Kaona Haʻahaʻa CuNi44 Copper – Nickel Alloy Foil

ʻO ka wehewehe pōkole:

Kaona Haʻahaʻa CuNi44 Copper – Nickel Alloy Foil


  • Kumukuai FOB:US $0.5 - 9,999 / ʻāpana
  • Ka nui o ke kauoha:100 ʻāpana/ ʻāpana
  • Hiki ke hoolako:10000 ʻāpana / ʻāpana i kēlā me kēia mahina
  • Awa:Shanghai, Ningbo, Shenzhen
  • Ka manawa hoʻouna:7-10 mau lā ma hope o ka hōʻoia ʻana i ke kauoha
  • kumu:Kina
  • Manawa Uku:T/T , L/C
  • Kūlana:ASTM, AISI, SUS, JIS, EN, DIN, GB, ASME, etc
  • Mill:Pocso/ Tisco/ Lisco/ Jisco/ Bao kila/ H Wang
  • Huahana Huahana

    Hōʻike ʻenehana

    Pūʻolo Huahana & Hoʻouna

    Hoʻolauna Hui

    Ninau & Pane

    Huahana Huahana

    Kaona Haahaa CuNi44 Copper– Nickel Alloy Foil

    ʻO Cu - Ni Foil kahi waiwai hui pū ʻia e hoʻohana ai no ka nui loa a me ka nui o ka hoʻohui ʻana i ka corrosion. ʻO kēia huila i loko o ka waika hydrofluoric a me ke kinoea fluoride me ke kūpaʻa maikaʻi maikaʻi loa, a me ka alkali wela. I ka manawa like, ʻo ia ka corrosion kūʻē i ka hopena kūʻokoʻa, ka wai kai, ka ea, nā mea hoʻohuihui. ʻO kahi hiʻohiʻona koʻikoʻi o kēia ka mea maʻamau ʻaʻole e hoʻohua i ke koʻikoʻi corrosion māwae, hana ʻoki maikaʻi.
    Cu - Ni Foil huila i loko o ka fluoride kinoea, hydrochloricʻakika, sulfuricʻakika, hydrofluoricʻakika a me kā lākou derivatives i ka maikaʻi loa corrosion kū'ē waiwai, a loaʻa i ka maikaʻi corrosion kū'ē ma mua o ke keleawe i loko o ka wai kai. ʻAno ʻakika: ʻO Cu - Ni Foil ka pale ʻana i ka corrosion ma lalo o 85% kūlike o ka sulfuric acid. ʻO Cu - Ni Foil kahi mea koʻikoʻi i kū i ka waika hydrofluoric. ʻO ka ʻino wai: Cu - Ni Foil alloy i ka nui o nā hihia corrosion o ka wai, ʻaʻole maikaʻi wale ke kūʻē ʻana i ka corrosion, akā ʻoi aku ka liʻiliʻi o ka lua, ka corrosion stress, ka nui o ka corrosion ma lalo o 0.025mm / a. Kiʻekiʻe wela corrosion: Cu – Ni Foil no ka hana o ka wela wela ma kahi o 600 °C ma ka laulā ma ka lewa, ma ka wela wela mahu, ka corrosion rate emi ma mua o 0.026mm / a. Ammonia: Cu - Ni Foil hiki ke kū'ē i ka hydrous ammonia a me nā kūlana aminate corrosion ma lalo o 585 ° C ma muli o ka nickel kiʻekiʻe.

    1. Ka wehewehe

    ʻO Cu - Ni Foil kahi pūʻulu nickel alloys, i haku mua ʻia me ka nickel (a hiki i 67%) a me ke keleawe, me kekahi hao a me nā mea ʻē aʻe.

