Zovala zosapanga dzimbiri za chitsulo chosapanga dzimbiri cholumikizira chimatha ma A403 mawonekedwe apafupi

Ngakhale magawo ovomerezeka amawonedwa opindulitsa a alloy, moyenera, zonyansa pa Asthe A182 F9 zotchinga zitha kukhala zotchinga kwambiri. Milandu imapangidwa pogwiritsa ntchito ziganizo Asm A182, amagwiranso ntchito kutentha kwambiri, amagwiritsa ntchito pokakamizidwa kwambiri.

Zokhala ndi chitsulo chosapanga dzimbiri cha 304 cha kukana kosankhidwa kwambiri, graider iyi kuvomerezedwa ndi makhosi a screck itha kuphatikizidwa ndi kachitidwe ka musidi wodula khosi. Dera lowonera limatha kuwunikiridwa mosavuta ndi radiography. Chitoliro chofanana ndi kuchepetsa chipwirikiti kumachepetsa mtima mkati mwa mapaipi. Flanger ndibwino kwambiri kugwiritsa ntchito ntchito zanu komanso ndi yabwino kugwiritsa ntchito ndi mpweya, madzi, mafuta, mpweya wachilengedwe, ndi nthunzi.

Chitoliro chachitsulo & chubu
Chitsulo chachitsulo
Super Dumlex S327660 bar imayenera kukhala yosinthira bwino kwambiri m'makalasi a austetitic m'madera a Marine. Super Dupper S327660 kuzungulira bar (ASTM A276 \ / Astm A479) imawonetsa kukana kwabwino mpaka 3005.
Adapangidwa \ / kutentha kumachitidwa ndikupangidwa

Mapaipi a Alloy ndi mitengo yabwino kwambiri yopsinjika kuwonongeka (SSC). Izi zimagwiranso ntchito m'malo omwe vutoli limatha komanso lotupa. Machubu awa ndi machubu amapezeka mkati mwa chilolezo chamakina ndi kulolera.

Incrooy 800h Valnge Tili ndi mbiri yolimba mu malonda popanga mitundu yayikulu ya mitundu yosiyanasiyana ya makasitomala athu. Timakhala ngati infolisoy ma fronges omwe ndi odalirika komanso apamwamba kwambiri. Timagwiritsa ntchito ndalama zotsogola komanso makina apamwamba popanga assowm B564 SIMIL N08800 Stuliloy ma fronges 800.

Alloy 800 ndi a nickeum-chromiam almoy mphamvu ndi mphamvu yayikulu komanso kukana kwa oxidation ndi kutupa kwambiri. ASTM B407 SINE N08800 infoloy 800 WR. 1.4876 Chitoliro chowala bwino chimagwiritsidwa ntchito kwambiri pomanga zida zofuna kukana kuchuluka, kukana kutentha, mphamvu, komanso kukhazikika pakuchita nawo ntchito mpaka 1500 ° C).

Ma coil 625 amadziwika ndi kukana kwake kwabwino kwa oxidation, kutentha kwambiri komanso kutopa. ASTM B443 SANDO N06625 SIVELEILE imagwiritsidwa ntchito kwambiri mu anthospace, mankhwala kutengera ndi mafuta ndi mafakitale chifukwa champhamvu kwambiri.

ASTM A240 Mtundu 2205 Plate ndi duwa losapanga dzimbiri lomwe limagwiritsidwa ntchito kwambiri m'mafakitale, kufufuza kwamafuta ndi mafuta, ndi ukadaulo wamadzi, ndi ukadaulo wamadzi. Mapepala 2205 amapangidwa kuchokera ku kalasi ya SAGIS 2205, chitsulo chosapanga dzimbiri, chomwe chimaphatikizika ndi chitsulo champhamvu.

Asme B36.19M ndiye wofanana ndendende ndi mapaipi achitsulo osapanga dzimbiri, zomwe zimafotokoza kukula kwake, kulolerana, ndi zomwe amapanga maenda owala komanso osaka.

Ma sheluloy 800 ndi kuphatikiza kwa nickel, chromium ndi chitsulo chowonjezera ndi maubwino a oxiyation kapena apakatikati kapena mphamvu yayikulu komanso yolimba kwambiri kutchula owerengeka.

