{"id":1096,"date":"2025-09-23T12:34:10","date_gmt":"2025-09-23T05:34:10","guid":{"rendered":"https:\/\/inoxcuongthinh.com\/bi-mat-chong-gi-cua-inox-khoa-hoc-ve-lop-mang-crom-thu-dong\/"},"modified":"2025-09-23T12:34:10","modified_gmt":"2025-09-23T05:34:10","slug":"bi-mat-chong-gi-cua-inox-khoa-hoc-ve-lop-mang-crom-thu-dong","status":"publish","type":"post","link":"https:\/\/inoxcuongthinh.com\/bi-mat-chong-gi-cua-inox-khoa-hoc-ve-lop-mang-crom-thu-dong\/","title":{"rendered":"B\u00ed m\u1eadt ch\u1ed1ng g\u1ec9 c\u1ee7a inox: khoa h\u1ecdc v\u1ec1 l\u1edbp m\u00e0ng crom th\u1ee5 \u0111\u1ed9ng"},"content":{"rendered":"<div class=\"custom-toc\">\n<h3>N\u1ed9i dung ch\u00ednh<\/h3>\n<ul>\n<li><a href=\"#toc-0-lop-mang-crom-thu-dong-la-gi-va-hinh-thanh-ra-sao\">L\u1edbp m\u00e0ng crom th\u1ee5 \u0111\u1ed9ng l\u00e0 g\u00ec v\u00e0 h\u00ecnh th\u00e0nh ra sao?<\/a><\/li>\n<li><a href=\"#toc-1-vi-sao-inox-van-gi-nhung-co-che-hu-hai-thuong-gap\">V\u00ec sao inox v\u1eabn \u201cg\u1ec9\u201d? Nh\u1eefng c\u01a1 ch\u1ebf h\u01b0 h\u1ea1i th\u01b0\u1eddng g\u1eb7p<\/a><\/li>\n<li><a href=\"#toc-2-thanh-phan-hop-kim-quyet-dinh-suc-ben-mang-crom\">Th\u00e0nh ph\u1ea7n h\u1ee3p kim quy\u1ebft \u0111\u1ecbnh s\u1ee9c b\u1ec1n m\u00e0ng crom<\/a><\/li>\n<li><a href=\"#toc-3-vi-cau-truc-va-gia-dinh-inox-anh-huong-den-mang\">Vi c\u1ea5u tr\u00fac v\u00e0 \u201cgia \u0111\u00ecnh\u201d inox: \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn m\u00e0ng<\/a><\/li>\n<li><a href=\"#toc-4-be-mat-han-va-xu-ly-sau-gia-cong-quyet-dinh-tuoi-t\">B\u1ec1 m\u1eb7t, h\u00e0n v\u00e0 x\u1eed l\u00fd sau gia c\u00f4ng: quy\u1ebft \u0111\u1ecbnh tu\u1ed5i th\u1ecd ngo\u00e0i hi\u1ec7n tr\u01b0\u1eddng<\/a><\/li>\n<li><a href=\"#toc-5-thiet-ke-giam-rui-ro-de-mang-crom-luon-tho-duoc\">Thi\u1ebft k\u1ebf gi\u1ea3m r\u1ee7i ro: \u0111\u1ec3 m\u00e0ng crom lu\u00f4n \u201cth\u1edf\u201d \u0111\u01b0\u1ee3c<\/a><\/li>\n<li><a href=\"#toc-6-chon-mac-inox-theo-moi-truong-su-dung-tai-viet-nam\">Ch\u1ecdn m\u00e1c inox theo m\u00f4i tr\u01b0\u1eddng s\u1eed d\u1ee5ng t\u1ea1i Vi\u1ec7t Nam<\/a><\/li>\n<li><a href=\"#toc-7-bao-tri-de-lop-mang-crom-luon-khoe\">B\u1ea3o tr\u00ec \u0111\u1ec3 l\u1edbp m\u00e0ng crom lu\u00f4n kh\u1ecfe<\/a><\/li>\n<li><a href=\"#toc-8-kiem-tra-va-xu-ly-khi-xuat-hien-gi-nauo-tra\">Ki\u1ec3m tra v\u00e0 x\u1eed l\u00fd khi xu\u1ea5t hi\u1ec7n g\u1ec9 n\u00e2u\/\u1ed1 tr\u00e0<\/a><\/li>\n<li><a href=\"#toc-9-giai-dap-nhanh-cac-cau-hoi-thuong-gap\">Gi\u1ea3i \u0111\u00e1p nhanh c\u00e1c c\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/a><\/li>\n<li><a href=\"#toc-10-khi-nao-nen-can-nhac-dung-duplex\">Khi n\u00e0o n\u00ean c\u00e2n nh\u1eafc du\u0300ng duplex?<\/a><\/li>\n<li><a href=\"#toc-11-lien-he-tieu-chuan-va-thuc-hanh-tot\">Li\u00ean h\u1ec7 ti\u00eau chu\u1ea9n v\u00e0 th\u1ef1c h\u00e0nh t\u1ed1t<\/a><\/li>\n<li><a href=\"#toc-12-ket-luan\">K\u1ebft lu\u1eadn<\/a><\/li>\n<\/ul>\n<\/div>\n<p>Trong m\u1ecdi ki\u1ebfn th\u1ee9c n\u1ec1n t\u1ea3ng v\u1ec1 th\u00e9p kh\u00f4ng g\u1ec9, l\u1edbp \u201cm\u00e0ng crom\u201d th\u1ee5 \u0111\u1ed9ng l\u00e0 ch\u00eca kh\u00f3a gi\u00fap inox ch\u1ed1ng g\u1ec9. B\u00e0i vi\u1ebft n\u00e0y \u0111i th\u1eb3ng v\u00e0o c\u01a1 ch\u1ebf khoa h\u1ecdc: l\u1edbp m\u00e0ng h\u00ecnh th\u00e0nh nh\u01b0 th\u1ebf n\u00e0o, v\u00ec sao t\u1ef1 ph\u1ee5c h\u1ed3i, khi n\u00e0o b\u1ecb ph\u00e1 v\u1ee1, c\u00f9ng h\u01b0\u1edbng d\u1eabn ch\u1ecdn m\u00e1c inox \u2013 gia c\u00f4ng \u2013 b\u1ea3o tr\u00ec t\u1ed1i \u01b0u cho \u0111i\u1ec1u ki\u1ec7n Vi\u1ec7t Nam.