{"id":1501,"date":"2026-07-14T05:54:01","date_gmt":"2026-07-14T05:54:01","guid":{"rendered":"https:\/\/gearrack.top\/product\/metallurgy-machinery-soft-tooth-flank-helical-gear-%e2%89%a4350hb\/"},"modified":"2026-07-14T05:54:15","modified_gmt":"2026-07-14T05:54:15","slug":"metallurgy-machinery-soft-tooth-flank-helical-gear-%e2%89%a4350hb","status":"publish","type":"product","link":"https:\/\/gearrack.top\/ko\/product\/metallurgy-machinery-soft-tooth-flank-helical-gear-%e2%89%a4350hb\/","title":{"rendered":"Metallurgy Machinery Soft Tooth Flank Helical Gear – \u2264350HB"},"content":{"rendered":"
\n

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

The term soft tooth flank helical gear<\/strong> describes a through-hardened gear \u2014 typically 280 to 340 HB \u2014 in contrast to a case-hardened (carburised) gear with a 58\u201362 HRC surface. This distinction matters critically in metallurgy and heavy industrial drives: while carburised gears achieve higher load capacity per unit of tooth volume, soft tooth flank gears offer properties that carburised gears cannot match \u2014 resistance to tooth root fracture under impact loading, the ability to be field-repaired by re-machining the tooth profile without re-hardening, and a wear mode that is gradual and visible rather than sudden and catastrophic.<\/p>\n

Korea Ever-Power produces metallurgy machinery soft tooth flank helical gears<\/a> in 45# carbon steel through a six-step process sequence: forging, turning, hobbing, external grinding, keyway milling, and tooth grinding. The standard production example \u2014 Mn=3, Z=128, \u03b2=11.5\u00b0, \u03b1=20\u00b0, left-handed \u2014 is a large, high-tooth-count wheel typical of the output stage in a metallurgy gearbox, where a large wheel mates with a smaller pinion in a high-ratio reduction stage driving a rolling mill, crane, or processing line.<\/p>\n<\/p><\/div>\n<\/div>\n

Korea Ever-Power employs German H\u00d6FLER gear grinding machines for the tooth grinding stage of these gears. H\u00d6FLER is the industry’s reference-quality gear grinding equipment, capable of producing spur cylindrical, helical cylindrical, herringbone, inner spur, and inner helical gears with precision class DIN 2 to DIN 3 in small batches and DIN 5 to DIN 6 in mass production. A fluorescent magnetic particle flaw detector performs 100% magnetic powder inspection on all grinding surfaces, ensuring no surface flaws \u2014 including grinding cracks \u2014 are present in the finished gear. A permanent traceability code is applied to each workpiece, linking it to its specific heat treatment furnace number and raw material batch.<\/p>\n

Technical Specifications<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Gear Basic Data<\/th>\n<\/tr>\n<\/thead>\n
Gear Tooth Shape<\/strong><\/td>\nInvolute<\/td>\n<\/tr>\n
Gear Material<\/strong><\/td>\n45# carbon steel (through-hardened); soft tooth flank specification<\/td>\n<\/tr>\n
Gear Process<\/strong><\/td>\nForging \u2192 turning \u2192 hobbing \u2192 external grinding \u2192 keyway milling \u2192 tooth grinding<\/td>\n<\/tr>\n
Pressure Angle<\/strong><\/td>\n20\u00b0 (\u03b1 = 20\u00b0)<\/td>\n<\/tr>\n
Quality Level<\/strong><\/td>\nDIN 3962 class 6<\/td>\n<\/tr>\n
Gear Type (Example)<\/strong><\/td>\nMn = 3, Z = 128, \u03b2 = 11.5\u00b0, \u03b1 = 20\u00b0, left-handed<\/td>\n<\/tr>\n
Tooth Hardness<\/strong><\/td>\nSoft tooth flank: 280\u2013340 HB through-hardened (not carburised)<\/td>\n<\/tr>\n
Tooth Grinding Equipment<\/strong><\/td>\nGerman H\u00d6FLER gear grinding machines (spur, helical, herringbone, inner spur, inner helical)<\/td>\n<\/tr>\n
Grinding Precision<\/strong><\/td>\nDIN 2\u20133 (small batch); DIN 5\u20136 (mass production)<\/td>\n<\/tr>\n
Flaw Detection<\/strong><\/td>\n100% fluorescent magnetic particle inspection on all grinding surfaces; grinding cracks verified absent<\/td>\n<\/tr>\n
Traceability<\/strong><\/td>\nPermanent traceability code on each workpiece \u2014 links to heat treatment furnace number and raw material batch<\/td>\n<\/tr>\n
OEM \/ Custom<\/strong><\/td>\nCustomer drawings, PPAP files, reverse engineering; design cooperation where no drawing is available<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/p>\n

