{"id":1753,"date":"2025-12-01T07:55:14","date_gmt":"2025-12-01T06:55:14","guid":{"rendered":"https:\/\/www.nickelcasting.com\/?p=1753"},"modified":"2026-01-30T03:07:49","modified_gmt":"2026-01-30T02:07:49","slug":"what-is-the-difference-between-625-and-725-alloy","status":"publish","type":"post","link":"https:\/\/www.nickelcasting.com\/fr\/what-is-the-difference-between-625-and-725-alloy\/","title":{"rendered":"Quelle est la diff\u00e9rence entre les alliages 625 et 725 ?"},"content":{"rendered":"<p data-path-to-node=\"17\">Bien qu'ils partagent un code g\u00e9n\u00e9tique presque identique en ce qui concerne la r\u00e9sistance \u00e0 la corrosion, la diff\u00e9rence r\u00e9side enti\u00e8rement dans la mani\u00e8re dont ils g\u00e8rent les contraintes m\u00e9caniques.<\/p>\n<p data-path-to-node=\"17\"><img fetchpriority=\"high\" decoding=\"async\" class=\"size-full wp-image-1754 aligncenter\" src=\"https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13.jpg\" alt=\"\" width=\"1200\" height=\"675\" srcset=\"https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13.jpg 1200w, https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-300x169.jpg 300w, https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-1024x576.jpg 1024w, https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-768x432.jpg 768w, https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-18x10.jpg 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/p>\n<h2>Composition chimique<\/h2>\n<p data-path-to-node=\"19\">Pour comprendre la diff\u00e9rence, il faut d'abord examiner la chimie. L'alliage 625 est un alliage de nickel-chrome-molybd\u00e8ne contenant du niobium. Cette combinaison offre une r\u00e9sistance exceptionnelle \u00e0 la corrosion par piq\u00fbres et par crevasses.<\/p>\n<p data-path-to-node=\"20\"><b>Alliage 725 (UNS N07725)<\/b> est essentiellement un alliage 625 avec une modification sp\u00e9cifique. Les m\u00e9tallurgistes ont pris la base r\u00e9sistante \u00e0 la corrosion de l'alliage 625 et y ont ajout\u00e9 de petites quantit\u00e9s pr\u00e9cises de <b>Titane (Ti) et aluminium (Al)<\/b>.<\/p>\n<ul data-path-to-node=\"21\">\n<li>\n<p data-path-to-node=\"21,0,0\"><b>Alliage 625 :<\/b> Renforc\u00e9 principalement par l'effet de raidissement du molybd\u00e8ne et du niobium dans la matrice nickel-chrome (Solid Solution Strengthening).<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"21,1,0\"><b>Alliage 725 :<\/b> Renforc\u00e9 par la pr\u00e9cipitation de phases microscopiques gamma-prime et gamma-double-prime pendant le traitement thermique (durcissement par pr\u00e9cipitation).<\/p>\n<\/li>\n<\/ul>\n<h2>La diff\u00e9rence du noyau : R\u00e9sistance au rendement<\/h2>\n<p data-path-to-node=\"23\">Si la r\u00e9sistance \u00e0 la corrosion est le bouclier, la limite d'\u00e9lasticit\u00e9 est le muscle. C'est l\u00e0 que la <b>diff\u00e9rence entre l'alliage 625 et l'alliage 725<\/b> devient ind\u00e9niable.<\/p>\n<p data-path-to-node=\"24\">Alloy 625 is tough, but in its annealed state, its yield strength is typically around 60-70 ksi (414-483 MPa). To make it stronger, it must be &#8220;cold worked&#8221; (physically compressed or drawn), which limits the shapes and sizes you can produce.<\/p>\n<p data-path-to-node=\"25\">L'alliage 725 change la donne. Gr\u00e2ce \u00e0 l'ajout de titane et d'aluminium, il peut \u00eatre trait\u00e9 thermiquement (vieilli) pour atteindre une r\u00e9sistance tr\u00e8s \u00e9lev\u00e9e sans n\u00e9cessiter d'usinage \u00e0 froid. <b>L'alliage 725 atteint couramment des limites d'\u00e9lasticit\u00e9 sup\u00e9rieures \u00e0 120 ksi (827 MPa), soit le double de celles de l'alliage 625 recuit.