<\/p>\n<h2 id=\"toc-0-lop-mang-crom-thu-dong-la-gi-va-hinh-thanh-ra-sao\">L\u1edbp m\u00e0ng crom th\u1ee5 \u0111\u1ed9ng l\u00e0 g\u00ec v\u00e0 h\u00ecnh th\u00e0nh ra sao?<\/h2>\n<p>Th\u00e9p \u201ckh\u00f4ng g\u1ec9\u201d l\u00e0 th\u00e9p c\u00f3 t\u1ed1i thi\u1ec3u 10,5% Crom (Cr). Khi ti\u1ebfp x\u00fac v\u1edbi kh\u00f4ng kh\u00ed hay n\u01b0\u1edbc c\u00f3 oxy h\u00f2a tan, crom ph\u1ea3n \u1ee9ng t\u1ea1o l\u1edbp m\u00e0ng oxit crom r\u1ea5t m\u1ecfng (ch\u1ee7 y\u1ebfu Cr2O3) b\u00e1m s\u00e1t b\u1ec1 m\u1eb7t kim lo\u1ea1i.<\/p>\n<p>&#8211; Th\u00e0nh ph\u1ea7n v\u00e0 \u0111\u1ed9 d\u00e0y: l\u1edbp m\u00e0ng d\u00e0y kho\u1ea3ng 1\u20133 nm (nanomet), g\u1ed3m Cr2O3 chi\u1ebfm \u01b0u th\u1ebf, c\u00f3 th\u1ec3 k\u00e8m oxit\/hydroxit s\u1eaft v\u00e0 niken. L\u1edbp n\u00e0y \u0111\u1eb7c, b\u1ec1n, kh\u00f3 h\u00f2a tan trong m\u00f4i tr\u01b0\u1eddng trung t\u00ednh.<br \/>\n&#8211; C\u01a1 ch\u1ebf b\u1ea3o v\u1ec7: m\u00e0ng Cr2O3 c\u1eaft \u0111\u1ee9t \u0111\u01b0\u1eddng d\u1eabn \u0111i\u1ec7n h\u00f3a gi\u1eefa kim lo\u1ea1i n\u1ec1n v\u00e0 m\u00f4i tr\u01b0\u1eddng, l\u00e0m t\u1ed1c \u0111\u1ed9 \u0103n m\u00f2n gi\u1ea3m h\u00e0ng ngh\u00ecn l\u1ea7n so v\u1edbi th\u00e9p th\u01b0\u1eddng.<br \/>\n&#8211; \u0110i\u1ec1u ki\u1ec7n h\u00ecnh th\u00e0nh: c\u1ea7n c\u00f3 \u0111\u1ee7 crom (\u226510,5%) v\u00e0 oxy (kh\u00f4ng kh\u00ed ho\u1eb7c n\u01b0\u1edbc c\u00f3 oxy). V\u00ec v\u1eady inox m\u1edbi gia c\u00f4ng xong, hay sau khi t\u1ea9y g\u1ec9\/pickling, s\u1ebd nhanh ch\u00f3ng \u201ct\u1ef1 th\u1ee5 \u0111\u1ed9ng h\u00f3a\u201d.<\/p>\n<h3>T\u1ef1 ph\u1ee5c h\u1ed3i (self-healing) di\u1ec5n ra th\u1ebf n\u00e0o?<\/h3>\n<p>Khi b\u1ec1 m\u1eb7t inox b\u1ecb x\u01b0\u1edbc nh\u1eb9, l\u1edbp m\u00e0ng b\u1ecb ph\u00e1 v\u1ee1 c\u1ee5c b\u1ed9. Trong m\u00f4i tr\u01b0\u1eddng c\u00f3 oxy, crom \u1edf v\u00f9ng l\u1ed9 ra l\u1eadp t\u1ee9c oxy h\u00f3a v\u00e0 t\u00e1i t\u1ea1o m\u00e0ng m\u1edbi. Qu\u00e1 tr\u00ecnh t\u00e1i th\u1ee5 \u0111\u1ed9ng c\u00f3 th\u1ec3 di\u1ec5n ra trong mili-gi\u00e2y \u0111\u1ebfn v\u00e0i gi\u00e2y. \u0110\u00e2y l\u00e0 l\u00fd do inox \u201ckh\u00f4ng c\u1ea7n s\u01a1n\u201d v\u1eabn b\u1ec1n trong nhi\u1ec1u n\u0103m.<\/p>\n<h3>Gi\u1edbi h\u1ea1n c\u1ee7a s\u1ef1 th\u1ee5 \u0111\u1ed9ng<\/h3>\n<p>M\u00e0ng crom b\u1ec1n v\u1eefng trong:<br \/>\n&#8211; pH kho\u1ea3ng 4\u201310, nhi\u1ec7t \u0111\u1ed9 th\u01b0\u1eddng \u0111\u1ebfn trung b\u00ecnh.<br \/>\n&#8211; M\u00f4i tr\u01b0\u1eddng c\u00f3 oxy \u0111\u1ea7y \u0111\u1ee7, \u00edt ion clorua.<\/p>\n<p>M\u00e0ng c\u00f3 th\u1ec3 suy y\u1ebfu ho\u1eb7c b\u1ecb ph\u00e1 v\u1ee1 trong:<br \/>\n&#8211; Axit kh\u1eed m\u1ea1nh (HCl, H2SO4 \u1edf n\u1ed3ng \u0111\u1ed9 cao, nhi\u1ec7t \u0111\u1ed9 cao).