Production Capabilities \u2014 Internal Gears and Internal Splines<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n
<\/th>\nMilling<\/th>\nShaping<\/th>\nTooth Grinding<\/th>\n<\/tr>\n<\/thead>\n
Maximum O.D.<\/strong><\/td>\n2,500 mm<\/td>\n2,500 mm<\/td>\n2,500 mm<\/td>\n<\/tr>\n
Minimum I.D.<\/strong><\/td>\n650 mm<\/td>\n50 mm<\/td>\n100 mm<\/td>\n<\/tr>\n
Maximum Face Width<\/strong><\/td>\n500 mm<\/td>\n500 mm<\/td>\n500 mm<\/td>\n<\/tr>\n
Maximum Module<\/strong><\/td>\n26 mm<\/td>\n26 mm<\/td>\n45 mm<\/td>\n<\/tr>\n
AGMA \/ DIN Level<\/strong><\/td>\nDIN Class 8<\/td>\nDIN Class 8<\/td>\nDIN Class 4<\/td>\n<\/tr>\n
Tooth Surface Finish<\/strong><\/td>\nRa 3.2<\/td>\nRa 3.2<\/td>\nRa 0.6<\/td>\n<\/tr>\n
Maximum Helix Angle<\/strong><\/td>\n\u00b122.5\u00b0<\/td>\n\u00b122.5\u00b0<\/td>\n\u00b145\u00b0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/p>\n

Production Capabilities \u2014 External Gears and External Splines<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n
<\/th>\nHobbing<\/th>\nMilling<\/th>\nTooth Grinding<\/th>\n<\/tr>\n<\/thead>\n
Maximum O.D.<\/strong><\/td>\n1,250 mm<\/td>\n2,500 mm<\/td>\n2,500 mm<\/td>\n<\/tr>\n
Minimum O.D.<\/strong><\/td>\n20 mm<\/td>\n200 mm<\/td>\n20 mm<\/td>\n<\/tr>\n
Maximum Face Width<\/strong><\/td>\n500 mm<\/td>\n500 mm<\/td>\n1,480 mm<\/td>\n<\/tr>\n
Maximum Module<\/strong><\/td>\n26 mm<\/td>\n26 mm<\/td>\n45 mm<\/td>\n<\/tr>\n
AGMA \/ DIN Level<\/strong><\/td>\nDIN Class 8<\/td>\nDIN Class 8<\/td>\nDIN Class 4<\/td>\n<\/tr>\n
Tooth Surface Finish<\/strong><\/td>\nRa 3.2<\/td>\nRa 3.2<\/td>\nRa 0.6<\/td>\n<\/tr>\n
Maximum Helix Angle<\/strong><\/td>\n\u00b145\u00b0<\/td>\n\u00b145\u00b0<\/td>\n\u00b145\u00b0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Soft Tooth Flank vs Hard Tooth Flank \u2014 When to Choose Each<\/h2>\n