<\/b><\/p>\n<p data-path-to-node=\"26\">Cela fait de l'alliage 725 le meilleur choix pour les grandes sections complexes qui n\u00e9cessitent une r\u00e9sistance \u00e9lev\u00e9e mais qui sont trop \u00e9paisses pour \u00eatre efficacement travaill\u00e9es \u00e0 froid.<\/p>\n<h2>R\u00e9sistance \u00e0 la corrosion<\/h2>\n<p data-path-to-node=\"28\">Engineers often fear that increasing strength means sacrificing corrosion resistance. Fortunately, with these two alloys, that isn&#8217;t the case.<\/p>\n<p data-path-to-node=\"29\">Parce que la chimie de base (forte teneur en nickel et en molybd\u00e8ne) reste constante, <b>L'alliage 725 conserve essentiellement la m\u00eame r\u00e9sistance \u00e0 la corrosion que l'alliage 625.<\/b> Ces deux alliages offrent une r\u00e9sistance exceptionnelle \u00e0 la corrosion :<\/p>\n<ul data-path-to-node=\"30\">\n<li>\n<p data-path-to-node=\"30,0,0\">Eau de mer et environnements marins.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"30,1,0\">Corrosion par piq\u00fbres et corrosion caverneuse.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"30,2,0\">Fissuration sous contrainte par le sulfure (SSC).<\/p>\n<\/li>\n<\/ul>\n<p data-path-to-node=\"31\">Cette combinaison unique place l'alliage 725 dans une cat\u00e9gorie distincte : il offre la r\u00e9sistance \u00e0 la corrosion de l'alliage 625 avec la solidit\u00e9 de l'alliage 718.<\/p>\n<h2>Sc\u00e9narios d'application : Quand utiliser Which ?<\/h2>\n<p data-path-to-node=\"33\">Le choix entre les deux se r\u00e9sume g\u00e9n\u00e9ralement \u00e0 la charge m\u00e9canique de l'application.<\/p>\n<p data-path-to-node=\"34\"><b>Choisissez l'alliage 625 lorsque :<\/b><\/p>\n<ul data-path-to-node=\"35\">\n<li>\n<p data-path-to-node=\"35,0,0\">Vous avez besoin d'une excellente aptitude \u00e0 la fabrication et \u00e0 la soudure.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"35,1,0\">L'application concerne le bardage (recouvrement) ou les composants en t\u00f4le tels que les conduits d'\u00e9chappement.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"35,2,0\">Une limite d'\u00e9lasticit\u00e9 extr\u00eame n'est pas la premi\u00e8re exigence.<\/p>\n<\/li>\n<\/ul>\n<p data-path-to-node=\"36\"><b>Choisissez l'alliage 725 lorsque :<\/b><\/p>\n<ul data-path-to-node=\"37\">\n<li>\n<p data-path-to-node=\"37,0,0\">You are designing <a href=\"https:\/\/www.nickelcasting.com\/pt\/product-forms\/fasteners\/\">fixations<\/a>, hangers, or landing nipples for Sour Gas service (NACE MR0175).<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"37,1,0\">Le mat\u00e9riau doit pouvoir r\u00e9sister \u00e0 des contraintes de traction massives en milieu marin.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"37,2,0\">Le composant est une barre de grande section ou une pi\u00e8ce forg\u00e9e pour laquelle l'usinage \u00e0 froid est impossible.<\/p>\n<\/li>\n<\/ul>\n<p data-path-to-node=\"39\"><img decoding=\"async\" class=\"size-full wp-image-1416 aligncenter\" src=\"https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/11\/suoluetu.jpg\" alt=\"\" width=\"1200\" height=\"675\" srcset=\"https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/11\/suoluetu.jpg 1200w, https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/11\/suoluetu-300x169.jpg 300w, https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/11\/suoluetu-1024x576.jpg 1024w, https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/11\/suoluetu-768x432.jpg 768w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/p>\n<h3>Foire aux questions (FAQ)<\/h3>\n<p data-path-to-node=\"42\"><b>Q1 : L'alliage 725 peut-il \u00eatre soud\u00e9 aussi facilement que l'alliage 625 ?