{"id":9390,"date":"2025-08-03T00:20:47","date_gmt":"2025-08-02T16:20:47","guid":{"rendered":"https:\/\/aobosteel.com\/?page_id=9390"},"modified":"2026-01-29T00:25:37","modified_gmt":"2026-01-28T16:25:37","slug":"h21-tool-steel","status":"publish","type":"page","link":"https:\/\/aobosteel.com\/ko\/h21-tool-steel\/","title":{"rendered":"H21 Tool Steel | 1.2581 | SKD7"},"content":{"rendered":"<div class=\"wp-block-cover alignfull\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"337\" class=\"wp-block-cover__image-background wp-image-7233 size-large\" alt=\"\" src=\"https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/05\/banner3-1024x337.webp\" data-object-fit=\"cover\" srcset=\"https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/05\/banner3-1024x337.webp 1024w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/05\/banner3-300x99.webp 300w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/05\/banner3-768x253.webp 768w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/05\/banner3-1536x506.webp 1536w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/05\/banner3-18x6.webp 18w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/05\/banner3.webp 1920w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><span aria-hidden=\"true\" class=\"wp-block-cover__background has-background-dim\" style=\"background-color:#4e4b40\"><\/span><div class=\"wp-block-cover__inner-container is-layout-constrained wp-block-cover-is-layout-constrained\">\n<div class=\"wp-block-uagb-container uagb-block-29fc5c3c alignfull uagb-is-root-container\"><div class=\"uagb-container-inner-blocks-wrap\">\n<div class=\"wp-block-uagb-advanced-heading uagb-block-c196a237\"><h6 class=\"uagb-heading-text\"><a href=\"https:\/\/aobosteel.com\/ko\/\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">Home<\/mark> <\/a>&gt; <a href=\"https:\/\/aobosteel.com\/ko\/tool-steels\/\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">Tool Steel Catalog<\/mark><u> <\/u><\/a>&gt; H21 Tool Steel<\/h6><\/div>\n\n\n\n<div class=\"wp-block-uagb-advanced-heading uagb-block-d1ce38c5\"><h5 class=\"uagb-heading-text\"><em>Aobo Steel | Global Tool Steel Supplier in China<\/em><\/h5><\/div>\n\n\n\n<div class=\"wp-block-uagb-advanced-heading uagb-block-5b6189ba\"><h2 class=\"uagb-heading-text\">AISI H21 Tool Steel | 1.2581 | SKD5 High Tungsten Hot Work Steel<\/h2><\/div>\n\n\n\n<div class=\"wp-block-uagb-advanced-heading uagb-block-914bcd03\"><h5 class=\"uagb-heading-text\">\u2713100% UT Tested Quality Assurance | SEP 1921-82 Class D\/d Guaranteed<\/h5><\/div>\n\n\n\n<div class=\"wp-block-uagb-advanced-heading uagb-block-84cd4af9\"><h5 class=\"uagb-heading-text\">\u2713Optimized for Hot Extrusion Dies &amp; Brass Casting | Superior Heat Resistance<\/h5><\/div>\n\n\n\n<div class=\"wp-block-uagb-advanced-heading uagb-block-20e20150\"><h5 class=\"uagb-heading-text\">\u2713Annealed State Delivery<\/h5><\/div>\n\n\n\n<div class=\"wp-block-uagb-advanced-heading uagb-block-33ee52f8\"><h5 class=\"uagb-heading-text\">\u2713Surface: Black Scale, Turned, Mill Finish, or Polished<\/h5><\/div>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button hs-cta-trigger-button hs-cta-trigger-button-230288465624\"><a class=\"wp-block-button__link wp-element-button\">Quick Inquiry For H21 Material<\/a><\/div>\n<\/div>\n<\/div><\/div>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group is-layout-constrained wp-block-group-is-layout-constrained\">\n<p class=\"wp-block-paragraph\">H21 Tool Steel is a tungsten-based hot-work tool steel, classified under the AISI H-group. These types of steels were among the earliest high-alloy options developed for demanding high-temperature tooling applications. At&nbsp;<a href=\"https:\/\/aobosteel.com\/ko\/\"><mark style=\"background-color:rgba(0, 0, 0, 0);color:#0693e3\" class=\"has-inline-color\">Aobo Steel<\/mark><\/a>, with our extensive experience in tool steel forging, we understand the nuances of materials.