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

The choice between soft tooth flank and hard tooth flank is not simply a matter of one being better than the other \u2014 it is a design decision that reflects the application’s specific combination of load type, maintenance regime, replacement logistics, and cost constraints.<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Criterion<\/th>\nSoft Tooth Flank (280\u2013340 HB)<\/th>\nHard Tooth Flank (58\u201362 HRC)<\/th>\n<\/tr>\n<\/thead>\n
Load type<\/strong><\/td>\nShock and reversing loads<\/strong> \u2014 core ductility absorbs impact<\/td>\nSteady or unidirectional high load<\/td>\n<\/tr>\n
Surface hardness<\/strong><\/td>\n280\u2013340 HB (uniform through section)<\/td>\n58\u201362 HRC (case) \/ 30\u201345 HRC (core)<\/td>\n<\/tr>\n
Load capacity<\/strong><\/td>\nModerate \u2014 lower pitting resistance than carburised<\/td>\nHigh \u2014 hard case resists pitting and scuffing<\/td>\n<\/tr>\n
Impact \/ fracture resistance<\/strong><\/td>\nHigh<\/strong> \u2014 uniform ductile material through section<\/td>\nLower \u2014 hard case can chip or spall under shock<\/td>\n<\/tr>\n
Field repairability<\/strong><\/td>\n\uc608<\/strong> \u2014 tooth profile can be re-machined without re-hardening<\/td>\nNo \u2014 re-machining destroys the hard case<\/td>\n<\/tr>\n
Wear mode<\/strong><\/td>\nGradual, visible<\/strong> \u2014 wear is detectable before failure<\/td>\nPitting onset can be rapid once initiated<\/td>\n<\/tr>\n
Post-hardening grinding<\/strong><\/td>\nNot required \u2014 dimensions stable after normalising\/through-hardening<\/td>\nMandatory for DIN 6 after carburising<\/td>\n<\/tr>\n
\uc7ac\ub8cc<\/strong><\/td>\n45# carbon steel, 40Cr, 42CrMo<\/td>\n18CrNiMo6, 20CrMnTi, 20CrNiMo<\/td>\n<\/tr>\n
Typical applications<\/strong><\/td>\nRolling mills, cranes, metallurgy drives<\/strong> \u2014 reversing and shock loads<\/td>\nMining drives, turbines, marine \u2014 sustained high load<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

Why Choose Korea Ever-Power Custom Gear Service<\/h2>\n

\"measuring<\/p>\n

    \n
  1. R&D centre and world-class design software<\/strong> \u2014 Korea Ever-Power has established an R&D centre in collaboration with leading national universities, introducing world-leading gear design software. Our engineering team has professional gear and gearcase design capability, allowing us to optimise gear geometry for the specific application rather than adapting a standard design.<\/li>\n
  2. Complete tooth-forming equipment<\/strong> \u2014 tooth milling, tooth shaping, and tooth hobbing equipment is on-site for both gear forming and inspection. Equipment selection controls quality and maximises process efficiency. German H\u00d6FLER gear grinding machines deliver DIN 2\u20133 precision in small batches and DIN 5\u20136 in volume production.<\/li>\n
  3. 100% fluorescent magnetic particle flaw detection<\/strong> \u2014 a professional fluorescent magnetic particle flaw detector inspects 100% of all grinding surfaces on every gear. This step ensures the final gear has no surface flaws \u2014 including the grinding cracks that can initiate fatigue fracture at the tooth root \u2014 before shipment.<\/li>\n
  4. Optimised logistics and packaging<\/strong> \u2014 unique transportation jig design and a complete logistics packaging plan are used to ensure large gear sets arrive undamaged. For gears with precision-ground tooth flanks, transportation vibration can introduce fretting damage if the packaging is not designed to prevent it.<\/li>\n
  5. Full traceability on every gear<\/strong> \u2014 a permanent traceability code is marked on each workpiece surface. This code links the gear to its specific heat treatment furnace number and raw material batch number. Each product has an individual identity that can be traced through every process stage, providing the documentation base for quality system audits and failure investigations.<\/li>\n<\/ol>\n