<br \/>\n&#8211; M\u00f4i tr\u01b0\u1eddng ng\u1eadp n\u01b0\u1edbc t\u00f9 \u0111\u1ecdng, thi\u1ebfu oxy.<br \/>\n&#8211; Dung d\u1ecbch c\u00f3 clorua (mu\u1ed1i, h\u01a1i bi\u1ec3n) \u1edf nhi\u1ec7t \u0111\u1ed9 cao, \u0111\u1eb7c bi\u1ec7t t\u1ea1i khe h\u1eb9p.<\/p>\n<h2 id=\"toc-1-vi-sao-inox-van-gi-nhung-co-che-hu-hai-thuong-gap\">V\u00ec sao inox v\u1eabn \u201cg\u1ec9\u201d? Nh\u1eefng c\u01a1 ch\u1ebf h\u01b0 h\u1ea1i th\u01b0\u1eddng g\u1eb7p<\/h2>\n<p>\u201cKh\u00f4ng g\u1ec9\u201d kh\u00f4ng c\u00f3 ngh\u0129a l\u00e0 \u201ckh\u00f4ng bao gi\u1edd g\u1ec9\u201d. Khi m\u00e0ng th\u1ee5 \u0111\u1ed9ng b\u1ecb ph\u00e1 c\u1ee5c b\u1ed9, x\u1ea3y ra \u0103n m\u00f2n c\u1ee5c b\u1ed9:<\/p>\n<p>&#8211; \u0102n m\u00f2n r\u1ed7 (pitting): do ion Cl\u2212 ph\u00e1 v\u1ee1 m\u00e0ng, t\u1ea1o r\u1ed7 li ti ph\u00e1t tri\u1ec3n s\u00e2u. Th\u01b0\u1eddng xu\u1ea5t hi\u1ec7n tr\u00ean 304 \u1edf v\u00f9ng ven bi\u1ec3n ho\u1eb7c g\u1ea7n b\u1ec3 b\u01a1i.<br \/>\n&#8211; \u0102n m\u00f2n khe (crevice): trong khe h\u1eb9p d\u01b0\u1edbi bul\u00f4ng, gio\u0103ng, c\u1ea1nh h\u00e0n\u2026 n\u01a1i thi\u1ebfu oxy, pH gi\u1ea3m, Cl\u2212 t\u1eadp trung, m\u00e0ng m\u1ea5t \u1ed5n \u0111\u1ecbnh.<br \/>\n&#8211; N\u1ee9t do \u0103n m\u00f2n \u1ee9ng su\u1ea5t (SCC): trong m\u00f4i tr\u01b0\u1eddng clorua + nhi\u1ec7t \u0111\u1ed9 cao + \u1ee9ng su\u1ea5t k\u00e9o (v\u00ed d\u1ee5 austenitic 304\/316 \u1edf ~60\u2013150\u00b0C).<br \/>\n&#8211; \u0102n m\u00f2n li\u00ean k\u1ebft h\u1ea1t (sensitization): khi v\u00f9ng \u1ea3nh h\u01b0\u1edfng nhi\u1ec7t (HAZ) trong kho\u1ea3ng 500\u2013800\u00b0C l\u00e0m Cr k\u1ebft t\u1ee7a th\u00e0nh Cr23C6 d\u1ecdc bi\u00ean h\u1ea1t, khi\u1ebfn m\u00e0ng thi\u1ebfu crom v\u00e0 y\u1ebfu \u0111i. Kh\u1eafc ph\u1ee5c b\u1eb1ng d\u00f9ng m\u00e1c L (C th\u1ea5p) ho\u1eb7c \u1ed5n \u0111\u1ecbnh Ti\/Nb, v\u00e0 t\u1ea9y g\u1ec9 ho\u00e0n thi\u1ec7n sau h\u00e0n.<br \/>\n&#8211; \u201c\u1ed0 tr\u00e0\u201d (tea staining): l\u1edbp b\u00e1m m\u00e0u n\u00e2u-v\u00e0ng tr\u00ean b\u1ec1 m\u1eb7t \u1edf kh\u00f4ng gian ven bi\u1ec3n do mu\u1ed1i, b\u1ee5i v\u00e0 s\u1ea3n ph\u1ea9m \u0103n m\u00f2n s\u1eaft ngo\u1ea1i lai \u2013 kh\u00f4ng ph\u1ea3i th\u00e9p n\u1ec1n b\u1ecb r\u1ec9 s\u00e2u, nh\u01b0ng l\u00e0 d\u1ea5u hi\u1ec7u b\u1ec1 m\u1eb7t v\u00e0 m\u00e0ng kh\u00f4ng \u0111\u01b0\u1ee3c b\u1ea3o tr\u00ec \u0111\u00fang.<\/p>\n<h3>Vai tr\u00f2 c\u1ee7a clorua v\u00e0 nhi\u1ec7t \u0111\u1ed9: CPT\/CCT<\/h3>\n<p>Clorua l\u00e0m gi\u1ea3m \u0111i\u1ec7n th\u1ebf ph\u00e1 m\u00e0ng. Hai ch\u1ec9 s\u1ed1 quan tr\u1ecdng:<br \/>\n&#8211; CPT (nhi\u1ec7t \u0111\u1ed9 t\u1edbi h\u1ea1n g\u00e2y r\u1ed7): c\u00e0ng cao c\u00e0ng t\u1ed1t.<br \/>\n&#8211; CCT (nhi\u1ec7t \u0111\u1ed9 t\u1edbi h\u1ea1n g\u00e2y \u0103n m\u00f2n khe): lu\u00f4n th\u1ea5p h\u01a1n CPT.<\/p>\n<p>Tham kh\u1ea3o \u0111i\u1ec3n h\u00ecnh (n\u01b0\u1edbc mu\u1ed1i ti\u00eau chu\u1ea9n, mang t\u00ednh \u0111\u1ecbnh h\u01b0\u1edbng):<br \/>\n&#8211; 304: CPT th\u1ea5p (d\u01b0\u1edbi ~10\u201320\u00b0C), kh\u00f4ng khuy\u1ebfn ngh\u1ecb cho kh\u00f4ng kh\u00ed m\u1eb7n s\u00e1t bi\u1ec3n.