Chromium yapamwamba, molybdenum ndi nayitrogeni imapangitsa kuti zikhale bwino kwambiri (zomwe zingachitike) zitsulo zokongoletsera ndi zotupa zosapanga dzimbiri, komanso kutentha kotsika kwambiri kuposa 50¡c.

Iswees osawoneka bwino kwambiri a sing'anga osawoneka N06600 ndi Astm B167 ndi omwe amapangidwa kuti apirire kwambiri ndikubwera ndi chitsimikizo chachikulu.

Zoyenera za chitoliro za mawonekedwe apadera kapena omwe sanali oyenera kufa kuti apangidwe ndi njira yopezerera Free. Ngati tee, iyenera kupangidwa kunja kwa nthambi.

Al6xn ndi chitsulo chosapanga dzimbiri chosakhazikika ku chloride pansi, crevice kutukuka komanso kupsinjika kuwonongeka. Al6xn ndi Alloy a 6 wokhazikika womwe umapangidwa ndipo umagwiritsidwa ntchito m'malo ovuta. Ili ndi Nickel (24%), Molybdenum (6.3%), nayitrogeni ndi chromium yomwe imapangitsa kuti zisautso, chloride pansi. Al6xn imagwiritsidwa ntchito makamaka pokana zolimba komanso zopondera ku chlorisi. Ndi chitsulo chosapanga dzimbiri.

Makina oyeserera a Hydrostatic \ / chonyansa cha UI

Invalsel 718 ndi alloy-chromium-chromium-chromium-chromium-chromium-chromium-chromium-chromium-chromium-chromium-chromium yomwe imagwiritsidwa ntchito kwambiri pamapulogalamu apamwamba monga Aweslospace ndi majini agalu. Chimodzi mwazinthu zofunika kwambiri pakupanga a Ism B670 Invelve 718 ndiye kuti mbale yogubuduza. Pali mitundu iwiri yayikulu ya mbale za Intery18 zomwe zilipo pamsika: kuwotcha mbale zowombera.

Mtundu wa 316 Chitsulo chosapanga dzimbiri chimafanana ndi 304, koma ndi kuwonjezera kwa Molybdenum, komwe kumathandizira kukana kwa Spores Trussion. Mapangidwe a austetic amalola kulimba mtima, ngakhale pansi mpaka kutentha kochepa kwambiri. Maphunzirowa ali ndi thanzi labwino kwambiri, ndi kapena popanda kuwonjezera pazitsulo zosefera. 316 \ /1l Imapezeka kuti yowonda komanso yosawoneka bwino. Ili ndi Molybdenum ndi nickel kuposa osapanga zinthu 304, omwe amawonjezera kukana kwachitsulo. Kutsika kwathyozedwa kumawonetsedwa mu 316l madontho chifukwa cha kuchuluka kwa kaboni mu alloy. Amagwiritsidwa ntchito ngati chubu m'matumba owopsa kuposa 304 chubu.

M'mafomu osiyanasiyana, mitundu, zida ndi masukulu, miyeso ndi zina mwazinthu zina. Mitundu iyi imatha kuwomeredwa pogwiritsa ntchito njira zosiyanasiyana zopeputsira kapena kuwunika kwambiri pogwiritsa ntchito magsiketi. M'makina a Pipring, kuti mulumikiza mapaipi, ma valves, mapampi ndi zida zina zimachitika. Ma flanges amapereka mwayi wofikira pakuwunikira, kuyeretsa, ndi zosintha. Zovala zosapanga masamba 304l zimasisita ma flanges ndi zitsulo zosapanga dzimbiri zomwe zimakhala ndi chipongwe chosiyanasiyana choponderezedwa ndi chitsulo. Amapereka chipongwe chokwanira cha & crevice chogwirizana. 

Masiku ano, alyoy B2 okhala ndi chemistry yoletsedwa amatha kugwiritsidwa ntchito munthawi yotentha ndipo sangakhale wotanganidwa ndi scc pansi pa zinthu zambiri. Monga nthawi zonse, chisamaliro chimayenera kutengedwa posankha chivomerezi choyenera pazomwe mukufuna.
B16.47 Ndege A & B \ / B16.48, BS4504 \ / Dost

Chitoliro chowoneka bwino chimapangidwa kuti chijambulidwe patsamba kumapeto kwake ndikulumikizani mapaipe (s) ndikulola kusintha njira kapena kuthirira kapena kutha.

