{"id":775,"date":"2025-12-11T08:29:56","date_gmt":"2025-12-11T08:29:56","guid":{"rendered":"https:\/\/www.materialstests.com\/?p=775"},"modified":"2025-12-11T08:29:58","modified_gmt":"2025-12-11T08:29:58","slug":"understanding-astm-d4974-hot-air-shrinkage-test-for-yarn-and-cord","status":"publish","type":"post","link":"https:\/\/www.materialstests.com\/lv\/news\/understanding-astm-d4974-hot-air-shrinkage-test-for-yarn-and-cord.html","title":{"rendered":"Izpratne par ASTM D4974: dzijas un auklas sarau\u0161an\u0101s tests karst\u0101 gais\u0101"},"content":{"rendered":"

Pastiprino\u0161\u0101 dzija un diegi r\u016bpnieciskaj\u0101m \u0161\u013c\u016bten\u0113m<\/h2>\n\n\n\n

Sint\u0113tiskie diegi, piem\u0113ram, neilons un poliesteris, ir paz\u012bstami ar to, ka, pak\u013caujot karstumam, tie sam\u0113r\u0101 stipri saraucas. Lai p\u0113c ekstr\u016bzijas saglab\u0101tu nemain\u012bgas fizik\u0101l\u0101s un meh\u0101nisk\u0101s \u012bpa\u0161\u012bbas, \u0161os pavedienus parasti pak\u013cauj termofiks\u0113\u0161anai. \u0160is process ietver dzijas izstiep\u0161anu kontrol\u0113t\u0101 spriegojum\u0101 paaugstin\u0101t\u0101 temperat\u016br\u0101, past\u0101v\u012bgi mainot \u0161\u0137iedras krist\u0101liskumu un iek\u0161\u0113jo strukt\u016bru. \u0160is process nodro\u0161ina, ka dzija saglab\u0101 savu izm\u0113ru stabilit\u0101ti un meh\u0101nisk\u0101s \u012bpa\u0161\u012bbas turpm\u0101kaj\u0101 apstr\u0101d\u0113 augst\u0101 temperat\u016br\u0101.<\/p>\n\n\n\n

Izv\u0113loties prec\u012bzus termisk\u0101s saciet\u0113\u0161anas apst\u0101k\u013cus, tostarp temperat\u016bru, spriegojumu un iedarb\u012bbas laiku, ra\u017eot\u0101ji var piel\u0101got dzijas sarau\u0161anos, stipr\u012bbu un elast\u012bbu, lai atbilstu konkr\u0113t\u0101m ekspluat\u0101cijas pras\u012bb\u0101m. Pareizi termiski nost\u0101din\u0101ti pavedieni ir notur\u012bgi pret deform\u0101ciju pak\u0101rtotajos procesos, piem\u0113ram, gumijas vulkaniz\u0101cij\u0101, un nodro\u0161ina ilgtermi\u0146a stabilit\u0101ti sare\u017e\u0123\u012btos r\u016bpnieciskos lietojumos.<\/p>\n\n\n\n

ASTM D4974: M\u0113r\u0137is un pielietojums<\/h2>\n\n\n\n

ASTM D4974 standartu pla\u0161i izmanto karstumiztur\u012bgiem pavedieniem, tostarp neilona, poliestera un aram\u012bda \u0161\u0137iedr\u0101m. \u0160os materi\u0101lus parasti izmanto riepu aukl\u0101s, jostu stiegrojumos un citos meh\u0101nisk\u0101s gumijas izstr\u0101d\u0101jumos (MRG), kas tiek vulkaniz\u0113ti. Vulkaniz\u0101cijas laik\u0101 gumija tiek pak\u013cauta augstam karstumam, lai ieg\u016btu t\u0101s gal\u012bg\u0101s meh\u0101nisk\u0101s un fizik\u0101l\u0101s \u012bpa\u0161\u012bbas. Ja pavedienam ir augsta termisk\u0101 sarau\u0161an\u0101s, \u0161\u012b procesa laik\u0101 tas var sa\u0161aurin\u0101t t\u0101dus komponentus k\u0101 \u0161\u013c\u016btenes vai jostas, potenci\u0101li apdraudot galaprodukta izm\u0113rus un veiktsp\u0113ju.<\/p>\n\n\n\n

Zema sarau\u0161an\u0101s pak\u0101pes dzijas, kas r\u016bp\u012bgi un atbilsto\u0161i parametriem termiski nost\u0101din\u0101tas, karstum\u0101 minim\u0101li maina izm\u0113rus. Tas padara tos piem\u0113rot\u0101kus r\u016bpnieciskiem lietojumiem, kur nepiecie\u0161ama augsta termisk\u0101 stabilit\u0101te, nemain\u012bga veiktsp\u0113ja un uzticama integr\u0101cija ar gumiju vai citiem karstumjut\u012bgiem materi\u0101liem.<\/p>\n\n\n\n

 <\/h2>\n\n\n\n

Karst\u0101 gaisa termisk\u0101s sarau\u0161an\u0101s testeris: Test\u0113\u0161anas proced\u016bra<\/h2>\n\n\n\n

Port\u0101ls Karst\u0101 gaisa termisk\u0101s sarau\u0161an\u0101s testeris<\/strong><\/a> ir galvenais r\u012bks, ar ko veikt ASTM D4974 test\u0113\u0161anu. Ar \u0161o instrumentu dzijas vai auklas paraugs tiek pak\u013cauts kontrol\u0113tam sausam karstumam, vienlaikus saglab\u0101jot prec\u012bzu spriegojumu. Sarau\u0161an\u0101s tiek m\u0113r\u012bta tie\u0161i procentos, kam\u0113r paraugs ir sasprindzin\u0101ts noteikt\u0101 temperat\u016br\u0101.<\/p>\n\n\n\n