<br \/>\n&#8211; 316\/316L (Mo ~2\u20132,5%): CPT ~20\u201330\u00b0C, d\u00f9ng \u0111\u01b0\u1ee3c ven bi\u1ec3n, n\u01b0\u1edbc l\u1ee3 nhi\u1ec1u \u1ee9ng d\u1ee5ng.<br \/>\n&#8211; Duplex 2205: CPT ~45\u201360\u00b0C, kh\u00e1ng clorua v\u01b0\u1ee3t tr\u1ed9i.<\/p>\n<h2 id=\"toc-2-thanh-phan-hop-kim-quyet-dinh-suc-ben-mang-crom\">Th\u00e0nh ph\u1ea7n h\u1ee3p kim quy\u1ebft \u0111\u1ecbnh s\u1ee9c b\u1ec1n m\u00e0ng crom<\/h2>\n<p>Crom t\u1ea1o m\u00e0ng; c\u00e1c nguy\u00ean t\u1ed1 kh\u00e1c tinh ch\u1ec9nh kh\u1ea3 n\u0103ng \u201cgi\u1eef m\u00e0ng\u201d trong m\u00f4i tr\u01b0\u1eddng kh\u1eafc nghi\u1ec7t:<br \/>\n&#8211; Molypden (Mo): t\u0103ng kh\u1ea3 n\u0103ng t\u00e1i th\u1ee5 \u0111\u1ed9ng trong clorua; c\u1ef1c h\u1eefu hi\u1ec7u ch\u1ed1ng r\u1ed7\/khe.<br \/>\n&#8211; Niken (Ni): \u1ed5n \u0111\u1ecbnh pha austenit, c\u1ea3i thi\u1ec7n d\u1ebbo dai v\u00e0 b\u1ec1n \u0103n m\u00f2n trong nhi\u1ec1u m\u00f4i tr\u01b0\u1eddng.<br \/>\n&#8211; Nit\u01a1 (N): t\u0103ng m\u1ea1nh kh\u00e1ng r\u1ed7, \u0111\u1eb7c bi\u1ec7t trong duplex.<br \/>\n&#8211; Silic, mangan, \u0111\u1ed3ng: c\u00f3 vai tr\u00f2 ph\u1ee5 thu\u1ed9c \u1ee9ng d\u1ee5ng (axit h\u1eefu c\u01a1, kh\u1eed\u2026).<\/p>\n<p>Ch\u1ec9 s\u1ed1 PREN (Pitting Resistance Equivalent Number) \u0111\u1ec3 so s\u00e1nh nhanh kh\u00e1ng r\u1ed7:<br \/>\nPREN = %Cr + 3,3\u00d7%Mo + 16\u00d7%N<\/p>\n<p>V\u00ed d\u1ee5 \u0111i\u1ec3n h\u00ecnh:<br \/>\n&#8211; 304 (\u224818%Cr, 0%Mo, 0,05%N): PREN \u2248 19<br \/>\n&#8211; 316L (\u224817%Cr, 2,2%Mo, 0,05%N): PREN \u2248 25<br \/>\n&#8211; Duplex 2205 (\u224822%Cr, 3%Mo, 0,18%N): PREN \u2248 35<\/p>\n<p>S\u1ed1 c\u00e0ng cao, kh\u1ea3 n\u0103ng ch\u1ed1ng r\u1ed7\/khe trong m\u00f4i tr\u01b0\u1eddng clorua c\u00e0ng t\u1ed1t.<\/p>\n<h2 id=\"toc-3-vi-cau-truc-va-gia-dinh-inox-anh-huong-den-mang\">Vi c\u1ea5u tr\u00fac v\u00e0 \u201cgia \u0111\u00ecnh\u201d inox: \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn m\u00e0ng<\/h2>\n<p>&#8211; Austenitic (304, 316): d\u1ec5 gia c\u00f4ng, b\u1ec1n d\u1ebbo, kh\u00e1ng \u0103n m\u00f2n t\u1ed1t; nh\u1ea1y SCC trong clorua \u1edf nhi\u1ec7t cao.<br \/>\n&#8211; Ferritic (430): kh\u00f4ng Ni, t\u1eeb t\u00ednh, chi ph\u00ed th\u1ea5p; kh\u00e1ng clorua k\u00e9m h\u01a1n 304\/316.<br \/>\n&#8211; Martensitic (410, 420): c\u00f3 th\u1ec3 t\u00f4i c\u1ee9ng; kh\u00e1ng \u0103n m\u00f2n th\u1ea5p h\u01a1n, th\u01b0\u1eddng d\u00f9ng d\u1ee5ng c\u1ee5, dao.<br \/>\n&#8211; Duplex (2205): pha k\u00e9p austenit + ferrit; kh\u00e1ng clorua v\u00e0 SCC xu\u1ea5t s\u1eafc, b\u1ec1n c\u01a1 h\u1ecdc cao.<\/p>\n<h2 id=\"toc-4-be-mat-han-va-xu-ly-sau-gia-cong-quyet-dinh-tuoi-t\">B\u1ec1 m\u1eb7t, h\u00e0n v\u00e0 x\u1eed l\u00fd sau gia c\u00f4ng: quy\u1ebft \u0111\u1ecbnh tu\u1ed5i th\u1ecd ngo\u00e0i hi\u1ec7n tr\u01b0\u1eddng<\/h2>\n<p>L\u1edbp m\u00e0ng crom m\u1ecfng n\u00ean b\u1ec1 m\u1eb7t v\u00e0 quy tr\u00ecnh gia c\u00f4ng c\u00f3 \u1ea3nh h\u01b0\u1edfng r\u1ea5t l\u1edbn.<\/p>\n<p>&#8211; \u0110\u1ed9 nh\u1eb5n b\u1ec1 m\u1eb7t: b\u1ec1 m\u1eb7t c\u00e0ng m\u1ecbn (BA, No.4 tinh, No.8 g\u01b0\u01a1ng, \u0111i\u1ec7n h\u00f3a) c\u00e0ng \u00edt b\u00e1m mu\u1ed1i\/b\u1ee5i, gi\u1ea3m \u201c\u1ed1 tr\u00e0\u201d. B\u1ec1 m\u1eb7t nh\u00e1m, x\u01b0\u1edbc s\u00e2u, hairline th\u00f4 c\u1ea7n v\u1ec7 sinh th\u01b0\u1eddng xuy\u00ean h\u01a1n.