ke kila kila (SS) a me ke ʻano o ka ferrite e pili ana i nā hui welded. ʻO ke kila ʻeleʻele a me nā alloys i ʻoi aku ma mua o 50% hao. ʻO kēia nā mea āpau āpau a me nā mea kila kila a me nā hui ʻē aʻe.
ʻO nā mea nui o kēia huila he kalapona kalapona me ka liʻiliʻi o 90% hao a me SS me 70 a 80% hao. No ka helu ʻia ʻana ma ke ʻano he SS, pono e loaʻa iā ia ma kahi o 11.5% chromium i hoʻohui ʻia. ʻO nā pae Chromium ma luna o kēia paepae liʻiliʻi e hoʻoikaika i ka hoʻokumu ʻana i nā kiʻiʻoniʻoni chromium oxide ma nā wahi kila a pale i ka hoʻokumu ʻana o ka oxidation e like me ka rust (iron oxide).
Hoʻokaʻawale nui ʻia ʻo SS i ʻekolu mau pūʻulu: austenite, ferrite a martensite. ʻO ko lākou inoa mai ka hale aniani keʻena wela o ka lumi e hana ai iā lākou.
ʻO nā māka Austenitic, ka 300 series, loaʻa iā 16% a 30% chromium a me 8% a 40% nickel, e hana ana i kahi ʻano kristal austenitic nui.hoʻohana mua ʻia i ka meaʻai, ka lawelawe kemika, ka lāʻau lapaʻau a me nā noi cryogenic. ʻO ka mana o ka hoʻokumu ʻana i ka ferrite e hāʻawi i ka paʻakikī haʻahaʻa haʻahaʻa.
Ferritic SS he 400 moʻo papa i piha magnetic, loaʻa 11.5% a 30% chromium, a he ferritic predominant crystal structure.No ka paipai 'ana i ka ferrite, stabilizers komo chromium, silicon, molybdenum, a me ka niobium i ke kila production.These mau 'ano o ka SS mea maʻamau hoʻohana 'ia i loko o ka automotive exhaust'ōnaehana a me 5S mau 'ano. 409, 430 a me 446.
ʻO nā māka Martensitic, i ʻike pū ʻia e ka moʻo 400 e like me 403, 410 a me 440, he magnetic, loaʻa iā 11.5% a 18% chromium, a he martensite e like me ke ʻano aniani.ikaika maikaʻi loa;a hoʻohana mau ʻia i nā lako papaʻaina, nā mea hana niho a me nā ʻokiʻoki, nā mea kuke, a me kekahi mau ʻano mea paahana.
Ke wiliʻoe iā SS,ʻo keʻano o ka substrate a me kāna noi i loko o ka lawelawe e hoʻoholo i ka mea hoʻopihapiha hoʻopihapiha kūpono e hoʻohana.
No ke kūʻai ʻana i ka 304 iā ia iho, pono ʻoe i kahi electrode E308 / 308L. ʻO ka "L" ke kū nei i ke kalapona haʻahaʻa, e kōkua ana i ka pale ʻana i ka corrosion intergranular. Loaʻa i kēia mau electrodes kahi mea kalapona ma lalo o 0.03%;ʻO nā mea ma luna aʻe o kēia e hoʻonui ai i ka pilikia o ke kalapona i nā palena o ka palaoa a hui pū me ka chromium e hana i ka chromium carbide, e hōʻemi pono ana i ka pale ʻana o ke kila.
No ka mea, 304 he austenitic ano o SS, e like me ka weld metala e loaʻa i ka hapa nui o ka austenite. Akā naʻe, i ka electrode pono e loaʻa i ka ferrite stabilizer, e like me molybdenum, e paipai i ka hookumu ana o ka ferrite i ka weld metala. i ka metala weld.
Loaʻa nā helu Ferrite mai ka Schaeffler diagram a me ka WRC-1992 diagram, e hoʻohana ana i ka nickel a me ka chromium equivalent formulas e helu ai i ka waiwai, i ka wā i hoʻolālā ʻia ma ke kiʻikuhi e hoʻopuka i kahi helu maʻamau.akā naʻe, ma nā pākēneka kiʻekiʻe, piʻi ka helu ferrite ma kahi wikiwiki. E hoʻomanaʻo ʻaʻole like ka ferrite i ka SS me ka ferrite kila kalapona, akā he māhele i kapa ʻia ʻo delta ferrite. ʻAʻohe hoʻololi o Austenitic SS e pili ana i nā kaʻina hana wela kiʻekiʻe e like me ka mālama wela.
Makemake ʻia ka hoʻokumu ʻana o ka ferrite no ka mea ʻoi aku ka ductile ma mua o ka austenite, akā pono e hoʻomalu ʻia. Hiki i nā helu ferrite haʻahaʻa ke hana i nā welds me ke kūpaʻa corrosion maikaʻi loa i kekahi mau noi, akā hiki ke maʻalahi i ka pohā wela i ka wā welding.
Ma muli o kou ʻōlelo ʻana he pilikia ʻoe a me ka helu ferrite haʻahaʻa, pono ʻoe e nānā pono i kāu metala hoʻopiha a hōʻoia i ka nui o ka helu ferrite - ma kahi o 8 pono e kōkua. Eia kekahi, inā ʻoe e hoʻohana nei i ka flux cored arc welding (FCAW), hoʻohana maʻamau kēia mau metala hoʻopiha i ka 100% carbon dioxide pale kinoea a i ʻole 75% hiki iā mākou ke hoʻololi i ke kalapona. he kaʻina hana hoʻoheheʻe metala kinoea (GMAW) a hoʻohana i ka hui ʻana o 98% argon/2% oxygen e hōʻemi i ka hiki ke kiʻi ʻia ke kalapona.
No ka weld SS i ke kila kalapona pono ʻoe e hoʻohana i ka E309L filler material.This filler metal is specially used for welding dissimilar metals and forms a certain amount of ferrite after the carbon steel is diluted in the weld.No ka mea, ua komo kekahi kalapona i loko o ke kila kalapona, ua hoʻohui ʻia nā ferrite stabilizers i ka metala filler e pale aku i ka manaʻo o ke kalapona i loko o ke kalapona e kōkua ai i ka aulding crack.
I ka hōʻuluʻulu manaʻo, inā makemake ʻoe e hoʻopau i nā māwae wela ma nā austenitic SS welded ami, e hōʻoia i ka lawa ʻana o ka ferrite filler metala a hahai i ka hana kuʻihao maikaʻi.
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