{"id":15314,"date":"2026-05-14T08:48:04","date_gmt":"2026-05-14T00:48:04","guid":{"rendered":"https:\/\/aobosteel.com\/?page_id=15314"},"modified":"2026-06-25T15:17:11","modified_gmt":"2026-06-25T07:17:11","slug":"o1-steel-hardness","status":"publish","type":"page","link":"https:\/\/aobosteel.com\/ko\/o1-steel-hardness\/","title":{"rendered":"O1 Steel Hardness: Annealed, Quenched &amp; Tempered HRC Guide"},"content":{"rendered":"<section class=\"aobo-o1-hardness-page\">\n  <style>\n    .aobo-o1-hardness-page {\n      --aobo-blue: #0c56d0;\n      --aobo-blue-dark: #073b8e;\n      --aobo-blue-soft: #eaf2ff;\n      --aobo-border: #d7e5fb;\n      --aobo-text: #203044;\n      --aobo-muted: #617087;\n      --aobo-orange: #f59b23;\n      --aobo-white: #ffffff;\n      --aobo-shadow: 0 18px 45px rgba(12, 86, 208, 0.10);\n      --aobo-page-width: 1180px;\n      font-family: inherit;\n      color: var(--aobo-text);\n      line-height: 1.7;\n      background: transparent;\n      padding: 0;\n      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.aobo-cta {\n        padding: 26px 22px;\n        border-radius: 22px;\n      }\n    }\n  <\/style>\n\n  <div class=\"aobo-wrap\">\n    <header class=\"aobo-hero\">\n      <h1>O1 Steel Hardness: Annealed, Quenched and Tempered HRC Range<\/h1>\n      <p>O1 tool steel is usually supplied in the annealed condition, with a hardness typically not exceeding about 217 HBW. After oil quenching, O1 can reach about 64\u201365 HRC in the as-quenched condition. For practical use, O1 steel is hardened and tempered. Its typical hardness is about 58\u201360 HRC, with a broader practical range of 56\u201362 HRC.<\/p>\n    <\/header>\n\n    <section class=\"aobo-supply-block\">\n      <div class=\"aobo-supply-image\">\n        <img decoding=\"async\" src=\"https:\/\/aobosteel.com\/wp-content\/uploads\/2025\/04\/o1-steel.avif\" alt=\"O1 \uacf5\uad6c\uac15 \ubd09\uc7ac\" loading=\"lazy\">\n      <\/div>\n      <div class=\"aobo-supply-content\">\n        <p>Aobo Steel supplies O1 \/ 1.2510 \/ SKS3 tool steel round bar and flat bar in annealed condition for bulk industrial orders. Send your required size, quantity, tolerance, and application.<\/p>\n        <div class=\"aobo-supply-actions\">\n          <a class=\"aobo-btn aobo-btn-primary popmake-16052\" href=\"javascript:void(0);\">\ubb38\uc758 \ubcf4\ub0b4\uae30<\/a>\n          <a class=\"aobo-btn aobo-btn-secondary\" href=\"https:\/\/aobosteel.com\/ko\/o1-tool-steel\/\">View O1 Tool Steel<\/a>\n        <\/div>\n      <\/div>\n    <\/section>\n\n    <main class=\"aobo-article\">\n      <h2>O1 Steel Hardness Quick Data<\/h2>\n      <div class=\"aobo-table-wrap\">\n        <table class=\"aobo-table\">\n          <thead>\n            <tr><th>\uc0c1\ud0dc<\/th><th>\uc77c\ubc18\uc801\uc778 \uacbd\ub3c4<\/th><th>\uc2e4\uc9c8\uc801\uc778 \uc758\ubbf8<\/th><\/tr>\n          <\/thead>\n          <tbody>\n            <tr><td>\uc5b4\ub2d0\ub9c1 \uc870\uac74<\/td><td>\u2264 217 HBW<\/td><td>Supplied condition for machining before hardening<\/td><\/tr>\n            <tr><td>As-quenched after oil quenching<\/td><td>about 64\u201365 HRC<\/td><td>Maximum hardness before tempering, not suitable for direct use<\/td><\/tr>\n            <tr><td>Common working hardness after tempering<\/td><td>58\u201360 HRC<\/td><td>Standard range for many O1 cold-work tools<\/td><\/tr>\n            <tr><td>Practical hardened range<\/td><td>56\u201362 HRC<\/td><td>Selected according to wear, shock, section size, and tool design<\/td><\/tr>\n            <tr><td>Higher-hardness tooling range<\/td><td>60\u201362 HRC<\/td><td>Used where edge holding and wear resistance are more important<\/td><\/tr>\n            <tr><td>Lower-hardness tooling range<\/td><td>56~58 HRC<\/td><td>Used where toughness and crack resistance are more