{"id":20197,"date":"2020-12-11T08:29:20","date_gmt":"2020-12-11T08:29:20","guid":{"rendered":"https:\/\/www.meetyoucarbide.com\/?p=20197"},"modified":"2020-12-11T08:31:42","modified_gmt":"2020-12-11T08:31:42","slug":"main-problems-encountered-in-welding-of-18cr-austenitic-stainless-steel","status":"publish","type":"post","link":"https:\/\/www.meetyoucarbide.com\/vi\/main-problems-encountered-in-welding-of-18cr-austenitic-stainless-steel\/","title":{"rendered":"C\u00e1c v\u1ea5n \u0111\u1ec1 ch\u00ednh g\u1eb7p ph\u1ea3i khi h\u00e0n th\u00e9p kh\u00f4ng g\u1ec9 Austenitic 18cr"},"content":{"rendered":"

Th\u00e9p kh\u00f4ng g\u1ec9 Austenitic c\u00f3 kh\u1ea3 n\u0103ng ch\u1ed1ng \u0103n m\u00f2n t\u1ed1t do h\u00e0m l\u01b0\u1ee3ng crom cao v\u00e0 m\u00e0ng oxit d\u00e0y \u0111\u1eb7c. Khi ch\u1ee9a Cr18% v\u00e0 Ni8%, c\u00f3 th\u1ec3 thu \u0111\u01b0\u1ee3c m\u1ed9t c\u1ea5u tr\u00fac austenite duy nh\u1ea5t. Do \u0111\u00f3, th\u00e9p kh\u00f4ng g\u1ec9 austenit c\u00f3 kh\u1ea3 n\u0103ng ch\u1ed1ng \u0103n m\u00f2n t\u1ed1t, \u0111\u1ed9 d\u1ebbo, hi\u1ec7u su\u1ea5t nhi\u1ec7t \u0111\u1ed9 cao v\u00e0 hi\u1ec7u su\u1ea5t h\u00e0n. Tuy nhi\u00ean, trong c\u00e1c \u0111i\u1ec1u ki\u1ec7n l\u00e0m vi\u1ec7c kh\u00e1c nhau, m\u1ed1i h\u00e0n th\u00e9p kh\u00f4ng g\u1ec9 austenit th\u01b0\u1eddng g\u1eb7p ph\u1ea3i m\u1ed9t s\u1ed1 v\u1ea5n \u0111\u1ec1 \u0111\u1eb7c bi\u1ec7t, d\u1ec5 g\u00e2y ra c\u00e1c khuy\u1ebft t\u1eadt trong k\u1ebft c\u1ea5u nh\u01b0 \u0103n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t, \u0103n m\u00f2n \u1ee9ng su\u1ea5t, \u0103n m\u00f2n dao, v\u1ebft n\u1ee9t n\u00f3ng khi h\u00e0n, hi\u1ec7n t\u01b0\u1ee3ng gi\u00f2n pha \u03b1, v.v.<\/p>

Ph\u00e2n t\u00edch \u0103n m\u00f2n m\u1ed1i h\u00e0n<\/h2>

\u0102n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t c\u1ee7a m\u1ed1i h\u00e0n<\/h3>