<\/b><\/p>\n<p data-path-to-node=\"42\">Bien que les deux puissent \u00eatre soud\u00e9s, l'alliage 625 est g\u00e9n\u00e9ralement consid\u00e9r\u00e9 comme ayant une soudabilit\u00e9 sup\u00e9rieure et est souvent utilis\u00e9 comme m\u00e9tal d'apport. L'alliage 725 peut \u00eatre soud\u00e9, mais comme il s'agit d'un alliage durcissable par vieillissement, il n\u00e9cessite g\u00e9n\u00e9ralement un traitement thermique apr\u00e8s soudage pour restaurer ses propri\u00e9t\u00e9s de haute r\u00e9sistance dans la zone affect\u00e9e thermiquement.<\/p>\n<p data-path-to-node=\"43\"><b>Q2 : L'alliage 725 est-il magn\u00e9tique ?<\/b><\/p>\n<p data-path-to-node=\"43\">Comme l'alliage 625, l'alliage 725 est un superalliage \u00e0 base de nickel et n'est pas magn\u00e9tique dans toutes les conditions. Ces deux alliages conviennent donc aux applications o\u00f9 la perm\u00e9abilit\u00e9 magn\u00e9tique doit \u00eatre minimis\u00e9e, comme dans les bo\u00eetiers \u00e9lectroniques sensibles ou les composants sous-marins.<\/p>\n<p data-path-to-node=\"44\"><b>Q3 : Pourquoi l'alliage 725 est-il plus cher que l'alliage 625 ?<\/b><\/p>\n<p data-path-to-node=\"44\">La diff\u00e9rence de co\u00fbt provient de la complexit\u00e9 du traitement. Alors que les co\u00fbts des mati\u00e8res premi\u00e8res sont comparables, l'alliage 725 n\u00e9cessite une fusion sous vide pr\u00e9cise et des cycles de traitement thermique prolong\u00e9s (recuit de mise en solution et vieillissement en deux \u00e9tapes) pour obtenir ses propri\u00e9t\u00e9s m\u00e9caniques. En outre, l'alliage 625 est produit dans des volumes beaucoup plus importants, ce qui permet de r\u00e9aliser des \u00e9conomies d'\u00e9chelle.<\/p>","protected":false},"excerpt":{"rendered":"<p>While they share a nearly identical genetic code regarding corrosion resistance, the distinction lies entirely in how they handle mechanical stress. Chemical Composition To understand the difference, we must first look at the chemistry. Alloy 625 is a nickel-chromium-molybdenum alloy containing niobium. This combination delivers outstanding resistance to pitting and crevice corrosion. Alloy 725 (UNS [&hellip;]<\/p>","protected":false},"author":1,"featured_media":1754,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[3],"tags":[],"class_list":["post-1753","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"spectra_custom_meta":{"_edit_lock":["1769738869:1"],"_edit_last":["1"],"_thumbnail_id":["1754"],"_wp_page_template":["default"],"site-sidebar-layout":["default"],"ast-site-content-layout":["default"],"site-content-style":["default"],"site-sidebar-style":["default"],"theme-transparent-header-meta":["default"],"_yoast_wpseo_primary_category":["3"],"_yoast_wpseo_focuskw":["What is the difference between 625 and 725 alloy"],"_yoast_wpseo_title":["%%title%% %%page%% %%sep%% 28Nickel"],"_yoast_wpseo_metadesc":["What is the difference between 625 and 725 alloy? While chemically similar, Alloy 725 offers significantly higher strength through precipitation hardening."],"_yoast_wpseo_linkdex":["70"],"_yoast_wpseo_content_score":["90"],"_yoast_wpseo_estimated-reading-time-minutes":["4"],"rank_math_primary_category":["3"],"rank_math_title":["%title% %page% %sep% 28Nickel"],"rank_math_description":["What