{"id":1225,"date":"2025-10-25T12:34:32","date_gmt":"2025-10-25T05:34:32","guid":{"rendered":"https:\/\/inoxcuongthinh.com\/nut-moi-han-ong-hop-inox-nguyen-nhan-va-giai-phap-triet-de\/"},"modified":"2025-10-25T12:34:32","modified_gmt":"2025-10-25T05:34:32","slug":"nut-moi-han-ong-hop-inox-nguyen-nhan-va-giai-phap-triet-de","status":"publish","type":"post","link":"https:\/\/inoxcuongthinh.com\/nut-moi-han-ong-hop-inox-nguyen-nhan-va-giai-phap-triet-de\/","title":{"rendered":"N\u1ee9t m\u1ed1i h\u00e0n \u1ed1ng, h\u1ed9p Inox: Nguy\u00ean nh\u00e2n v\u00e0 gi\u1ea3i ph\u00e1p tri\u1ec7t \u0111\u1ec3"},"content":{"rendered":"<div class=\"custom-toc\">\n<h3>N\u1ed9i dung ch\u00ednh<\/h3>\n<ul>\n<li><a href=\"#toc-0-cac-dang-nut-moi-han-thuong-gap-tren-ong-hop-inox\">C\u00e1c d\u1ea1ng n\u1ee9t m\u1ed1i h\u00e0n th\u01b0\u1eddng g\u1eb7p tr\u00ean \u1ed1ng, h\u1ed9p Inox<\/a><\/li>\n<li><a href=\"#toc-1-nguyen-nhan-goc-re-vat-lieu-thiet-ke-quy-trinh\">Nguy\u00ean nh\u00e2n g\u1ed1c r\u1ec5: v\u1eadt li\u1ec7u, thi\u1ebft k\u1ebf, quy tr\u00ecnh<\/a><\/li>\n<li><a href=\"#toc-2-quy-trinh-chan-doan-nhanh-tai-xuong\">Quy tr\u00ecnh ch\u1ea9n \u0111o\u00e1n nhanh t\u1ea1i x\u01b0\u1edfng<\/a><\/li>\n<li><a href=\"#toc-3-thong-so-khuyen-nghi-tham-khao-cho-ong-hop-mong-in\">Th\u00f4ng s\u1ed1 khuy\u1ebfn ngh\u1ecb (tham kh\u1ea3o) cho \u1ed1ng, h\u1ed9p m\u1ecfng Inox<\/a><\/li>\n<li><a href=\"#toc-4-giai-phap-khac-phuc-tai-cho-va-phong-ngua-dai-han\">Gi\u1ea3i ph\u00e1p kh\u1eafc ph\u1ee5c t\u1ea1i ch\u1ed7 v\u00e0 ph\u00f2ng ng\u1eeba d\u00e0i h\u1ea1n<\/a><\/li>\n<li><a href=\"#toc-5-tieu-chuan-va-muc-chap-nhan\">Ti\u00eau chu\u1ea9n v\u00e0 m\u1ee9c ch\u1ea5p nh\u1eadn<\/a><\/li>\n<li><a href=\"#toc-6-cau-hoi-thuong-gap\">C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/a><\/li>\n<li><a href=\"#toc-7-ket-luan\">K\u1ebft lu\u1eadn<\/a><\/li>\n<\/ul>\n<\/div>\n<p>Trong ch\u1ebf t\u1ea1o v\u00e0 l\u1eafp d\u1ef1ng \u1ed1ng, h\u1ed9p Inox, m\u1ed1i h\u00e0n l\u00e0 \u201c\u0111i\u1ec3m s\u1ed1ng c\u00f2n\u201d quy\u1ebft \u0111\u1ecbnh \u0111\u1ed9 k\u00edn, \u0111\u1ed9 b\u1ec1n v\u00e0 th\u1ea9m m\u1ef9. N\u1ee9t m\u1ed1i h\u00e0n l\u00e0 khuy\u1ebft t\u1eadt nghi\u00eam tr\u1ecdng, kh\u00f4ng \u0111\u01b0\u1ee3c ch\u1ea5p nh\u1eadn theo h\u1ea7u h\u1ebft ti\u00eau chu\u1ea9n. B\u00e0i vi\u1ebft n\u00e0y ph\u00e2n t\u00edch \u0111\u1ea7y \u0111\u1ee7 c\u00e1c d\u1ea1ng n\u1ee9t, nguy\u00ean nh\u00e2n g\u1ed1c r\u1ec5 v\u00e0 c\u00e1ch kh\u1eafc ph\u1ee5c\u2013ph\u00f2ng ng\u1eeba t\u1ed1i \u01b0u cho \u1ed1ng, h\u1ed9p Inox (201\/304\/316\/430) trong \u0111i\u1ec1u ki\u1ec7n x\u01b0\u1edfng c\u01a1 kh\u00ed t\u1ea1i Vi\u1ec7t Nam.