important<\/td><\/tr>\n          <\/tbody>\n        <\/table>\n      <\/div>\n\n      <h2>O1 Steel Hardness by Application<\/h2>\n      <div class=\"aobo-table-wrap\">\n        <table class=\"aobo-table\">\n          <thead>\n            <tr><th>\uc560\ud50c\ub9ac\ucf00\uc774\uc158<\/th><th>\uad8c\uc7a5 \uacbd\ub3c4<\/th><th>\uacf5\ud559\uc801 \uc774\uc720<\/th><\/tr>\n          <\/thead>\n          <tbody>\n            <tr><td>Blanking dies and punches<\/td><td>58\u201360 HRC<\/td><td>Good edge retention with lower chipping risk<\/td><\/tr>\n            <tr><td>Trimming punches<\/td><td>58\u201360 HRC<\/td><td>Stable cutting performance in general cold-work use<\/td><\/tr>\n            <tr><td>Counterpunches and ejectors<\/td><td>60\u201362 HRC<\/td><td>Higher hardness for surface pressure and wear<\/td><\/tr>\n            <tr><td>\ubca4\ub529 \ub2e4\uc774<\/td><td>58\u201360 HRC<\/td><td>Balanced hardness for forming pressure and toughness<\/td><\/tr>\n            <tr><td>\ub4dc\ub85c\uc789 \ub2e4\uc774<\/td><td>58\u201362 HRC<\/td><td>Selected according to sliding wear and tool support<\/td><\/tr>\n            <tr><td>Forward cold extrusion punches<\/td><td>60\u201362 HRC<\/td><td>Higher hardness for compressive load and wear resistance<\/td><\/tr>\n            <tr><td>Punch shanks and mandrels<\/td><td>56~58 HRC<\/td><td>Lower hardness improves toughness under load<\/td><\/tr>\n            <tr><td>Cutoff blades for cold heading<\/td><td>60\u201364 HRC<\/td><td>Higher hardness improves cutting edge retention when shock is controlled<\/td><\/tr>\n            <tr><td>\uc5e0\ubcf4\uc2f1 \ub2e4\uc774<\/td><td>58\u201361 HRC<\/td><td>Balances surface definition, wear resistance, and crack resistance<\/td><\/tr>\n            <tr><td>\uc8fc\ud654 \uc81c\uc791\uc6a9 \uc8fc\ud615<\/td><td>58\u201360 HRC<\/td><td>Practical balance between hardness and fracture resistance<\/td><\/tr>\n            <tr><td>Small cold rolls<\/td><td>60\u201362 HRC<\/td><td>Suitable where the section can be hardened effectively in oil<\/td><\/tr>\n            <tr><td>\uc815\ubc00 \uac8c\uc774\uc9c0 \ubc0f \uce21\uc815 \ub3c4\uad6c<\/td><td>58\u201362 HRC<\/td><td>High hardness with good dimensional control<\/td><\/tr>\n            <tr><td>Sliding components, bushings, cams<\/td><td>50\u201358 HRC<\/td><td>Depends on load, wear, and toughness requirements<\/td><\/tr>\n            <tr><td>Pressure plates requiring about 1700 MPa strength<\/td><td>58\u201361 HRC<\/td><td>High strength and surface resistance<\/td><\/tr>\n            <tr><td>Pressure plates requiring about 1400 MPa strength<\/td><td>50\u201354 HRC<\/td><td>Lower hardness for better load absorption<\/td><\/tr>\n            <tr><td>Pressure plates requiring about 1100 MPa strength<\/td><td>40\u201344 HRC<\/td><td>Used where toughness is more important than cutting hardness<\/td><\/tr>\n          <\/tbody>\n        <\/table>\n      <\/div>\n      <p>For uncertain cold-work applications, 58\u201360 HRC is usually the most practical starting point. Hardness above 62 HRC should be used with caution, as O1 becomes more prone to chipping and cracking.<\/p>\n\n      <h2>O1 Steel Tempering Hardness Chart<\/h2>\n      <p>After oil quenching, O1 must be tempered to reduce internal stress and adjust final hardness. O1 does not have the same secondary hardening behavior as D2. As tempering temperature increases, O1 generally softens.