<br \/>\n&#8211; Nhi\u1ec5m s\u1eaft ngo\u1ea1i lai: v\u1ee5n th\u00e9p cacbon, b\u1ee5i m\u00e0i, b\u00e0n ch\u1ea3i th\u00e9p th\u01b0\u1eddng\u2026 b\u00e1m l\u00ean inox s\u1ebd r\u1ec9 n\u00e2u. D\u00f9ng d\u1ee5ng c\u1ee5 chuy\u00ean inox, che ch\u1eafn khi m\u00e0i c\u1eaft g\u1ea7n \u0111\u00f3, l\u00e0m s\u1ea1ch b\u1eb1ng t\u1ea9y g\u1ec9 v\u00e0 th\u1ee5 \u0111\u1ed9ng h\u00f3a.<br \/>\n&#8211; V\u00f9ng bi\u1ebfn m\u00e0u sau h\u00e0n (heat tint): l\u00e0 oxit d\u00e0y, ngh\u00e8o crom. C\u1ea7n lo\u1ea1i b\u1ecf b\u1eb1ng t\u1ea9y g\u1ec9\/pickling (th\u01b0\u1eddng d\u00f9ng h\u1ed7n h\u1ee3p HNO3+HF d\u1ea1ng gel\/paste theo quy tr\u00ecnh an to\u00e0n) ho\u1eb7c m\u00e0i tinh r\u1ed3i th\u1ee5 \u0111\u1ed9ng h\u00f3a.<br \/>\n&#8211; Th\u1ee5 \u0111\u1ed9ng h\u00f3a (passivation): d\u00f9ng dung d\u1ecbch axit nitric ho\u1eb7c citric \u0111\u1ec3 h\u00f2a tan s\u1eaft t\u1ef1 do, l\u00e0m gi\u00e0u crom b\u1ec1 m\u1eb7t, t\u00e1i t\u1ea1o m\u00e0ng. Tham kh\u1ea3o ti\u00eau chu\u1ea9n quy tr\u00ecnh: ASTM A380\/A380M (l\u00e0m s\u1ea1ch, t\u1ea9y g\u1ec9) v\u00e0 ASTM A967\/A967M (th\u1ee5 \u0111\u1ed9ng h\u00f3a).<br \/>\n&#8211; \u0110i\u1ec7n \u0111\u00e1nh b\u00f3ng (electropolishing): l\u00e0m ph\u1eb3ng \u0111\u1ec9nh nh\u1ea5p nh\u00f4 vi m\u00f4, t\u0103ng \u0111\u1ed9 b\u1ec1n \u0103n m\u00f2n r\u00f5 r\u1ec7t cho chi ti\u1ebft trang tr\u00ed\/thi\u1ebft b\u1ecb y t\u1ebf\/th\u1ef1c ph\u1ea9m.<\/p>\n<h2 id=\"toc-5-thiet-ke-giam-rui-ro-de-mang-crom-luon-tho-duoc\">Thi\u1ebft k\u1ebf gi\u1ea3m r\u1ee7i ro: \u0111\u1ec3 m\u00e0ng crom lu\u00f4n \u201cth\u1edf\u201d \u0111\u01b0\u1ee3c<\/h2>\n<p>&#8211; Tr\u00e1nh khe h\u1eb9p v\u00e0 n\u01b0\u1edbc \u0111\u1ecdng: bo c\u1ea1nh, tho\u00e1t n\u01b0\u1edbc, \u0111\u1ec7m gi\u00e3n c\u00e1ch; tr\u00e1nh k\u1eb9p k\u00edn l\u00e2u d\u00e0i \u1edf ngo\u00e0i tr\u1eddi.<br \/>\n&#8211; H\u1ea1n ch\u1ebf ti\u1ebfp \u0111i\u1ec3m kh\u00e1c kim lo\u1ea1i g\u00e2y pin \u0111i\u1ec7n h\u00f3a: n\u1ebfu b\u1eaft bu\u1ed9c, d\u00f9ng v\u00f2ng c\u00e1ch \u0111i\u1ec7n\/keo b\u1ecbt k\u00edn, ch\u1ecdn c\u1eb7p v\u1eadt li\u1ec7u g\u1ea7n nhau v\u1ec1 \u0111i\u1ec7n th\u1ebf.<br \/>\n&#8211; Ph\u00f9 h\u1ee3p b\u1ec1 m\u1eb7t v\u1edbi m\u00f4i tr\u01b0\u1eddng: m\u1eb7t g\u01b0\u01a1ng\/\u0111i\u1ec7n h\u00f3a cho bi\u1ec3n; No.4 tinh cho \u0111\u00f4 th\u1ecb; h\u1ea1n ch\u1ebf hairline th\u00f4 \u1edf ven bi\u1ec3n.<br \/>\n&#8211; L\u1ef1a ch\u1ecdn bul\u00f4ng\/\u1ed1c v\u00e0 ph\u1ee5 ki\u1ec7n c\u00f9ng c\u1ea5p kh\u00e1ng g\u1ec9 ho\u1eb7c cao h\u01a1n (v\u00ed d\u1ee5 k\u1ebft c\u1ea5u 316 th\u00ec v\u00edt 316).<\/p>\n<h2 id=\"toc-6-chon-mac-inox-theo-moi-truong-su-dung-tai-viet-nam\">Ch\u1ecdn m\u00e1c inox theo m\u00f4i tr\u01b0\u1eddng s\u1eed d\u1ee5ng t\u1ea1i Vi\u1ec7t Nam<\/h2>\n<p>&#8211; N\u1ed9i th\u1ea5t kh\u00f4, xa bi\u1ec3n, \u00edt h\u00f3a ch\u1ea5t: 201\/430 (ti\u1ebft ki\u1ec7m) ho\u1eb7c 304 cho \u0111\u1ed9 b\u1ec1n th\u1ea9m m\u1ef9 cao h\u01a1n.