Q: Ua hoʻomaka koke nei mākou e hana i kekahi mau hana e pono ai kekahi mau ʻāpana e hana ʻia me ke kila kila 304, kahi i hoʻopaʻa ʻia iā ia iho a me ke kila palupalu. Ua ʻike mākou i kekahi mau pilikia haki ma nā kila kila i nā wili kila kila a hiki i ka 1.25″ ka mānoanoa. Ua ʻōlelo ʻia he haʻahaʻa kā mākou helu ferrite. Hiki iā ʻoe ke wehewehe i ke ʻano o kēia a pehea e hoʻoponopono ai?
A: He nīnau maikaʻi kēia. ʻAe, hiki iā mākou ke kōkua iā ʻoe e hoʻomaopopo i ke ʻano o nā helu ferrite haʻahaʻa a pehea e pale aku ai.
ʻO ka mea mua, e nānā hou kākou i ka wehewehe ʻana o ke kila kila (SS) a pehea e pili ai ka ferrite i nā hui i hoʻopili ʻia. Loaʻa i ke kila ʻeleʻele a me nā mea hoʻohuihui ma mua o 50% ka hao. Hoʻokomo pū kēia i nā kalapona a me nā kila kila a me nā hui i wehewehe ʻia. ʻAʻole i loko o ka alumini, ke keleawe a me ka titanium ka hao, no laila he mau laʻana maikaʻi loa lākou o nā mea hoʻohuihui non-ferrous.
ʻO nā ʻāpana nui o kēia metala hao he kila kalapona me ka liʻiliʻi he 90% hao a me SS me 70 a 80% hao. I mea e hoʻokaʻawale ʻia ai he SS, pono e loaʻa iā ia ma ka liʻiliʻi he 11.5% chromium i hoʻohui ʻia. Hoʻolaha nā pae chromium ma luna o kēia paepae liʻiliʻi loa i ka hoʻokumu ʻia ʻana o nā kiʻiʻoniʻoni chromium oxide ma nā ʻili kila a pale i ka hoʻokumu ʻia ʻana o ka oxidation e like me ka rust (iron oxide) a i ʻole ka corrosion i hoʻokumu ʻia e ka hoʻouka kemika.
Ua māhele nui ʻia ʻo SS i ʻekolu mau pūʻulu: austenite, ferrite a me martensite. Loaʻa ko lākou inoa mai ke ʻano kristal mahana o ka lumi e hana ai iā lākou. ʻO kekahi hui maʻamau ʻo duplex SS, ʻo ia ke kaulike ma waena o ka ferrite a me ka austenite i loko o ke ʻano kristal.
ʻO nā papa Austenitic, ʻo ka moʻo 300, aia he 16% a 30% chromium a me 8% a 40% nickel, e hana ana i kahi ʻano kristal austenitic nui. No ka hoʻolaha ʻana i ka hoʻokumu ʻana o ka ratio austenite-ferrite, hoʻohui ʻia nā mea hoʻopaʻa e like me ka nickel, carbon, manganese a me ka nitrogen i ka wā o ke kaʻina hana kila. ʻO kekahi mau papa maʻamau he 304, 316 a me 347. Hāʻawi i ke kūpaʻa maikaʻi i ka corrosion; hoʻohana nui ʻia i ka meaʻai, ka lawelawe kemika, nā lāʻau lapaʻau a me nā noi cryogenic. ʻO ka kaohi ʻana i ka hoʻokumu ʻana o ka ferrite e hāʻawi i ka paʻakikī haʻahaʻa haʻahaʻa maikaʻi loa.
ʻO Ferritic SS kahi papa moʻo 400 i piha i ka magnetic, aia he 11.5% a 30% chromium, a he ʻano kristal ferritic predominant. No ka hoʻolaha ʻana i ka hoʻokumu ʻia ʻana o ka ferrite, ʻo nā mea hoʻopaʻa e komo pū me ka chromium, silicon, molybdenum, a me ka niobium i ka wā o ka hana kila. Hoʻohana pinepine ʻia kēia mau ʻano SS i nā ʻōnaehana hoʻopau kaʻa a me nā mea kanu mana a he palena palena ko lākou no nā noi wela kiʻekiʻe. ʻO kekahi mau ʻano i hoʻohana pinepine ʻia he 405, 409, 430 a me 446.