<\/p>\n      <div class=\"aobo-table-wrap\">\n        <table class=\"aobo-table\">\n          <thead>\n            <tr><th>\ud15c\ud37c\ub9c1 \uc628\ub3c4<\/th><th>\ub300\ub7b5\uc801\uc778 \uacbd\ub3c4<\/th><\/tr>\n          <\/thead>\n          <tbody>\n            <tr><td>\uac08\uc99d\uc774 \ud574\uc18c\ub41c \uac83\ucc98\ub7fc<\/td><td>64\u201365 HRC<\/td><\/tr>\n            <tr><td>300\u00b0F \/ 150\u00b0C<\/td><td>about 63 HRC<\/td><\/tr>\n            <tr><td>350\u00b0F \/ 177\u00b0C<\/td><td>62\u201363 HRC<\/td><\/tr>\n            <tr><td>400\u00b0F \/ 204\u00b0C<\/td><td>about 62 HRC<\/td><\/tr>\n            <tr><td>500\u00b0F \/ 260\u00b0C<\/td><td>about 60 HRC<\/td><\/tr>\n            <tr><td>600\u00b0F \/ 316\u00b0C<\/td><td>about 57 HRC<\/td><\/tr>\n            <tr><td>700\u00b0F \/ 371\u00b0C<\/td><td>about 53 HRC<\/td><\/tr>\n            <tr><td>800\u00b0F \/ 427\u00b0C<\/td><td>about 50 HRC<\/td><\/tr>\n            <tr><td>900\u00b0F \/ 482\u00b0C<\/td><td>about 47 HRC<\/td><\/tr>\n          <\/tbody>\n        <\/table>\n      <\/div>\n      <div class=\"aobo-note\">These values are typical references. Actual hardness can vary with austenitizing temperature, soaking time, oil quench speed, section size, tempering time, and test position.<\/div>\n      <p>For most O1 tooling, the common tempering range is about 150\u2013260\u00b0C (300\u2013500\u00b0F). This range keeps O1 in a useful high-hardness condition for cold-work tools. Higher tempering temperatures improve toughness but reduce hardness and wear resistance. For detailed information, see <a href=\"https:\/\/aobosteel.com\/ko\/o1-tool-steel-heat-treatment\/\">how to heat treat O1 tool steel<\/a>.<\/p>\n\n      <h2>Annealed Hardness of O1 Steel and Machining Behavior<\/h2>\n      <p>O1 steel is normally supplied in the annealed condition, with hardness typically not exceeding about 217 HBW. This condition is used for machining, drilling, milling, turning, and grinding preparation before hardening.<\/p>\n      <p>Compared with D2, O1 is easier to machine because it has a lower volume fraction of alloy carbide. This is one reason O1 is widely used for general-purpose tools, gauges, fixtures, punches, and smaller dies.<\/p>\n      <p>Major machining should be completed before hardening. After O1 is hardened, conventional machining becomes difficult, and finishing is usually limited to grinding, polishing, EDM, or other post-hardening operations.<\/p>\n\n      <h2>Failure Risks Related to O1 Steel Hardness<\/h2>\n      <p>O1 failure is often related to excessive hardness, poor heat-treatment control, stress concentrations, or surface damage after hardening.<\/p>\n      <div class=\"aobo-table-wrap\">\n        <table class=\"aobo-table\">\n          <thead>\n            <tr><th>\uc2e4\ud328 \uc704\ud5d8<\/th><th>\uacf5\ud1b5 \uc6d0\uc778<\/th><th>\uc2e4\uc9c8\uc801\uc778 \uacb0\uacfc<\/th><\/tr>\n          <\/thead>\n          <tbody>\n            <tr><td>\ubaa8\uc11c\ub9ac \uae68\uc9d0<\/td><td>Hardness too high, impact loading, poor support<\/td><td>Cutting edge breaks before normal wear<\/td><\/tr>\n            <tr><td>\ub2f4\uae08\uc9c8 \uade0\uc5f4<\/td><td>Sharp corners, uneven section thickness, delayed tempering<\/td><td>Tool cracks before or shortly after service<\/td><\/tr>\n            <tr><td>Brittle fracture<\/td><td>High hardness combined with shock or bending stress<\/td><td>Sudden tool failure<\/td><\/tr>\n            <tr><td>\ucc28\uc6d0 \ubcc0\ud654<\/td><td>Unstable structure or poor heat treatment control<\/td><td>Tool size changes after hardening or during use<\/td><\/tr>\n            <tr><td>\uade0\uc5f4\uc744 \uac08\uc544\ub0b4\ub2e4<\/td><td>Overheating during grinding on hardened O1<\/td><td>Microcracks grow under working load<\/td><\/tr>\n            <tr><td>Soft spots<\/td><td>Uneven hardening or excessive tempering heat<\/td><td>Local wear or deformation<\/td><\/tr>\n          <\/tbody>\n        <\/table>\n      <\/div>\n      <p>To reduce these risks, O1 tools should have smooth transitions, proper radii, controlled heat treatment, immediate tempering after quenching, and careful grinding after hardening.