Neke atu i te 80% o te whakamahinga o ngā momo kowiri tira takirua, takirua nui, me te takirua nui e whakamahia ana. I whakawhanakehia i ngā tau 1930 hei whakamahi i roto i te hanga pepa me te penupenu, ko ngā koranu takirua he mea hanga mai i te 22% Cr me te hanganga moroiti austenitic:ferritic e whakarato ana i ngā āhuatanga miihini e hiahiatia ana.
Ki te whakatauritea ki ngā maitai kore waikura austenitic 304/316 whānui, ko te whānau o ngā momo takirua ka rua te kaha, ā, ka nui ake te ātete ki te waikura. Mā te whakanui ake i te nui o te chromium o ngā maitai kore waikura ka nui ake te ātete ki te waikura pitting. Heoi, ko te Pitting Resistance Equivalent Number (PREN) e whakaatu ana i te ātete o te koranu ki te waikura pitting kei roto hoki he maha atu ngā huānga i roto i tana tauira. Ka taea te whakamahi i tēnei āhuatanga ngawari hei whakamārama i te whanaketanga o te rerekētanga i waenga i te UNS S31803 me te UNS S32205, me te mea he mea nui.
Whai muri i te whanaketanga o ngā maitai kore waikura takirua, i hopukina tō rātou whakatakotoranga tuatahi ko UNS S31803. Heoi, he maha ngā kaihanga matua i whakaputa tonu i tēnei tohu ki te pito o runga o te whakatakotoranga e whakaaetia ana. I whakaatahia tēnei i tō rātou hiahia ki te whakanui ake i te mahi waikura o te koranu, me te āwhina a te whanaketanga o te tukanga hanga maitai AOD i taea ai te whakahaere pakari ake i te hanganga. Hei tāpiri, i taea ai hoki te awe i te taumata o ngā tāpiri hauota, kaua ko te mea papamuri anake. Nō reira, ko te tohu takirua tino pai i whai ki te whakanui ake i ngā taumata o te chromium (Cr), te molybdenum (Mo) me te hauota (N). Ko te rerekētanga i waenga i te koranu takirua ko tōna hanganga e tutuki ana ki te pito o raro o te whakatakotoranga, me te mea e pa ana ki te tihi o te whakatakotoranga ka taea te maha o ngā tohu i runga i te tātai PREN = %Cr + 3.3 %Mo + 16 % N.
Hei wehewehe i te maitai kore waikura takirua i hangaia i te pito o runga o te awhe hanganga, i whakaurua mai tētahi atu whakatakotoranga, arā, ko te UNS S32205. Ko te maitai kore waikura takirua i hangaia ki te tapanga S32205 (F60) ka tutuki katoa i te tapanga S31803 (F51), engari kāore te ritenga kē. Nō reira, ka taea te whakamana takirua i te S32205 hei S31803.
| Tau | Ni | Cr | C | P | N | Mn | Si | Mo | S |
| S31803 | 4.5-6.5 | 21.0-23.0 | Teitei 0.03 | Teitei 0.03 | 0.08-0.20 | Mōrahi 2.00 | Mōrahi 1.00 | 2.5-3.5 | Mōrahi 0.02 |
| S32205 | 4.5-6.5 | 22-23.0 | Teitei 0.03 | Teitei 0.03 | 0.14-0.20 | Mōrahi 2.00 | Mōrahi 1.00 | 3.0-3.5 | Mōrahi 0.02 |
Kei a SAKYSTEEL he whānuitanga whānui o te maitai kore waikura takirua hei hoa tohatoha pai mō Sandvik. Kei a mātou te S32205 i ngā rahi mai i te 5/8″ ki te 18″ te diameter i roto i te pae porowhita, ko te nuinga o ā mātou taonga kei roto i te taumata Sanmac® 2205, e tāpiri ana i te 'kaha miihini whakarei ake hei paerewa' ki ngā āhuatanga kē atu. Hei tāpiri, kei a mātou hoki te whānuitanga o te pae kau S32205 mai i tō mātou whare putunga UK, me te pereti tae atu ki te 3″ mai i tō mātou whare putunga Portland, USA.
Wā tuku: Oketopa-25-2019