<\/p>\n<h2 id=\"toc-0-cac-dang-nut-moi-han-thuong-gap-tren-ong-hop-inox\">C\u00e1c d\u1ea1ng n\u1ee9t m\u1ed1i h\u00e0n th\u01b0\u1eddng g\u1eb7p tr\u00ean \u1ed1ng, h\u1ed9p Inox<\/h2>\n<h3>N\u1ee9t n\u00f3ng (n\u1ee9t khi \u0111\u00f4ng \u0111\u1eb7c\/solidification cracking)<\/h3>\n<p>&#8211; Xu\u1ea5t hi\u1ec7n ngay khi h\u00e0n, d\u1ecdc theo t\u00e2m m\u1ed1i h\u00e0n ho\u1eb7c r\u00e3nh k\u1ebft tinh.<br \/>\n&#8211; C\u01a1 ch\u1ebf: kim lo\u1ea1i n\u00f3ng ch\u1ea3y \u0111\u00f4ng \u0111\u1eb7c c\u00f3 d\u1ea3i \u0111\u00f4ng \u0111\u1eb7c r\u1ed9ng + t\u1ea1p ch\u1ea5t S, P, Si t\u1eadp trung + \u1ee9ng su\u1ea5t co ng\u00f3t cao. Austenitic Inox (201\/304\/316) c\u00f3 nguy c\u01a1 cao n\u1ebfu h\u00e0m l\u01b0\u1ee3ng delta-ferrite qu\u00e1 th\u1ea5p (FN\u22480).<\/p>\n<h3>N\u1ee9t h\u00f3a l\u1ecfng v\u00f9ng HAZ (liquation cracking)<\/h3>\n<p>&#8211; N\u1ee9t \u1edf v\u00f9ng \u1ea3nh h\u01b0\u1edfng nhi\u1ec7t (HAZ), s\u00e1t m\u00e9p h\u00e0n khi m\u1ed9t ph\u1ea7n ranh gi\u1edbi h\u1ea1t b\u1ecb h\u00f3a l\u1ecfng.<br \/>\n&#8211; D\u1ec5 g\u1eb7p \u1edf m\u1ed1i h\u00e0n m\u1ecfng, t\u1ed1c \u0111\u1ed9 h\u00e0n cao, chu\u1ea9n b\u1ecb m\u00e9p v\u00e0 l\u00e0m s\u1ea1ch k\u00e9m.<\/p>\n<h3>N\u1ee9t ngu\u1ed9i do hydro (hydrogen-assisted cracking)<\/h3>\n<p>&#8211; Th\u01b0\u1eddng xu\u1ea5t hi\u1ec7n sau h\u00e0n v\u00e0i gi\u1edd \u0111\u1ebfn v\u00e0i ng\u00e0y. Austenitic \u00edt nh\u1ea1y h\u01a1n, nh\u01b0ng c\u00f3 th\u1ec3 n\u1ee9t t\u1ea1i v\u00f9ng pha lo\u00e3ng khi h\u00e0n v\u1edbi th\u00e9p cacbon, ho\u1eb7c \u1edf ferritic\/martensitic (430\/410).<br \/>\n&#8211; Ngu\u1ed3n hydro: \u1ea9m trong kh\u00ed b\u1ea3o v\u1ec7, que\/d\u00e2y h\u00e0n \u1ea9m, d\u1ea7u m\u1ee1, r\u1ec9 s\u00e9t.<\/p>\n<h3>N\u1ee9t mi\u1ec7ng h\u00e0n (crater crack), n\u1ee9t ch\u00e2n m\u1ed1i (root crack), n\u1ee9t HAZ<\/h3>\n<p>&#8211; N\u1ee9t mi\u1ec7ng xu\u1ea5t hi\u1ec7n cu\u1ed1i \u0111\u01b0\u1eddng h\u00e0n khi ng\u1eaft h\u1ed3 quang \u0111\u1ed9t ng\u1ed9t, kim lo\u1ea1i \u0111\u00f4ng \u0111\u1eb7c co r\u00fat.<br \/>\n&#8211; N\u1ee9t ch\u00e2n m\u1ed1i ph\u1ed5 bi\u1ebfn khi h\u00e0n k\u00edn g\u00f3c trong c\u1ee7a h\u1ed9p\/\u1ed1ng, thi\u1ebfu b\u1ea3o v\u1ec7 m\u1eb7t sau (sugaring) t\u1ea1o v\u00f9ng gi\u00f2n.<br \/>\n&#8211; N\u1ee9t HAZ \u1edf ferritic (430) do t\u0103ng tr\u01b0\u1edfng h\u1ea1t v\u00e0 gi\u00f2n h\u00f3a n\u1ebfu nhi\u1ec7t v\u00e0o cao.<\/p>\n<h3>N\u1ee9t do \u0103n m\u00f2n \u1ee9ng su\u1ea5t clorua (SCC) sau khi \u0111\u01b0a v\u00e0o s\u1eed d\u1ee5ng<\/h3>\n<p>&#8211; X\u1ea3y ra trong m\u00f4i tr\u01b0\u1eddng c\u00f3 Cl- (n\u01b0\u1edbc bi\u1ec3n, h\u00f3a ch\u1ea5t, t\u1ea9y r\u1eeda ch\u1ee9a clorua), nhi\u1ec7t \u0111\u1ed9 >50\u201360\u00b0C v\u00e0 \u1ee9ng su\u1ea5t d\u01b0 cao. V\u1ebft n\u1ee9t th\u01b0\u1eddng m\u1ea3nh, lan d\u00e0i theo h\u01b0\u1edbng \u1ee9ng su\u1ea5t.