<\/p>\n\n      <h2>O1 vs A2 vs D2 Hardness Comparison<\/h2>\n      <p>O1, A2, and D2 can all work in similar HRC ranges, but they do not perform the same way. Hardness alone cannot explain tool life. Their differences come from hardenability, carbide volume, wear resistance, toughness, and machinability.<\/p>\n      <div class=\"aobo-table-wrap\">\n        <table class=\"aobo-table\">\n          <thead>\n            <tr><th>\uac15\ucca0 \ub4f1\uae09<\/th><th>Common Working Hardness<\/th><th>Hardening Type<\/th><th>\ub0b4\ub9c8\ubaa8\uc131<\/th><th>\uac15\uc778\ud568<\/th><th>\uac00\uacf5\uc131<\/th><\/tr>\n          <\/thead>\n          <tbody>\n            <tr><td>\uc6241<\/td><td>58\u201360 HRC<\/td><td>Oil-hardening<\/td><td>\uc88b\uc740<\/td><td>Good for general cold-work use<\/td><td>\uc88b\uc740<\/td><\/tr>\n            <tr><td>A2<\/td><td>57\u201360 HRC<\/td><td>\uacf5\uae30 \uacbd\ud654<\/td><td>Higher than O1<\/td><td>Better balance than D2<\/td><td>\ubcf4\ud1b5\uc758<\/td><\/tr>\n            <tr><td>\ub5142<\/td><td>58\u201360 HRC<\/td><td>\uacf5\uae30 \uacbd\ud654<\/td><td>\ub9e4\uc6b0 \ub192\uc74c<\/td><td>\ub0ae\ucd94\ub2e4<\/td><td>\uac00\ub09c\ud55c<\/td><\/tr>\n          <\/tbody>\n        <\/table>\n      <\/div>\n      <p>O1 is usually selected when machinability, simple heat treatment, and general-purpose cold-work performance are important. It is suitable for small- and medium-sized tools where oil quenching can provide sufficient hardness.<\/p>\n      <p>A2 is better when dimensional stability, higher hardenability, and better resistance to chipping are needed. D2 is better when abrasive wear resistance is the main requirement, but it is more difficult to machine and less forgiving under impact.<\/p>\n      <p>The selection should not be based only on HRC. O1, A2, and D2 may all be used at around 58\u201360 HRC, but their performance will differ under wear, impact, sliding, and cracking conditions.<\/p>\n    <\/main>\n\n    <section class=\"aobo-cta\">\n      <div>\n        <h2>Request Annealed O1 Steel Quote<\/h2>\n        <p>Aobo Steel supplies annealed O1 tool steel for machining and further heat treatment. For available sizes, supply conditions, and bulk order details, please visit our O1 tool steel product page.<\/p>\n      <\/div>\n      <div class=\"aobo-cta-actions\">\n        <a class=\"aobo-btn aobo-btn-primary popmake-16052\" href=\"javascript:void(0);\">Request Annealed O1 Steel Quote<\/a>\n        <a class=\"aobo-btn aobo-btn-secondary\" href=\"https:\/\/aobosteel.com\/ko\/o1-tool-steel\/\">O1 tool steel product page<\/a>\n      <\/div>\n    <\/section>\n  <\/div>\n<\/section>\n\n\n\n<ul class=\"wp-block-yoast-seo-related-links yoast-seo-related-links\">\n<li><a href=\"https:\/\/aobosteel.com\/ko\/o1-tool-steel\/\">O1 \uacf5\uad6c\uac15 | 1.2510 | SKS3<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/aobosteel.com\/ko\/h13-steel-heat-treatment\/\">H13 \uc5f4\ucc98\ub9ac \uac00\uc774\ub4dc | \uc544\uc624\ubcf4 \uc2a4\ud2f8<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/aobosteel.com\/ko\/h13-steel-hardness\/\">H13\uac15 \uacbd\ub3c4: HRC \ubc94\uc704, \ud15c\ud37c\ub9c1 \ucc28\ud2b8 \ubc0f \uc801\uc6a9 \ubd84\uc57c<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/aobosteel.com\/ko\/420-stainless-steel-heat-treatment\/\">420\uac15 \uc5f4\ucc98\ub9ac \uac00\uc774\ub4dc | \uacbd\ud654, \ub2f4\uae08\uc9c8 \ubc0f \ud15c\ud37c\ub9c1<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/aobosteel.com\/ko\/s7-tool-steel-rockwell-hardness-chart\/\">S7 \uacf5\uad6c\uac15 \ub85c\ud06c\uc6f0 \uacbd\ub3c4\ud45c | HRC, HB \ubc0f \uc791\uc5c5 \ubc94\uc704<\/a><\/li>\n<\/ul>\n\n\n\n<h2 id=\"h-faq\" class=\"wp-block-heading\">\uc790\uc8fc \ubb3b\ub294 \uc9c8\ubb38<\/h2>\n\n\n\n<div class=\"schema-faq wp-block-yoast-faq-block\"><div class=\"schema-faq-section\" id=\"faq-question-1778719081160\"><strong class=\"schema-faq-question\">What is the typical hardness of annealed O1 steel?