T: +86-0731-85185770
E: enquiry@qilumetal.com
E: enquiry@qilumetal.com
No. 18 Xiangfu Middle Road,Yuhua District, Changsha City
 |
| Quantity: | |
|---|---|
18CrNiMo7-6
Qilu
18CrNiMo7-6, material number 1.6587, is a premium Cr-Ni-Mo alloy case hardening steel defined by EN 10084 standard, widely recognized as the upgraded alternative to 17CrNiMo6 steel grade. This low-carbon carburizing steel features balanced chromium, nickel and molybdenum alloy elements, delivering ultra-high hardenability, outstanding core toughness and surface wear resistance after carburizing quenching. It is specially engineered for large cross-section, heavy-load, high-impact mechanical components that require both hard wear-resistant surface and ductile shock-resistant core
Country | USA | Europe | Germany | British |
Standard | ASTM A29 | EN10084 | DIN 17210 | BS |
Grade | 4815/3215 | 18CrNiMo7-6/1.6587 | 17CrNiMo6 | 820A16 |
Grade | C | Si | Mn | P | S | Cr | Ni | Mo |
4815 | 0.13-0.18 | 0.15-0.35 | 0.40-0.60 | 0.035Max | 0.040Max | / | 3.25-3.75 | 0.20-0.30 |
18CrNiMo7-6 /1.6587 | 0.15-0.21 | 0.40Max | 0.50-0.90 | 0.025Max | 0.035Max | 1.50-1.80 | 1.40-1.70 | 0.25-0.35 |
17CrNiMo6 | 0.15-0.20 | 0.40Max | 0.40-0.60 | 0.035Max | 0.035Max | 1.50-1.80 | 1.40-1.70 | 0.25-0.35 |
Size range | Tensile strength |
d≤16 | 1200-1400Mpa |
16＜d≤40 | 1000-1100Mpa |
40＜d≤100 | 800-900Mpa |
Size range | Tensile strength | Yield strength | Alongation | Impact value At RT/J |
d=16 | 1030-1380Mpa | 700Mpa Min | 8% Min | 25J Min |
d=30 | 900-1250Mpa | 600Mpa Min | 9% Min | 25J Min |
d=63 | 810-1160Mpa | 550Mpa Min | 10% Min | 30J Min |
Heat Treatment | Hardness |
Treated to improve shearability (+S) | HB255Max |
Soft annealed (+A) | HB229Max |
Treated to hardness range(+TH) | 179-229HBW |
| Treated to ferrite-pearlite structure and hardness range(+FP) | 159-207HBW |
When ordered with normal (+H), high (+HH) or low (+HL) hardenability requirements, the hardness values at different distances from the quenched end meet the following standards (the core index for judging the hardenability of large-section parts):
| Distance in mm from quenched end | ||||||||||||||
Distance | 1.5 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 20 | 25 | 30 | 35 | 40 | |
Hardness In HRC + H | max | 48 | 48 | 48 | 48 | 47 | 47 | 46 | 46 | 44 | 43 | 42 | 41 | 41 |
min | 40 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 32 | 31 | 30 | 29 | 29 | |
Hardness In HRC + HH | max | 48 | 48 | 48 | 48 | 47 | 47 | 46 | 46 | 44 | 43 | 42 | 41 | 41 |
min | 43 | 43 | 42 | 41 | 40 | 40 | 39 | 38 | 36 | 35 | 34 | 33 | 33 | |
Hardness In HRC + HL | max | 45 | 45 | 45 | 45 | 44 | 43 | 42 | 42 | 40 | 39 | 38 | 37 | 37 |
min | 40 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 32 | 31 | 30 | 29 | 29 | |
Scatter bands for the Rockwell - C hardness in the end quench hardenability test.
Product type | Size range | Length |
Hot rolled bar | Φ14-Φ280mm | 6000-9000mm |
Hot forged bar | Φ140-Φ1200mm | 3000-5800mm |
Hot rolled plate/sheet | T:20-120mm; W:410-810mm | 2000-5800mm |
Hot Forged block | T: 80-800mm; W: 100-2500mm | 2000-5800mm |
Surface Finish | Turned | Milled | Grinding(Best) | Polished(Best) | Peeled(Best) | Black Forged | Black Rolled |
Tolerance | +0/+3mm | +0/+3mm | +0/+0.05mm | +0/+0.05mm | +0/+0.1mm | +0/+5mm | +0/+1mm |
Straighness | 1mm/1000mm max. | 3mm/1000mm max. | |||||
We maintain abundant monthly inventory of hot rolled and forged 18CrNiMo7-6 steel bars, covering a full range of commonly used diameters to support fast delivery for gear manufacturing and heavy machinery projects.