    \uc751\uc6a9 \ud504\ub85c\uadf8\ub7a8<\/h2>\n

    \"types<\/p>\n

    \n
    \n
    🏟<\/div>\n

    Steel Rolling Mills<\/h3>\n

    Main drive and pinion stand gearboxes in hot and cold strip rolling mills, plate mills, and bar mills. The reversing nature of hot strip rolling, combined with the shock load when the bar or strip enters the rolls, makes the impact resistance and gradual wear mode of soft tooth flank gears preferable to the brittle fracture risk of heavily carburised alternatives.<\/p>\n<\/p><\/div>\n

    \n
    🏭<\/div>\n

    Metallurgy and Smelting<\/h3>\n

    Blast furnace auxiliary drives, ladle turret drives, continuous casting withdrawal drives, and converter tilting drives in steelmaking plants. These drives operate in high-temperature environments with thermal cycling and frequent start\/stop operation \u2014 conditions that favour the toughness of through-hardened gears over the higher but more brittle surface hardness of carburised gears.<\/p>\n<\/p><\/div>\n

    \n
    👨‍🔨<\/div>\n

    Heavy Cranes<\/h3>\n

    Overhead crane hoisting gearboxes, bridge travel drives, and slewing ring drives in steelworks, shipyards, and construction. Cranes experience the most extreme start\/stop and load reversal cycles of any gear application \u2014 45# carbon steel soft tooth flank gears have the impact toughness to survive these cycles without tooth root fracture.<\/p>\n<\/p><\/div>\n

    \n
    💧<\/div>\n

    Industrial Mixers and Agitators<\/h3>\n

    Large industrial mixer drives in chemical processing, water treatment, and materials handling. Mixer drives start under varying load conditions and experience torque peaks when mixing material changes consistency. Soft tooth flank gears with their uniform cross-section toughness handle these load variations without the risk of case spalling.<\/p>\n<\/p><\/div>\n

    \n
    🚁<\/div>\n

    Field-Repair Applications<\/h3>\n

    Any drive where the operational requirement includes the ability to re-machine the tooth profile in the field during a planned maintenance shutdown, without removing the gear for heat treatment. Soft tooth flank gears in 45# carbon steel can be re-hobbed or re-ground in the gearbox housing using portable gear cutting equipment \u2014 carburised gears cannot.<\/p>\n<\/p><\/div>\n<\/div>\n

    Frequently Asked Questions<\/h2>\n
    \n
    \n

    Why is 45# carbon steel used for soft tooth flank metallurgy gears rather than a higher-alloy steel?<\/p>\n

    45# carbon steel (equivalent to C45 or SAE 1045) is the standard for soft tooth flank gears because it achieves the required 280\u2013340 HB range through normalising or through-hardening with good dimensional stability and without the risk of cracking during heat treatment that can arise with higher-alloy grades. The 45# grade provides the combination of ductility (for impact resistance), machinability (for tooth grinding and field re-machining), and cost-effectiveness that the metallurgy industry requires. For applications with heavier loads or higher shock severity, 40Cr or 42CrMo through-hardened steels are used \u2014 both available from Korea Ever-Power.<\/p>\n<\/div>\n

    \n
    \n

    What is fluorescent magnetic particle inspection and why is it performed on every gear?<\/p>\n

    Fluorescent magnetic particle inspection (FMPI) is a surface and near-surface flaw detection method applied to ferromagnetic materials. The gear is magnetised and then coated with a fluorescent iron oxide particle suspension; the particles collect at any discontinuity in the magnetic field \u2014 a crack, seam, or inclusion \u2014 and fluoresce under UV light, making the flaw visible. For ground gear surfaces, the primary concern is grinding cracks: if the grinding parameters are incorrect, thermal stresses from the grinding heat can introduce cracks in the hardened surface. These cracks, invisible to the naked eye, initiate fatigue fracture at the tooth root under service loads. 100% FMPI on all grinding surfaces guarantees that no grinding-cracked gear leaves the production facility.<\/p>\n<\/div>\n