<\/p>\n<h2 id=\"toc-1-nguyen-nhan-goc-re-vat-lieu-thiet-ke-quy-trinh\">Nguy\u00ean nh\u00e2n g\u1ed1c r\u1ec5: v\u1eadt li\u1ec7u, thi\u1ebft k\u1ebf, quy tr\u00ecnh<\/h2>\n<h3>V\u1eadt li\u1ec7u v\u00e0 que\/d\u00e2y h\u00e0n<\/h3>\n<p>&#8211; Th\u00e0nh ph\u1ea7n h\u00f3a h\u1ecdc: S, P cao t\u0103ng nguy c\u01a1 n\u1ee9t n\u00f3ng. \u1ed0ng\/h\u1ed9p theo ASTM A554 ch\u1ea5t l\u01b0\u1ee3ng \u1ed5n \u0111\u1ecbnh gi\u00fap gi\u1ea3m r\u1ee7i ro.<br \/>\n&#8211; C\u1ea5u tr\u00fac: Austenitic (201\/304\/316) c\u1ea7n delta-ferrite FN\u22483\u201310 \u0111\u1ec3 gi\u1ea3m n\u1ee9t n\u00f3ng. Filler qu\u00e1 \u201caustenitic\u201d (FN\u22480) t\u0103ng r\u1ee7i ro.<br \/>\n&#8211; L\u1ef1a ch\u1ecdn v\u1eadt li\u1ec7u \u0111i\u1ec1n:<br \/>\n  &#8211; 304\/201 \u2192 ER308L (GTAW\/GMAW), E308L-16\/-17 (SMAW).<br \/>\n  &#8211; 316 \u2192 ER316L\/E316L.<br \/>\n  &#8211; Dissimilar (Inox \u2194 th\u00e9p cacbon, ho\u1eb7c 430\u2194304) \u2192 ER309L\/309Mo \u0111\u1ec3 gi\u1ea3m pha lo\u00e3ng v\u00e0 n\u1ee9t.<br \/>\n&#8211; L-grade (\u22640.03%C) gi\u1ea3m nh\u1ea1y c\u1ea3m h\u00f3a b\u1ec1n\/nhi\u1ec5m b\u1ea9n ranh gi\u1edbi h\u1ea1t.<\/p>\n<h3>Thi\u1ebft k\u1ebf li\u00ean k\u1ebft v\u00e0 \u0111\u1ed9 k\u1eb9p ch\u1eb7t<\/h3>\n<p>&#8211; \u1ed0ng\/h\u1ed9p c\u00f3 ti\u1ebft di\u1ec7n k\u00edn g\u00e2y \u0111\u1ed9 c\u1ea3n bi\u1ebfn d\u1ea1ng cao, t\u1ea1o \u1ee9ng su\u1ea5t ba tr\u1ee5c \u2192 d\u1ec5 n\u1ee9t.<br \/>\n&#8211; G\u00e1 l\u1eafp qu\u00e1 c\u1ee9ng, kh\u00f4ng khe h\u1edf ho\u1eb7c khe qu\u00e1 l\u1edbn \u0111\u1ec1u b\u1ea5t l\u1ee3i:<br \/>\n  &#8211; V\u1edbi chi\u1ec1u d\u00e0y 1\u20133 mm: khe h\u1edf g\u1ed1c 0.3\u20130.8 mm l\u00e0 h\u1ee3p l\u00fd khi h\u00e0n ng\u1ea5u.<br \/>\n&#8211; Chi\u1ec1u d\u00e0i h\u00e0n li\u00ean t\u1ee5c qu\u00e1 d\u00e0i tr\u00ean khung h\u1ed9p m\u1ecfng g\u00e2y co r\u00fat t\u1eadp trung.<\/p>\n<h3>Chu\u1ea9n b\u1ecb m\u00e9p, l\u00e0m s\u1ea1ch v\u00e0 b\u1ea3o v\u1ec7 kh\u00ed<\/h3>\n<p>&#8211; L\u1edbp oxit Cr2O3, d\u1ea7u m\u1ee1, b\u1ee5i s\u1eaft (nhi\u1ec5m b\u1ea9n t\u1eeb th\u00e9p \u0111en) l\u00e0m t\u0103ng gi\u00f2n n\u00f3ng v\u00e0 \u0111\u01b0a hydro v\u00e0o v\u0169ng h\u00e0n.<br \/>\n&#8211; L\u00e0m s\u1ea1ch c\u01a1 h\u1ecdc (m\u00e0i flap disc ri\u00eang cho Inox), sau \u0111\u00f3 dung m\u00f4i (acetone\/isopropanol). Kh\u00f4ng d\u00f9ng b\u00e0n ch\u1ea3i th\u00e9p cacbon.<br \/>\n&#8211; Kh\u00ed b\u1ea3o v\u1ec7: TIG d\u00f9ng 100% Ar; MIG d\u00f9ng Ar + 1\u20132% O2 ho\u1eb7c Ar + 1\u20132% CO2. CO2 cao g\u00e2y oxy h\u00f3a m\u1ea1nh, t\u0103ng v\u1ea3y x\u1ec9 gi\u00f2n.<br \/>\n&#8211; S\u1ea5y, b\u1ea3o qu\u1ea3n que\/d\u00e2y h\u00e0n kh\u00f4, tr\u00e1nh \u1ea9m.<\/p>\n<h3>Th\u00f4ng s\u1ed1 h\u00e0n v\u00e0 ki\u1ec3m so\u00e1t nhi\u1ec7t<\/h3>\n<p>&#8211; Nhi\u1ec7t v\u00e0o qu\u00e1 cao \u2192 n\u1ee9t n\u00f3ng\/gi\u00f2n HAZ; qu\u00e1 th\u1ea5p \u2192 thi\u1ebfu ng\u1ea5u, bi\u00ean d\u1ea1ng x\u1ea5u, n\u1ee9t do kh\u1edfi n\u00fat.