Our standard stocked bar sizes are listed below:
16, 20, 25, 30, 35, 38, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 250, 280, 300mm
Remark: Inventory sizes and stock volumes change dynamically based on ongoing production and customer orders. If you want to check up-to-date stock availability, lead time and spot pricing, please contact us.
Forging: Pre-heat to 1200°C, forge down to 850°C, then slow cool or anneal.
Machining: Comparable to other low-alloy carburizing steels; carbide tools recommended for turning, HSS or carbide for milling/drilling.
Welding: Requires preheating (250–350°C) and post-weld stress relief due to high hardenability; low-hydrogen welding consumables are mandatory.
| Process | Temperature Range |
| End Quench Test Austenitizing | 860℃ |
| Carburizing | 880-980℃ |
| Core-hardening | 830-870℃ |
| Case-hardening | 780-820℃ |
| Tempering | 150-200℃ |
Remark: The above parameters are for guidance only, and the specific process shall be optimized according to the actual production equipment and part requirements.
18CrNiMo7-6 features higher nickel and molybdenum content than 17CrNiMo6, significantly boosting hardenability and low-temperature toughness. When manufacturing gear blanks with diameter above 150mm or equipment working in cold outdoor environments such as wind power generators, 18CrNiMo7-6 is the preferred material to avoid soft core, quenching cracks and early fatigue failure. 17CrNiMo6 is a cost-saving choice for medium-size gears without extreme low-temperature service requirements.
16MnCr5 is a low-cost simple Mn-Cr steel without nickel element, only applicable to small light-load gears below 80mm. It has poor hardenability and low impact resistance. 18CrNiMo7-6 adds Ni-Mo alloy to solve the defects of shallow carburizing layer and brittle core of 16MnCr5, completely replacing 16MnCr5 for heavy-load industrial transmission components.
20CrMnMo contains no nickel, so its low-temperature toughness and anti-fatigue performance lag far behind 18CrNiMo7-6. It is widely used in general construction machinery, but cannot meet the long-life standards of wind power and marine high-end gearboxes. 18CrNiMo7-6 eliminates temper brittleness with nickel-molybdenum composite alloy design.
The essential difference is product positioning: 18CrNiMo7-6 is low-carbon carburizing steel for hard surface + tough core; 4140 is medium carbon QT steel for overall strength. 4140 cannot form a high-hardness wear-resistant surface after carburizing, so it cannot substitute 18CrNiMo7-6 for gear parts requiring friction resistance.
Wind turbine main gearbox large module gears, planet gear, sun gear, output shaft, heavy bearing seat; long service life under continuous variable load
Industrial heavy-duty reducer gears, mining machinery transmission shafts, construction machinery gear parts, crane gear components
Heavy truck gearbox gears, drive axle bevel gear, truck spindle, high-load spline shaft, large bolt fasteners
Aero engine auxiliary transmission gears, high-precision machine tool spindle, heavy load rack & pinion
Ship power transmission gear, turbine connecting rod, pressure vessel high-strength fasteners
A1: Standard material grade No. is 1.6587, European EN 10084 case hardening steel standard.
A2: 18CrNiMo7-6 contains higher nickel and molybdenum, better hardenability and impact toughness, preferred for large-size heavy-duty wind power gears.
A3: Surface hardness reaches 58–62 HRC, core maintains high toughness to avoid breakage under impact.
A4: Yes, we support any length cutting, rough turning, forging blank processing according to customer drawings.
A5: Wind turbine gearbox, heavy truck transmission, mining machinery, large industrial reducer, aerospace transmission parts.
Should you need custom forging, cutting, MTC certificates or bulk quotations for 18CrNiMo7-6 steel, please contact us with your drawings and technical requirements, and our team will reply within 24 hours.
