Q: Ua hoʻomaka koke nei mākou e hana i kekahi mau hana e pono ai kekahi mau ʻāpana e hana ʻia mai ke kila kila 304, kahi i hoʻopaʻa ʻia iā ia iho a me ke kila palupalu. Ua ʻike mākou i kekahi mau pilikia me ka haki ʻana o ka weld ma waena o ke kila kila a me ke kila kila a hiki i ka 1.25″ ka mānoanoa. Ua ʻōlelo ʻia he haʻahaʻa ko mākou mau pae ferrite. Hiki iā ʻoe ke wehewehe i ke ʻano o ia mea a pehea e hoʻoponopono ai?
A: He nīnau maikaʻi kēlā. ʻAe, hiki iā mākou ke kōkua iā ʻoe e hoʻomaopopo i ke ʻano o ka ferrite haʻahaʻa a pehea e pale aku ai.
ʻO ka mea mua, e nānā 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 kila, a me kekahi mau hui ʻē aʻe. ʻAʻohe hao i loko o ka aluminika, ke keleawe, a me ka titanium, 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 nui o ka hao ma ka liʻiliʻi he 90% a me ke kila kila ʻole me ka nui o ka hao ma 70 a 80%. I mea e hoʻokaʻawale ʻia ai he SS, pono e loaʻa iā ia ma ka liʻiliʻi he 11.5% chromium i hoʻohui ʻia. ʻO nā pae chromium ma luna o kēia paepae haʻahaʻa loa e paipai i ka hoʻokumu ʻana o kahi 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 hoʻouka kemika.
Ua māhele nui ʻia ke kila kila i ʻekolu mau pūʻulu: austenitic, ferritic a me martensitic. Loaʻa ko lākou inoa mai ke ʻano kristal ma ka mahana o ka lumi i haku ʻia ai lākou. ʻO kekahi hui maʻamau ʻo ke kila kila duplex, ʻo ia ke kaulike ma waena o ka ferrite a me ka austenite i loko o ke ʻano kristal.
ʻO nā papa Austenitic, 300 series, aia he 16% a 30% chromium a me 8% a 40% nickel, e hana ana i kahi ʻano kristal austenitic nui. Hoʻohui ʻia nā mea hoʻopaʻa e like me ka nickel, carbon, manganese, a me ka nitrogen i ka wā o ke kaʻina hana kila e kōkua i ka hoʻokumu ʻana i ka ratio austenite-ferrite. ʻO kekahi mau papa maʻamau he 304, 316 a me 347. Hāʻawi i ke kūpaʻa maikaʻi i ka pala; hoʻohana nui ʻia i nā ʻoihana meaʻai, kemika, lāʻau lapaʻau a me cryogenic. ʻO ka kaohi ʻana i ka hoʻokumu ʻana o ka ferrite e hāʻawi i ka paʻakikī maikaʻi loa i nā mahana haʻahaʻa.
ʻO Ferritic SS kahi papa moʻo 400 i piha i ka magnetic, aia he 11.5% a 30% chromium, a he ʻano kristal ferritic nui kona. 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 powertrains a he palena ko lākou mau noi wela kiʻekiʻe. He nui nā ʻano i hoʻohana pinepine ʻia: 405, 409, 430 a me 446.
ʻO nā papa Martensitic, i kapa ʻia hoʻi ʻo ka moʻo 400, e like me 403, 410, a me 440, he magnetic, aia he 11.5% a 18% chromium, a he ʻano kristal martensitic. ʻO kēia hui pū ʻana ka mea gula haʻahaʻa loa, e lilo ai lākou i mea liʻiliʻi loa ke kumukūʻai e hana ai. Hāʻawi lākou i kekahi kūpaʻa i ka pala, ikaika kiʻekiʻe, a hoʻohana pinepine ʻia i nā mea ʻaina, nā lako niho a me nā lako ʻokiʻoki, nā mea kuke, a me kekahi mau ʻano mea hana.
Ke hoʻoheheʻe ʻoe i ke kila kila, ʻo ke ʻano o ka substrate a me kāna hoʻohana ʻana i ka lawelawe e hoʻoholo i ka metala hoʻopihapiha kūpono e hoʻohana ʻia. Inā ʻoe e hoʻohana ana i kahi kaʻina hana kinoea pale, pono paha ʻoe e makaʻala kūikawā i nā hui kinoea pale e pale aku i kekahi mau pilikia e pili ana me ka hoʻoheheʻe ʻana.