    Na Waiwai Mechanical

    ʻO ka mānoanoa8.83 g/cm3
    Lahui hehee1300-1390 ºC
    Ka ikaika hua>170 Mpa
    Ikaika U'i> 480 Mpa
    Elongation ma 2 in.> 35%

     

    2. nui
    Foil mānoanoa: emi ma mua o 0.05mm
    laula: emi iho ma mua o 200mm

     

    3. Hoʻohana

    ʻO Cu - Ni Foil kahi mea waiwai nui i nā noi ʻoihana he nui:

    1. He paipu wai ʻole i loko o ka hale hana mana
    2. Mea hoʻololi kai-wai a evaporator
    3. Sulfuric acid a me hydrochloric acid kaiapuni
    4. Hoʻoheheʻe ʻia
    5. Ka wai kai i ka hoʻohana ʻana i nā mea hana a me ka propeller shaft
    6. ʻOihana Nukelea a hoʻohana ʻia i ka hana ʻana i nā mea hoʻokaʻawale isotope hoʻonui i ka uranium.

    7. ʻO ka hana ʻana i nā lako hydrochloric acid i hoʻohana ʻia i ka hana ʻana i ka paila a me ka valve.
    4. Nā huahana a me nā lawelawe

    1. Pass: ISO9001 palapala hōʻoia, a me SO14001cetification;
    2. Nā lawelawe ma hope o ke kūʻai aku;
    3. Ua ʻae ʻia ke kauoha liʻiliʻi;
    4. Hoʻouna wikiwiki;

     


  • Mua:
  • Aʻe:

  • Papa Mea

    Mea waiwai ASTM A240 maʻamau 201, 304 304L 304H 309S 309H 310S 310H 316 316H 316L 316Ti 317 317L 321 321H 347 347H 409 410 410L
    ASTM A480 maʻamau 302, s30215, s30452, s30615, 308, 309. 347H, 348H, S31060, N08811, N08020, N08367, N08810, N08904, N08926, S31277, S20161, S30600, S30601, S31254, S31266, S32050, S32654, S32053, S31727, S334525, S334525 03, S32001, S32550, S31260, S32003, S32101, S32205, S32304, S32506, S32520, S32750, S32760, S32900, S32906, S32950, ​​S32974
    JIS 4304-2005 Kūlana SUS301L,SUS301J1,SUS302,SUS304, SUS304L, SUS316/316L, SUS309S, SUS310S, 3SUS21L, SUS347, SUS410L, SUS430, SUS630  
    JIS G4305 Kūlana SUS301, SUS301L, SUS301J1, SUS302B, SUS304, SUS304Cu, SUS304L, SUS304N1, SUS304N2, SUS304LN, SUS304J1, SUSJ2, SUS305, SUS3010S, SUS309S, SUS309S, SUS5SUS J2,SUS316, SUS316L, SUS316N, SUS316LN, SUS316Ti, SUS316J1, SUS316J1L, SUS317, SUS317L, SUS317LN, SUS317J1, SUS317J2, SUS836L, SUS890L, SUS321, SUS347, SUSXM7, SUSXM15J1, SUS329J1, SUS329J3L, SUS329J3L, SUS329J4L, SUS329J4 0, SUS430LX, SUS430J1L, SUS434, SUS436L, SUS436J1L, SUS444, SUS445J1, SUS445J2, SUS447J1, SUSXM27, SUS403, SUS410, SUS410S, SUS420J1, SUS420J2, SUS440A