<br \/>\n&#8211; Interpass nhi\u1ec7t \u0111\u1ed9 cho austenitic: \u2264150\u00b0C; ferritic 430: \u2264150\u00b0C, tr\u00e1nh l\u01b0u nhi\u1ec7t l\u00e2u.<br \/>\n&#8211; K\u1ebft th\u00fac \u0111\u01b0\u1eddng h\u00e0n c\u1ea7n \u0111\u1eafp b\u00f9 mi\u1ec7ng (crater fill), kh\u00f4ng c\u1eaft h\u1ed3 quang \u0111\u1ed9t ng\u1ed9t.<\/p>\n<h3>Ki\u1ec3m so\u00e1t m\u1eb7t trong (back purging) v\u1edbi \u1ed1ng, h\u1ed9p<\/h3>\n<p>&#8211; Kh\u00f4ng c\u00f3 kh\u00ed l\u00f3t m\u1eb7t sau \u2192 \u201csugaring\u201d (oxy h\u00f3a \u0111\u01b0\u1eddng r\u1ec5) gi\u00f2n, d\u1ec5 n\u1ee9t ch\u00e2n m\u1ed1i v\u00e0 l\u00e0 \u0111i\u1ec3m kh\u1edfi ph\u00e1t \u0103n m\u00f2n.<br \/>\n&#8211; Purge Ar 5\u201310 L\/ph\u00fat \u0111\u1ebfn khi O2 < 50 ppm tr\u01b0\u1edbc khi m\u1ed3i h\u1ed3 quang. D\u00f9ng b\u0103ng keo nhi\u1ec7t, n\u00fat cao su, b\u00f3ng purge ho\u1eb7c backing \u0111\u1ed3ng.\n\n\n\n<h2 id=\"toc-2-quy-trinh-chan-doan-nhanh-tai-xuong\">Quy tr\u00ecnh ch\u1ea9n \u0111o\u00e1n nhanh t\u1ea1i x\u01b0\u1edfng<\/h2>\n<p>&#8211; 1) Ph\u00e2n lo\u1ea1i th\u1eddi \u0111i\u1ec3m n\u1ee9t: xu\u1ea5t hi\u1ec7n ngay khi h\u00e0n, v\u00e0i gi\u1edd sau, hay trong v\u1eadn h\u00e0nh.<br \/>\n&#8211; 2) Ki\u1ec3m tra b\u1eb1ng m\u1eaft v\u00e0 ch\u1ea5t th\u1ea9m th\u1ea5u m\u00e0u (PT) to\u00e0n b\u1ed9 m\u1ed1i h\u00e0n, \u0111\u1eb7c bi\u1ec7t ch\u00e2n\/r\u00eca v\u00e0 mi\u1ec7ng h\u00e0n.<br \/>\n&#8211; 3) Ki\u1ec3m tra ch\u1ea5t l\u01b0\u1ee3ng l\u00e0m s\u1ea1ch, d\u1ea5u v\u1ebft \u201csugaring\u201d m\u1eb7t trong, v\u1ea3y \u00f4xy h\u00f3a d\u00e0y.<br \/>\n&#8211; 4) R\u00e0 so\u00e1t WPS\/thi\u1ebft l\u1eadp: c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng, \u0111i\u1ec7n \u00e1p, t\u1ed1c \u0111\u1ed9, kh\u00ed, l\u01b0u l\u01b0\u1ee3ng, interpass.<br \/>\n&#8211; 5) \u0110\u00e1nh gi\u00e1 g\u00e1 l\u1eafp: \u0111\u1ed9 k\u1eb9p, tr\u00ecnh t\u1ef1 \u0111i\u1ec3m \u0111\u1ecbnh v\u1ecb, chi\u1ec1u d\u00e0i l\u01b0\u1ee3t h\u00e0n.<br \/>\n&#8211; 6) X\u00e1c nh\u1eadn v\u1eadt li\u1ec7u: m\u00e1c Inox, ch\u1ee9ng ch\u1ec9 v\u1eadt li\u1ec7u \u1ed1ng\/h\u1ed9p v\u00e0 d\u00e2y\/que h\u00e0n; t\u01b0\u01a1ng th\u00edch filler (308L\/316L\/309L).<br \/>\n&#8211; 7) Ki\u1ec3m tra \u0111\u1ed9 \u1ea9m kho ti\u00eau hao, kh\u00ed (\u0111i\u1ec3m s\u01b0\u01a1ng), v\u00e0 r\u00f2 r\u1ec9 kh\u00ed b\u1ea3o v\u1ec7.<br \/>\n&#8211; 8) V\u1edbi n\u1ee9t trong s\u1eed d\u1ee5ng: ph\u00e2n t\u00edch m\u00f4i tr\u01b0\u1eddng (Cl-, nhi\u1ec7t \u0111\u1ed9), quan s\u00e1t d\u1ea1ng n\u1ee9t SCC.