<br \/>\n&#8211; Nh\u00e0 b\u1ebfp, th\u1ef1c ph\u1ea9m, n\u01b0\u1edbc sinh ho\u1ea1t: 304\/304L; n\u1ebfu c\u00f3 clorua (n\u01b0\u1edbc m\u1ec1m b\u1eb1ng mu\u1ed1i, s\u00e1t bi\u1ec3n) \u01b0u ti\u00ean 316L.<br \/>\n&#8211; Ngo\u1ea1i th\u1ea5t \u0111\u00f4 th\u1ecb H\u00e0 N\u1ed9i, H\u1ea3i Ph\u00f2ng (xa b\u1edd bi\u1ec3n >5 km): 304\/304L v\u1edbi b\u1ec1 m\u1eb7t m\u1ecbn v\u00e0 v\u1ec7 sinh \u0111\u1ecbnh k\u1ef3.<br \/>\n&#8211; Ven bi\u1ec3n, c\u00f4ng tr\u00ecnh m\u1eb7t ti\u1ec1n \u0110\u00e0 N\u1eb5ng\/Nha Trang, b\u1ebfn c\u1ea3ng, t\u00e0u: 316\/316L; b\u1ec1 m\u1eb7t m\u1ecbn, v\u1ec7 sinh \u0111\u1ec1u \u0111\u1eb7n; xem x\u00e9t duplex 2205 cho k\u1ebft c\u1ea5u ch\u1ecbu l\u1ef1c.<br \/>\n&#8211; B\u1ec3 b\u01a1i, spa (clorua cao, clo h\u00f3a): 316L t\u1ed1i thi\u1ec3u; ph\u00f2ng \u1ea9m n\u00f3ng k\u00edn n\u00ean c\u00e2n nh\u1eafc duplex 2205 \u1edf v\u1ecb tr\u00ed ch\u1ecbu t\u1ea3i\/kh\u00f3 b\u1ea3o tr\u00ec.<br \/>\n&#8211; H\u00f3a ch\u1ea5t\/gi\u1ea5y\/b\u1ed9t gi\u1ea5y, n\u01b0\u1edbc bi\u1ec3n \u1ea5m: duplex 2205 ho\u1eb7c b\u1eadc cao h\u01a1n; tham v\u1ea5n v\u1eadt li\u1ec7u tr\u01b0\u1edbc khi ch\u1ecdn.<\/p>\n<p>L\u01b0u \u00fd: lu\u00f4n \u0111\u1ed3ng b\u1ed9 c\u1ea5p v\u1eadt li\u1ec7u cho ph\u1ee5 ki\u1ec7n, m\u1ed1i h\u00e0n, v\u00e0 tu\u00e2n th\u1ee7 x\u1eed l\u00fd sau gia c\u00f4ng.<\/p>\n<h2 id=\"toc-7-bao-tri-de-lop-mang-crom-luon-khoe\">B\u1ea3o tr\u00ec \u0111\u1ec3 l\u1edbp m\u00e0ng crom lu\u00f4n kh\u1ecfe<\/h2>\n<p>&#8211; R\u1eeda \u0111\u1ecbnh k\u1ef3 b\u1eb1ng n\u01b0\u1edbc s\u1ea1ch v\u00e0 x\u00e0 ph\u00f2ng trung t\u00ednh; t\u0103ng t\u1ea7n su\u1ea5t \u1edf ven bi\u1ec3n (2\u20134 tu\u1ea7n\/l\u1ea7n).<br \/>\n&#8211; Tr\u00e1nh ch\u1ea5t t\u1ea9y clo\/bleach, axit muriatic; n\u1ebfu d\u00f9ng c\u1ea7n r\u1eeda l\u1ea1i th\u1eadt k\u1ef9.<br \/>\n&#8211; Sau thi c\u00f4ng: b\u00f3c keo\/b\u1ea3o v\u1ec7 ngay, r\u1eeda s\u1ea1ch b\u1ee5i xi m\u0103ng, mu\u1ed1i; t\u1ea9y g\u1ec9 v\u00f9ng h\u00e0n v\u00e0 nhi\u1ec5m s\u1eaft; th\u1ee5 \u0111\u1ed9ng h\u00f3a khi c\u1ea7n.<br \/>\n&#8211; Quan s\u00e1t s\u1edbm \u201c\u1ed1 tr\u00e0\u201d: x\u1eed l\u00fd k\u1ecbp th\u1eddi b\u1eb1ng dung d\u1ecbch t\u1ea9y g\u1ec9 nh\u1eb9 ho\u1eb7c gel passivation gi\u00fap ph\u1ee5c h\u1ed3i b\u1ec1 m\u1eb7t v\u00e0 m\u00e0ng.<\/p>\n<h2 id=\"toc-8-kiem-tra-va-xu-ly-khi-xuat-hien-gi-nauo-tra\">Ki\u1ec3m tra v\u00e0 x\u1eed l\u00fd khi xu\u1ea5t hi\u1ec7n g\u1ec9 n\u00e2u\/\u1ed1 tr\u00e0<\/h2>\n<p>&#8211; B\u01b0\u1edbc 1 \u2013 V\u1ec7 sinh: r\u1eeda n\u01b0\u1edbc ng\u1ecdt \u00e1p l\u1ef1c nh\u1eb9, x\u00e0 ph\u00f2ng trung t\u00ednh, kh\u0103n m\u1ec1m. Kh\u00f4ng d\u00f9ng m\u00fat th\u00e9p th\u01b0\u1eddng.<br \/>\n&#8211; B\u01b0\u1edbc 2 \u2013 T\u1ea9y v\u1ebft: d\u00f9ng dung d\u1ecbch t\u1ea9y g\u1ec9 d\u00e0nh cho inox (kh\u00f4ng ch\u1ee9a clorua), ch\u00e0 nh\u1eb9 theo th\u1edb, r\u1eeda s\u1ea1ch.<br \/>\n&#8211; B\u01b0\u1edbc 3 \u2013 Th\u1ee5 \u0111\u1ed9ng h\u00f3a: \u00e1p gel citric ho\u1eb7c nitric theo h\u01b0\u1edbng d\u1eabn nh\u00e0 s\u1ea3n xu\u1ea5t, r\u1eeda k\u1ef9, l\u00e0m kh\u00f4.