    Huahana Huahana

    Hoʻopau mānoanoa Nā hiʻohiʻona Nā noi
    Helu 1 3.0mm~50.0mm Hoʻopau ʻia e ka ʻōwili wela, annealing a me ka pickling, i hōʻike ʻia e ka ʻili keʻokeʻo pickled Nā lako hana kemika, nā pahu pahu hana
    Helu 2B 0.3mm~6.0mm Hoʻopau ʻia e ka mālama wela, pickling ma hope o ka ʻōwili anu, a ukali ʻia e ka laina pass ili e ʻoi aku ka mālamalama a me ka maʻalahi o ka ʻili Na Lapaau Lapaau Lapaau Lapaau, Mea Pakaukau
    ʻAʻole. BA (Bright Annealed) 0.5mm~2.0mm Hoʻomaʻamaʻa wela ma hope o ka ʻōwili anu Mea lako kīhini, lako kīhini, kumu hoʻolālā
    Helu 4 0.4mm~3.0mm ʻO ka polishing me ka helu 150 a hiki i ka No.180 mesh abrasives. ʻO nā hoʻopau kaulana loa Nā lako hana waiu a me nā meaʻai, Lako Halemai, ʻauʻau
    Helu 8 0.5mm~2.0mm ʻO kahi aniani e like me ka hoʻohālikelike ʻana ma o ka poli ʻana me nā abrasive ʻoi aku ka maikaʻi ma mua o 800 mesh Reflector, Mirror, Kalaiaina-waho no ke kūkulu hale
    HL(Laina lauoho) 0.4mm~3.0mm Hoʻopau ʻia e ka hoʻopololei laina mau Nā kumu hoʻolālā, nā escalators, nā kaʻa lako kīhini

