Khoom nta

Lub zog muaj zog sib tw nrog zoo toughness (core kom zoo dua)
Lub ntsiab kom zoo dua ntawm 13-8Mo PH nyob rau hauv nws ua ke ntawm tsis tshua muaj zog thiab zoo heev toughness. Tom qab kev daws teeb meem thiab kev laus, nws lub zog tensile ntau dua los yog sib npaug rau 965 MPa (tshaj 1400 MPa rau H950 kev laus), yield zog Ntau dua lossis sib npaug rau 860 MPa, elongation Ntau dua lossis sib npaug li 10%, thiab txo qhov chaw zoo. Nws cov pob txha toughness thiab kev ntxhov siab corrosion cracking kuj yog qhov zoo tshaj rau cov ntawm 17-4PH, muab siab dua toughness cia ntawm tib lub zog. Cov yam ntxwv no ua rau nws yog ib qho khoom siv zoo tshaj plaws rau cov ntawv thov xws li aerospace structural Cheebtsam, roj thiab roj downhole cov cuab yeej, thiab nuclear kev lag luam qhov chaw, qhov kev nyab xeeb thiab kev ntseeg siab yog qhov tseem ceeb.

Zoo heev kev nyuaj siab corrosion cracking kuj
Kev ntxhov siab corrosion cracking (SCC) tsis kam ntawm 13-8Mo PH yog nws qhov zoo tshaj plaws ntawm 17-4PH. Nyob rau hauv ib puag ncig uas muaj chloride thiab acidic ib puag ncig nrog hydrogen sulfide (H₂S), SCC tsis kam ntawm 13-8Mo PH yog qhov zoo tshaj ntawm 17-4PH. Kev sib xyaw ua ke ntawm martensitic matrix nrog qhov sib ntxiv ntawm molybdenum (Mo) zoo txhim khu kev ruaj ntseg ntawm cov yeeb yaj kiab passive thiab txo qis kev cuam tshuam rau hydrogen embrittlement. Cov hlau no kuj ua raws li NACE MR0175 / ISO 15156 tus qauv, ua rau nws haum rau cov roj acidic thiab roj ib puag ncig uas muaj hydrogen sulfide. Cov yam ntxwv no ua rau nws xaiv cov khoom siv zoo tshaj plaws rau cov ntawv thov xws li offshore platforms, cov cuab yeej siv roj thiab roj, thiab cov nroj tsuag tshuaj uas muaj chloride ions, H₂S, thiab kev ntxhov siab coexist.

Zoo corrosion kuj
13-8Mo PH qhia tau zoo heev tiv thaiv corrosion thiab pitting nyob rau hauv seawater, chloride tov, thiab atmospheric ib puag ncig vim ib tug ntom, ruaj khov, thiab nws tus kheej- kho Cr₂O₃ oxide zaj duab xis tsim spontaneously ntawm nws nto. Nws cov corrosion kuj tshaj li ntawm 17-4PH (630), tshwj xeeb tshaj yog nyob rau hauv high-kev nyuaj siab corrosion ib puag ncig. Nws kuj pom zoo corrosion kuj nyob rau hauv xov xwm xws li nitric acid, organic acids, thiab alkaline daws. Cov cuab yeej no ua rau nws xaiv cov khoom siv zoo tshaj plaws rau cov ntawv thov uas muaj kev tiv thaiv corrosion siab, suav nrog kev tsim khoom hauv hiav txwv, cov khoom siv tshuaj, thiab cov khoom siv kho mob.

Kev ua haujlwm vuam zoo
13-8Mo PH nthuav tawm cov khoom siv vuam zoo thiab tuaj yeem txuas nrog ntau txoj kev vuam xws li TIG, MIG, thiab SMAW. Thaum lub sij hawm vuam, kev tswj xyuas nruj ntawm cov khoom siv hluav taws xob thiab kev sib tshuam ntawm qhov kub thiab txias yuav tsum tau tiv thaiv cov nplej coarsening nyob rau hauv tshav kub- cuam tshuam cheeb tsam thiab nag lossis daus ntawm cov theem teeb meem. Tom qab vuam, kev daws kev kho mob raws li kev laus yog feem ntau tsim nyog los kho lub zog thiab corrosion kuj ntawm thaj chaw weld. Nws raug nquahu kom siv cov ntaub ntawv sib txuam (piv txwv li, 13-8Mo PH hlau ntawm tib yam muaj pes tsawg leeg) kom ntseeg tau tias cov khoom siv vuam tsis qis dua li cov khoom siv hauv paus.