<\/p>\n<h2 id=\"toc-3-thong-so-khuyen-nghi-tham-khao-cho-ong-hop-mong-in\">Th\u00f4ng s\u1ed1 khuy\u1ebfn ngh\u1ecb (tham kh\u1ea3o) cho \u1ed1ng, h\u1ed9p m\u1ecfng Inox<\/h2>\n<p>L\u01b0u \u00fd: \u0111i\u1ec1u ch\u1ec9nh theo v\u1ecb tr\u00ed, li\u00ean k\u1ebft v\u00e0 m\u00e1y th\u1ef1c t\u1ebf. \u01afu ti\u00ean m\u1ed1i h\u00e0n d\u1ea1ng \u201cstringer\u201d, h\u1ea1n ch\u1ebf l\u1eafc r\u1ed9ng.<\/p>\n<p>&#8211; TIG (GTAW), chi\u1ec1u d\u00e0y 1.0\u20133.0 mm (304\/201\/316)<br \/>\n  &#8211; \u0110i\u1ec7n c\u1ef1c: Tungsten 2% Th\/La 1.6\u20132.4 mm, m\u00e0i nh\u1ecdn.<br \/>\n  &#8211; D\u00f2ng DCEN: 45\u2013120 A (1.0 mm: 45\u201370 A; 2.0 mm: 70\u201395 A; 3.0 mm: 90\u2013120 A).<br \/>\n  &#8211; Kh\u00ed: Ar 100%, 8\u201312 L\/ph\u00fat; purge m\u1eb7t sau 5\u20138 L\/ph\u00fat (O2 < 50 ppm).\n  - Filler: ER308L (304\/201), ER316L (316), ER309L (dissimilar), \u0111\u01b0\u1eddng k\u00ednh 1.0\u20131.6 mm.\n  - Interpass \u2264150\u00b0C; \u0111\u1eafp b\u00f9 mi\u1ec7ng h\u00e0n tr\u01b0\u1edbc khi ng\u1eaft h\u1ed3 quang.\n\n- MIG (GMAW), d\u00e2y 0.8\u20131.0 mm\n  - Kh\u00ed: Ar + 1\u20132% O2 ho\u1eb7c Ar + 1\u20132% CO2, 12\u201316 L\/ph\u00fat.\n  - \u0110i\u1ec7n \u00e1p\/d\u00f2ng: 16\u201319 V, 70\u2013140 A (ng\u1eafn m\u1ea1ch\/spray th\u1ea5p).\n  - T\u1ed1c \u0111\u1ed9 c\u1ea5p d\u00e2y: 3.5\u20136.0 m\/ph\u00fat; t\u1ed1c \u0111\u1ed9 ch\u1ea1y 250\u2013450 mm\/ph\u00fat t\u00f9y d\u00e0y.\n  - \u01afu ti\u00ean \u0111i m\u1ed9t l\u01b0\u1ee3t m\u1ea3nh, \u00edt ch\u1ed3ng l\u1edbp \u0111\u1ec3 gi\u1ea3m nhi\u1ec7t v\u00e0o.\n\n- SMAW (h\u00e0n que), chi\u1ec1u d\u00e0y \u22652.0 mm\n  - Que E308L-16\/-17, E316L-16, E309L-16; \u03a62.5\u20133.2 mm.\n  - D\u00f2ng 65\u2013110 A; s\u1ea5y\/gi\u1eef kh\u00f4 que; h\u1ed3 quang ng\u1eafn.\n\n- G\u00e1 l\u1eafp &#038; tr\u00ecnh t\u1ef1\n  - \u0110i\u1ec3m \u0111\u1ecbnh v\u1ecb d\u00e0i 8\u201312 mm c\u00e1ch nhau 50\u201380 mm, \u0111\u1ed1i x\u1ee9ng \u0111\u1ec3 ph\u00e2n t\u00e1n \u1ee9ng su\u1ea5t.\n  - H\u00e0n so le c\u00e1c c\u1ea1nh khung h\u1ed9p, tr\u00e1nh k\u00e9o d\u00e0i li\u00ean t\u1ee5c m\u1ed9t ph\u00eda.\n\n\n\n<h2 id=\"toc-4-giai-phap-khac-phuc-tai-cho-va-phong-ngua-dai-han\">Gi\u1ea3i ph\u00e1p kh\u1eafc ph\u1ee5c t\u1ea1i ch\u1ed7 v\u00e0 ph\u00f2ng ng\u1eeba d\u00e0i h\u1ea1n<\/h2>\n<h3>S\u1eeda ch\u1eefa v\u1ebft n\u1ee9t hi\u1ec7n h\u1eefu (\u0111\u00fang k\u1ef9 thu\u1eadt)<\/h3>\n<p>&#8211; Khoanh v\u00f9ng b\u1eb1ng PT \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u1ea7y \u0111\u1ee7 chi\u1ec1u d\u00e0i n\u1ee9t.<br \/>\n&#8211; Khoan \u201cstop-hole\u201d \u03a61.5\u20132.0 mm t\u1ea1i hai \u0111\u1ea7u v\u1ebft n\u1ee9t nh\u1eb1m ch\u1eb7n lan truy\u1ec1n (\u00e1p d\u1ee5ng cho t\u1ea5m\/khung ch\u1ecbu \u1ee9ng su\u1ea5t).<br \/>\n&#8211; M\u00e0i b\u1ecf ho\u00e0n to\u00e0n v\u1ebft n\u1ee9t \u0111\u1ebfn n\u1ec1n kim lo\u1ea1i t\u1ed1t (V\/U-groove nh\u1ecf), l\u00e0m s\u1ea1ch c\u01a1 h\u1ecdc + dung m\u00f4i.