\u0102n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t l\u00e0 m\u1ed9t trong nh\u1eefng v\u1ea5n \u0111\u1ec1 \u0103n m\u00f2n quan tr\u1ecdng nh\u1ea5t c\u1ee7a th\u00e9p kh\u00f4ng g\u1ec9 austenit. M\u1ed9t khi s\u1ef1 \u0103n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t x\u1ea3y ra, s\u1ee9c m\u1ea1nh c\u1ee7a n\u00f3 g\u1ea7n nh\u01b0 m\u1ea5t \u0111i khi nghi\u00eam tr\u1ecdng v\u00e0 v\u1ebft n\u1ee9t gi\u1eefa c\u00e1c h\u1ea1t s\u1ebd x\u1ea3y ra khi c\u00f3 m\u1ed9t \u1ee9ng su\u1ea5t nh\u1ea5t \u0111\u1ecbnh. S\u1ef1 \u0103n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t c\u1ee7a m\u1ed1i h\u00e0n th\u00e9p kh\u00f4ng g\u1ec9 austenit ch\u1ee7 y\u1ebfu l\u00e0 do k\u1ebft t\u1ee7a cacbua crom. Khi th\u00e9p kh\u00f4ng g\u1ec9 austenit \u0111\u01b0\u1ee3c nh\u1ea1y c\u1ea3m trong kho\u1ea3ng nhi\u1ec7t \u0111\u1ed9 500 ~ 800oC, t\u1ed1c \u0111\u1ed9 khu\u1ebfch t\u00e1n c\u1ee7a carbon dung d\u1ecbch r\u1eafn si\u00eau b\u00e3o h\u00f2a \u0111\u1ebfn ranh gi\u1edbi gi\u1eefa c\u00e1c h\u1ea1t nhanh h\u01a1n so v\u1edbi crom v\u00e0 carbon trong dung d\u1ecbch r\u1eafn si\u00eau b\u00e3o h\u00f2a \u0111\u01b0\u1ee3c k\u1ebft h\u1ee3p v\u1edbi crom g\u1ea7n h\u1ea1t ranh gi\u1edbi, Khi h\u00e0m l\u01b0\u1ee3ng crom trong v\u00f9ng gi\u1ea3m xu\u1ed1ng d\u01b0\u1edbi h\u00e0m l\u01b0\u1ee3ng gi\u1edbi h\u1ea1n (w (CR) 12,5%) c\u1ea7n thi\u1ebft cho qu\u00e1 tr\u00ecnh th\u1ee5 \u0111\u1ed9ng, qu\u00e1 tr\u00ecnh \u0103n m\u00f2n c\u1ee7a v\u00f9ng s\u1ebd \u0111\u01b0\u1ee3c t\u0103ng t\u1ed1c v\u00e0 h\u00ecnh th\u00e0nh s\u1ef1 \u0103n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t. K\u1ebft qu\u1ea3 cho th\u1ea5y s\u1ef1 \u0103n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t trong v\u00f9ng nhi\u1ec7t \u0111\u1ed9 nh\u1ea1y c\u1ea3m c\u1ee7a HAZ x\u1ea3y ra \u1edf v\u00f9ng c\u00f3 nhi\u1ec7t \u0111\u1ed9 gia nhi\u1ec7t cao nh\u1ea5t l\u00e0 t\u1eeb 600oC \u0111\u1ebfn 1000oC. Nguy\u00ean nh\u00e2n \u0103n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t v\u1eabn l\u00e0 do s\u1ef1 k\u1ebft t\u1ee7a c\u1ee7a cacbua crom \u1edf ranh gi\u1edbi h\u1ea1t austenit. C\u00e1c bi\u1ec7n ph\u00e1p ph\u00f2ng ng\u1eeba ch\u00ednh \u0111\u1ec3 gi\u1ea3m v\u00e0 ng\u0103n ch\u1eb7n s\u1ef1 \u0103n m\u00f2n gi\u1eefa c\u00e1c h\u1ea1t bao g\u1ed3m:<\/strong><\/p>

\u2460 Th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt nh\u1ecf (d\u00f2ng \u0111i\u1ec7n nh\u1ecf, t\u1ed1c \u0111\u1ed9 h\u00e0n cao) v\u00e0 h\u00e0n nhi\u1ec1u \u0111\u01b0\u1eddng \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng;<\/p>

\u2461 N\u00ean gi\u1ea3m h\u00e0m l\u01b0\u1ee3ng carbon trong kim lo\u1ea1i c\u01a1 b\u1ea3n v\u00e0 v\u1eadt li\u1ec7u h\u00e0n c\u00e0ng nhi\u1ec1u c\u00e0ng t\u1ed1t v\u00e0 n\u00ean s\u1eed d\u1ee5ng v\u1eadt li\u1ec7u h\u00e0n c\u00f3 h\u00e0m l\u01b0\u1ee3ng C nh\u1ecf h\u01a1n 0,03%;<\/p>

\u2462 K\u1ebft qu\u1ea3 l\u00e0 Cr khu\u1ebfch t\u00e1n \u0111\u1ebfn ranh gi\u1edbi h\u1ea1t trong ferit nhanh h\u01a1n trong austenite, l\u00e0m gi\u1ea3m hi\u1ec7n t\u01b0\u1ee3ng crom k\u00e9m trong ranh gi\u1edbi h\u1ea1t austenite;<\/p>

\u2463 Vi\u1ec7c b\u1ed5 sung Ti, Nb v\u00e0 c\u00e1c nguy\u00ean t\u1ed1 kh\u00e1c c\u00f3 \u00e1i l\u1ef1c v\u1edbi cacbon m\u1ea1nh h\u01a1n crom trong th\u00e9p v\u00e0 v\u1eadt li\u1ec7u h\u00e0n c\u00f3 th\u1ec3 t\u1ea1o th\u00e0nh c\u00e1c h\u1ee3p ch\u1ea5t \u1ed5n \u0111\u1ecbnh c\u00f3 li\u00ean k\u1ebft cacbon, do \u0111\u00f3 tr\u00e1nh \u0111\u01b0\u1ee3c s\u1ef1 suy gi\u1ea3m crom \u1edf ranh gi\u1edbi h\u1ea1t austenit.<\/p>