Ua haujlwm kub thiab txias ua haujlwm zoo
13-8Mo PH nthuav tawm cov khoom ua haujlwm kub zoo heev thiab tuaj yeem tsim los ntawm kub forging, kub dov, kub extrusion, thiab lwm yam txheej txheem kub ua haujlwm nyob rau hauv qhov kub ntawm 950-1150 degree. Tom qab ua haujlwm kub, kev kho kev daws teeb meem (kwv yees li 1010-1050 degree) yog xav tau kom ua tiav qhov zoo tshaj plaws hardenability thiab cov lus teb tom qab laus. Cov khoom ua haujlwm txias txias yog qhov zoo tshaj rau cov 17-4PH, tso cai rau txias khoov, txias dov, stamping, thiab lwm yam kev ua haujlwm. Txawm li cas los xij, nws muaj qhov xav tau ntau dua rau kev ua haujlwm hardening piv rau austenitic stainless hlau. Intermediate annealing yog pom zoo thaum txias deformation tshaj 5-10%.
Technical Specifications
Tshuaj muaj pes tsawg leeg (ASTM A564 / UNS S13800)
|
Lub ntsiab |
Standard Requirements |
Sau ntawv |
|
Cr |
12.25 - 13.25% |
Cov ntsiab lus tseem ceeb uas tsim cov zaj duab xis ntom ntom kom muab kev tiv thaiv corrosion; martensite- tsim cov khoom |
|
Ni |
7.5 - 8.5% |
Austenite stabilizing cov ntsiab lus uas txhim kho toughness thiab tsis kam rau kev ntxhov siab corrosion cracking (SCC) kev ua tau zoo |
|
Mo |
2.0 - 2.5% |
Txhim khu kev tiv thaiv rau pitting corrosion thiab kev nyuaj siab corrosion cracking, thiab txhim kho stability ntawm passive zaj duab xis |
|
Al |
0.90 - 1.35% |
Precipitate thiab ntxiv dag zog rau cov ntsiab lus, tsim NiAl precipitates nrog Ni los muab lub zog siab |
|
Mn |
Tsawg dua lossis sib npaug li 0.10% |
Kev tswj nruj nruj kom tsis txhob muaj kev cuam tshuam tsis zoo rau lub zog thiab corrosion kuj |
|
Si |
Tsawg dua lossis sib npaug li 0.10% |
Tswj nruj |
|
C |
Tsawg dua lossis sib npaug li 0.05% |
Kev tswj nruj nruj kom tiv thaiv cov nag lossis daus ntawm carbide, uas tuaj yeem ua rau muaj kev tiv thaiv corrosion thiab toughness |
|
P |
Tsawg dua lossis sib npaug li 0.010% |
Cov ntsiab lus impurity, tswj nruj heev |
|
S |
Tsawg dua lossis sib npaug li 0.008% |
Cov ntsiab lus impurity, nruj me ntsis tswj kom tsis txhob kub brittleness |
|
Fe |
Qhov seem tshuav (≈ 73.5%) |
Matrix element |
Lub cev muaj zog
|
Khoom |
Tus nqi / Ntau |
Kev Xeem |
|
Qhov ntom |
7.74 g / cm³ |
Chav ntsuas kub (20 degree) |
|
Melting Point |
≈ 1420 degree |
- |
|
Thermal conductivity |
≈ 16 W/(m·K) |
Chav ntsuas kub |
|
Coefficient ntawm thermal expansion (20-100 degree) |
≈ 10.8 × 10⁻⁶ /K |
- |
|
Kev tiv thaiv |
≈ 0.80 μΩ·m |
Chav ntsuas kub |
|
Elastic Modulus (Young's Modulus) |
190 - 200 GPa |
Chav ntsuas kub |
|
Poisson tus ratio |
0.27 - 0.30 |
Chav ntsuas kub |
|
Magnetism |
Ferromagnetic |
Martensitic qauv muaj cov khoom sib nqus |