is the difference between 625 and 725 alloy? While chemically similar, Alloy 725 offers significantly higher strength through precipitation hardening."],"rank_math_focus_keyword":["What is the difference between 625 and 725 alloy"],"rank_math_news_sitemap_robots":["index"],"rank_math_robots":["a:1:{i:0;s:5:\"index\";}"],"rank_math_seo_score":["55"],"rank_math_internal_links_processed":["1"],"ilj_blacklistdefinition":["a:0:{}"],"ilj_linkdefinition":["a:1:{i:0;s:48:\"What is the difference between 625 and 725 alloy\";}"],"astra-migrate-meta-layouts":["set"],"_uag_page_assets":["a:9:{s:3:\"css\";s:263:\".uag-blocks-common-selector{z-index:var(--z-index-desktop) !important}@media (max-width: 976px){.uag-blocks-common-selector{z-index:var(--z-index-tablet) !important}}@media (max-width: 767px){.uag-blocks-common-selector{z-index:var(--z-index-mobile) !important}}\n\";s:2:\"js\";s:0:\"\";s:18:\"current_block_list\";a:8:{i:0;s:11:\"core\/search\";i:1;s:10:\"core\/group\";i:2;s:12:\"core\/heading\";i:3;s:17:\"core\/latest-posts\";i:4;s:20:\"core\/latest-comments\";i:5;s:13:\"core\/archives\";i:6;s:15:\"core\/categories\";i:7;s:10:\"core\/image\";}s:8:\"uag_flag\";b:0;s:11:\"uag_version\";s:10:\"1775384825\";s:6:\"gfonts\";a:0:{}s:10:\"gfonts_url\";s:0:\"\";s:12:\"gfonts_files\";a:0:{}s:14:\"uag_faq_layout\";b:0;}"],"_elementor_page_assets":["a:0:{}"],"_uag_css_file_name":["uag-css-1753.css"]},"uagb_featured_image_src":{"full":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13.jpg",1200,675,false],"thumbnail":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-150x150.jpg",150,150,true],"medium":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-300x169.jpg",300,169,true],"medium_large":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-768x432.jpg",768,432,true],"large":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-1024x576.jpg",1024,576,true],"1536x1536":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13.jpg",1200,675,false],"2048x2048":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13.jpg",1200,675,false],"trp-custom-language-flag":["https:\/\/www.nickelcasting.com\/wp-content\/uploads\/2025\/12\/13-18x10.jpg",18,10,true]},"uagb_author_info":{"display_name":"nickel","author_link":"https:\/\/www.nickelcasting.com\/fr\/author\/nickel\/"},"uagb_comment_info":0,"uagb_excerpt":"While they share a nearly identical genetic code regarding corrosion resistance, the distinction lies entirely in how they handle mechanical stress. Chemical Composition To understand the difference, we must first look at the chemistry. Alloy 625 is a nickel-chromium-molybdenum alloy containing niobium. This combination delivers outstanding resistance to pitting and crevice corrosion. Alloy 725 (UNS\u2026","_links":{"self":[{"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/posts\/1753","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/comments?post=1753"}],"version-history":[{"count":2,"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/posts\/1753\/revisions"}],"predecessor-version":[{"id":2555,"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/posts\/1753\/revisions\/2555"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/media\/1754"}],"wp:attachment":[{"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/media?parent=1753"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/categories?post=1753"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nickelcasting.com\/fr\/wp-json\/wp\/v2\/tags?post=1753"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}