Alloy Steel 18CrNiMo7-6 Round Bar
➡️ UNS G48200 | EN 1.6587 | AISI 4820 | ASTM A29
➡️ ASTM, EN, JIS & International Standards
➡️ Supply Conditions
➡️ Multiple Diameters & Supply Lengths
➡️ Global Export & International Delivery
Country of Origin:
Europe, Japan, USA
Material Type:
Alloy Steel
UNS Number:
G48200
Wr. No.:
1.6587
MTC Available:
EN 10204 3.1
Product Description for Alloy Steel 18CrNiMo7-6 Round Bar
Alloy Steel 18CrNiMo7-6 Round Bar is a high-hardenability nickel-chromium-molybdenum case-hardening steel to EN 10084, with material number 1.6587. It was formerly known in Germany as 17CrNiMo6. It contains about 1.5–1.8% chromium, 1.4–1.7% nickel and 0.25–0.35% molybdenum.
The high alloy content gives very good hardenability. This means large sections can be carburised and quenched while still achieving high core strength and toughness. After heat treatment the part has a hard, wear-resistant surface and a strong, tough core that resists shock and fatigue.
Because of these properties, 18CrNiMo7-6 is one of the preferred steels for heavily loaded gears in wind turbines, mining equipment, rolling mills, marine drives and heavy trucks. Nickel improves core toughness, while chromium and molybdenum increase hardenability and resistance to tempering.
Bars are supplied hot rolled or forged, in untreated, +S, +A, +TH or +FP conditions. Grades with hardenability bands (+H, +HH, +HL) are used for tight control. Large forged bars often receive ultrasonic testing and clean steel checks.
Common applications include large gears and pinions, gear shafts, crown wheels, heavy-duty camshafts, bearing parts and other components that need a deep, hard case and a tough core. The UK counterpart is BS 970 820M17 and the nearest American grade is SAE 4320. 18CrNiMo7-6 is the standard case-hardening steel for large gearboxes in wind turbines, mining equipment, marine drives and heavy machinery. Large bars are often ordered with extra cleanliness, grain size and ultrasonic testing limits, because inclusions can start fatigue cracks in gear teeth. Bars can be supplied soft annealed for machining or as forged blanks for large gears.
Common Applications of Alloy Steel 18CrNiMo7-6 Round Bar
➡️ Machined shafts, spindles, valve stems, pump sleeves and pins for food, beverage, dairy and pharmaceutical equipment, where the passive chromium oxide film resists both product acids and caustic clean-in-place chemicals.
➡️ Fasteners, studs, bolts, threaded rod and anchor components produced from bar stock, chosen for corrosion resistance combined with the ductility needed for cold heading and thread rolling.
➡️ Chemical, water treatment and general process plant parts such as agitator shafts, flange blanks, nozzles and support components handling water, steam and mildly corrosive media free of significant chlorides.
➡️ Architectural and structural hardware including handrail stanchions, balustrade fittings, tension rods and bollards, where a bright ground or polished bar finish provides both appearance and low maintenance.