Mechanical Properties (Kev daws-kho thiab hnub nyoog, tus nqi raug, ASTM A564)
|
Khoom |
H950 lub sij hawm tus nqi |
Hom H1000 Lub Sijhawm Tus Nqi |
Cov qauv kev coj ua |
|
Tensile zog |
Ntau dua lossis sib npaug li 1400 MPa |
Ntau dua lossis sib npaug li 1170 MPa |
ASTM A564 Cov Lus Qhia Tshwj Xeeb |
|
Yield zog (0.2% Offset) |
Ntau dua lossis sib npaug li 1340 MPa |
Ntau dua lossis sib npaug li 1100 MPa |
ASTM A564 Cov Lus Qhia Tshwj Xeeb |
|
Elongation |
Ntau dua lossis sib npaug li 8% |
Ntau dua lossis sib npaug li 12% |
ASTM A564 Cov Lus Qhia Tshwj Xeeb |
|
Kev txo qis ntawm - ntu ntu |
Ntau dua lossis sib npaug li 25% |
Ntau dua lossis sib npaug li 35% |
- |
|
Hardness (Rockwell C) |
≈ 45 - 47 HRC |
≈ 40 - 42 HRC |
- |
|
Impact Toughness (Charpy V-notch) |
20 - 35 J |
40 - 65 J |
- |
Lus Cim: Kev sib xyaw ua ke ntawm lub zog thiab lub zog ntawm 13-8Mo PH yog qhov zoo tshaj ntawm 17-4PH (630), muab siab dua toughness thiab SCC tsis kam ntawm tib theem zog. Cov khoom tshwj xeeb tuaj yeem hloov kho raws li cov neeg siv khoom tshwj xeeb kev laus kub (H950, H1000, H1050, H1100, H1150). Raws li kev laus kub nce, lub zog txo qis me ntsis, tab sis toughness thiab SCC kuj txhim kho.
Corrosion Resistance (Tswj tus nqi)
|
Nruab nrab |
Nco ntsoov |
Kub |
Corrosion tus nqi |
Kev ntsuas |
|
Dej hiav txwv |
- |
Chav tsev kub kom kub |
Tsis quav ntsej |
Zoo heev |
|
Chloride daws (ntsev dej) |
- |
Kub kub |
Tsis quav ntsej |
Zoo heev |
|
Nitric acid (HNO ₃) |
Tsawg dua lossis sib npaug li 40% |
Chav ntsuas kub |
<0.05 |
Zoo heev |
|
Sulfuric acid (H₂SO₄) |
Tsawg dua lossis sib npaug li 20% |
Chav ntsuas kub |
<0.1 |
Zoo |
|
Hydrochloric acid (HCl) |
Tsawg concentration |
Chav ntsuas kub |
<0.1 |
Zoo |
|
Sodium hydroxide (NaOH) |
- |
Chav ntsuas kub |
Tsis quav ntsej |
Zoo heev |
|
Organic acids (xws li acetic acid, citric acid, thiab lwm yam) |
- |
Chav ntsuas kub |
Tsis quav ntsej |
Zoo heev |
|
Dej Chlorine Gas |
- |
Chav ntsuas kub |
Tsis quav ntsej |
Zoo heev |
Lus Cim: Qhov kev tiv thaiv corrosion ntawm 13-8Mo PH yog qhov zoo tshaj ntawm 17-4PH (630) nyob rau hauv feem ntau ib puag ncig, tshwj xeeb tshaj yog nyob rau hauv siab -kev nyuaj siab corrosion ib puag ncig. Nws nthuav tawm cov kev tiv thaiv zoo heev rau kev ntxhov siab corrosion cracking (SCC) nyob rau hauv cov tshuaj chloride thiab H₂S ib puag ncig, tab sis nws cov corrosion kuj yog txwv nyob rau hauv tsis tshua muaj zog txo cov xov xwm xws li high-temperature concentrated hydrochloric acid thiab hydrofluoric acid. Nyob rau hauv ib puag ncig uas muaj hydrogen, hydrogen embrittlement rhiab heev yuav tsum tau ua tib zoo soj ntsuam.