    Hoʻohui Kimia

    Papa

    C

    Si

    Mn

    P

    S

    Cr

    Ni

    Mo

    Ti

    N

    Cu

    Nb

    201

    ≤0.15

    ≤1.0

    5.50-7.50

    ≤0.05

    ≤0.03

    16.00-18.00

    3.50-5.50

    -

    -

    0.05-0.25

    -

    -

    202

    ≤0.15

    ≤1.0

    7.50-10.00

    ≤0.05

    ≤0.03

    17.00-19.00

    4.00-6.00

    -

    -

    0.05-0.25

    -

    -

    301

    ≤0.15

    ≤1.0

    ≤2.0

    ≤0.045

    ≤0.03

    16.00-18.00

    6.00-8.00

    -

    -

    ≤0.1

    -

    -

    302

    ≤0.15

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    17.00-19.00

    8.00-10.00

    -

    -

    ≤0.1

    -

    -

    303

    ≤0.15

    ≤1.0

    ≤2.0

    ≤0.2

    ≥0.15

    17.00-19.00

    8.00-10.00

    ≤0.6

    -

    ≤0.1

    -

    -

    304

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    17.00-19.00

    8.00-10.00

    -

    -

    -

    -

    -

    304L

    ≤0.03

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    18.00-20.00

    8.00-10.00

    -

    -

    -

    -

    -

    304H

    0.04-0.1

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    18.00-20.00

    8.00-10.00

    -

    -

    -

    -

    -

    304N

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    18.00-20.00

    8.00-10.00

    -

    -

    0.10-0.16

    -

    -

    304J1

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    18.00-20.00

    6.00-9.00

    -

    -

    -

    1.00-3.00

    -

    305

    ≤0.12

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    17.00-19.00

    10.50-13.00

    -

    -

    -

    -

    -

    309S

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    22.00-24.00

    12.00-15.00

    -

    -

    -

    -

    -

    310S

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    24.00-26.00

    19.00-22.00

    -

    -

    -

    -

    -

    316

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    16.00-18.00

    10.00-14.00

    2.00-3.00

    -

    -

    -

    -

    316L

    ≤0.03

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    16.00-18.00

    12.00-15.00

    2.00-3.00

    -

    -

    -

    -

    316H

    ≤0.1

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    16.00-18.00

    10.00-14.00

    2.00-3.00

    -

    -

    -

    -

    316N

    ≤0.03

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    16.00-18.00

    10.00-14.00

    2.00-3.00

    -

    0.10-0.16

    -

    -

    316Ti

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    16.00-19.00

    11.00-14.00

    2.00-3.00

    ≥5C

    -

    -

    -

    317L

    ≤0.03

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    18.00-20.00

    11.00-15.00

    3.00-4.00

    -

    -

    -

    -

    321

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    17.00-19.00

    9.00-12.00

    -

    5C-0.7

    -

    -

    -

    347

    ≤0.08

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    17.00-19.00

    9.00-12.00

    -

    -

    -

    -

    10C-1.10

    347H

    ≤0.1

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    17.00-19.00

    9.00-12.00

    -

    -

    -

    -

    8C-1.10

    2205

    ≤0.03

    ≤1.0

    ≤2.0

    ≤0.035

    ≤0.03

    21.00-24.00

    4.50-6.50

    2.50-3.50

    -

    0.08-0.20

    -

    -

    2507

    ≤0.03

    ≤0.8

    ≤1.2

    ≤0.035

    ≤0.02

    24.00-26.00

    6.00-8.00

    3.00-5.00

    -

    0.24-0.32

    -

    -

    904L

    ≤0.02

    ≤1.0

    ≤2.0

    ≤0.045

    ≤0.03

    19.00-23.00

    23.00-28.00

    4.00-5.00

    -

    -

    1.00-2.00

    -

    C276

    ≤0.02

    ≤0.05

    ≤1.0

    -

    -

    14.00-16.50

    'ē aʻe

    -

    -

    -

    -

    -

    Monel400

    ≤0.3

    ≤0.5

    ≤2.0

    -

    ≤0.024

    -

    ≥63

    -

    -

    -

    28-34

    -

    409L

    ≤0.03

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    17.00-19.00

    -

    -

    -

    -

    -

    -

    410

    ≤0.15

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    11.50-13.50

    -

    -

    -

    -

    -

    -

    410L

    ≤0.03

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    11.50-13.50

    -

    -

    -

    -

    -

    -

    420J1

    0.16-0.25

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    12.00-14.00

    -

    -

    -

    -

    -

    -

    420J2

    0.26-0.40

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    12.00-14.00

    -

    -

    -

    -

    -

    -

    430

    ≤0.12

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    16.00-18.00

    -

    -

    -

    -

    -

    -

    436L

    ≤0.025

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    16.00-19.00

    -

    -

    -

    -

    -

    -

    439

    ≤0.03

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    16.00-18.00

    -

    -

    -

    -

    -

    -

    440A

    0.60-0.75

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    16.00-18.00

    -

    ≤0.75

    -

    -

    -

    -

    440B

    0.75-0.95

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    16.00-18.00

    -

    ≤0.75

    -

    -

    -

    -

    440C

    0.95-1.2

    ≤1.0

    ≤1.0

    ≤0.035

    ≤0.03

    16.00-18.00

    -

    ≤0.75

    -

    -

    -

    -

    441

    ≤0.03

    0.2-0.8

    ≤0.7

    ≤0.03

    ≤0.015

    17.50-18.50

    -

    ≤0.5

    0.1-0.5

    ≤0.025

    -

    0.3+3C-0.9

    mākoue hoʻopili i nā huahana kila me ka pepa anti-rust a me nā apo kila e pale ai i ka pōʻino.

    Hoʻopili ʻia nā lepili ʻike e like me ke kikoʻī maʻamau a i ʻole nā ​​ʻōlelo a ka mea kūʻai aku.

    Loaʻa ka paʻi kūikawā e like me ka makemake o ka mea kūʻai aku.

    Pūʻulu Coil Kuhili ʻole

    ʻO ka pūʻolo wili kila kila cepheus (1)

    ʻO ka pūʻolo wili kila kila cepheus (2)

     

    ʻO ka Pepa Kūleʻa Kūleʻa / Pāʻani Pāʻani Kūleʻa

    ʻO ka pūʻolo pepa kila kila cepheus (3)

    cepheus pā kila kila 1_副本

     

    Pūʻolo ʻōniʻoniʻo hao hao

    ʻO ka pūʻolo ʻili kila ʻili cepheus (5)

    Pūʻolo Hoʻouna

    Hoʻouna ʻia ʻo Cepheus Stainless Steel (1)

    Hoʻouna ʻia ʻo Cepheus Stainless Steel (2)

    Hoʻouna ʻia ʻo Cepheus Stainless Steel (3)

    Hoʻokumu ʻia kā mākou hui ma Wuxi, e hōʻiliʻili i ke kūlanakauhale o ke kila kila kila ma Kina.

