{"id":9865,"date":"2026-02-24T15:11:46","date_gmt":"2026-02-24T07:11:46","guid":{"rendered":"https:\/\/www.packqc.com\/standard\/astm-d751\/"},"modified":"2026-04-16T09:53:21","modified_gmt":"2026-04-16T01:53:21","slug":"astm-d751","status":"publish","type":"standard","link":"https:\/\/www.packqc.com\/vi\/standard\/astm-d751\/","title":{"rendered":"Ti\u00eau chu\u1ea9n ASTM D751"},"content":{"rendered":"

T\u1ed5ng quan v\u1ec1 ph\u01b0\u01a1ng ph\u00e1p th\u1eed nghi\u1ec7m v\u1ea3i ph\u1ee7<\/h2>\n\n\n\n

C\u00e1c Ph\u01b0\u01a1ng ph\u00e1p th\u1eed nghi\u1ec7m v\u1ea3i ph\u1ee7<\/strong> Trong ti\u00eau chu\u1ea9n ASTM D751, c\u00f3 m\u1ed9t s\u1ed1 quy tr\u00ecnh quan tr\u1ecdng \u0111\u1ec3 \u0111\u00e1nh gi\u00e1 c\u00e1c t\u00ednh ch\u1ea5t v\u1eadt l\u00fd c\u1ee7a v\u1ea3i ph\u1ee7. C\u00e1c quy tr\u00ecnh n\u00e0y bao g\u1ed3m ph\u01b0\u01a1ng ph\u00e1p th\u1eed k\u00e9o \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u1ed9 b\u1ec1n k\u00e9o, \u0111\u1ed9 gi\u00e3n d\u00e0i khi \u0111\u1ee9t, th\u1eed nghi\u1ec7m \u0111\u1ed9 b\u1ec1n v\u1ee1, kh\u1ea3 n\u0103ng ch\u1ed1ng \u0111\u00e2m th\u1ee7ng v\u00e0 \u0111\u00e1nh gi\u00e1 \u0111\u1ed9 b\u1ec1n r\u00e1ch. C\u00e1c ph\u01b0\u01a1ng ph\u00e1p n\u00e0y gi\u00fap x\u00e1c \u0111\u1ecbnh kh\u1ea3 n\u0103ng ch\u1ecbu l\u1ef1c c\u01a1 h\u1ecdc c\u1ee7a v\u1eadt li\u1ec7u, do \u0111\u00f3 ch\u00fang l\u00e0 y\u1ebfu t\u1ed1 quan tr\u1ecdng \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o ch\u1ea5t l\u01b0\u1ee3ng v\u00e0 \u0111\u1ed9 tin c\u1eady c\u1ee7a v\u1ea3i ph\u1ee7 trong c\u00e1c \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf.<\/p>\n\n\n\n

Th\u1eed nghi\u1ec7m \u0111\u1ed9 b\u1ec1n k\u00e9o: Ph\u01b0\u01a1ng ph\u00e1p th\u1eed nghi\u1ec7m b\u1eb1ng c\u00e1ch n\u1eafm gi\u1eef<\/h2>\n\n\n\n

C\u00e1c Ph\u01b0\u01a1ng ph\u00e1p th\u1eed nghi\u1ec7m grab<\/strong> l\u00e0 m\u1ed9t trong nh\u1eefng k\u1ef9 thu\u1eadt \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i nh\u1ea5t \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u1ed9 b\u1ec1n k\u00e9o<\/strong> C\u1ee7a v\u1ea3i ph\u1ee7. Th\u1eed nghi\u1ec7m n\u00e0y \u0111o l\u1ef1c t\u1ea1i \u0111i\u1ec3m v\u1ea3i b\u1ecb r\u00e1ch khi ch\u1ecbu l\u1ef1c k\u00e9o. \u0110\u1ed9 b\u1ec1n k\u00e9o l\u00e0 ch\u1ec9 s\u1ed1 hi\u1ec7u su\u1ea5t quan tr\u1ecdng \u0111\u1ed1i v\u1edbi c\u00e1c v\u1eadt li\u1ec7u \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c \u1ee9ng d\u1ee5ng ch\u1ecbu l\u1ef1c cao, nh\u01b0 bao b\u00ec ch\u1ecbu l\u1ef1c n\u1eb7ng ho\u1eb7c v\u1ea3i b\u1ea3o h\u1ed9.<\/p>\n\n\n\n

