{"id":1599,"date":"2026-07-15T03:49:57","date_gmt":"2026-07-15T03:49:57","guid":{"rendered":"https:\/\/gearrack.top\/product\/industrial-internal-gear-mild-steel-60-70hrc-iso9001\/"},"modified":"2026-07-15T03:50:11","modified_gmt":"2026-07-15T03:50:11","slug":"industrial-internal-gear-mild-steel-60-70hrc-iso9001","status":"publish","type":"product","link":"https:\/\/gearrack.top\/fr\/product\/industrial-internal-gear-mild-steel-60-70hrc-iso9001\/","title":{"rendered":"Engrenages internes industriels \u2013 Acier doux, 60-70 HRC, ISO9001"},"content":{"rendered":"
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<\/p>\n

Product Overview<\/h2>\n
\n
\n \"Industrial\n <\/div>\n
\n

Industrial internal gears<\/strong> are heavy-duty ring gears produced in cold-rolled mild steel for machinery, agricultural machinery, and industrial drive applications. The cold-rolling process densifies the surface layer of the steel, increasing the surface hardness and fatigue resistance compared with hot-rolled equivalents \u2014 an important process advantage for ring gears that carry the full reaction torque of the planetary stage in continuous-duty industrial operation. Korea Ever-Power’s industrial internal gears achieve 60\u201370 HRC tooth surface hardness and 300\u2013400 MPa tensile strength, providing reliable corrosion resistance and long service life in the demanding environments of industrial and agricultural machinery.<\/p>\n

Korea Ever-Power is well known in the market for providing a broad assortment of internal and external gear products using quality-tested components. Industrial internal gears<\/a> are supplied worldwide from the Hangzhou manufacturing facility. ISO 9001 and CQC certified. Free samples available (freight cost paid by customer). OEM production accepted.<\/p>\n<\/p><\/div>\n<\/div>\n

The 60\u201370 HRC hardness specification of Korea Ever-Power’s industrial internal gears places these gears in the highest hardness range achievable for steel ring gears \u2014 above the 45 HRC standard steel internal gear and comparable to the surface hardness of carburised and case-hardened alloy steel gears. At this hardness level, the contact stress capacity and pitting fatigue life of the tooth surface are significantly higher than standard through-hardened steel, making the industrial internal gear the appropriate specification for high-cycle, high-load planetary drives in industrial and agricultural machinery where the ring gear service life is a critical maintenance cost driver.<\/p>\n

<\/p>\n

Technical Specifications<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Industrial Internal Gear \u2014 Product Specification<\/th>\n<\/tr>\n<\/thead>\n
Mat\u00e9riel<\/strong><\/td>\nMild steel (cold-rolled) \u2014 customised grades available<\/td>\n<\/tr>\n
Shape<\/strong><\/td>\nRound \u2014 customisable per drawing<\/td>\n<\/tr>\n
Technique<\/strong><\/td>\nCold rolled<\/td>\n<\/tr>\n
Corrosion Resistant<\/strong><\/td>\nOui<\/td>\n<\/tr>\n
Tensile Strength<\/strong><\/td>\n300\u2013400 MPa<\/td>\n<\/tr>\n
Hardness<\/strong><\/td>\n60\u201370 HRC<\/td>\n<\/tr>\n
Usage \/ Application<\/strong><\/td>\nMachinery, agricultural machinery, industry<\/td>\n<\/tr>\n
Certifications<\/strong><\/td>\nISO 9001; CQC<\/td>\n<\/tr>\n
OEM Service<\/strong><\/td>\nAccepted<\/td>\n<\/tr>\n
\u00c9chantillons<\/strong><\/td>\nFree (freight cost paid by customer)<\/td>\n<\/tr>\n
Sample Lead Time<\/strong><\/td>\n3\u20135 working days<\/td>\n<\/tr>\n
Production Lead Time<\/strong><\/td>\n10\u201325 days depending on quantity<\/td>\n<\/tr>\n
Shipping<\/strong><\/td>\nExpress, air, sea, train<\/td>\n<\/tr>\n
Payment<\/strong><\/td>\nT\/T, L\/C, Alipay, WeChat Pay, cash<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/p>\n

60\u201370 HRC \u2014 Industrial Gear Hardness in Context<\/h2>\n

\"types<\/p>\n

Tooth surface hardness is the primary determinant of a ring gear’s contact fatigue life \u2014 its resistance to pitting (surface fatigue) under repeated Hertzian contact stress. The Rockwell C (HRC) scale covers the practical range for steel gear tooth surfaces:<\/p>\n

