Engrenages internes industriels – Acier doux, 60-70 HRC, ISO9001

Industrial internal gears 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 — 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 60–70 HRC tooth surface hardness and 300–400 MPa tensile strength, providing reliable corrosion resistance and long service life in the demanding environments of industrial and agricultural machinery.

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 are supplied worldwide from the Hangzhou manufacturing facility. ISO 9001 and CQC certified. Free samples available (freight cost paid by customer). OEM production accepted.

Surface Layer Densification

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.

Compressive Residual Stress

Cold rolling introduces compressive residual stress in the surface layer — 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.

Improved Corrosion Resistance

The densified, lower-roughness surface of cold-rolled mild steel has higher corrosion resistance than hot-rolled or machined steel at the same composition — 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.

Dimensional Consistency

Cold-rolled blanks have tighter dimensional tolerances than hot-rolled equivalents — 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.

General Machinery

Industrial internal ring gears at 60–70 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.

Agricultural Machinery

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 — all three factors favour the highest achievable tooth hardness.

Cranes and Hoisting Equipment

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 — the ring gear's fatigue life directly determines the crane's maintenance interval and safe working life.

Mining Equipment

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 — high torque, continuous operation, dusty abrasive environments, and infrequent maintenance access. The 60–70 HRC hardness and corrosion resistance of Korea Ever-Power's industrial internal gear suit this extreme duty profile.

Marine and Offshore

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.

Industrial OEM Export

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.

Are free samples available for industrial internal gears?

Yes — 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 — 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.

What quality certificates does Korea Ever-Power hold?

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 — 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.

How does Korea Ever-Power control quality across the production process?

Quality control follows a four-stage process. First, high-quality raw materials are selected — 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 — 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.

What ideas or designs can Korea Ever-Power help develop?

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 ≥ 1.5 × 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 — torque, speed, ratio, OD envelope, material preference, and operating environment — and Korea Ever-Power's team will propose the gear specification. Contact our team to begin.

"We manufacture conveyor system planetary gearboxes for mining and specified industrial internal gears at 60–65 HRC from Korea Ever-Power. The free sample confirmed the hardness at our incoming Rockwell test — all 3 sample gears measured 62–64 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."

Kim Jae-won  |  Mining Equipment Drive Engineer, Incheon Industrial Drives Co.  ·  Q1 2026

"We supply tractor wheel hub planetary final drives for the Korean market. Korea Ever-Power's industrial internal gears at 60–70 HRC replaced our previous 45 HRC ring gears — 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."

Lee Sang-hyeon  |  Tractor Drive Systems Engineer, Gyeonggi Agricultural Equipment Co.  ·  Q4 2025

"We needed industrial internal gears for a crane hoisting planetary drive — 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."

Park Yong-jun  |  Crane Drive Systems Engineer, Busan Heavy Lifting Equipment Co.  ·  Q2 2026

"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 3–5 day sample lead time means customers get the verification part within one working week. CQC certificate supplements ISO 9001 for our Chinese domestic customers."

Choi Hyun-seok  |  Industrial Gear Distribution Manager, Daejeon Machinery Parts Co.  ·  Q3 2025

"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. 60–70 HRC hardness confirmed by our incoming Brinell conversion test on all batches — no out-of-specification gears in two years of supply."

Yoon Tae-min  |  Mining Equipment Parts Import Manager, Ulsan Pacific Industrial Supply Co.  ·  Q1 2025