High -kev ua haujlwm kub
13-8Mo PH tuav lub zog siab ntawm qhov kub nruab nrab (H1000 hnub nyoog mob):
|
Kub |
Tensile zog (MPa) |
Kev tuav pov hwm tus nqi |
|
Chav ntsuas kub (20 degree) |
Ntau dua lossis sib npaug rau 1170 |
100% |
|
200 degree |
≈ 1070 |
Ntau dua lossis sib npaug li 91% |
|
300 degree |
≈ 1000 |
Ntau dua lossis sib npaug li 85% |
|
400 degree |
≈ 900 |
Ntau dua lossis sib npaug li 77% |
Ntev -lub sij hawm thermal stability thiab microstructural stability:
13-8Mo PH qhia txog kev ruaj ntseg microstructural zoo thiab nag lossis daus ruaj khov- cov theem tawv tawv thaum nyob rau lub sijhawm ua haujlwm ntev ntawm qhov kub tsawg dua lossis sib npaug li 300℃.
Nco tseg: Lub sijhawm ntev raug ntawm 300-450℃tuaj yeem ua rau dhau- kev laus, ua rau txo qis zog, thiab yog li kev siv mus sij hawm ntev hauv qhov ntsuas kub no tsis pom zoo. Ntawm qhov kub siab tshaj 500 degree, cov theem precipitate pib coarsen, ua rau txo qis zog.
Antioxidant Performance:
13-8Mo PH tuaj yeem tsim cov txheej tiv thaiv oxide hauv qab 650 degree. Rau kev ua haujlwm ntev ntawm qhov kub thiab txias, nws raug nquahu kom ntsuas oxidation qhov hnyav nce thiab kev ua haujlwm degradation.
Kev kho cua sov
Kev kho cua sov ntawm 13-8Mo PH muaj qhov cuam tshuam rau qhov kawg microstructure thiab cov khoom, nrog rau cov lus qhia tshwj xeeb raws li hauv qab no:
1. Kev kho mob (kom tau txais kev pom zoo hardenability thiab cov lus teb kev laus tom ntej):
Tshav kub rau 1010-1050 degree, tuav lub sijhawm txaus (kwv yees li 15-30 feeb ib nti ntawm tuab), ces roj quench lossis cua txias. Qhov no npaj ib qho qauv martensitic rau kev laus tom ntej.
2. Lub Sijhawm Ua Haujlwm (kom tau txais qib uas yuav tsum tau muaj zog):
Kub rau 480-620℃(H950-H1150), tuav rau 4-8 teev, ces cua txias. Precipitate NiAl precipitates kom tau txais kev sib xyaw ua ke ntawm lub hom phiaj lub zog thiab toughness.
|
Kev laus |
Kub |
Hom tensile zog |
Daim ntawv thov scenarios |
|
H950 |
480-495 degree |
Ntau dua lossis sib npaug li 1400 MPa |
Cov kev xav tau siab tshaj plaws |
|
H1000 |
540-555 degree |
Ntau dua lossis sib npaug li 1170 MPa |
Qhov sib npaug ntawm lub zog siab thiab zoo toughness |
|
H1050 |
565-580 degree |
Ntau dua lossis sib npaug li 1100 MPa |
High toughness + zoo zog |
|
H1100 |
595-610 degree |
Ntau dua lossis sib npaug li 1030 MPa |
Kev tiv thaiv zoo tshaj -SCC kev ua tau zoo |
|
H1150 |
620-635 degree |
Ntau dua lossis sib npaug li 965 MPa |
Qhov siab tshaj plaws toughness thiab SCC tsis kam ua haujlwm |
Nco tseg:
Kev kho cua sov yuav tsum tau ua nyob rau hauv lub tshuab nqus tsev los yog inert gas tiv thaiv kom tsis txhob nto oxidation thiab decarburization.
Kev sib txawv ntawm qhov kub thiab lub sijhawm tuaj yeem cuam tshuam rau cov khoom siv kho tshuab kawg thiab yuav tsum tau tswj nruj me ntsis.
Nws raug nquahu kom ua pickling lossis passivation tom qab kev kho cua sov kom tshem tawm cov nplai.