<\/strong> <p class=\"schema-faq-answer\">Annealed O1 steel is usually supplied at not more than about <strong>217 HBW<\/strong>. This is the soft condition used for machining before hardening.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1778719105773\"><strong class=\"schema-faq-question\">How hard can O1 steel get after quenching?<\/strong> <p class=\"schema-faq-answer\">After proper oil quenching, O1 steel can reach about <strong>64\u201365 HRC<\/strong> in the as-quenched condition. However, it must be tempered before use with tools.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1778719106539\"><strong class=\"schema-faq-question\">What is the common working hardness of O1 tool steel?<\/strong> <p class=\"schema-faq-answer\">The typical hardness of O1 tool steel is about <strong>58\u201360 HRC<\/strong> after hardening and tempering. The broader practical range is about <strong>56\u201362 HRC<\/strong>.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1778719107523\"><strong class=\"schema-faq-question\">Is 62 HRC too hard for O1 steel?<\/strong> <p class=\"schema-faq-answer\">Not always. An HRC of\u00a0<strong>60\u201362<\/strong>\u00a0can be suitable for tools that require better edge retention and wear resistance. For tools exposed to impact, poor support, or cracking risk, a slightly lower hardness may be safer.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1778719138724\"><strong class=\"schema-faq-question\">Why does O1 steel lose hardness during tempering?<\/strong> <p class=\"schema-faq-answer\">O1 loses hardness during tempering because the hard martensite formed during quenching becomes tempered martensite. As tempering temperature increases, hardness decreases and toughness improves.<\/p> <\/div> <div class=\"schema-faq-section\" id=\"faq-question-1778719139476\"><strong class=\"schema-faq-question\">Is O1 more wear-resistant than D2?<\/strong> <p class=\"schema-faq-answer\">No. O1 has good wear resistance for general cold-work tools, but D2 has much higher abrasive wear resistance because of its high carbon and high chromium carbide content.<\/p> <\/div> <\/div>","protected":false},"excerpt":{"rendered":"<p>O1 Steel Hardness: Annealed, Quenched and Tempered HRC Range O1 tool steel is usually supplied in the annealed condition, with a hardness typically not exceeding about 217 HBW. After oil quenching, O1 can reach about 64\u201365 HRC in the as-quenched condition. For practical use, O1 steel is hardened and tempered. Its typical hardness is about [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":15315,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"normal-width-container","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":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"disabled","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","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":"","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":""},"class_list":["post-15314","page","type-page","status-publish","has-post-thumbnail","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.9 (Yoast SEO v27.9) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>O1 Steel Hardness: Annealed, Quenched &amp; Tempered HRC Guide - AoboSteel<\/title>\n<meta name=\"description\" content=\"O1 steel typically works at 58\u201360 HRC after hardening and tempering. 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This is the soft condition used for machining before hardening.\",\"inLanguage\":\"ko-KR\"},\"inLanguage\":\"ko-KR\"},{\"@type\":\"Question\",\"@id\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719105773\",\"position\":2,\"url\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719105773\",\"name\":\"How hard can O1 steel get after quenching?