FSTEOLLOY C2000 mapaipi a ASME SB626 FOTELOLELOY C2000 Worded Bis
FSTEOLLOY C2000 ikupezeka mu mitundu yosiyanasiyana ndi makulidwe amtunduwu, mtundu uwu wa chromium-molybdenum aroyoy amadziwika bwino chifukwa cha mphamvu zake zazikulu komanso kukana.
316 Zosapanga Zosapanga

Aloy 800h wediod mapaipi (omwe amadziwikanso kuti wnr 1.4958 chitoliro). Makina a mankhwala ndi mafuta osinthira mafakitale a N08881 a kusinthidwa kwa kutentha ndi makina ena a Nitric acid makamaka pokana kutsitsa kwa chloride. Zomera zamagetsi zimawagwiritsa ntchito popanga zouzira zapamwamba komanso zokuwotcha.

Kuchulukitsa kwa titanium ndi pafupifupi 60% yomwe ya chitsulo chosapanga dzimbiri ndi nickel polosys, kupulumutsa thupi kumeneku kumapangitsa kuti ikhale chisankho chodziwika bwino pakugwiritsa ntchito monga Arrospace.

304, 316 ndi 316l ndi 316l osapanga dzimbiri ndi austetic, mawu omwe amagwiritsidwa ntchito kuti afotokozere kapangidwe kake. Kapangidwe kake kamakwaniritsidwa ndi kutentha kuchitira kutentha kwambiri kumatsatiridwa ¨C yozizira yozizira yomwe imatseka mawonekedwe ake. Mapangidwe a austetitic ndi amphamvu kuposa matentheti a Martienitic kapena andewu. Zitsulo zachangu ndi zamatsenga, zimakhala ndi zokhudzana ndi kaboni, ndikutsutsa osavomerezeka.

S32750 S32760 Super Duptux dambo wosapanga matope osakhazikika

A789 S31803 ndi S32205 ndi zitsulo ziwiri zosapanga dzimbiri zomwe zimagwiritsidwa ntchito kwambiri pantchito zosiyanasiyana. Mapaipi awa a duplex s31803 osakhala opanda chidwi amadziwika chifukwa chokana kwambiri kuwonongeka, mphamvu zazikulu, komanso kutopa kwambiri. A789 ndi lingaliro lomwe limakwirira osawoneka bwino komanso machubu opangidwa ndi chitsulo chosapanga dzimbiri.

FOSTELOLOY C2000 amagwiritsidwa ntchito m'mafakitale ambiri kuphatikizapo mafakitale a petrochemical, makonzedwe a mankhwala opanga mafuta, zophika zamafuta ndi zomera.

316l 1.4401 s31603 Chipika chosapanga dzimbiri ndi njira yolimba komanso yolimba yofananira yomwe imagwiritsidwa ntchito pazosiyanasiyana za mafakitale ndi malonda. Izi s31603 chitoliro chimapangidwa kuchokera pazinthu zapamwamba za 316l osapanga dzimbiri mosapanga dzimbiri mosapanga chipongwe, oxidation ndi chomata, zomwe zimapangitsa kuti zikhale zabwino m'malo mwazinthu zovuta kapena zovuta.

Asme \ / ANSI B16.5 \ A ANINI B16.47 \ / ASE SP-44L SPARTE, 304l Wopwala, 304l Wosayenda Maso.

Magalasi okhazikika - omwe adayikapo sayansi-nickel-cobalt matobala, Kovar Smows, ali ndi mzere wowonjezera wowonjezera wofanana ndi galasi lolimba mkati mwa kutentha kwina

304 Nphwemba zopondapondazikulu zimapangidwa ndi chitsulo chosapanga dzimbiri, zinthu wamba komanso zodziwika bwino muzogwiritsidwa ntchito zambiri zamakampani zomwe zimafunikira kukana kuwonongeka ndi oxidation. Nyansiweli iyi ya S30400 imakonzedwa pogwiritsa ntchito makina apadera ndi njira, zomwe zikuwonetsetsa kuti ndi olondola komanso odalirika.
Imbani 36 K93600
Chubu chosowa
Chitoliro chowala
Chubu chowala
Kovar Aloy 4j29
Nickel alloy pipe & chubu
Nickel alloy mbale & ma sheets & coils
Mipiringidzo yachitsulo & ndodo
Itar 36 Tubed OD: 0.2-6mm, WT: 0.02-2mm
A182 F316L Slanger Winey
KOR8367 SUMFY SUBE AL6XN WOPHUNZITSIRA