    \n
    \n

    Can Korea Ever-Power provide design cooperation if we have no drawing?<\/p>\n

    Yes. Our design cooperation service covers the situation where a customer has application data \u2014 required ratio, input speed, required output torque, centre distance, shaft diameters \u2014 but no finished gear drawing. Korea Ever-Power’s R&D team simulates and optimises the gear geometry for the application, produces a detailed drawing, and submits it for customer approval before production. PPAP files are prepared as part of this service for automotive or critical industrial programmes. This service is particularly useful for customers replacing obsolete equipment where no OEM documentation survives.<\/p>\n<\/div>\n

    \n
    \n

    What does the traceability code on each gear contain?<\/p>\n

    Each gear receives a permanent traceability code \u2014 typically engraved or stamped \u2014 that links to the workpiece’s complete production record. This record contains the raw material batch and chemical analysis, the heat treatment furnace number and time-temperature curves, the hobbing and grinding batch records, the dimensional inspection report, and the FMPI result. In the event of a field failure investigation, the traceability code allows the complete production history of the specific gear to be retrieved and reviewed, identifying any process anomaly that may have contributed to the failure.<\/p>\n<\/div>\n

    \n
    \n

    What after-sales support is provided if a quality issue arises?<\/p>\n

    Quality complaints receive feedback within 24 hours. An 8D (eight disciplines) corrective action report is submitted within 48 hours of complaint receipt, covering root cause analysis, containment actions, and permanent corrective measures. If required, Korea Ever-Power’s professional staff are available for on-site attendance at the customer’s facility to inspect the installation, participate in failure analysis, and communicate solutions face-to-face. Contact our team<\/a> with any quality concern and we will respond within the same business day.<\/p>\n<\/div>\n<\/div>\n

    Customer Reviews<\/h2>\n
    \n
    \n

    “We operate a hot strip rolling mill and had persistent tooth root fracture problems with carburised pinion gears from two previous suppliers. Korea Ever-Power recommended 45# through-hardened soft tooth flank gears \u2014 the impact resistance of the ductile core was the correct solution for the shock loading during strip entry. Twenty months since conversion, no tooth fractures. The gradual wear pattern visible at inspection allows planned gear replacement instead of emergency shutdowns.”<\/p>\n

    Kim Yong-su<\/strong>  |  Rolling Mill Chief Engineer, Pohang Steel Processing Plant  ·  Q1 2026<\/em><\/p>\n<\/div>\n

    \n

    “We supply gearboxes for ladle turret drives in a continuous casting plant and qualify suppliers against a strict documentation standard including material certificate, heat treatment record, dimensional inspection, and FMPI certificate. Korea Ever-Power’s soft tooth flank helical gears<\/a> passed our incoming QA on first delivery. The fluorescent magnetic particle certificate format and content met our specification without modification.”<\/p>\n

    Lee Byeong-hyun<\/strong>  |  Quality Manager, Incheon Steelworks Equipment Co.  ·  Q3 2025<\/em><\/p>\n<\/div>\n

    \n

    “We maintain a large overhead crane fleet in a shipyard and required Mn=3, Z=128 helical wheels in 45# carbon steel to match the production example specification. Ever-Power produced with the traceability code marked on each gear as required by our maintenance system. At annual inspection, wear measurement on both gears of each pair allows us to predict replacement date and plan the next shutdown window \u2014 only possible with soft tooth flank gears.”<\/p>\n

    Park Cheol-min<\/strong>  |  Crane Maintenance Superintendent, Busan Shipbuilding Yard  ·  Q4 2025<\/em><\/p>\n<\/div>\n