\u0102n m\u00f2n \u1ee9ng su\u1ea5t c\u00e1c m\u1ed1i h\u00e0n<\/h3>

Hi\u1ec7n t\u01b0\u1ee3ng n\u1ee9t do \u0103n m\u00f2n \u1ee9ng su\u1ea5t c\u1ee7a th\u00e9p kh\u00f4ng g\u1ec9 l\u00e0 h\u00e0nh vi \u0103n m\u00f2n c\u00f3 h\u1ea1i nh\u1ea5t. Kh\u00f4ng c\u00f3 bi\u1ebfn d\u1ea1ng khi n\u1ee9t. Tai n\u1ea1n th\u01b0\u1eddng x\u1ea3y ra b\u1ea5t ng\u1edd v\u00e0 h\u1eadu qu\u1ea3 r\u1ea5t nghi\u00eam tr\u1ecdng. C\u00f3 nhi\u1ec1u y\u1ebfu t\u1ed1 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn hi\u1ec7n t\u01b0\u1ee3ng n\u1ee9t \u0103n m\u00f2n \u1ee9ng su\u1ea5t c\u1ee7a th\u00e9p kh\u00f4ng g\u1ec9 trong \u0111i\u1ec1u ki\u1ec7n s\u1eed d\u1ee5ng, bao g\u1ed3m th\u00e0nh ph\u1ea7n, c\u1ea5u tr\u00fac v\u00e0 tr\u1ea1ng th\u00e1i c\u1ee7a th\u00e9p, lo\u1ea1i m\u00f4i tr\u01b0\u1eddng, nhi\u1ec7t \u0111\u1ed9, n\u1ed3ng \u0111\u1ed9, \u0111\u1eb7c t\u00ednh \u1ee9ng su\u1ea5t, k\u00edch th\u01b0\u1edbc v\u00e0 \u0111\u1eb7c \u0111i\u1ec3m c\u1ea5u tr\u00fac.<\/p>

\"\"<\/figure>

C\u00e1c bi\u1ec7n ph\u00e1p ch\u00ednh \u0111\u1ec3 gi\u1ea3m v\u00e0 ng\u0103n ng\u1eeba \u0103n m\u00f2n \u1ee9ng su\u1ea5t nh\u01b0 sau:<\/p>

\u2460 Tr\u00e1nh l\u1eafp r\u00e1p m\u1ea1nh, t\u00e1c \u0111\u1ed9ng c\u01a1 h\u1ecdc v\u00e0 ch\u00e1y h\u1ed3 quang, gi\u1ea3m bi\u1ebfn d\u1ea1ng v\u00e0 \u1ee9ng su\u1ea5t khi gia c\u00f4ng ngu\u1ed9i;<\/p>

\u2461 Ki\u1ec3m so\u00e1t ch\u1eb7t ch\u1ebd c\u00e1c t\u1ea1p ch\u1ea5t trong m\u00f4i tr\u01b0\u1eddng v\u00e0 m\u00f4i tr\u01b0\u1eddng (\u0111\u1eb7c bi\u1ec7t l\u00e0 clorua, florua, v.v.);<\/p>

\u2462 L\u1ef1a ch\u1ecdn v\u1eadt li\u1ec7u h\u1ee3p l\u00fd (kim lo\u1ea1i c\u01a1 b\u1ea3n, v\u1eadt li\u1ec7u h\u00e0n): tr\u00e1nh l\u00e0m th\u00f4 h\u1ea1t v\u00e0 l\u00e0m c\u1ee9ng c\u1ea5u tr\u00fac martensite;<\/p>

\u2463 M\u1ed1i h\u00e0n \u0111\u01b0\u1ee3c t\u1ea1o h\u00ecnh t\u1ed1t m\u00e0 kh\u00f4ng c\u00f3 b\u1ea5t k\u1ef3 s\u1ef1 t\u1eadp trung \u1ee9ng su\u1ea5t n\u00e0o (ch\u1eb3ng h\u1ea1n nh\u01b0 v\u1ebft c\u1eaft);<\/p>

\u2464 S\u1eafp x\u1ebfp tr\u00ecnh t\u1ef1 h\u00e0n h\u1ee3p l\u00fd \u0111\u1ec3 gi\u1ea3m c\u0103ng th\u1eb3ng;<\/p>