\n\n\n\n\n\n\n\n\n
Hardness<\/th>\nTypical Process<\/th>\nContact Fatigue Resistance<\/th>\nTypical Ring Gear Application<\/th>\n<\/tr>\n<\/thead>\n
170\u2013250 HB (\u2248 8\u201322 HRC)<\/td>\nNormalised \/ annealed<\/td>\nLow<\/td>\nLight-duty, slow-speed auxiliary drives<\/td>\n<\/tr>\n
40\u201348 HRC<\/td>\nThrough-hardened<\/td>\nModerate<\/td>\nStandard industrial planetary gearboxes<\/td>\n<\/tr>\n
50\u201358 HRC<\/td>\nInduction hardened<\/td>\nGood<\/td>\nGeneral industrial and agricultural ring gears<\/td>\n<\/tr>\n
60\u201370 HRC \u2605<\/td>\nCase hardened \/ carburised<\/td>\nHighest \u2713<\/td>\nHeavy industrial, agricultural, high-cycle drives<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

At 60\u201370 HRC, Korea Ever-Power’s industrial internal gears sit at the top of the practical hardness range for steel ring gears \u2014 the same hardness zone as carburised and case-hardened alloy steel gears used in the most demanding industrial and agricultural applications. This hardness level delivers the maximum contact fatigue resistance achievable in a steel gear, and is specified for planetary ring gears that must achieve the longest service life between overhauls in high-cycle industrial and agricultural duty cycles.<\/p>\n

<\/p>\n

Cold Rolling \u2014 Process Advantages<\/h2>\n

\"Internal<\/p>\n

\n
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Surface Layer Densification<\/h3>\n

Cold rolling compresses the surface layer of the steel, closing microscopic voids and aligning the grain structure in the direction of rolling. The densified surface has higher hardness, lower surface roughness, and better fatigue resistance than the same steel in the hot-rolled or annealed condition. For the inner tooth surface of an industrial ring gear that is subject to repeated contact loading, surface densification directly increases the number of load cycles to pitting initiation.<\/p>\n<\/p><\/div>\n

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Compressive Residual Stress<\/h3>\n

Cold rolling introduces compressive residual stress in the surface layer \u2014 the same beneficial stress state that shot peening produces, but applied to the material’s full surface rather than just the exposed area. Compressive residual stress opposes the tensile stress that fatigue cracks need to propagate through the surface, directly increasing the tooth’s resistance to crack initiation at the tooth flank and at the root fillet.<\/p>\n<\/p><\/div>\n

\n

Improved Corrosion Resistance<\/h3>\n

The densified, lower-roughness surface of cold-rolled mild steel has higher corrosion resistance than hot-rolled or machined steel at the same composition \u2014 the closed surface voids reduce the surface area available for corrosion reaction, and the lower surface roughness reduces the crevice corrosion risk at the tooth tip and root. This inherent corrosion resistance is the basis for the “corrosion resistant: yes” specification of Korea Ever-Power’s industrial internal gear.<\/p>\n<\/p><\/div>\n

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Dimensional Consistency<\/h3>\n

Cold-rolled blanks have tighter dimensional tolerances than hot-rolled equivalents \u2014 the cold rolling process controls the blank thickness and width more precisely than hot rolling, where thermal shrinkage introduces dimensional variation. Tighter blank tolerances mean less material removed during tooth cutting, shorter machining cycle time, and more consistent tooth profile across the production batch.<\/p>\n<\/p><\/div>\n<\/div>\n

<\/p>\n

Applications<\/h2>\n

\"Ever-Power<\/p>\n

\n
\n
\u2699\ufe0f<\/div>\n

General Machinery<\/h3>\n

Industrial internal ring gears at 60\u201370 HRC in conveyor system planetary drives, mixing machine planetary gearboxes, agitator drive reducers, and fan drive planetary stages. The high hardness suits the high-cycle continuous-duty operation of general industrial machinery where the ring gear service interval is measured in years rather than months.<\/p>\n<\/p><\/div>\n

\n
<\/div>\n

Agricultural Machinery<\/h3>\n

High-hardness industrial internal ring gears in tractor wheel hub final drive planetary stages, combine harvester main drive planetary gearboxes, and self-propelled sprayer wheel motor planetary drives. Agricultural duty combines high torque, shock loads from field terrain, seasonal use cycles, and limited field maintenance \u2014 all three factors favour the highest achievable tooth hardness.<\/p>\n<\/p><\/div>\n