Nickel Anoy 400 ndi Monl 400, omwe amadziwikanso kuti ndi N04400 Nictal-Copy-Copy-Copy kukhala makamaka mwa atatu a Nickel ndi chachitatu. Nickel Anoy 400 amadziwika chifukwa chokana kusiyanasiyana, kuphatikiza alkalis (kapena asidi), madzi amchere, ma hydrofluoric acid. Kuyambira monoy 400 kapena Aloy 400 ndi chitsulo chozizira chogwira ntchito, chivomerezichi chimakhala cholimba, kuuma ndi mphamvu. Pogwira ntchito yozizira astm B164 SARD N04400 bar stock, alloy imayang'aniridwa ndi kupsinjika kwamakina, komwe kumapangitsa kusintha kwa micrestructuctuctution ya Alloy.

Makina okankha \ / makina am'madzi am'madzi owonera \ / kanikizani makina \ / makina owombera \ / makina otentha

Chitsito chopanda maziko cha 316 chakhala chinthu chofunikira kwambiri kwa gawo la mafakitale. Chitsulo ichi ndi chrome chimadziwika kuti ndikukana kwake kuvunda, komanso kukhazikika kwake. 316 Chitsulo chosapanga dzimbiri chimatha kupangidwa muzosaso komanso machubu owuma kuti akwaniritse zosowa zapadera za kasitomala.
Imbani 36 K93600
Chubu chosowa
Chitoliro chowala
Chubu chowala
Kovar Aloy 4j29
Nickel alloy pipe & chubu
Nickel alloy mbale & ma sheets & coils
Mipiringidzo yachitsulo & ndodo
Itar 36 Tubed OD: 0.2-6mm, WT: 0.02-2mm
A182 F316L Slanger Winey
Incoloy 800h chitoliro chokhala ndi temple wambiri

Super Pumplex amafufuza kuchuluka kwa kaboni, phosphorous, sulfure, silicon, nayitrogeni, ndi mkuwa. Ili ndi pokana kwambiri kukana, akufuna kuti agwiritse ntchito mpaka 600¡ f, ndi pang'ono pokhazikika.

Ma Bols 625 amagwiritsidwa ntchito makamaka pakuzizira kwa cyclic ndikutenthetsa. Ndiwothandiza pamagetsi oundana. Ma bolts amagwiritsidwa ntchito m'nyumba ya injini, zisa za uchi komanso m'mizere ya hydraulic

Montel K500 ndi chinsinsi cha zaka zolimbitsa thupi zomwe zimagwirizanitsa kukana kwa Aloy 400 ndi mphamvu yayikulu yotopa komanso kukana kukokoloka.

Nilo Anoy 36, w.NR 1.3912, Inciar 36 ® ndi chitsulo chotsika kwambiri chomwe chili ndi 36% Nickel ndipo ali ndi gawo la kufalikira kwa gawo limodzi la chitsulo cha kaboni pafupifupi.

Amagwiritsidwa ntchito kwambiri mu zopondaponda m'mafuta ndi mafuta a gasi \ / kupanga ndi kusinthidwa kwa kutentha mu petrochemical \ / mankhwala.

S32750 S32760 Super Duple Dambo Sipei Mapaipi Osiyanasiyana Amagwiritsidwa Ntchito Kuti Akwaniritse Mphamvu Yofanana ndi Mphamvu ya Thicker Nickel

Alloy 400 akutsutsana ndi kutukwana, mphamvu zazikulu komanso zowoneka bwino. Monl 400 ili ndi makina odabwitsa pamakina ku Ser-zero kutentha. Imakhala ndi mutu wa 2370-2406f ndipo imagwiritsidwa ntchito mosavuta pamatenthedwe mpaka 1000¡f.

Mitundu ya 304 ndi 316 ndi makonda ambiri achitsulo chopanda dzimbiri ndikutchula chitsulo chimodzi chokha. Ngati mungayang'ane mtundu wa mtundu wa 304 kapena 316 mwa osapanga dzimbiri mu Mabuku a Asther a Startner, simupeza. Izi ndichifukwa choti ndi zitsulo zosalala osati zosintha, koma mainjiniya adzawatchula kuti ndi makontrakita amafunikira.