ʻO nā papa Martensitic, i ʻike ʻia hoʻi e ka moʻo 400 e like me 403, 410 a me 440, he magnetic, aia he 11.5% a 18% chromium, a he martensite ma ke ʻano he ʻano kristal. ʻO kēia hui pū ʻana ka mea gula haʻahaʻa loa, ʻo ia ka mea e lilo ai lākou i mea liʻiliʻi loa ke kumukūʻai e hana ai. Hāʻawi lākou i kekahi pale ʻana i ka pala; ikaika maikaʻi loa; a hoʻohana pinepine ʻia i nā mea ʻaina, nā lako niho a me nā mea ʻokiʻoki, nā mea kuke, a me kekahi mau ʻano mea hana.
Ke hoʻoheheʻe ʻoe i ka SS, ʻo ke ʻano o ka substrate a me kāna noi i loko o ka lawelawe e hoʻoholo i ka metala hoʻopihapiha kūpono e hoʻohana ai. Inā ʻoe e hoʻohana i kahi kaʻina hana pale kinoea, pono paha ʻoe e makaʻala kūikawā i ka pale ʻana i nā hui kinoea e pale aku i kekahi mau pilikia e pili ana i ka hoʻoheheʻe ʻana.
No ke kāpili ʻana i ka 304 iā ia iho, pono ʻoe i kahi electrode E308/308L. ʻO ke "L" ke kū nei no ke kalapona haʻahaʻa, kahi e kōkua ai i ka pale ʻana i ka pala intergranular. Loaʻa i kēia mau electrodes kahi ʻike kalapona ma lalo o 0.03%; ʻo kēlā me kēia mea ma luna o kēia e hoʻonui i ka pilikia o ke kalapona e piʻi ana i nā palena o ka palaoa a hui pū me ka chromium e hana i nā carbides chromium, e hōʻemi pono ana i ke kūpaʻa ʻana o ke kila. ʻIke ʻia kēia inā loaʻa ka pala ma ka ʻāpana i hoʻopilikia ʻia i ka wela (HAZ) o nā hui SS i hoʻopaʻa ʻia. ʻO kekahi mea e noʻonoʻo ai no ka papa L SS ʻo ia ka haʻahaʻa o ka ikaika tensile ma nā mahana lawelawe kiʻekiʻe ma mua o nā papa SS pololei.
ʻOiai ʻo 304 kahi ʻano austenitic o SS, e loaʻa i ka metala weld pili ka hapa nui o ka austenite. Eia nō naʻe, e loaʻa i ka electrode ponoʻī kahi mea hoʻopaʻa ferrite, e like me ka molybdenum, e hoʻolaha i ka hoʻokumu ʻia ʻana o ka ferrite i loko o ka metala weld. Hoʻopaʻa pinepine nā mea hana i kahi laulā maʻamau o nā nui ferrite no ka metala weld. E like me ka mea i ʻōlelo ʻia ma mua, he mea hoʻopaʻa austenitic ikaika ke kalapona, a no kēia mau kumu he mea nui ia e pale aku iā ia mai ka hoʻohui ʻia ʻana i ka metala weld.
Ua loaʻa nā helu Ferrite mai ka kiʻikuhi Schaeffler a me ka kiʻikuhi WRC-1992, kahi e hoʻohana ai i nā ʻano like nickel a me chromium e helu ai i ka waiwai, kahi i ka wā e hoʻolālā ʻia ai ma ke kiʻikuhi e hana i kahi helu maʻamau. ʻO ka helu ferrite ma waena o 0 a me 7 e pili ana i ka pakeneka nui o ke ʻano kristal ferrite i loko o ka metala weld; eia naʻe, ma nā pakeneka kiʻekiʻe, piʻi ka helu ferrite ma ka wikiwiki. E hoʻomanaʻo ʻaʻole like ka ferrite ma SS me ka ferrite kila kalapona, akā he pae i kapa ʻia ʻo delta ferrite. ʻAʻohe hoʻololi pae o Austenitic SS e pili ana i nā kaʻina hana wela kiʻekiʻe e like me ka mālama wela.