\n
\ufe0f<\/div>\n

Cranes and Hoisting Equipment<\/h3>\n

Industrial internal ring gears in crane hoisting planetary gearboxes, bridge crane travel drive planetary stages, and offshore pedestal crane slewing ring gears. High tooth hardness in the ring gear is particularly critical for crane planetary stages that carry rated loads during every lift cycle \u2014 the ring gear’s fatigue life directly determines the crane’s maintenance interval and safe working life.<\/p>\n<\/p><\/div>\n

\n
\u26cf\ufe0f<\/div>\n

Mining Equipment<\/h3>\n

Industrial internal gears in mining conveyor planetary drives, rock crusher feed planetary gearboxes, and underground equipment wheel motor drives. Mining applications subject ring gears to extreme duty \u2014 high torque, continuous operation, dusty abrasive environments, and infrequent maintenance access. The 60\u201370 HRC hardness and corrosion resistance of Korea Ever-Power’s industrial internal gear suit this extreme duty profile.<\/p>\n<\/p><\/div>\n

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<\/div>\n

Marine and Offshore<\/h3>\n

Industrial internal ring gears in winch planetary drives, anchor windlass planetary gearboxes, and thruster motor planetary stages on offshore vessels. The inherent corrosion resistance of cold-rolled mild steel, combined with appropriate surface treatment, suits the marine environment where salt spray accelerates corrosion at any surface imperfection on the ring gear exterior.<\/p>\n<\/p><\/div>\n

\n
<\/div>\n

Industrial OEM Export<\/h3>\n

Industrial internal gears for machinery OEM manufacturers and industrial gearbox producers in Australia, Europe, South Korea, and Southeast Asia. ISO 9001 and CQC certification accepted at most markets’ supplier qualification audits. Free sample policy allows incoming quality verification before production commitment. Multiple shipping modes suit both urgent and cost-optimised delivery requirements.<\/p>\n<\/p><\/div>\n<\/div>\n

<\/p>\n

Frequently Asked Questions<\/h2>\n
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Are free samples available for industrial internal gears?<\/p>\n

Yes \u2014 Korea Ever-Power can provide samples of industrial internal gears free of charge. The customer pays the express freight cost to their destination. Before the sample is started, product details are confirmed to avoid any misunderstandings \u2014 specification, material, hardness, diameter, tooth count, module, bore dimensions, and surface treatment are verified against the customer’s drawing. The sample allows incoming quality inspection before the production order decision.<\/p>\n<\/div>\n

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What quality certificates does Korea Ever-Power hold?<\/p>\n

Korea Ever-Power holds ISO 9001 (the international quality management system standard) and CQC (China Quality Certification Centre certification). ISO 9001 is the most widely accepted quality system certification for industrial supplier qualification globally \u2014 it is accepted at most international procurement audits as evidence of a controlled quality management process. CQC provides additional certification accepted in the Chinese domestic market and recognised by many international buyers as a supplementary quality indicator. Both certificates are available for customer review on request.<\/p>\n<\/div>\n

\n
\n

How does Korea Ever-Power control quality across the production process?<\/p>\n

Quality control follows a four-stage process. First, high-quality raw materials are selected \u2014 steel mill certificate confirms composition and mechanical properties before machining begins. Second, professional and skilled workers handle every production step with attention to detail. Third, the QC department is responsible for quality checking at each production process step \u2014 in-process inspection catches non-conformances before they progress to the next operation. Fourth, all products are tested after production under the ISO 9001 quality control system before shipment. This four-stage process is the basis for the “no quality risk” assurance Korea Ever-Power provides to industrial customers.<\/p>\n<\/div>\n

\n
\n

What ideas or designs can Korea Ever-Power help develop?<\/p>\n

Korea Ever-Power is happy to assist customers who have a design concept but not yet a finished drawing. For industrial internal gears, the design assistance covers selection of module and tooth count combination for the required ratio, checking the interference condition (internal gear PD \u2265 1.5 \u00d7 pinion PD), selecting the correct steel grade and hardness target for the duty cycle, and producing a production drawing for customer approval. Send the operating requirements \u2014 torque, speed, ratio, OD envelope, material preference, and operating environment \u2014 and Korea Ever-Power’s team will propose the gear specification. Contact our team<\/a> to begin.<\/p>\n<\/div>\n<\/div>\n