Kugonjetsedwa kwa Prososion Fretelloy kumagwiritsidwa ntchito kwambiri ndi mafakitale a mankhwala. Kufunika koyenera kumabweretsa mwayi wovomerezeka ndi mphamvu zawo, thanzi komanso zachilengedwe, mafuta ndi mpweya, mafakitale a mankhwala osokoneza bongo.

Zizindikiro za Nickel-Copy-Copy 400 monol 2.4360 molunjika rod ndiyabwino kwambiri opsinjika ku chloride ku chloride movutikira mukakumana ndi zowononga m'matumbo. Monl 400 ndi a Haloy ndi Nickel omwe amadziwika masiku ano chifukwa cha ntchito yake yayitali. Alloy ali ndi kukana bwino acid ndi alkali. Kuphatikiza apo, ili ndi mphamvu zabwino zokhala ndi mphamvu, duckity, kukhala waulimi wabwino kwambiri, ndipo imatha kuumitsidwa ndi ntchito yozizira. Kuphatikiza apo, itha kugwiritsidwa ntchito poizona ndi kutentha kuyambira kuchotsera mpaka 538 digiri Celsius.

Nickel 200 Amalongosola Nickel 200 Malawi amakhala olimba, osasunthika, ndipo amaliza bwino. Kuphatikiza apo, Astm B564 SP52200 N02200 Zisoka zakhungu zimalimbana ndi kutengera ndale komanso zotsatsa, zimapangitsa kukhala bwino kugwiritsa ntchito zida zogwirizira.

ASMM A312 TP316 ndi njira yokhazikika ya msoko, komanso kuzizira kwambiri osakhazikika opaleshoni ya chitsulo chosapanga dzimbiri zomwe zimagwiritsidwa ntchito kutentha kwambiri ndi ntchito wamba. Chitoliro chosawoneka bwino mafakitale chimapangidwa kuchokera ku chromium, nickel, ndi molybdenum, omwe amapereka SS Quams Stuam Turnion ku kutukula ndi dzimbiri.

Zopanga zosapanga dzimbiri zopanga 316L 1.4401 s31603 chitoliro chachitsulo chosapanga chitsulo

Chitoliro cha HT ndi chimodzi mwazomwe zimadalira & stoctist wa Aisi 304L kumachitika ku China.  Izi asi 304l ma flanges amapangidwa komanso miyezo yapadziko lonse. Monga othandizira ovomerezeka, tapereka izi

SA 182 F53 S32750 Flange ndi chitsulo chosapanga dzimbiri chomwe chimaperekedwa potentha ndikusintha njira.

Ictives 600 yozungulira ndi intoy-valkel-brad-cenel carburrization ndi kukana bwino kuwonongedwa kwakukulu. Zingwe zozungulira 600 zozungulira zimagwira ntchito kuyanika cl2 ndi mipweya ina yambiri yofananira ndi kutentha kwambiri. Alloy 600 bar ndi a chromial-cromiyal-cromiyal-cromiyal-chloride bwino oxidation ndi kukana ku chloride kuwonongeka kwa chloride kugwa, ukhondo wamadzi acid kumatentha.

ASTM AS 403 WP 316L ndi yolimba kwambiri kudutsa zigawo za acidic ndi mankhwala. Kalasi ili ndi mphamvu yofananira ndi ma 500 pa 20 \ / kg k.

Zigawo zikuluzikulu za magawo 304 osapanga dzimbiri kuchokera pazitsulo ndi chitsulo ndi nickel. 304 Muli ndi 18 - 20% chromium (cr). Chromium ndi mankhwala ofunikira mu chitsulo chosapanga dzimbiri, chimapangitsa kuti "osakhazikika"

A789 S31803 ndi S320205 BUM
CU-NI 90 \ / 10 ma flanges akhungu amadziwika kuti amatha kuthana ndi kututa m'malo ovuta. Copper-nickel 90 \ / flange ilinso yolimbana kwambiri ndi mabulalidwe.
ASME A240 Mtundu 2205 Drite Stockgerder SA 240 GRE 2205

Kuchulukitsa kwa nickel mu 316 ss kumathandizira kukonza kwake kutukuka kwa 304. Chifukwa chake, ndikulimbikitsidwa kuti mugwiritse ntchito mchere wambiri, kapena madera okhala ndi mankhwala, makamaka chlorides.