Kev sib piv ntawm Magnetic Properties thiab Application Selection
|
Performance indicators, As |
13-8 PHN |
17-4 PH (630) |
15-5 PHN |
|
Tensile zog (MPa) |
Ntau dua lossis sib npaug rau 1170-1400 |
Ntau dua lossis sib npaug rau 1100-1310 |
Ntau dua lossis sib npaug rau 1060-1310 |
|
Yield zog (MPa) |
Ntau dua lossis sib npaug rau 1100-1340 |
Ntau dua lossis sib npaug rau 1000-1170 |
Ntau dua lossis sib npaug rau 1000-1170 |
|
Elongation (%) |
Ntau dua lossis sib npaug li 8-12 |
Ntau dua lossis sib npaug li 10-15 |
Ntau dua lossis sib npaug li 10-15 |
|
Anti-SCC Kev Ua Haujlwm |
Superior (zoo dua 17-4PH) |
General |
Zoo |
|
Fracture toughness |
Superior (zoo dua 17-4PH) |
Zoo |
Zoo |
|
Tsawg-kev ua haujlwm kub |
Zoo heev |
General |
General |
|
Corrosion Resistance |
Zoo tshaj 17-4PH |
Zoo |
Zoo |
|
Magnetism |
Ferromagnetism |
Ferromagnetism |
Ferromagnetism |
|
Cov lus qhia xaiv |
Feem ntau yog siv rau cov ntawv thov nrog kev xav tau ntawm lub zog siab, siab tawv, thiab SCC tsis kam: aerospace, roj thiab roj, kev lag luam nuclear, khoom siv kho mob |
Feem ntau siv nyob rau hauv dav dav siab - siv corrosion resistant ib puag ncig |
Feem ntau siv nyob rau hauv nruab nrab lub zog thiab zoo toughness ib puag ncig |
Siv tau Media
1. Seawater thiab chloride daws: Zoo heev tiv thaiv pitting corrosion, crevice corrosion, thiab kev nyuaj siab corrosion cracking.
2. Oxidizing acids: xws li nitric acid (tsawg dua los yog sib npaug li 40%), nrog zoo corrosion kuj.
3. Cov ntsiab lus qis qis qis: xws li sulfuric acid (tsawg dua lossis sib npaug li 20%).
4. Organic acids: Acetic acid, citric acid, formic acid, thiab lwm yam.
5. Alkaline daws: Sodium hydroxide, potassium hydroxide, thiab lwm yam.
6. Chloride-muaj cov roj thiab roj av: Petroleum thiab natural gas tsim thiab ua ib puag ncig, ua raws li NACE MR0175 tus qauv (nyob ntawm cov kev pabcuam).
7. Siab -kub dej vapor (kub yuav tsum tau soj ntsuam).
Faj seeb: 13-8Mo PH tsis tiv taus kom txo qis tshaj tawm xws li hydrofluoric acid thiab siab - kub concentrated hydrochloric acid. Nyob rau hauv ib puag ncig uas muaj hydrogen, hydrogen embrittlement rhiab heev yuav tsum tau ua tib zoo soj ntsuam.
13-8Mo PH yog qhov tsim nyog rau cov xwm txheej hnyav nrog cov kev cai dav dav rau lub zog siab heev, siab tawv, thiab tsis kam rau kev ntxhov siab corrosion tawg (SCC), thiab pom zoo siv rau hauv cov nram qab no:
Daim ntawv thov teb
-
Aerospace
● Aircraft structural Cheebtsam, tsaws iav qhov chaw, hydraulic actuators
● Cav accessories, fasteners, missile casings
● Spacecraft structural Cheebtsam -
Kev lag luam roj thiab Natural Gas (Core Applications)
● Cov cuab yeej Downhole (xws li cov yeeb nkab sib txuas, packers, kev ruaj ntseg li qub)
● Cov khoom siv Wellhead, li qub, cov yeeb nkab fittings, flanges
● Acid nruab nrab cov cuab yeej kho mob (tiv taus H₂S thiab CO₂ corrosion), ua raws NACE MR0175 tus qauv
● Marine platform fasteners, siab -siab pipeline systems -
Kev lag luam nuclear
● Nuclear Reactor Control Qws Tsav Mechanism Cheebtsam
● Nuclear roj ua khoom siv
● Nuclear - qib fasteners thiab cov khoom siv -
Kev kho mob thiab Biomedical Engineering
● Orthopedic implants (hip stems, hauv caug Cheebtsam)
● Cov cuab yeej phais
● Cov cuab yeej kho hniav -
Chemical Engineering thiab Petrochemical Engineering
● High-siab li qub, lub twj tso kua mis, cov fasteners
● Kub exchangers, reactor internals
● Pipeline system rau conveying corrosive media -
Offshore engineering
● Sib sib zog nqus-cov khoom siv hauv hiav txwv cov khoom siv, cov nkoj khi
● Marine dej twj tso kua mis valve Cheebtsam -
Tsheb thiab High -Kev Lag Luam Kev Ua Haujlwm
● High-kev ua haujlwm springs, valve springs
● Cav txuas rods, lub teeb yuag kis tau tus mob Cheebtsam
● Sib tw fasteners
Kev xa khoom thiab Customization
Peb muab cov khoom lag luam hloov pauv tau yooj yim thiab txhim khu kev qha los xyuas kom meej tias koj tau txais 13-8Mo PH cov ntaub ntawv uas zoo kawg nkaus phim koj qhov kev xav tau.