<br \/>\n&#8211; B\u01b0\u1edbc 4 \u2013 Ki\u1ec3m tra nhi\u1ec5m s\u1eaft: c\u00f3 th\u1ec3 d\u00f9ng th\u1eed Ferroxyl ho\u1eb7c mi\u1ebfng test th\u01b0\u01a1ng m\u1ea1i n\u1ebfu v\u1ebft t\u00e1i ph\u00e1t nhanh.<br \/>\n&#8211; B\u01b0\u1edbc 5 \u2013 Ph\u00f2ng ng\u1eeba: c\u1ea3i thi\u1ec7n tho\u00e1t n\u01b0\u1edbc, gi\u1ea3m khe h\u1eb9p, \u0111\u1ecbnh k\u1ef3 v\u1ec7 sinh. N\u1ebfu \u0111\u00e3 h\u00ecnh th\u00e0nh r\u1ed7 s\u00e2u, c\u1ea7n m\u00e0i v\u00e0 \u0111\u00e1nh b\u00f3ng l\u1ea1i; tr\u01b0\u1eddng h\u1ee3p n\u1eb7ng ph\u1ea3i thay chi ti\u1ebft.<\/p>\n<h2 id=\"toc-9-giai-dap-nhanh-cac-cau-hoi-thuong-gap\">Gi\u1ea3i \u0111\u00e1p nhanh c\u00e1c c\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/h2>\n<p>&#8211; Inox c\u00f3 bao gi\u1edd g\u1ec9 kh\u00f4ng? C\u00f3, n\u1ebfu m\u00e0ng crom b\u1ecb ph\u00e1 c\u1ee5c b\u1ed9 (clorua, khe h\u1eb9p, nhi\u1ec7t, nhi\u1ec5m s\u1eaft). Nh\u01b0ng c\u00f3 th\u1ec3 ng\u0103n ng\u1eeba b\u1eb1ng ch\u1ecdn m\u00e1c \u0111\u00fang, gia c\u00f4ng chu\u1ea9n, b\u1ea3o tr\u00ec t\u1ed1t.<br \/>\n&#8211; V\u00ec sao 304 g\u1ec9 ven bi\u1ec3n c\u00f2n 316 th\u00ec kh\u00f4ng? 316 ch\u1ee9a Mo (~2\u20132,5%) n\u00e2ng PREN v\u00e0 CPT, b\u1ec1n clorua h\u01a1n 304.<br \/>\n&#8211; D\u00f9ng 201 ngo\u00e0i tr\u1eddi \u0111\u01b0\u1ee3c kh\u00f4ng? Ch\u1ec9 n\u00ean \u1edf m\u00f4i tr\u01b0\u1eddng s\u1ea1ch, xa bi\u1ec3n, c\u00f3 b\u1ea3o tr\u00ec; 201 k\u00e9m b\u1ec1n clorua h\u01a1n 304.<br \/>\n&#8211; \u201c\u1ed0 tr\u00e0\u201d c\u00f3 nguy hi\u1ec3m? Ch\u1ee7 y\u1ebfu l\u00e0 v\u1ea5n \u0111\u1ec1 th\u1ea9m m\u1ef9 v\u00e0 l\u00e0 d\u1ea5u hi\u1ec7u c\u1ea7n v\u1ec7 sinh\/th\u1ee5 \u0111\u1ed9ng h\u00f3a; n\u1ebfu \u0111\u1ec3 l\u00e2u c\u00f3 th\u1ec3 ph\u00e1t tri\u1ec3n th\u00e0nh r\u1ed7.<br \/>\n&#8211; C\u00f3 c\u1ea7n s\u01a1n inox kh\u00f4ng? Kh\u00f4ng b\u1eaft bu\u1ed9c. V\u1edbi m\u00f4i tr\u01b0\u1eddng c\u1ef1c kh\u1eafc nghi\u1ec7t, c\u00f3 th\u1ec3 d\u00f9ng ph\u1ee7 b\u1ea3o v\u1ec7 trong thi\u1ebft k\u1ebf \u0111\u1eb7c th\u00f9, nh\u01b0ng c\u1ed1t l\u00f5i v\u1eabn l\u00e0 ch\u1ecdn m\u00e1c \u0111\u00fang v\u00e0 b\u1ec1 m\u1eb7t m\u1ecbn.<br \/>\n&#8211; Sau h\u00e0n c\u00f3 c\u1ea7n x\u1eed l\u00fd? C\u00f3. C\u1ea7n t\u1ea9y g\u1ec9 lo\u1ea1i b\u1ecf heat tint v\u00e0 th\u1ee5 \u0111\u1ed9ng h\u00f3a \u0111\u1ec3 ph\u1ee5c h\u1ed3i l\u1edbp m\u00e0ng crom.<\/p>\n<h2 id=\"toc-10-khi-nao-nen-can-nhac-dung-duplex\">Khi n\u00e0o n\u00ean c\u00e2n nh\u1eafc du\u0300ng duplex?<\/h2>\n<p>&#8211; Khi m\u00f4i tr\u01b0\u1eddng clorua cao (ven bi\u1ec3n s\u00e1t m\u00e9p n\u01b0\u1edbc, h\u00f3a ch\u1ea5t, n\u01b0\u1edbc bi\u1ec3n \u1ea5m).<br \/>\n&#8211; Khi c\u1ea7n \u0111\u1ed9 b\u1ec1n c\u01a1 h\u1ecdc cao v\u00e0 ch\u1ed1ng SCC t\u1ed1t h\u01a1n austenitic.<br \/>\n&#8211; Khi y\u00eau c\u1ea7u tu\u1ed5i th\u1ecd d\u00e0i v\u1edbi chi ph\u00ed v\u00f2ng \u0111\u1eddi th\u1ea5p h\u01a1n (d\u00f9 v\u1eadt li\u1ec7u ban \u0111\u1ea7u \u0111\u1eaft h\u01a1n).<\/p>\n<h2 id=\"toc-11-lien-he-tieu-chuan-va-thuc-hanh-tot\">Li\u00ean h\u1ec7 ti\u00eau chu\u1ea9n v\u00e0 th\u1ef1c h\u00e0nh t\u1ed1t<\/h2>\n<p>&#8211; Thi\u1ebft k\u1ebf, v\u1eadt li\u1ec7u: EN 10088 (th\u00e0nh ph\u1ea7n, m\u00e1c); tham chi\u1ebfu th\u00eam ASTM A240 cho t\u1ea5m\/coil.