Saska\u0146\u0101 ar ASTM D4974 proced\u016bru dzija parasti 2 min\u016btes tiek kars\u0113ta l\u012bdz 177\u00b0C (350\u00b0F) temperat\u016br\u0101 ar 0,05 gramu uz den\u0113ru (gpd) iepriek\u0161\u0113jas nospriego\u0161anas slodzi. Dzij\u0101m ar \u013coti mazu sarau\u0161an\u0101s sp\u0113ju prec\u012bz\u0101ku m\u0113r\u012bjumu veik\u0161anai ieteicams izmantot maz\u0101ku iepriek\u0161\u0113ju spriegojumu - 0,01 gpd. Priek\u0161sprieguma korekcijas var ietekm\u0113t sarau\u0161an\u0101s r\u0101d\u012bjumu, jo liel\u0101kas priek\u0161sprieguma v\u0113rt\u012bbas parasti samazina izm\u0113r\u012bto sarau\u0161anos.
\u0160\u012b test\u0113\u0161anas metode \u013cauj ra\u017eot\u0101jiem p\u0101rliecin\u0101ties, ka dzija vai aukla saglab\u0101 savu fizisko stabilit\u0101ti augstas temperat\u016bras apst\u0101k\u013cos, nodro\u0161inot prognoz\u0113jamu veiktsp\u0113ju vulkaniz\u0101cijas un citu termisko procesu laik\u0101.<\/p>\n\n\n\n


Test\u0113\u0161anas vari\u0101cijas un apsv\u0113rumi<\/h2>\n\n\n\n

Ir svar\u012bgi atz\u012bm\u0113t, ka ne visi ra\u017eot\u0101ji prec\u012bzi iev\u0113ro ASTM D4974. Test\u0113\u0161anas temperat\u016bras, ilguma vai pielikt\u0101 spriegojuma at\u0161\u0137ir\u012bbas var b\u016btiski ietekm\u0113t izm\u0113r\u012bto sarau\u0161anos. Piem\u0113ram, pavediens, kas test\u0113ts 190 \u00b0C temperat\u016br\u0101 10 min\u016btes ar noteiktu slodzi, var dot at\u0161\u0137ir\u012bgus rezult\u0101tus sal\u012bdzin\u0101jum\u0101 ar pavedienu, kas test\u0113ts ASTM D4974 standart\u0101 177 \u00b0C temperat\u016br\u0101 2 min\u016btes. Neraugoties uz \u0161\u012bm at\u0161\u0137ir\u012bb\u0101m, ja abus materi\u0101lus test\u0113 vien\u0101dos apst\u0101k\u013cos, to termisk\u0101 sarau\u0161an\u0101s var b\u016bt gandr\u012bz vien\u0101da.
Materi\u0101liem ar zem\u0101ku ku\u0161anas temperat\u016bru vai pazemin\u0101tu karstumiztur\u012bbu ir j\u0101piel\u0101go test\u0113\u0161anas apst\u0101k\u013ci, lai izvair\u012btos no \u0161\u0137iedru boj\u0101jumiem. T\u0101p\u0113c sarau\u0161an\u0101s testa parametri bie\u017ei vien ir skaidri nor\u0101d\u012bti materi\u0101lu specifik\u0101cij\u0101s, \u013caujot galalietot\u0101jiem prec\u012bzi sal\u012bdzin\u0101t rezult\u0101tus un izv\u0113l\u0113ties vispiem\u0113rot\u0101ko dziju savam pielietojumam.<\/p>\n\n\n\n

Kvalit\u0101tes un uzticam\u012bbas nodro\u0161in\u0101\u0161ana<\/h2>\n\n\n\n

Karst\u0101 gaisa termisk\u0101s sarau\u0161an\u0101s testera izmanto\u0161ana ir b\u016btiska, lai p\u0101rbaud\u012btu dzijas un auklu termisko stabilit\u0101ti. Veicot ASTM D4974 test\u0113\u0161anu, ra\u017eot\u0101ji var nodro\u0161in\u0101t, ka materi\u0101li saglab\u0101s savus izm\u0113rus un meh\u0101nisk\u0101s \u012bpa\u0161\u012bbas augstas temperat\u016bras procesos, piem\u0113ram, gumijas izstr\u0101d\u0101jumu vulkaniz\u0101cijas proces\u0101.
Lai veiktu prec\u012bzus m\u0113r\u012bjumus, ir svar\u012bgi izprast test\u0113\u0161anas iestat\u012bjumus, proced\u016bru un rezult\u0101tu interpret\u0101ciju. Nozares profesion\u0101\u013ci var pal\u012bdz\u0113t \u012bstenot ASTM D4974 test\u0113\u0161anu, pal\u012bdzot ra\u017eot\u0101jiem un galalietot\u0101jiem ieg\u016bt konsekventus, augstas kvalit\u0101tes materi\u0101lus, kas uzticami darbojas sare\u017e\u0123\u012btos r\u016bpnieciskos lietojumos.<\/p>\n\n\n\n

\"Izpratne<\/a><\/figure>","protected":false},"excerpt":{"rendered":"

Reinforcement Yarn and Thread for Industrial Hoses Synthetic yarns, such as nylon and polyester, are known for their relatively high shrinkage when exposed to heat. To maintain consistent physical and mechanical properties after extrusion, these yarns are commonly subjected to heat setting. This process involves stretching the yarn under controlled tension at elevated temperatures, permanently […]<\/p>","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-775","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/posts\/775","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/comments?post=775"}],"version-history":[{"count":0,"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/posts\/775\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/media?parent=775"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/categories?post=775"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.materialstests.com\/lv\/wp-json\/wp\/v2\/tags?post=775"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}