ʻO ke kūkulu ʻia ʻana o ka ferrite he mea makemake ʻia no ka mea ʻoi aku ka ductile ma mua o ka austenite, akā pono e kāohi ʻia. Hiki i nā helu ferrite haʻahaʻa ke hana i nā welds me ke kūpaʻa maikaʻi loa i ka corrosion i kekahi mau noi, akā he mea maʻalahi loa ia i ka haki wela i ka wā o ka welding. No nā kūlana hoʻohana maʻamau, pono ka helu ferrite ma waena o 5 a me 10, akā no kekahi mau noi e koi ʻia nā waiwai haʻahaʻa a kiʻekiʻe paha. Hiki ke hōʻoia maʻalahi ʻia nā Ferrites ma ka hana me ka hoʻohana ʻana i kahi hōʻailona ferrite.
ʻOiai ʻoe i ʻōlelo ai he mau pilikia haki kou a me ka helu ferrite haʻahaʻa, pono ʻoe e nānā pono i kāu metala hoʻopihapiha a e hōʻoia i ka lawa ʻana o ka helu ferrite - ma kahi o 8 e kōkua. Eia kekahi, inā ʻoe e hoʻohana ana i ka flux cored arc welding (FCAW), hoʻohana pinepine kēia mau metala hoʻopihapiha i kahi kinoea pale carbon dioxide 100% a i ʻole kahi hui 75% argon/25% CO2, hiki ke hoʻoulu i ka lawe ʻana o ke kalapona i loko o ka metala weld. Makemake paha ʻoe e hoʻololi i kahi kaʻina hana gas metal arc welding (GMAW) a hoʻohana i kahi hui 98% argon/2% oxygen e hōʻemi i ka hiki ke hōʻiliʻili kalapona.
No ka hoʻopili ʻana iā SS i ke kila kalapona, pono ʻoe e hoʻohana i ka mea hoʻopihapiha E309L. Hoʻohana kūikawā ʻia kēia metala hoʻopihapiha no ka hoʻopili ʻana i nā metala like ʻole a hana i kahi nui o ka ferrite ma hope o ka hoʻoheheʻe ʻia ʻana o ke kila kalapona i loko o ka hoʻopili ʻana. No ka mea e omo ke kila kalapona i kekahi kalapona, hoʻohui ʻia nā mea hoʻopaʻa ferrite i ka metala hoʻopihapiha e pale aku i ke ʻano o ke kalapona e hana i ka austenite. E kōkua kēia i ka pale ʻana i ka haki wela i nā noi hoʻopili.
I ka hōʻuluʻulu manaʻo, inā makemake ʻoe e hoʻopau i nā māwae wela ma nā hui welded austenitic SS, e hōʻoia i ka metala hoʻopihapiha ferrite kūpono a hahai i nā hana wili maikaʻi. E mālama i ka hoʻokomo wela ma lalo o 50 kJ/ʻīniha, e mālama i nā mahana interpass haʻahaʻa a haʻahaʻa, a e hōʻoia i ka ʻole o nā hui solder mai kekahi haumia ma mua o ke kūʻai ʻana. E hoʻohana i kahi ana kūpono e hōʻoia i ka nui o ka ferrite ma ka hui welded, e kuhikuhi ana i 5 a 10.
ʻO WELDER, ʻo Practical Welding Today ma mua, hōʻike i nā poʻe maoli e hana ana i nā huahana a mākou e hoʻohana ai a hana pū me kēlā me kēia lā. Ua lawelawe kēia makasina i ke kaiāulu wili ma ʻAmelika ʻĀkau no nā makahiki he 20 a ʻoi.
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