\",\"answerCount\":1,\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"After proper oil quenching, O1 steel can reach about <strong>64\u201365 HRC<\\\/strong> in the as-quenched condition. However, it must be tempered before use with tools.\",\"inLanguage\":\"ko-KR\"},\"inLanguage\":\"ko-KR\"},{\"@type\":\"Question\",\"@id\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719106539\",\"position\":3,\"url\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719106539\",\"name\":\"What is the common working hardness of O1 tool steel?\",\"answerCount\":1,\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The typical hardness of O1 tool steel is about <strong>58\u201360 HRC<\\\/strong> after hardening and tempering. The broader practical range is about <strong>56\u201362 HRC<\\\/strong>.\",\"inLanguage\":\"ko-KR\"},\"inLanguage\":\"ko-KR\"},{\"@type\":\"Question\",\"@id\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719107523\",\"position\":4,\"url\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719107523\",\"name\":\"Is 62 HRC too hard for O1 steel?\",\"answerCount\":1,\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Not always. An HRC of\u00a0<strong>60\u201362<\\\/strong>\u00a0can be suitable for tools that require better edge retention and wear resistance. For tools exposed to impact, poor support, or cracking risk, a slightly lower hardness may be safer.\",\"inLanguage\":\"ko-KR\"},\"inLanguage\":\"ko-KR\"},{\"@type\":\"Question\",\"@id\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719138724\",\"position\":5,\"url\":\"https:\\\/\\\/aobosteel.com\\\/o1-steel-hardness\\\/#faq-question-1778719138724\",\"name\":\"Why does O1 steel lose hardness during tempering?\",\"answerCount\":1,\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"O1 loses hardness during tempering because the hard martensite formed during quenching becomes tempered martensite. 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This is the soft condition used for machining before hardening.","inLanguage":"ko-KR"},"inLanguage":"ko-KR"},{"@type":"Question","@id":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719105773","position":2,"url":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719105773","name":"How hard can O1 steel get after quenching?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"After proper oil quenching, O1 steel can reach about <strong>64\u201365 HRC<\/strong> in the as-quenched condition. However, it must be tempered before use with tools.","inLanguage":"ko-KR"},"inLanguage":"ko-KR"},{"@type":"Question","@id":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719106539","position":3,"url":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719106539","name":"What is the common working hardness of O1 tool steel?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"The typical hardness of O1 tool steel is about <strong>58\u201360 HRC<\/strong> after hardening and tempering. The broader practical range is about <strong>56\u201362 HRC<\/strong>.","inLanguage":"ko-KR"},"inLanguage":"ko-KR"},{"@type":"Question","@id":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719107523","position":4,"url":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719107523","name":"Is 62 HRC too hard for O1 steel?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"Not always. An HRC of\u00a0<strong>60\u201362<\/strong>\u00a0can be suitable for tools that require better edge retention and wear resistance. For tools exposed to impact, poor support, or cracking risk, a slightly lower hardness may be safer.","inLanguage":"ko-KR"},"inLanguage":"ko-KR"},{"@type":"Question","@id":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719138724","position":5,"url":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719138724","name":"Why does O1 steel lose hardness during tempering?