    Hoʻomaʻamaʻa mākou i nā wili kulika, nā lau a me ka pā, ka paipu kila kila a me nā mea pono, nā paipu kila kila, a me nā huahana aluminika a me nā huahana keleawe.

    Ua mahalo nui ʻia kā mākou huahana e kā mākou mea kūʻai mai ʻEulopa, ʻAmelika, ka Middle East, ʻApelika a me Asia Hema. E hāʻawi mākou i nā huahana hoʻokūkū a me ka lawelawe piha i nā mea kūʻai aku.

    Papa kila kila: 201, 202, 202cu, 204, 204cu, 303, 304, 304L, 308, 308L, 309, 309s, 310, 310s, 316, 316L, 47, 4, 4, 4, 4, 4 30F, 440, 440c,

    Alloy Grade : Monel, Inconel, Hastolley, Duplex, Super Duplex, Titanium, Tantalum, High Speed ​​Steel, Mild Steel, Aluminum, Alloy Steel, Carbon Steel, Special Nickel Alloys

     

    Ma ke ano o: Poepoe Bars, Hexagonal Bars, Flat Bars, Angles, Channels, Profiles, Wire Rods, Sheets, Plates, Seamless Pipes, ERW Pipes, Flanges, Fittings, etc.

    wuxi cepheus kila kila (1)

     

    wuxi cepheus kila kila (5)

    wuxi cepheus kila kila (4)

    wuxi cepheus kila kila (3)

     

    wuxi cepheus kila kila (2)

     

    Q1: He aha ka mea kila?

    A: ʻAʻohe mea hōʻailona ma ka ʻili kila, a i ʻole kekahi ʻano kila ʻaʻole i hoʻopōʻino ʻia e ka ea a i ʻole ka wai a ʻaʻole hoʻololi i ka waihoʻoluʻu, kīnā ʻole, kūpaʻa i ka ʻili, ka ʻōpala, ka hopena corrosive o nā kemika.

    Q2: ʻAʻole manaʻo ʻia ʻaʻohe ʻōpala?

    A: ʻAʻole, ʻaʻole maʻalahi ke ʻano ʻeleʻele a ʻulaʻula paha, hiki iā ia ke hoʻihoʻi hou i ka staining, ka ʻōpala a me ka ʻino.

    Q3: Ke hoʻolako nei ʻoe i nā ʻāpana kila kila?

    A: ʻAe, hāʻawi mākou i nā ʻano like ʻole o nā ʻāpana kila kila, me nā pae mānoanoa mai 0.3-3.0mm. a ma nā hoʻopau like ʻole.

    Q4: Keʻae neiʻoe i kaʻokiʻana i ka lawelawe lōʻihi?

    A: ʻOiaʻiʻo, ʻo ka ʻoluʻolu o ka mea kūʻai aku ko mākou mea nui.

    Q5: Inā loaʻa iaʻu kahi kauoha liʻiliʻi, e ʻae ʻoe i kahi kauoha liʻiliʻi?

    A: ʻAʻole pilikia, ʻo kou hopohopo ko mākou hopohopo, ʻae ʻia nā mea liʻiliʻi.

    Q6: Pehea e hiki ai iā ʻoe ke hōʻoia i ka maikaʻi o kāu huahana?

    A: ʻO ka mea mua, mai ka hoʻomaka ʻana, ua hoʻokō mākou i kahi ʻuhane i ko lākou noʻonoʻo, ʻo ia ka maikaʻi o ke ola, ʻo kā mākou limahana limahana a me nā limahana e hahai i kēlā me kēia hana a hoʻopaʻa maikaʻi ʻia nā ukana a hoʻouna ʻia i waho.