<br \/>\n&#8211; H\u00e0n l\u1ea1i v\u1edbi filler ph\u00f9 h\u1ee3p, gi\u1ea3m nhi\u1ec7t v\u00e0o, c\u00f3 purge m\u1eb7t sau n\u1ebfu l\u00e0 m\u1ed1i ng\u1ea5u.<br \/>\n&#8211; PT l\u1ea1i sau s\u1eeda; n\u1ebfu l\u00e0 k\u1ebft c\u1ea5u ch\u1ecbu t\u1ea3i\/\u00e1p l\u1ef1c, c\u00e2n nh\u1eafc th\u1eed k\u00edn, th\u1eed u\u1ed1n\/loe \u0111\u1ea7u (v\u1edbi \u1ed1ng).<\/p>\n<h3>Ph\u00f2ng ng\u1eeba n\u1ee9t n\u00f3ng<\/h3>\n<p>&#8211; Ch\u1ecdn filler c\u00f3 FN 3\u201310: ER308L\/316L ti\u00eau chu\u1ea9n; tr\u00e1nh d\u00f9ng filler ho\u00e0n to\u00e0n austenitic (nh\u01b0 310) cho 304\/316 tr\u1eeb khi c\u00f3 t\u00ednh to\u00e1n.<br \/>\n&#8211; H\u1ea1n ch\u1ebf nhi\u1ec7t v\u00e0o: d\u00f2ng\/\u0111i\u1ec7n \u00e1p h\u1ee3p l\u00fd, t\u0103ng t\u1ed1c \u0111\u1ed9, kh\u00f4ng l\u1eafc r\u1ed9ng, h\u1ea1n ch\u1ebf \u0111\u1eafp nhi\u1ec1u l\u1edbp kh\u00f4ng c\u1ea7n thi\u1ebft.<br \/>\n&#8211; Ki\u1ec3m so\u00e1t t\u1ea1p ch\u1ea5t: d\u00f9ng \u1ed1ng\/h\u1ed9p chu\u1ea9n ASTM A554; thay ngu\u1ed3n v\u1eadt li\u1ec7u c\u00f3 S, P cao.<br \/>\n&#8211; Thi\u1ebft k\u1ebf gi\u1ea3m k\u1eb9p ch\u1eb7t, t\u0103ng khe h\u1edf g\u1ed1c h\u1ee3p l\u00fd, h\u00e0n so le.<\/p>\n<h3>Ph\u00f2ng ng\u1eeba n\u1ee9t ngu\u1ed9i\/hydro<\/h3>\n<p>&#8211; L\u00e0m kh\u00f4 kh\u00ed b\u1ea3o v\u1ec7 (\u0111i\u1ec3m s\u01b0\u01a1ng th\u1ea5p), ki\u1ec3m tra r\u00f2 r\u1ec9 v\u00e0 l\u01b0u l\u01b0\u1ee3ng.<br \/>\n&#8211; S\u1ea5y que\/d\u00e2y theo khuy\u1ebfn c\u00e1o, b\u1ea3o qu\u1ea3n k\u00edn \u1ea9m; l\u00e0m s\u1ea1ch d\u1ea7u\/m\u1ee1 ho\u00e0n to\u00e0n.<br \/>\n&#8211; V\u1edbi ferritic\/martensitic ho\u1eb7c li\u00ean k\u1ebft v\u1edbi th\u00e9p cacbon: c\u00e2n nh\u1eafc preheat nh\u1eb9 80\u2013150\u00b0C (430 c\u00f3 th\u1ec3 preheat th\u1ea5p khi chi ti\u1ebft d\u00e0y\/\u0111\u1ed9 k\u1eb9p cao), ch\u1ecdn ER309L cho m\u1ed1i h\u00e0n d\u1ecb v\u1eadt li\u1ec7u.<\/p>\n<h3>Ph\u00f2ng ng\u1eeba n\u1ee9t mi\u1ec7ng\/\u0111\u00e1y m\u1ed1i<\/h3>\n<p>&#8211; Lu\u00f4n \u0111\u1eafp b\u00f9 mi\u1ec7ng h\u00e0n; d\u00f9ng t\u00ednh n\u0103ng crater-fill (MIG) ho\u1eb7c gi\u1ea3m d\u1ea7n d\u00f2ng (TIG slope-down).<br \/>\n&#8211; Purge m\u1eb7t sau \u0111\u1ee7 th\u1eddi gian v\u00e0 l\u01b0u l\u01b0\u1ee3ng; d\u00f9ng backing \u0111\u1ed3ng khi kh\u00f4ng th\u1ec3 purge.<\/p>\n<h3>Ph\u00f2ng ng\u1eeba SCC trong v\u1eadn h\u00e0nh<\/h3>\n<p>&#8211; Ch\u1ecdn m\u00e1c ph\u00f9 h\u1ee3p m\u00f4i tr\u01b0\u1eddng: 316\/316L ho\u1eb7c duplex cho clorua; tr\u00e1nh 201\/304 trong m\u00f4i tr\u01b0\u1eddng Cl- n\u00f3ng.<br \/>\n&#8211; Gi\u1ea3m \u1ee9ng su\u1ea5t d\u01b0: thi\u1ebft k\u1ebf gi\u1ea3m k\u1eb9p; m\u00e0i ph\u00e1 s\u1eafc c\u1ea1nh; ph\u00e2n b\u1ed1 m\u1ed1i h\u00e0n. (Austenitic kh\u00f3 x\u1eed l\u00fd nhi\u1ec7t gi\u1ea3m \u1ee9ng su\u1ea5t m\u00e0 kh\u00f4ng g\u00e2y nh\u1ea1y c\u1ea3m; \u01b0u ti\u00ean bi\u1ec7n ph\u00e1p c\u01a1 h\u1ecdc).