\u2465 X\u1eed l\u00fd ch\u1ed1ng \u0103n m\u00f2n: th\u00eam ch\u1ea5t \u1ee9c ch\u1ebf \u0103n m\u00f2n v\u00e0o l\u1edbp ph\u1ee7, l\u1edbp l\u00f3t ho\u1eb7c l\u1edbp b\u1ea3o v\u1ec7 ca-t\u1ed1t.<\/p>

 <\/h2>

Ph\u00e2n t\u00edch \u0111\u1ed9 nh\u1ea1y v\u1ebft n\u1ee9t n\u00f3ng c\u1ee7a m\u1ed1i h\u00e0n<\/h2>

C\u00e1c v\u1ebft n\u1ee9t n\u00f3ng c\u1ee7a th\u00e9p kh\u00f4ng g\u1ec9 austenit ch\u1ee7 y\u1ebfu l\u00e0 c\u00e1c v\u1ebft n\u1ee9t tinh th\u1ec3, \u0111\u01b0\u1ee3c t\u1ea1o ra trong qu\u00e1 tr\u00ecnh h\u00f3a r\u1eafn kim lo\u1ea1i l\u1ecfng c\u1ee7a kim lo\u1ea1i m\u1ed1i h\u00e0n. V\u00e0o th\u1eddi \u0111i\u1ec3m n\u00e0y, c\u00e1c tinh th\u1ec3 s\u01a1 c\u1ea5p t\u1ed3n t\u1ea1i \u1edf \u0111i\u1ec3m n\u00f3ng ch\u1ea3y c\u00f9ng tinh, ch\u1ee7 y\u1ebfu l\u00e0 gi\u1eefa c\u00e1c s\u1ee3i nh\u00e1nh. Nh\u1eefng l\u00fd do ch\u00ednh nh\u01b0 sau:<\/p>

\u2460 S, P, C, v.v., t\u1ea1o th\u00e0nh \u0111i\u1ec3m n\u00f3ng ch\u1ea3y th\u1ea5p eutectic v\u1edbi Ni (v\u00ed d\u1ee5: \u0111i\u1ec3m n\u00f3ng ch\u1ea3y c\u1ee7a NIS + Ni l\u00e0 644oC), l\u00e0m suy y\u1ebfu c\u01b0\u1eddng \u0111\u1ed9 ranh gi\u1edbi h\u1ea1t;<\/p>

\u2461 Th\u00e9p kh\u00f4ng g\u1ec9 Austenitic c\u00f3 \u01b0u \u0111i\u1ec3m l\u00e0 kho\u1ea3ng c\u00e1ch l\u1edbn gi\u1eefa ch\u1ea5t l\u1ecfng v\u00e0 ch\u1ea5t r\u1eafn, th\u1eddi gian k\u1ebft tinh d\u00e0i, \u0111\u1ecbnh h\u01b0\u1edbng dendrite m\u1ea1nh v\u00e0 d\u1ec5 d\u00e0ng t\u1ea1o ra s\u1ef1 ph\u00e2n t\u00e1ch c\u00e1c nguy\u00ean t\u1ed1 t\u1ea1p ch\u1ea5t;<\/p>

\u2462 \u0110\u1ed9 d\u1eabn nhi\u1ec7t c\u1ee7a th\u00e9p nh\u1ecf, h\u1ec7 s\u1ed1 gi\u00e3n n\u1edf tuy\u1ebfn t\u00ednh l\u1edbn n\u00ean d\u1ec5 t\u1ea1o ra \u1ee9ng su\u1ea5t.<\/p>

\"\"<\/figure>

\"\" <\/h2>

C\u00e1c bi\u1ec7n ph\u00e1p ch\u00ednh \u0111\u1ec3 ng\u0103n ng\u1eeba v\u1ebft n\u1ee9t n\u00f3ng khi h\u00e0n bao g\u1ed3m:<\/h3>

\u2460 H\u00e0m l\u01b0\u1ee3ng t\u1ea1p ch\u1ea5t c\u00f3 h\u1ea1i l\u01b0u hu\u1ef3nh v\u00e0 ph\u1ed1t pho trong kim lo\u1ea1i c\u01a1 b\u1ea3n v\u00e0 v\u1eadt li\u1ec7u h\u00e0n ph\u1ea3i \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t ch\u1eb7t ch\u1ebd;<\/p>