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"1-eael-table-of-content\">1. H21 Tool Steel Chemical Composition<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The performance of H21 steel is largely determined by its alloying elements. A typical composition includes:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Carbon (C):<\/strong>&nbsp;0.26% \u2013 0.36% (Provides hardenability and wear resistance)<\/li>\n\n\n\n<li><strong>Manganese (Mn):<\/strong>&nbsp;0.15% \u2013 0.40% (Improves hardenability, acts as deoxidizer\/desulfurizer)<\/li>\n\n\n\n<li><strong>Silicon (Si):<\/strong>&nbsp;0.15% \u2013 0.50% (Increases strength and hardness, acts as a deoxidizer)<\/li>\n\n\n\n<li><strong>Chromium (Cr):<\/strong>&nbsp;3.00% \u2013 3.75% (Enhances resistance to high-temperature oxidation and corrosion)<\/li>\n\n\n\n<li><strong>Vanadium (V):<\/strong>&nbsp;0.30% \u2013 0.60% (Forms hard carbides, increasing wear resistance and hot strength)<\/li>\n\n\n\n<li><strong>Tungsten (W):<\/strong>&nbsp;8.50% \u2013 10.00% (Key element for hot hardness, high-temperature strength, and wear resistance)<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"2-eael-table-of-content\">2. H21 Tool Steel Properties<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"3-eael-table-of-content\">2.1 Hardness and Heat Resistance<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">H21 steel is recognized for its good heat resistance and ability to maintain hardness at elevated temperatures, a critical factor in hot-work applications.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Tempered Hardness:<\/strong>&nbsp;After austenitizing and <a href=\"https:\/\/aobosteel.com\/ko\/knowledge-hub\/what-is-tempering\/\">tempering<\/a> (e.g., 2 hours at 595\u00b0C \/ 1100\u00b0F), a hardness of approximately 529 HB can be achieved. Increasing the tempering temperature (e.g., to 650\u00b0C \/ 1200\u00b0F) reduces hardness to approximately 437 HB.<\/li>\n\n\n\n<li><strong>Hot Hardness:<\/strong>&nbsp;At operating temperatures, hardness decreases. For instance, hot hardness might be around 280 HB at 595\u00b0C (1100\u00b0F) and 211 HB at 650\u00b0C (1200\u00b0F). (Based on typical data with initial room temp hardness of 444 HB).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"4-eael-table-of-content\">2.2 Toughness and Ductility<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">While offering good hot strength, H21\u2019s&nbsp;toughness&nbsp;and shock resistance are generally lower compared to chromium-based&nbsp;<a href=\"https:\/\/aobosteel.com\/ko\/hot-work-tool-steels\/\">hot-work steels<\/a>, such as&nbsp;<a href=\"https:\/\/aobosteel.com\/ko\/h11-tool-steel\/\">H11<\/a>&nbsp;or&nbsp;<a href=\"https:\/\/aobosteel.com\/ko\/h13-tool-steel\/\">H13<\/a>. Its shock characteristics are also considered inferior to H19.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The chosen tempering temperature and the cooling rate after hardening, such as oil <a href=\"https:\/\/aobosteel.com\/ko\/knowledge-hub\/what-is-quenching\/\">quenching <\/a>versus slower cooling, significantly influence impact toughness (Izod or Charpy V-notch).<\/li>\n\n\n\n<li>Torsional properties can vary significantly depending on the specific heat treatment parameters used to achieve the target hardness, typically within the 42-55 HRC range.<\/li>\n<\/ul>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"810\" height=\"810\" src=\"https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif\" alt=\"H21 TOOL STEEL\" class=\"wp-image-9156\" srcset=\"https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif 810w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL-300x300.avif 300w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL-150x150.avif 150w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL-768x768.avif 768w, https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL-12x12.avif 12w\" sizes=\"auto, (max-width: 810px) 100vw, 810px\" \/><figcaption class=\"wp-element-caption\">H21 tool steel<\/figcaption><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\">\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color wp-elements-e31ffddc1b0b39d41f21db8b0c3fd2ef wp-block-paragraph\"><strong>Are you looking for H21 tool steel? Please complete the following form to contact us today.<\/strong><\/p>\n\n\n\n<div class=\"wp-block-leadin-hubspot-form-block\">\n\t\t\t\t\t\t<script>\n\t\t\t\t\t\t\twindow.hsFormsOnReady = window.hsFormsOnReady || [];\n\t\t\t\t\t\t\twindow.hsFormsOnReady.push(()=>{\n\t\t\t\t\t\t\t\thbspt.forms.create({\n\t\t\t\t\t\t\t\t\tportalId: 242461771,\n\t\t\t\t\t\t\t\t\tformId: \"1f7a4dcb-eb56-45e5-bd4f-5921cbf714c1\",\n\t\t\t\t\t\t\t\t\ttarget: \"#hbspt-form-1781065809000-7326958186\",\n\t\t\t\t\t\t\t\t\tregion: \"na2\",\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t})});\n\t\t\t\t\t\t<\/script>\n\t\t\t\t\t\t<div class=\"hbspt-form\" id=\"hbspt-form-1781065809000-7326958186\"><\/div><\/div>\n<\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"5-eael-table-of-content\">3. Heat Treatment<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Achieving the optimal performance from H21 tool steel relies heavily on a precise&nbsp;heat treatment&nbsp;process. This procedure develops the necessary hardness, wear resistance, and toughness essential for demanding hot work applications.