Quy tr\u00ecnh th\u1ef1c hi\u1ec7n ph\u01b0\u01a1ng ph\u00e1p th\u1eed nghi\u1ec7m Grab<\/strong><\/h3>\n\n\n\n
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  1. Chu\u1ea9n b\u1ecb m\u1eabu:<\/strong> M\u1eabu \u0111\u01b0\u1ee3c c\u1eaft th\u00e0nh k\u00edch th\u01b0\u1edbc c\u1ee5 th\u1ec3, th\u01b0\u1eddng l\u00e0 102 mm (4 inch) v\u1ec1 chi\u1ec1u r\u1ed9ng v\u00e0 152 mm (6 inch) v\u1ec1 chi\u1ec1u d\u00e0i. V\u1ea3i sau \u0111\u00f3 \u0111\u01b0\u1ee3c \u0111\u1eb7t v\u00e0o m\u00e1y th\u1eed nghi\u1ec7m, \u0111\u1ea3m b\u1ea3o \u0111\u01b0\u1ee3c c\u0103n ch\u1ec9nh ch\u00ednh x\u00e1c.<\/li>\n\n\n\n
  2. C\u00e0i \u0111\u1eb7t m\u00e1y:<\/strong> M\u1eabu \u0111\u01b0\u1ee3c k\u1eb9p ch\u1eb7t \u1edf c\u1ea3 hai \u0111\u1ea7u, v\u00e0 m\u00e1y \u00e1p d\u1ee5ng l\u1ef1c k\u00e9o \u0111\u1ec1u \u0111\u1eb7n v\u1edbi t\u1ed1c \u0111\u1ed9 5 \u00b1 0.2 mm\/s (12 \u00b1 0.5 in.\/min).<\/li>\n\n\n\n

  3. \u0110o l\u01b0\u1eddng:<\/strong> M\u00e1y ghi l\u1ea1i l\u1ef1c t\u00e1c \u0111\u1ed9ng l\u00ean v\u1ea3i cho \u0111\u1ebfn khi v\u1ea3i b\u1ecb r\u00e1ch, cung c\u1ea5p d\u1eef li\u1ec7u quan tr\u1ecdng v\u1ec1 \u0111\u1ed9 b\u1ec1n c\u1ee7a v\u1ea3i. \u0111\u1ed9 b\u1ec1n k\u00e9o<\/strong> V\u00e0 \u0110\u1ed9 gi\u00e3n d\u00e0i khi \u0111\u1ee9t<\/strong>.<\/p><\/li>\n<\/ol>\n\n\n\n

    K\u1ebft qu\u1ea3 t\u1eeb ph\u01b0\u01a1ng ph\u00e1p th\u1eed nghi\u1ec7m k\u00e9o cho th\u1ea5y kh\u1ea3 n\u0103ng b\u1ec1n b\u1ec9 c\u1ee7a v\u1ea3i, \u0111\u1eb7c bi\u1ec7t l\u00e0 kh\u1ea3 n\u0103ng ch\u1ed1ng r\u00e1ch khi ch\u1ecbu t\u00e1c \u0111\u1ed9ng c\u1ee7a l\u1ef1c b\u00ean ngo\u00e0i. \u0110\u1ed1i v\u1edbi c\u00e1c \u1ee9ng d\u1ee5ng nh\u01b0 bao b\u00ec b\u1ea3o v\u1ec7 ho\u1eb7c v\u1ea3i ngo\u00e0i tr\u1eddi, \u0111\u1ed9 b\u1ec1n k\u00e9o cao l\u00e0 y\u1ebfu t\u1ed1 quan tr\u1ecdng \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o v\u1eadt li\u1ec7u c\u00f3 th\u1ec3 ch\u1ecbu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng n\u1eb7ng.<\/p>\n\n\n\n

    \u0110\u1ed9 gi\u00e3n d\u00e0i khi \u0111\u1ee9t<\/h2>\n\n\n\n

    \u0110\u1ed9 gi\u00e3n d\u00e0i<\/strong> \u0110o kh\u1ea3 n\u0103ng co gi\u00e3n c\u1ee7a v\u1ea3i tr\u01b0\u1edbc khi b\u1ecb \u0111\u1ee9t. \u0110i\u1ec1u n\u00e0y \u0111\u1eb7c bi\u1ec7t quan tr\u1ecdng \u0111\u1ed1i v\u1edbi v\u1eadt li\u1ec7u \u0111\u00f3ng g\u00f3i, v\u00ec v\u1ea3i c\u00f3 \u0111\u1ed9 co gi\u00e3n cao c\u00f3 th\u1ec3 ch\u1ecbu \u0111\u01b0\u1ee3c l\u1ef1c t\u00e1c \u0111\u1ed9ng l\u1edbn h\u01a1n, gi\u00fap ng\u0103n ng\u1eeba h\u01b0 h\u1ecfng trong qu\u00e1 tr\u00ecnh x\u1eed l\u00fd v\u00e0 v\u1eadn chuy\u1ec3n.<\/p>\n\n\n\n

    Quy tr\u00ecnh \u0111o \u0111\u1ed9 gi\u00e3n d\u00e0i:<\/h3>\n\n\n\n