No ke kāpili ʻana i ka 304 iā ia iho, pono ʻoe i kahi electrode E308/308L. ʻO "L" ke kū nei no ke kalapona haʻahaʻa, kahi e kōkua ai i ka pale ʻana i ka pala intergranular. ʻOi aku ka liʻiliʻi o ke kalapona o kēia mau electrodes ma mua o 0.03%, inā ʻoi aku kēia waiwai, piʻi ka pilikia o ka waiho ʻana o ke kalapona ma nā palena o ka palaoa a me ka hoʻopaʻa ʻana o ka chromium e hana i nā carbides chromium, kahi e hōʻemi pono ai i ke kūpaʻa ʻana o ke kila. ʻIke ʻia kēia inā loaʻa ka pala ma ka ʻāpana i hoʻopilikia ʻia e ka wela (HAZ) o nā wili kila kila. ʻO kekahi mea e noʻonoʻo ai no ke kila kila kila papa L, ʻo ia ka haʻahaʻa o ko lākou ikaika tensile ma nā mahana hana kiʻekiʻe ma mua o nā papa kila kila pololei.
ʻOiai ʻo 304 kahi ʻano kila kila austenitic, e loaʻa i ka metala weld like 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 pae maʻamau no ka nui o ka ferrite no kahi 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 e pale i kona hoʻohui ʻia ʻana i ka metala weld.
Ua loaʻa nā helu Ferrite mai ka pakuhi Scheffler a me ka pakuhi WRC-1992, kahi e hoʻohana ai i nā ʻano like nickel a me chromium e helu ai i ka waiwai i ka wā e kaha ʻia ai ma ka pakuhi e hāʻawi 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 ferritic i loko o ka metala weld, akā naʻe, ma nā pakeneka kiʻekiʻe, piʻi wikiwiki ka helu ferrite. E hoʻomanaʻo ʻaʻole like ka ferrite ma SS me ka ferrite kila kalapona, akā he pae i kapa ʻia ʻo delta ferrite. ʻAʻole hana ke kila kila Austenitic i nā hoʻololi pae e pili ana i nā kaʻina hana wela kiʻekiʻe e like me ka mālama wela.
He mea makemake ʻia ka hoʻokumu ʻana o Ferrite no ka mea ʻoi aku ka ductile ma mua o ka austenite, akā pono e kāohi ʻia. Hiki i ka haʻahaʻa o ka ferrite ke hāʻawi i nā welds me ke kūpaʻa maikaʻi loa i ka corrosion i kekahi mau noi, akā he mea maʻalahi loa lākou i ka haki wela i ka wā o ka welding. No ka hoʻohana maʻamau, pono ka helu o nā ferrites ma waena o 5 a me 10, akā koi paha kekahi mau noi i nā waiwai haʻahaʻa a kiʻekiʻe paha. Hiki ke nānā maʻalahi ʻia nā Ferrites ma ka wahi hana me kahi hōʻailona ferrite.
ʻOiai ua ʻōlelo ʻoe he pilikia kou me ka haki ʻana a me nā ferrites haʻahaʻa, pono ʻoe e nānā pono i kāu metala hoʻopihapiha a e hōʻoia i ka lawa ʻana o nā ferrites - ma kahi o 8 e hana i ka hana. Eia kekahi, inā ʻoe e hoʻohana ana i ka flux-cored arc welding (FCAW), hoʻohana pinepine kēia mau metala hoʻopihapiha i kahi kinoea pale o 100% carbon dioxide a i ʻole ka hui ʻana o 75% argon a me 25% CO2, hiki ke hoʻoulu i ka metala weld e omo i ke kalapona. Hiki iā ʻoe ke hoʻololi i ke kaʻina hana metal arc welding (GMAW) a hoʻohana i kahi hui 98% argon/2% oxygen e hōʻemi i ka hiki ke waiho ʻia o ke kalapona.
I ka wā e hoʻopili ai i ke kila kila kila, pono e hoʻohana i ka mea hoʻopihapiha E309L. Hoʻohana kūikawā ʻia kēia metala hoʻopihapiha no ka hoʻopili ʻana i nā metala like ʻole, e hana ana 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, 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 ka wā o ka hoʻopili ʻana.
I ka hopena, inā makemake ʻoe e hoʻoponopono i nā māwae wela i nā wili kila kila austenitic, e nānā i ka lawa ʻana o ka metala hoʻopihapiha ferrite a hahai i ka hana wili maikaʻi. E mālama i ka hoʻokomo wela ma lalo o 50 kJ/in, e mālama i nā mahana waena haʻahaʻa a haʻahaʻa, a e hōʻoia i ka maʻemaʻe o nā hono solder ma mua o ke wili ʻana. E hoʻohana i kahi ana kūpono e nānā i ka nui o ka ferrite ma ka wili, e kuhikuhi ana i 5-10.
ʻO WELDER, i kapa ʻia ma mua ʻo Practical Welding Today, ke hōʻike nei 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 welding ma ʻAmelika ʻĀkau no nā makahiki he 20 a ʻoi.
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