|
Daim ntawv |
![]() Ntawv / phaj
|
![]() Bar / Qws
|
![]() Tube / Tube
|
![]() Sawb / Sheet Coil
|
![]() Hlau / Hlau Rod
|
|---|---|---|---|---|---|
|
Pauv ntau yam |
Thickness: 0.5 - 100 hli |
Txoj kab uas hla Φ6-500mm |
Sab nraud txoj kab uas hla Φ10-300mm |
Thickness: 0.05-3.0 hli |
Txoj kab uas hla Φ0.5-10mm |
|
Customization Muaj peev xwm |
Kub- dov los yog txias - dov daim hlau, ultra- daim hlau nyias (pib los ntawm 0.1mm), stamped qhov chaw, ntev- txiav mus rau qhov ntev, tshwj xeeb kev kho mob (pickling, polishing) |
Forged tuav, kub-khoov tuav, polished tuav, zoo li tus tuav, thiab sib txawv cua sov- kho tej yam kev mob (kev daws-kho, H950-H1150 laus tej yam kev mob) |
Seamless raj / welded raj, ruaj -ntev txiav |
Precision strip cov ntaub ntawv, stamping coil Tshuag, laminated blanking, tsis yog - qauv dav, tshwj xeeb tiv thaiv zaj duab xis |
Precision drawing, vuam muab tub lim, tshwj xeeb nto kho |
Vim li cas thiaj xaiv peb? - Txhim khu kev qha Engineering Technology. Dependable xa khoom.
Peb tsis yog ib tus neeg muag khoom xwb, tab sis yog ib tus neeg koom tes nrog cov ntaub ntawv ntseeg siab rau koj hauv Suav teb.

Vertically Integrated Production
Muaj 20,000㎡ qhov chaw nrog 10+ automated kab (8, 000+ tons / xyoo). Hauv - tsev cuab yeej & qhov chaw tuag ua rau muaj kev hloov kho sai thiab tswj tus nqi zoo - tsis muaj tus neeg nruab nrab kos npe.

Kev Tswjhwm nruj nruj ntawm txhua theem
Tag nrho traceability nyob rau hauv lub tseem ceeb QC checkpoints thoob plaws hauv ntau lawm . 100% raws li ASTM/ASME, EN, thiab GB qauv. Cov ntaub ntawv xeem cov ntaub ntawv muaj nyob nrog txhua qhov khoom xa tuaj.

Txhim khu kev xa khoom & Export ntim
10+ xyoo xa tawm mus rau Tebchaws Europe, North America, Southeast Asia & Middle East nrog cov dej tsis zoo thiab tiv thaiv- xeb, ua ke nrog cov kev xaiv thauj khoom yooj yim kom muaj kev nyab xeeb thiab nyob rau - lub sijhawm tuaj txog.

Qauv validation ua ntej pawg ntau lawm
Peb muab cov qauv dawb rau kev kuaj xyuas zoo, tso cai rau koj tso cov xaj xaj tsuas yog tom qab kev pom zoo. Peb xyuas kom meej qhov sib xws los ntawm cov qauv mus rau cov khoom loj los ntawm qhov ntsuas qhov tseeb thiab kev tsim pob tshab.
FAQ
Q: Dab tsi yog qhov zoo ntawm 13-8Mo PH?
Q: Qhov txawv ntawm 13-8Mo PH thiab 17-4PH (630) yog dab tsi? Yuav xaiv li cas?
Q: Dab tsi yog qhov siab tshaj plaws kev siv kub rau 13-8Mo PH?
Q: Lub vuam kev ua tau zoo ntawm 13-8Mo PH yog dab tsi?
Q: Yuav 13-8Mo PH hloov 17-4PH?
Cim npe nrov: 13-8moph, Tuam Tshoj 13-8moph manufacturers, lwm tus neeg, Hoobkas