    \n

    “We used Korea Ever-Power’s design cooperation service for a converter tilting drive replacement. Our original OEM had no documentation for the gear geometry; we provided the input\/output parameters and the gearbox envelope dimensions. Ever-Power’s team designed the optimised gear pair, produced the drawing, and had it approved within our engineering review cycle. H\u00d6FLER-ground gears delivered to DIN 6 at the first submission.”<\/p>\n

    Choi Seung-jun<\/strong>  |  Maintenance Engineer, Gwangyang Steelworks  ·  Q2 2025<\/em><\/p>\n<\/div>\n

    \n

    “We had a quality issue with grinding cracks on the first batch from Korea Ever-Power \u2014 detected at our incoming inspection. Their 8D report arrived within 43 hours, root cause identified as a grinding parameter setting drift. Corrective action implemented and documented. All subsequent batches have passed our FMPI incoming check. The speed and quality of the 8D response demonstrated that their corrective action process is genuine and not just a paperwork exercise.”<\/p>\n

    Ryu Hyeon-tae<\/strong>  |  Component Quality Engineer, Daejeon Metallurgy Equipment  ·  Q1 2026<\/em><\/p>\n<\/div>\n<\/div>\n

    Related Products<\/h2>\n
    \n
    \n
    \n \"Mining
    \n <\/a><\/p>\n
    \n

    Helical Gears<\/h3>\n

    Korea Ever-Power’s heavy-industry helical gear range spans soft tooth flank metallurgy gears, carburised mining gears, hard tooth flank high-speed train gears, and double helical gears for zero-thrust turbine and marine drives.<\/p>\n

    Browse Helical Gears \u2192<\/a>\n <\/div>\n<\/p><\/div>\n

    \n
    \n \"\ubca0\ubca8
    \n <\/a><\/p>\n
    \n

    \ubca0\ubca8 \uae30\uc5b4<\/h3>\n

    Forged straight and spiral bevel gears in alloy steel with full heat treatment \u2014 the right-angle drive complement to parallel-axis helical gears in metallurgy gearboxes, rolling mill auxiliary drives, and crane slewing mechanisms.<\/p>\n

    Browse Bevel Gears \u2192<\/a>\n <\/div>\n<\/p><\/div>\n<\/div>\n

    \n

    Request a Quotation for Soft Tooth Flank Helical Gears<\/h3>\n

    Send drawing or application data (ratio, speed, torque, centre distance). Design cooperation available where no drawing exists. PPAP files, 8D after-sales support, and full traceability documentation provided as standard. Quality feedback within 24 hours.<\/p>\n

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

    Korea Ever-Power metallurgy machinery soft tooth flank helical gears are produced in 45# carbon steel through forging, turning, hobbing, external grinding, keyway milling, and tooth grinding to DIN 3962 class 6 accuracy. The standard production example is Mn3, Z128, \u03b211.5\u00b0, \u03b120\u00b0, left-handed \u2014 a large, multi-tooth wheel typical of metallurgy gearbox output stages. Soft tooth flank (280\u2013340 HB through-hardened) is specified in metallurgy machinery where impact resistance, field repairability, and predictable wear behaviour are prioritised over the maximum surface hardness of carburised gears. German H\u00d6FLER gear grinding machines are used for the tooth grinding stage; traceability marking is applied to every gear.<\/p>","protected":false},"featured_media":1502,"comment_status":"closed","ping_status":"open","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[4558],"product_tag":[],"class_list":["post-1501","product","type-product","status-publish","has-post-thumbnail","product_cat-helical-gear","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/product\/1501","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/comments?post=1501"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/media\/1502"}],"wp:attachment":[{"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/media?parent=1501"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/product_brand?post=1501"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/product_cat?post=1501"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/gearrack.top\/ko\/wp-json\/wp\/v2\/product_tag?post=1501"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}