    Q7: E hoʻopili anei ʻoe i nā huahana?

    A: Hana ka poʻe ʻoihana i ka hoʻopili ʻana i ka ʻoihana, loaʻa iā mākou nā ʻano ʻokoʻa o ka packing koho i nā mea kūʻai aku, hoʻokele waiwai a ʻoi aku paha.

    Q8: He aha kāu e pono ai e ʻike mai ka mea kūʻai aku ma mua o ka ʻōlelo pololei?

    A: No ka ʻōlelo kikoʻī, pono mākou e ʻike i ka papa, ka mānoanoa, ka nui, ka pau ʻana o ka ʻili, ka waihoʻoluʻu a me ka nui o kāu kauoha, a me ka huakaʻi o ka waiwai. E makemake nui ʻia ka ʻike huahana maʻamau, e like me ke kaha kiʻi, ka hoʻolālā a me ka hoʻolālā. A laila e hāʻawi mākou i ka ʻōlelo hoʻokūkū me ka ʻike ma luna.

    Q9: He aha ke ʻano o ka manawa uku āu e ʻae ai?

    A: Keʻae nei mākou iā T / T, West union, L / C.

    Q10: Inā he kauoha liʻiliʻi kēia, e hāʻawi anei ʻoe i nā waiwai i kā mākou luna?

    A: ʻAe, ua hānau ʻia mākou e hoʻoponopono i nā pilikia o kā mākou mea kūʻai aku, e kiʻi pono mākou i nā waiwai i ka hale kūʻai o kāu luna a hoʻouna aku iā ʻoe i nā kiʻi.

    Q11: Ke hana wale nei ʻoe i ka pepa pālahalaha? Makemake au e hana i mea hana no ka'u papahana hou.

    A: ʻAʻole, hana nui mākou i ka hoʻomaʻamaʻa ʻana i ke kila kila, i ka manawa like, hana mākou i nā huahana metala maʻamau e like me ke kiʻi a me ka hoʻolālā o ka mea kūʻai aku, e mālama kā mākou ʻenehana i ke koena.

    Q12: ʻEhia mau ʻāina āu i lawe aku ai?
    A: Ua lawe ʻia aku i nā ʻāina ʻoi aku ma mua o 50 mai ʻAmelika, Russia, UK, Kuwait, Egypt, Iran,
    Tureke, Ioredane, etc.
    Q13: Pehea e hiki ai iaʻu ke loaʻa kekahi mau laʻana?
    A: Nā mea liʻiliʻi liʻiliʻi ma ka hale kūʻai a hiki ke hāʻawi i nā hōʻailona no ka manuahi. Loaʻa ka Catalgue, ka hapa nui
    nā hiʻohiʻona ua mākaukau mākou i nā laʻana i ka waihona. Hoʻopili ʻia nā laʻana e pili ana i 5-7days.
    Q14: He aha ka lawe ʻana?
    A: ʻO ka manawa hāʻawi o ka laʻana he 5-7 lā. ʻO nā kauoha pahu ma kahi o 15-20 mau lā.

    Q15: He aha ka noi e pili ana i kāu huahana?
    A: 1.elevator puka / hale 'ole a me ka escalator 'aoʻao-pā.
    2. Pā i loko a ma waho paha o ka lumi hālāwai / hale ʻaina.
    3.Facade i ka wā e hoʻopaʻa ai i kekahi mea, e like me nā kolamu i loko o ke keʻena.
    4.Ceiling ma ka hale kūʻai. 5.Decorative kiʻi ma kekahi mau wahi leʻaleʻa.
    Q16: Pehea ka lōʻihi e hiki ai iā ʻoe ke hōʻoiaʻiʻo no kēia huahana / hoʻopau?
    A: Hōʻoia kala no nā makahiki he 10. Hiki i ka palapala hōʻoia waiwai kumu
    e hoolakoia.

    Nā Huahana Pili