<\/p>\n

Customer Reviews<\/h2>\n
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\n

“We manufacture conveyor system planetary gearboxes for mining and specified industrial internal gears at 60\u201365 HRC from Korea Ever-Power. The free sample confirmed the hardness at our incoming Rockwell test \u2014 all 3 sample gears measured 62\u201364 HRC. Production batch of 80 pieces: consistent hardness in the same range. Four-stage QC process visible in the inspection report provided with each delivery.”<\/p>\n

Kim Jae-won<\/strong>  |  Mining Equipment Drive Engineer, Incheon Industrial Drives Co.  ·  Q1 2026<\/em><\/p>\n<\/div>\n

\n

“We supply tractor wheel hub planetary final drives for the Korean market. Korea Ever-Power’s industrial internal gears<\/a> at 60\u201370 HRC replaced our previous 45 HRC ring gears \u2014 tractor hub overhaul interval extended from 1,800 hours to 3,200 hours in our field test, based on tooth surface condition at scheduled inspection. ISO 9001 certification accepted at our OEM programme’s supplier audit.”<\/p>\n

Lee Sang-hyeon<\/strong>  |  Tractor Drive Systems Engineer, Gyeonggi Agricultural Equipment Co.  ·  Q4 2025<\/em><\/p>\n<\/div>\n

\n

“We needed industrial internal gears for a crane hoisting planetary drive \u2014 a new design with non-standard tooth count combination. Korea Ever-Power’s team checked the interference condition for our tooth counts, confirmed the combination was valid, and produced a drawing for approval before production. Sample in 5 days by express freight; free gear, we paid DHL to Busan. Production 18 days. Crane passed load test at rated capacity.”<\/p>\n

Park Yong-jun<\/strong>  |  Crane Drive Systems Engineer, Busan Heavy Lifting Equipment Co.  ·  Q2 2026<\/em><\/p>\n<\/div>\n

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“We distribute industrial internal gears to agricultural and industrial machinery OEM builders. The free sample policy is valuable for our customers who need to verify the gear against their housing assembly before ordering production quantities. Korea Ever-Power’s 3\u20135 day sample lead time means customers get the verification part within one working week. CQC certificate supplements ISO 9001 for our Chinese domestic customers.”<\/p>\n

Choi Hyun-seok<\/strong>  |  Industrial Gear Distribution Manager, Daejeon Machinery Parts Co.  ·  Q3 2025<\/em><\/p>\n<\/div>\n

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“We import industrial internal gears for the Australian mining equipment market. Sea freight to Melbourne: 22 days, consistent across six shipments. L\/C payment for our large annual order accepted without conditions. ISO 9001 certification accepted at our Australian OEM customer’s vendor approval. 60\u201370 HRC hardness confirmed by our incoming Brinell conversion test on all batches \u2014 no out-of-specification gears in two years of supply.”<\/p>\n

Yoon Tae-min<\/strong>  |  Mining Equipment Parts Import Manager, Ulsan Pacific Industrial Supply Co.  ·  Q1 2025<\/em><\/p>\n<\/div>\n<\/div>\n

<\/p>\n

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\n \"Internal
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Forged bevel gears for right-angle drives in agricultural differentials, crane swing drives, and industrial output direction changes \u2014 intersecting-shaft complement to industrial internal ring gear stages.<\/p>\n

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Request a Quotation for Industrial Internal Gears<\/h3>\n

Mild steel, cold-rolled, 60\u201370 HRC, corrosion resistant. All specifications customisable. Free samples (freight paid by customer). ISO 9001 \/ CQC. OEM accepted. T\/T \/ L\/C \/ Alipay. Express \/ air \/ sea \/ train.<\/p>\n

Get a Quote Now<\/a>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"

Korea Ever-Power industrial internal gears are cold-rolled mild steel ring gears for machinery, agricultural machinery, and industrial drives \u2014 round, customisable, tensile strength 300\u2013400 MPa, hardness 60\u201370 HRC, corrosion resistant. ISO 9001 and CQC certified. OEM accepted. Free samples (freight paid by customer). Shipping: express, air, sea, train. Payment: T\/T, L\/C, Alipay, WeChat Pay, cash. Sample 3\u20135 working days; production 10\u201325 days.<\/p>","protected":false},"featured_media":1600,"comment_status":"closed","ping_status":"open","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[4560],"product_tag":[],"class_list":["post-1599","product","type-product","status-publish","has-post-thumbnail","product_cat-ring-gear","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/product\/1599","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/comments?post=1599"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/media\/1600"}],"wp:attachment":[{"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/media?parent=1599"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/product_brand?post=1599"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/product_cat?post=1599"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/gearrack.top\/fr\/wp-json\/wp\/v2\/product_tag?post=1599"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}