<br \/>\n&#8211; L\u00e0m s\u1ea1ch\/t\u1ea9y g\u1ec9\/th\u1ee5 \u0111\u1ed9ng h\u00f3a: ASTM A380\/A380M, ASTM A967\/A967M (nitric\/citric).<br \/>\n&#8211; Gia c\u00f4ng: d\u00f9ng d\u1ee5ng c\u1ee5 ri\u00eang cho inox; tr\u00e1nh tia l\u1eeda\/m\u1ea1t th\u00e9p th\u01b0\u1eddng; che ch\u1eafn khi m\u00e0i c\u1eaft g\u1ea7n \u0111\u00f3.<\/p>\n<h2 id=\"toc-12-ket-luan\">K\u1ebft lu\u1eadn<\/h2>\n<p>S\u1ee9c m\u1ea1nh \u201ckh\u00f4ng g\u1ec9\u201d c\u1ee7a inox \u0111\u1ebfn t\u1eeb l\u1edbp m\u00e0ng crom th\u1ee5 \u0111\u1ed9ng si\u00eau m\u1ecfng, t\u1ef1 ph\u1ee5c h\u1ed3i trong m\u00f4i tr\u01b0\u1eddng gi\u00e0u oxy. M\u00e0ng n\u00e0y r\u1ea5t b\u1ec1n, nh\u01b0ng c\u00f3 th\u1ec3 b\u1ecb ph\u00e1 v\u1ee1 c\u1ee5c b\u1ed9 b\u1edfi clorua, nhi\u1ec7t \u0111\u1ed9, khe h\u1eb9p, thi\u1ebfu oxy v\u00e0 nhi\u1ec5m s\u1eaft ngo\u1ea1i lai. \u0110\u1ec3 l\u1edbp m\u00e0ng l\u00e0m \u0111\u00fang \u201cnhi\u1ec7m v\u1ee5\u201d, c\u1ea7n:<br \/>\n&#8211; Ch\u1ecdn m\u00e1c theo m\u00f4i tr\u01b0\u1eddng: 304 cho \u0111\u00f4 th\u1ecb s\u1ea1ch, 316 cho ven bi\u1ec3n\/b\u1ec3 b\u01a1i, duplex 2205 cho clorua cao.<br \/>\n&#8211; Gia c\u00f4ng v\u00e0 x\u1eed l\u00fd chu\u1ea9n: t\u1ea9y g\u1ec9 v\u00f9ng h\u00e0n, th\u1ee5 \u0111\u1ed9ng h\u00f3a, b\u1ec1 m\u1eb7t m\u1ecbn, tr\u00e1nh nhi\u1ec5m s\u1eaft.<br \/>\n&#8211; Thi\u1ebft k\u1ebf th\u00f4ng minh v\u00e0 b\u1ea3o tr\u00ec \u0111\u1ec1u \u0111\u1eb7n: tr\u00e1nh khe h\u1eb9p, tho\u00e1t n\u01b0\u1edbc t\u1ed1t, v\u1ec7 sinh \u0111\u1ecbnh k\u1ef3.<\/p>\n<p>L\u00e0m \u0111\u00fang ba \u0111i\u1ec3m c\u1ed1t l\u00f5i n\u00e0y, b\u1ea1n s\u1ebd khai th\u00e1c tr\u1ecdn v\u1eb9n \u201cb\u00ed m\u1eadt\u201d c\u1ee7a l\u1edbp m\u00e0ng crom \u2013 tu\u1ed5i th\u1ecd d\u00e0i, th\u1ea9m m\u1ef9 b\u1ec1n v\u00e0 chi ph\u00ed v\u00f2ng \u0111\u1eddi t\u1ed1i \u01b0u cho c\u00f4ng tr\u00ecnh, thi\u1ebft b\u1ecb inox t\u1ea1i Vi\u1ec7t Nam.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Gi\u1ea3i m\u00e3 c\u01a1 ch\u1ebf ch\u1ed1ng g\u1ec9 c\u1ee7a inox: l\u1edbp m\u00e0ng crom (Cr2O3) nano t\u1ef1 ph\u1ee5c h\u1ed3i, c\u00e1c y\u1ebfu t\u1ed1 ph\u00e1 v\u1ee1 (clorua, nhi\u1ec7t, oxy th\u1ea5p) v\u00e0 c\u00e1ch ch\u1ecdn m\u00e1c, x\u1eed l\u00fd chu\u1ea9n.<\/p>\n","protected":false},"author":7,"featured_media":1064,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[23],"tags":[],"class_list":["post-1096","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tin-tuc"],"acf":[],"_links":{"self":[{"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/posts\/1096","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/comments?post=1096"}],"version-history":[{"count":0,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/posts\/1096\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/media\/1064"}],"wp:attachment":[{"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/media?parent=1096"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/categories?post=1096"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/tags?post=1096"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}