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"O1 loses hardness during tempering because the hard martensite formed during quenching becomes tempered martensite. As tempering temperature increases, hardness decreases and toughness improves.","inLanguage":"ko-KR"},"inLanguage":"ko-KR"},{"@type":"Question","@id":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719139476","position":6,"url":"https:\/\/aobosteel.com\/o1-steel-hardness\/#faq-question-1778719139476","name":"Is O1 more wear-resistant than D2?","answerCount":1,"acceptedAnswer":{"@type":"Answer","text":"No. O1 has good wear resistance for general cold-work tools, but D2 has much higher abrasive wear resistance because of its high carbon and high chromium carbide content.","inLanguage":"ko-KR"},"inLanguage":"ko-KR"}]}},"uagb_featured_image_src":{"full":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"thumbnail":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-150x150.avif",150,150,true],"medium":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-300x300.avif",300,300,true],"medium_large":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-768x768.avif",768,768,true],"large":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-1024x1024.avif",1024,1024,true],"1536x1536":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"2048x2048":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"trp-custom-language-flag":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-12x12.avif",12,12,true]},"uagb_author_info":{"display_name":"Evan","author_link":"https:\/\/aobosteel.com\/ko\/blog\/author\/admin\/"},"uagb_comment_info":0,"uagb_excerpt":"O1 Steel Hardness: Annealed, Quenched and Tempered HRC Range O1 tool steel is usually supplied in the annealed condition, with a hardness typically not exceeding about 217 HBW. After oil quenching, O1 can reach about 64\u201365 HRC in the as-quenched condition. For practical use, O1 steel is hardened and tempered. Its typical hardness is about&hellip;","rttpg_featured_image_url":{"full":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"landscape":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"portraits":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"thumbnail":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-150x150.avif",150,150,true],"medium":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-300x300.avif",300,300,true],"large":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-1024x1024.avif",1024,1024,true],"1536x1536":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"2048x2048":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad.avif",1254,1254,false],"trp-custom-language-flag":["https:\/\/aobosteel.com\/wp-content\/uploads\/2026\/05\/O1-hardness-ad-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":"O1 Steel Hardness: Annealed, Quenched and Tempered HRC Range O1 tool steel is usually supplied in the annealed condition, with a hardness typically not exceeding about 217 HBW. After oil quenching, O1 can reach about 64\u201365 HRC in the as-quenched condition. For practical use, O1 steel is hardened and tempered. Its typical hardness is about&hellip;","_links":{"self":[{"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/pages\/15314","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=15314"}],"version-history":[{"count":1,"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/pages\/15314\/revisions"}],"predecessor-version":[{"id":16157,"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/pages\/15314\/revisions\/16157"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/media\/15315"}],"wp:attachment":[{"href":"https:\/\/aobosteel.com\/ko\/wp-json\/wp\/v2\/media?parent=15314"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}