{"id":4980,"date":"2025-06-17T10:40:42","date_gmt":"2025-06-17T05:10:42","guid":{"rendered":"https:\/\/study.madeeasy.in\/?p=4980"},"modified":"2025-07-22T11:59:12","modified_gmt":"2025-07-22T06:29:12","slug":"hardening-process","status":"publish","type":"post","link":"https:\/\/www.madeeasy.in\/study\/me\/engineering-materials\/hardening-process","title":{"rendered":"Hardening Process"},"content":{"rendered":"<h2 style=\"text-align: justify;\">Process of\u00a0Hardening<\/h2>\n<p style=\"text-align: justify;\"><strong>Purpose<\/strong><\/p>\n<ol style=\"text-align: justify;\">\n<li style=\"text-align: justify;\">To increase the hardness of steel to maximum extent by austenite to martensite transformation.<\/li>\n<li style=\"text-align: justify;\">To increase the wear resistance and cutting ability of tool steels.<\/li>\n<\/ol>\n<p style=\"text-align: justify;\"><strong>Principle<\/strong><\/p>\n<p style=\"text-align: justify;\">Hypoeutectoid steel are heated to above A3 and hyper eutectoid steels are heated to above A1 by 30 to 50\u00b0C followed by sudden cooling to room temperature or below room temperature in a quenching medium, after uniform austenization. To prevent oxidation and decarburisation effect we are not going up to Acm.<\/p>\n<ul style=\"text-align: justify;\">\n<li>Martensite is defined as a super saturated solid solution of carbon in BCC form of \u03b1-iron which exist in BCT configuration.<\/li>\n<\/ul>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_79_1 ez-toc-wrap-left counter-hierarchy ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.madeeasy.in\/study\/me\/engineering-materials\/hardening-process\/#Characteristics-of-Austenite-to-Martensite-Transformation\" >Characteristics of Austenite to Martensite Transformation<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.madeeasy.in\/study\/me\/engineering-materials\/hardening-process\/#Problems-with-sudden-cooling\" >Problems with sudden cooling<\/a><\/li><\/ul><\/nav><\/div>\n<h3 style=\"text-align: justify;\"><span class=\"ez-toc-section\" id=\"Characteristics-of-Austenite-to-Martensite-Transformation\"><\/span>Characteristics of Austenite to Martensite Transformation<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul style=\"text-align: justify;\">\n<li style=\"text-align: justify;\">Austenite to martensite transformation take place at the speed of sound.<\/li>\n<li style=\"text-align: justify;\">Austenite to martensite transformation is independent of time.<\/li>\n<li style=\"text-align: justify;\">Austenite to martensite transformation is a &#8220;diffusionless&#8221; process.<\/li>\n<li style=\"text-align: justify;\">Austenite to martensite transformation takes place by process of shear.<\/li>\n<li style=\"text-align: justify;\">Austenite to martensite transformation never goes to 100% completion at room temperature.<\/li>\n<\/ul>\n<h3 style=\"text-align: justify;\"><span class=\"ez-toc-section\" id=\"Problems-with-sudden-cooling\"><\/span>Problems with sudden cooling<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li style=\"text-align: justify;\">Residual stresses and due to this corrosion resistance decreases.<\/li>\n<li style=\"text-align: justify;\">Distortion of shape take place.<\/li>\n<li style=\"text-align: justify;\">Quench crack formation take place when component is not capable of withstanding rapid density changes.<\/li>\n<li style=\"text-align: justify;\">Retained austenite formation take place. Retained austenite brings out the dimensional changes in the previously quenched components from season to season since this is not acceptable in precision engineering application retained &#8216;\u03b3&#8217; should be eliminated.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Process of\u00a0Hardening Purpose To increase the hardness of steel to maximum extent by austenite to martensite transformation. To increase the<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1578,10],"tags":[1598,1599],"class_list":["post-4980","post","type-post","status-publish","format-standard","hentry","category-engineering-materials","category-me","tag-austenite-to-martensite-transformation","tag-problems-with-sudden-cooling"],"_links":{"self":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts\/4980","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/comments?post=4980"}],"version-history":[{"count":0,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/posts\/4980\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/media?parent=4980"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/categories?post=4980"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madeeasy.in\/study\/wp-json\/wp\/v2\/tags?post=4980"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}