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"6-eael-table-of-content\">3.1 Preheating<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Before the main hardening process, H21 tool steel must be carefully preheated.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Temperature:<\/strong>&nbsp;Heat uniformly to 760\u2013815 \u00b0C (1400\u20131500 \u00b0F).<\/li>\n\n\n\n<li><strong>Purpose:<\/strong>&nbsp;This crucial step minimizes thermal shock and prevents cracking, especially in components with complex shapes or varying thicknesses. Slow and even heating ensures that the temperature is evenly distributed throughout the steel, preparing it for the high temperatures of&nbsp;austenitizing.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"7-eael-table-of-content\">3.2 Austenitizing (Hardening)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Following preheating, the steel is brought to the austenitizing temperature.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Temperature:<\/strong>&nbsp;Heat to 1095\u20131205 \u00b0C.<\/li>\n\n\n\n<li><strong>Purpose:<\/strong>&nbsp;At this stage, the steel\u2019s microstructure transforms into <mark style=\"background-color:rgba(0, 0, 0, 0);color:#0693e3\" class=\"has-inline-color\"><a href=\"https:\/\/aobosteel.com\/ko\/knowledge-hub\/what-is-austenite\/\">austenite<\/a><\/mark>. This allows carbon and critical alloying elements, such as tungsten (W) and chromium (Cr), to dissolve into the structure, which is fundamental for achieving hardness upon cooling.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"8-eael-table-of-content\">Soaking at Austenitizing Temperature<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Holding the steel at the austenitizing temperature (soaking) is vital.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Duration:<\/strong>&nbsp;Typically 2 to 5 hours, depending on the cross-section thickness (allow sufficient time, e.g., 1 hour per inch of thickness).<\/li>\n\n\n\n<li><strong>Purpose:<\/strong>&nbsp;H21\u2019s high content of tungsten and chromium forms stable carbides. Sufficient soaking time ensures these carbides fully dissolve and distribute evenly within the austenite, leading to a uniform structure ready for quenching.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"9-eael-table-of-content\">3.3 Quenching (Cooling)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Rapid cooling transforms the austenite into hard, martensitic steel.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Methods:<\/strong>&nbsp;H21 steel can be quenched in either air or oil.<\/li>\n\n\n\n<li><strong>Considerations:<\/strong>&nbsp;Due to its high hardenability, H21 readily hardens even with slower air cooling. Air quenching is often preferred as it significantly reduces the risk of distortion and quench cracking compared to more severe oil quenching, especially for larger or intricate parts. Oil quenching can be used if maximum hardness is the primary goal. The cooling rate must be sufficiently fast to prevent the formation of softer structures, such as pearlite or bainite.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"10-eael-table-of-content\">3.4 Tempering<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Quenched H21 steel is extremely hard but also brittle. Tempering is necessary to refine its properties.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Temperature:<\/strong>&nbsp;Reheat the steel to 595\u2013675 \u00b0C.<\/li>\n\n\n\n<li><strong>Purpose:<\/strong>&nbsp;Tempering reduces brittleness and significantly improves toughness and ductility while retaining substantial hardness. The specific temperature and time used will determine the final balance between hardness and toughness.<\/li>\n\n\n\n<li><strong>Multiple Tempers:<\/strong>&nbsp;For high-alloy tool steels like H21, performing two or more tempering cycles is common practice. This ensures structural stability, transforms any retained austenite, and can contribute to secondary hardening, further enhancing performance at elevated temperatures.