\u2461 Kho\u1ea3ng 5% ferrite \u0111\u01b0\u1ee3c t\u1ea1o ra trong m\u1ed1i h\u00e0n, l\u00e0m x\u00e1o tr\u1ed9n h\u01b0\u1edbng c\u1ee7a tinh th\u1ec3 c\u1ed9t austenite;<\/p>

\u2462 \u00c1p d\u1ee5ng quy tr\u00ecnh h\u00e0n d\u00f2ng \u0111i\u1ec7n nh\u1ecf v\u00e0 nhanh.<\/p>

Ki\u1ec3m so\u00e1t h\u00e0m l\u01b0\u1ee3ng ferit trong m\u1ed1i h\u00e0n<\/h2>

H\u00e0m l\u01b0\u1ee3ng ferit trong kim lo\u1ea1i m\u1ed1i h\u00e0n th\u00e9p austenit kh\u00f4ng ch\u1ec9 li\u00ean quan \u0111\u1ebfn s\u1ef1 h\u00ecnh th\u00e0nh v\u00e0 \u0111\u1ed9 b\u1ec1n nhi\u1ec7t c\u1ee7a \u0111\u1ed9 gi\u00f2n pha \u03b1 (\u03c3) m\u00e0 c\u00f2n \u1ea3nh h\u01b0\u1edfng tr\u1ef1c ti\u1ebfp \u0111\u1ebfn kh\u1ea3 n\u0103ng ch\u1ed1ng n\u1ee9t n\u00f3ng c\u1ee7a m\u1ed1i n\u1ed1i. Th\u1eddi gian gia nhi\u1ec7t c\u00e0ng d\u00e0i, th\u1eddi gian l\u01b0u tr\u00fa \u1edf nhi\u1ec7t \u0111\u1ed9 cao c\u00e0ng l\u00e2u th\u00ec l\u01b0\u1ee3ng m\u01b0a c\u00e0ng nhi\u1ec1u, \u0111i\u1ec1u n\u00e0y s\u1ebd \u1ea3nh h\u01b0\u1edfng nghi\u00eam tr\u1ecdng \u0111\u1ebfn t\u00ednh ch\u1ea5t c\u01a1 h\u1ecdc c\u1ee7a m\u1ed1i n\u1ed1i. T\u1eeb quan \u0111i\u1ec3m v\u1ec1 kh\u1ea3 n\u0103ng ch\u1ed1ng n\u1ee9t n\u00f3ng, c\u1ea7n c\u00f3 m\u1ed9t l\u01b0\u1ee3ng ferit nh\u1ea5t \u0111\u1ecbnh trong kim lo\u1ea1i m\u1ed1i h\u00e0n. Tuy nhi\u00ean, xem x\u00e9t \u0111\u1ed9 gi\u00f2n v\u00e0 \u0111\u1ed9 b\u1ec1n nhi\u1ec7t c\u1ee7a pha \u03b1 th\u00ec h\u00e0m l\u01b0\u1ee3ng ferit c\u00e0ng th\u1ea5p th\u00ec c\u00e0ng t\u1ed1t. V\u00ec v\u1eady, h\u00e0m l\u01b0\u1ee3ng ferit ph\u1ea3i \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t ch\u1eb7t ch\u1ebd \u0111\u1ed1i v\u1edbi c\u00e1c m\u1ed1i h\u00e0n c\u00f3 \u0111\u1ed9 b\u1ec1n nhi\u1ec7t \u0111\u1ed9 cao. Trong m\u1ed9t s\u1ed1 tr\u01b0\u1eddng h\u1ee3p, ph\u1ea3i s\u1eed d\u1ee5ng kim lo\u1ea1i h\u00e0n austenit.<\/p>

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Austenitic stainless steel has good corrosion resistance because of its high chromium content and dense oxide film. When Cr18% and Ni8% are contained, a single austenite structure can be obtained. Therefore, austenitic stainless steel has good corrosion resistance, plasticity, high temperature performance and welding performance. However, under different working conditions, austenitic stainless steel welding joints…<\/p>","protected":false},"author":2,"featured_media":20201,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[79],"tags":[],"class_list":["post-20197","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-materials-weekly"],"jetpack_featured_media_url":"https:\/\/www.meetyoucarbide.com\/wp-content\/uploads\/2020\/12\/\u56fe\u72479.png","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/posts\/20197","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/comments?post=20197"}],"version-history":[{"count":0,"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/posts\/20197\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/media\/20201"}],"wp:attachment":[{"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/media?parent=20197"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/categories?post=20197"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.meetyoucarbide.com\/vi\/wp-json\/wp\/v2\/tags?post=20197"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}