<br \/>\n&#8211; L\u00e0m s\u1ea1ch, t\u1ea9y g\u1ec9\u2013th\u1ee5 \u0111\u1ed9ng h\u00f3a sau h\u00e0n; tr\u00e1nh d\u00f9ng h\u00f3a ch\u1ea5t ch\u1ee9a Cl- trong b\u1ea3o tr\u00ec; r\u1eeda tr\u00e1ng k\u1ef9.<\/p>\n<h3>Khuy\u1ebfn ngh\u1ecb theo m\u00e1c Inox ph\u1ed5 bi\u1ebfn<\/h3>\n<p>&#8211; 201: D\u1ec5 n\u1ee9t n\u00f3ng h\u01a1n 304 khi pha lo\u00e3ng l\u1edbn; d\u00f9ng ER308L, ki\u1ec3m so\u00e1t nhi\u1ec7t v\u00e0o, purge t\u1ed1t.<br \/>\n&#8211; 304: D\u1ec5 h\u00e0n; ki\u1ec3m so\u00e1t interpass \u2264150\u00b0C; ER308L l\u00e0 ti\u00eau chu\u1ea9n.<br \/>\n&#8211; 316: T\u01b0\u01a1ng t\u1ef1 304; d\u00f9ng ER316L; th\u00edch h\u1ee3p m\u00f4i tr\u01b0\u1eddng Cl- nh\u1eb9, nh\u01b0ng SCC v\u1eabn c\u00f3 th\u1ec3 x\u1ea3y ra >60\u00b0C.<br \/>\n&#8211; 430 (ferritic): Tr\u00e1nh nhi\u1ec7t v\u00e0o cao v\u00e0 gi\u1eef nhi\u1ec7t l\u00e2u; c\u00f3 th\u1ec3 preheat nh\u1eb9 (\u2264150\u00b0C) khi d\u00e0y\/k\u1eb9p ch\u1eb7t; d\u00f9ng ER430Ti ho\u1eb7c ER309L cho m\u1ed1i d\u1ecb v\u1eadt li\u1ec7u; kh\u00f4ng PWHT \u1edf nhi\u1ec7t cao v\u00ec nguy c\u01a1 gi\u00f2n.<\/p>\n<h2 id=\"toc-5-tieu-chuan-va-muc-chap-nhan\">Ti\u00eau chu\u1ea9n v\u00e0 m\u1ee9c ch\u1ea5p nh\u1eadn<\/h2>\n<p>&#8211; ISO 5817 (C\u1ea5p B\/C\/D) quy \u0111\u1ecbnh ch\u1ea5t l\u01b0\u1ee3ng m\u1ed1i h\u00e0n h\u1ed3 quang kim lo\u1ea1i \u2013 \u201cV\u1ebft n\u1ee9t\u201d b\u1ecb c\u1ea5m \u1edf m\u1ecdi c\u1ea5p ch\u1ea5t l\u01b0\u1ee3ng.<br \/>\n&#8211; AWS D1.6 (K\u1ebft c\u1ea5u Inox) v\u00e0 TCVN li\u00ean quan: n\u1ee9t l\u00e0 khuy\u1ebft t\u1eadt kh\u00f4ng ch\u1ea5p nh\u1eadn.<br \/>\n&#8211; EN 1011-3 (H\u01b0\u1edbng d\u1eabn h\u00e0n Inox) \u2013 ki\u1ec3m so\u00e1t nhi\u1ec7t v\u00e0o, v\u1eadt li\u1ec7u ti\u00eau hao, ch\u1ed1ng n\u1ee9t n\u00f3ng\/ngu\u1ed9i.<br \/>\n&#8211; ASTM A554 (\u1ed0ng\/h\u1ed9p Inox h\u00e0n c\u01a1 kh\u00ed) \u2013 y\u00eau c\u1ea7u v\u1ec1 th\u00e0nh ph\u1ea7n, c\u01a1 t\u00ednh v\u00e0 ch\u1ea5t l\u01b0\u1ee3ng \u0111\u01b0\u1eddng h\u00e0n s\u1ea3n xu\u1ea5t.<\/p>\n<h2 id=\"toc-6-cau-hoi-thuong-gap\">C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p<\/h2>\n<p>&#8211; C\u00f3 c\u1ea7n preheat khi h\u00e0n Inox? V\u1edbi austenitic (201\/304\/316) th\u01b0\u1eddng kh\u00f4ng; gi\u1eef interpass \u2264150\u00b0C. Ferritic d\u00e0y\/k\u1eb9p ch\u1eb7t c\u00f3 th\u1ec3 preheat nh\u1eb9 \u2264150\u00b0C; martensitic c\u1ea7n preheat\/PWHT theo WPS.<br \/>\n&#8211; MIG h\u00e0n Inox c\u00f3 d\u00f9ng CO2 tinh khi\u1ebft? Kh\u00f4ng. D\u00f9ng Ar + 1\u20132% CO2 ho\u1eb7c 1\u20132% O2 \u0111\u1ec3 \u1ed5n \u0111\u1ecbnh h\u1ed3 quang, h\u1ea1n ch\u1ebf oxy h\u00f3a.