<\/li>\n<\/ul>\n\n\n\n<p class=\"has-text-align-center wp-block-paragraph\">Table of Hardness and Tempering Temperature for H21 Steel<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td class=\"has-text-align-center\" data-align=\"center\"><strong>Tempering Temperature<\/strong><\/td><td class=\"has-text-align-center\" data-align=\"center\"><strong>Rockwell C<\/strong><\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">As quenched<\/td><td class=\"has-text-align-center\" data-align=\"center\">55<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">600\u00b0F\/315\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">51<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">700\u00b0F\/370\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">52<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">800\u00b0F\/425\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">52<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">900\u00b0F\/480\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">54<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">1000\u00b0F\/540\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">54<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">1100\u00b0F\/595\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">51<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">1200\u00b0F\/650\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">40<\/td><\/tr><tr><td class=\"has-text-align-center\" data-align=\"center\">1300\u00b0F\/705\u00b0C<\/td><td class=\"has-text-align-center\" data-align=\"center\">32<\/td><\/tr><\/tbody><\/table><figcaption class=\"wp-element-caption\">Experimental Conditions: 1. PREHEAT TEMPERATURE 1500\u00b0F\/815\u00b0C 2. HARDENING TEMPERATURE 2125\u00b0F\/1160\u00b0C 3. OIL OR SALT QUENCH 4. CHEMISTRY Carbon 0.33% Manganese 0.25% Silicon 0.45% Chromium 3.30% Vanadium 0.45% Tungsten 9.15%<\/figcaption><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"11-eael-table-of-content\">3.5 Important Process Controls<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"12-eael-table-of-content\">3.5.1 Preventing Decarburization<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">H21 steel is prone to&nbsp;decarburization, or the loss of carbon from the surface, at high heat treatment temperatures, resulting in a soft and weak surface layer.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Solution:<\/strong>&nbsp;Protective measures are essential during austenitizing. This includes using controlled atmosphere furnaces, salt baths, or wrapping the parts in protective material like stainless steel foil.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"13-eael-table-of-content\">3.5.2 Cooling After Forging<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Due to H21\u2019s high hardenability, forgings should be cooled slowly (e.g., furnace cooling or burying in insulation) immediately after the forging operation.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Reason:<\/strong>&nbsp;Avoid normalizing (air cooling from high temperature), as this can cause the steel to partially or fully harden, leading to brittleness and potential cracking before the intended hardening and tempering process. Slow cooling ensures a more suitable structure for subsequent heat treatment.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This structured approach to heat treating H21 tool steel ensures the material delivers the high performance required for its intended hot work tooling applications. Precise control over each parameter is key to success.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"14-eael-table-of-content\">4. H21 Tool Steel Applications<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Thanks to its hot hardness and wear resistance, H21 steel is used in various hot-work processes:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Forging Dies and Inserts<\/li>\n\n\n\n<li>Hot Work Punches, Piercers, and Mandrels<\/li>\n\n\n\n<li>Hot Extrusion Tooling<\/li>\n\n\n\n<li>Hot Shear Blades (especially for severe applications, sometimes alongside H25)<\/li>\n\n\n\n<li>Die Casting Dies (particularly for brass)<\/li>\n\n\n\n<li>Coining Dies (especially where some wear resistance can be traded for better breakage resistance in thin sections)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">H21 is often considered a suitable choice for tooling intended for medium production runs.