Kuwala ndi mphete ya chitsulo (kupangidwa kuchokera ku mbale, kapena yolumikizidwa) kupangidwira zigawo za chitoliro, kapena kuti mulowetse chitoliro cha sitimayo, misonkhano ina kapena pamsonkhano wina wophatikizika. Zowawa zimaphatikizidwa wina ndi mnzake, ndipo kumapazi polowera kapena kupukusa (kapena kumasula pomwe madotolo amagwiritsidwa ntchito). Chitani chitsulo chosapanga dzimbiri chimasankhidwa kukhala SS nyambo, amatanthauza ma mbengo omwe adapanga chitsulo chosapanga dzimbiri. Miyezo yodziwika bwino ndi Stadem ndi Asso A182 REPE F304 \ / l ndi 300
Imbani 36 K93600
Chubu chosowa
Chitoliro chowala
Chubu chowala
Kovar Aloy 4j29
Nickel alloy pipe & chubu
Nickel alloy mbale & ma sheets & coils
Mipiringidzo yachitsulo & ndodo
Itar 36 Tubed OD: 0.2-6mm, WT: 0.02-2mm
A182 F316L Slanger Winey
ASME A182 Mkulu F316 Thitct

HISTELOLOY C22 bar ili ndi Nickel-Molybdenum-chromium Superraloy komanso tungsten ndipo amapangidwa kuti athe kutsutsana ndi malo okhala. Zimakhala zolimbana kwambiri ndi kuwonongeka m'malo omitikana ndipo amagwiritsidwa ntchito pogwiritsa ntchito mankhwala m'malo owala.

Mapaipi a kusokonekera kosasaka kumakhala ndi mwayi wokhala ndi katundu wapamwamba kwambiri komanso mphamvu zambiri.
SS 304l kuchepetsa ma flanges
Chubu chosowa
Chitoliro chowala
Chubu chowala
Kovar Aloy 4j29
Nickel alloy pipe & chubu
Zhengzhou Huitong Mapaipel Counc CO., LTD.
Mipiringidzo yachitsulo & ndodo
Itar 36 Tubed OD: 0.2-6mm, WT: 0.02-2mm

Chifukwa Chomwe ASTM BH637 Balts N07718 amasankhidwa makamaka chifukwa chopanga ma injini a Turbinine. Popeza injini ya Turbine imagwira ntchito pamfundo zoyambira za thermodynamic, injini ya injini ya Turbine imachuluka ngati kutentha kwa turbine kusenza.

Pofuna kufafanizira mapaipi, ndikofunikira kuchotsa payipi yolunjika pa mapaipi. Mukamagwiritsa ntchito ma piipelines osiyanasiyana, mapaipi osiyanasiyana ayenera kugwiritsidwa ntchito. Pamene mapaipiwo amagwiritsidwa ntchito, chikopa chiyenera kugwiritsidwa ntchito kusintha kukula kwa mapaipi. Mukamacheza, chipika chanjira zitatu chowonekacho chimagwiritsidwa ntchito ngati cholumikizira cholumikizira, kuti chikhazikitse chipani cholumikizirana kapena kukula kwa nthawi yayitali komanso cholumikizira cholumikizira cha mapaipi. , Pakulumikizana ndi zida zosiyanasiyana, palinso zolumikizira ndi mapulagini a gawo la chida.

Inter 36 ® ndi chitsulo-chitsulo chotsika kwambiri chomwe chili ndi 36% Nickel, IMPARS 36 ili ndi zochulukirapo pakukula kwa kutentha kwa a Crogenic pafupifupi + 260 ° C).

Kenako kuyenera kukhala gawo la kachitidwe koyendetsa madzi (mafuta, gasi, nthunzi, macheza, ...) mtunda wautali kapena wautali.

Izi zimathandizira kuthana ndi sulufuric acid. Ilinso ndi mawu apamwamba kwambiri, kuti apititsenso kukana kwake kuti athe kugwiritsa ntchito mankhwala ndi njira zomwe zimapangidwa ndi mitsinje yolimba ndi mpweya wosungunuka.