<br \/>\n&#8211; V\u00ec sao c\u1ea7n purge m\u1eb7t sau khi h\u00e0n \u1ed1ng\/h\u1ed9p k\u00edn ng\u1ea5u? \u0110\u1ec3 tr\u00e1nh \u201csugaring\u201d gi\u00f2n, gi\u1ea3m nguy c\u01a1 n\u1ee9t ch\u00e2n m\u1ed1i v\u00e0 \u0103n m\u00f2n s\u1edbm.<br \/>\n&#8211; Crater crack x\u1eed l\u00fd th\u1ebf n\u00e0o? M\u00e0i b\u1ecf, h\u00e0n s\u1eeda v\u00e0 d\u00f9ng ch\u1ee9c n\u0103ng crater-fill ho\u1eb7c gi\u1ea3m d\u1ea7n d\u00f2ng (downslope) cho l\u1ea7n sau.<\/p>\n<h2 id=\"toc-7-ket-luan\">K\u1ebft lu\u1eadn<\/h2>\n<p>N\u1ee9t m\u1ed1i h\u00e0n tr\u00ean \u1ed1ng, h\u1ed9p Inox b\u1eaft ngu\u1ed3n t\u1eeb ba nh\u00f3m ch\u00ednh: v\u1eadt li\u1ec7u\/filler kh\u00f4ng ph\u00f9 h\u1ee3p, thi\u1ebft k\u1ebf\u2013\u0111\u1ed9 k\u1eb9p ch\u1eb7t g\u00e2y \u1ee9ng su\u1ea5t cao, v\u00e0 quy tr\u00ecnh h\u00e0n\u2013b\u1ea3o v\u1ec7 kh\u00ed\u2013nhi\u1ec7t v\u00e0o ch\u01b0a ki\u1ec3m so\u00e1t. C\u00e1ch kh\u1eafc ph\u1ee5c hi\u1ec7u qu\u1ea3 g\u1ed3m: ch\u1ecdn \u0111\u00fang filler (ER308L\/316L\/309L) v\u1edbi FN ph\u00f9 h\u1ee3p, t\u1ed1i \u01b0u th\u00f4ng s\u1ed1 h\u00e0n \u0111\u1ec3 gi\u1ea3m nhi\u1ec7t v\u00e0o, b\u1ea3o v\u1ec7 m\u1eb7t sau (purge) nghi\u00eam ng\u1eb7t, l\u00e0m s\u1ea1ch tri\u1ec7t \u0111\u1ec3, thi\u1ebft k\u1ebf g\u00e1 l\u1eafp cho ph\u00e9p co ng\u00f3t, v\u00e0 x\u1eed l\u00fd \u0111\u00fang k\u1ef9 thu\u1eadt khi s\u1eeda ch\u1eefa. V\u1edbi m\u00f4i tr\u01b0\u1eddng s\u1eed d\u1ee5ng c\u00f3 clorua, \u01b0u ti\u00ean v\u1eadt li\u1ec7u ch\u1ed1ng SCC v\u00e0 ho\u00e0n thi\u1ec7n b\u1ec1 m\u1eb7t sau h\u00e0n. Tu\u00e2n th\u1ee7 c\u00e1c ti\u00eau chu\u1ea9n (ISO 5817, AWS D1.6, EN 1011-3, ASTM A554) s\u1ebd gi\u00fap lo\u1ea1i b\u1ecf n\u1ee9t t\u1eeb g\u1ed1c v\u00e0 \u0111\u1ea3m b\u1ea3o tu\u1ed5i th\u1ecd k\u1ebft c\u1ea5u Inox trong s\u1ea3n xu\u1ea5t v\u00e0 v\u1eadn h\u00e0nh.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Gi\u1ea3i th\u00edch nguy\u00ean nh\u00e2n n\u1ee9t m\u1ed1i h\u00e0n \u1ed1ng, h\u1ed9p Inox v\u00e0 quy tr\u00ecnh ch\u1ea9n \u0111o\u00e1n\u2013kh\u1eafc ph\u1ee5c k\u00e8m th\u00f4ng s\u1ed1 h\u00e0n khuy\u1ebfn ngh\u1ecb, gi\u00fap ng\u0103n n\u1ee9t t\u00e1i di\u1ec5n.<\/p>\n","protected":false},"author":7,"featured_media":1036,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[23],"tags":[],"class_list":["post-1225","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\/1225","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=1225"}],"version-history":[{"count":0,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/posts\/1225\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/media\/1036"}],"wp:attachment":[{"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/media?parent=1225"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/categories?post=1225"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/inoxcuongthinh.com\/inct\/wp\/v2\/tags?post=1225"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}