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"15-eael-table-of-content\">5. H21 Tool Steel Equivalent grades<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>European (EN)<\/strong>: X30WCrV9-3 (1.2581)<\/li>\n\n\n\n<li><strong>Germany (DIN)<\/strong>: 1.2581<\/li>\n\n\n\n<li><strong>Japan (JIS)<\/strong>: SKD5<\/li>\n\n\n\n<li><strong>France (AFNOR)<\/strong>: 32CDV12-28<\/li>\n\n\n\n<li><strong>China (GB)<\/strong>:&nbsp;<a href=\"https:\/\/aobosteel.com\/ko\/3cr2w8v-tool-steel\/\">3Cr2W8V<\/a><\/li>\n<\/ul>\n\n\n\n<div class=\"wp-block-group has-ast-global-color-8-background-color has-background is-layout-constrained wp-block-group-is-layout-constrained\">\n<h2 class=\"wp-block-heading has-text-align-center\">Need High-Performance H21 Tool Steel?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Leverage Aobo Steel\u2019s 20+ years of forging expertise for your critical high-temperature applications. Our H21 Tool Steel offers exceptional toughness and heat resistance, ensuring reliability and longevity for your tools and dies.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Let our specialists provide you with tailored advice, superior quality H21 steel, and competitive quotes.<\/p>\n\n\n\n<p class=\"has-ast-global-color-0-color has-text-color has-link-color wp-elements-9d4e054cfdf1fbf3c7a6f1e66d0b8bc7 wp-block-paragraph\"><strong>Ready to enhance your operations? Contact us today! Please fill out the form below to get started, and our experts will be in touch with you shortly.<\/strong><\/p>\n\n\n\n<div class=\"wp-block-leadin-hubspot-form-block\">\n\t\t\t\t\t\t<script>\n\t\t\t\t\t\t\twindow.hsFormsOnReady = window.hsFormsOnReady || [];\n\t\t\t\t\t\t\twindow.hsFormsOnReady.push(()=>{\n\t\t\t\t\t\t\t\thbspt.forms.create({\n\t\t\t\t\t\t\t\t\tportalId: 242461771,\n\t\t\t\t\t\t\t\t\tformId: \"1f7a4dcb-eb56-45e5-bd4f-5921cbf714c1\",\n\t\t\t\t\t\t\t\t\ttarget: \"#hbspt-form-1781065809000-7678800573\",\n\t\t\t\t\t\t\t\t\tregion: \"na2\",\n\t\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t})});\n\t\t\t\t\t\t<\/script>\n\t\t\t\t\t\t<div class=\"hbspt-form\" id=\"hbspt-form-1781065809000-7678800573\"><\/div><\/div>\n<\/div>\n<\/div>\n\n\n\n<script type=\"application\/ld+json\">{\n    \"@context\": \"https:\\\/\\\/schema.org\\\/\",\n    \"@type\": \"Product\",\n    \"name\": \"Forged H21 \\\/ 1.2581 \\\/ SKD5 Tungsten Hot Work Tool Steel Round Bar\",\n    \"image\": \"https:\\\/\\\/aobosteel.com\\\/wp-content\\\/uploads\\\/2025\\\/07\\\/H21-TOOL-STEEL.avif\",\n    \"description\": \"Premium Forged H21 (1.2581 \\\/ SKD5) Tungsten Hot Work Tool Steel directly from Aobo Steel factory. 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H21 Tool Steel Chemical Composition The performance of&hellip;","rttpg_featured_image_url":{"full":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif",810,810,false],"landscape":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif",810,810,false],"portraits":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif",810,810,false],"thumbnail":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL-150x150.avif",150,150,true],"medium":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL-300x300.avif",300,300,true],"large":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif",810,810,false],"1536x1536":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif",810,810,false],"2048x2048":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL.avif",810,810,false],"trp-custom-language-flag":["https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/07\/H21-TOOL-STEEL-12x12.avif",12,12,true]},"rttpg_author":{"display_name":"Evan","author_link":"https:\/\/aobosteel.com\/ko\/blog\/author\/admin\/"},"rttpg_comment":0,"rttpg_category":null,"rttpg_excerpt":"H21 Tool Steel is a tungsten-based hot-work tool steel, classified under the AISI H-group. These types of steels were among the earliest high-alloy options developed for demanding high-temperature tooling applications. At&nbsp;Aobo Steel, with our extensive experience in tool steel forging, we understand the nuances of materials. 1. H21 Tool Steel Chemical Composition The performance of&hellip;","_links":{"self":[{"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/pages\/9390","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/comments?post=9390"}],"version-history":[{"count":0,"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/pages\/9390\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/media\/9156"}],"wp:attachment":[{"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/media?parent=9390"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}