International Equivalent Grade for 18CrNiMo7-6 Round Bar
Standard
Country / Region
Grade
UNS
USA
UNS G48200
SAE / AISI
USA
AISI 4820 / SAE 4320
EN 10084
Europe
EN 1.6587 (18CrNiMo7-6)
BS
United Kingdom
820A16 / BS EN355
GB
China
17Cr2Ni2Mo
JIS G4053
Japan
SNCM420 / SNCM815
KS
South Korea
KS SNCM420 / KS SNCM815
AFNOR
France
18NCD6
UNI
Italy
18NiCrMo7
ISO 683-3
International
18CrNiMo7-6
Technical Specification for Alloy Steel 18CrNiMo7-6 Round Bar
Specification
Value
Unit
Material
Alloy steel
-
Grade
18CrNiMo7-6 / 1.6587
-
Standard
EN 10084 (forgings EN 10250-3)
-
Product Form
Round bar (hot rolled, forged or bright)
-
Diameter (supply range)
20–800 (forged)
mm
Length (random)
3–6
m
Manufacturing Process
Hot rolled or forged, optional peeling, turning, cold drawing or grinding
-
Production Route
EAF or BOF + ladle refining + vacuum degassing
-
Surface Finish
Black, shot blasted, peeled, turned, cold drawn or ground
-
Heat Treatment / Delivery Condition
Untreated, +S, +A, +TH or +FP as ordered
-
Tolerance Standard
EN 10060 (hot rolled), EN 10278 (bright, h9-h11), ASTM A29 / A484 style tables for US orders
-
Carbon Equivalent CEV (IIW, calculated from mid-range analysis)
≈ 0.79
-
Density
7.85
g/cm³
Thermal Conductivity at 20°C
42
W/m·K
Coefficient of Thermal Expansion 20–100°C
11.5
µm/m·K
Specific Heat at 20°C
460
J/kg·K
Modulus of Elasticity at 20°C
210
GPa
Magnetic Properties
Ferromagnetic
-
Testing / Inspection
Chemical analysis, hardness, tensile and impact where specified, UT (EN 10308 / SEP 1921 / ASTM A388), grain size, Jominy on request
-
Certification
EN 10204 3.1 mill test certificate (3.2 on request)
-
Technical Specifications
Get the key technical specifications for Alloy Steel 18CrNiMo7-6 Round Bar
Alloy Steel 18CrNiMo7-6 Round Bar is ordered to EN 10084. Large forged bars may also be ordered to EN 10250-3. The delivery condition, such as +A or +FP, should be stated, together with any hardenability band (+H, +HH or +HL).
Large 18CrNiMo7-6 gears are carburised at about 880–980°C, oil quenched and tempered at about 150–200°C. Because of the high hardenability, large parts can be quenched in oil with good core response.
Large bars for gears are often ordered with ultrasonic testing, micro-cleanliness limits and grain size control. These requirements should be written into the order.
The carbon equivalent shown is calculated from mid-range chemistry and is high. Welding needs careful preheat and procedure control and is normally avoided on finished parts. The physical values for 18CrNiMo7-6 are reference data for Ni-Cr-Mo case-hardening steel.
For wind turbine gears and other critical parts, buyers often specify vacuum-degassed steel, micro-cleanliness limits to ISO 4967 or DIN 50602, and ultrasonic testing to EN 10228-3. Grain size is usually required to be fine, often ASTM 5 or finer. State these requirements clearly, because they add cost and lead time.
Large bars are often forged rather than rolled.
Chemical Composition for Alloy Steel 18CrNiMo7-6 Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
0.15
0.21
%
Silicon
Si
-
0.40
%
Manganese
Mn
0.50
0.90
%
Phosphorus
P
-
0.025
%
Sulfur
S
-
0.035
%
Chromium
Cr
1.50
1.80
%
Molybdenum
Mo
0.25
0.35
%
Nickel
Ni
1.40
1.70
%
Chemical Composition
View the chemical composition and applicable material limits for 18CrNiMo7-6 Round Bar
The table shows the EN 10084 heat analysis limits for 18CrNiMo7-6.
Carbon at 0.15–0.21% keeps the core tough after hardening, while carburising raises surface carbon for a hard case. Chromium at 1.50–1.80% is the main hardenability element and adds wear resistance in the case.
Nickel at 1.40–1.70% improves core toughness and impact strength, which is important in large gears that see shock loads. Molybdenum at 0.25–0.35% raises hardenability, improves resistance to tempering and reduces temper embrittlement.
In 18CrNiMo7-6, manganese adds a little hardenability and deoxidises the melt. Phosphorus and sulfur are kept low to protect toughness and fatigue strength. Clean steel practice is important for gear fatigue life. Nickel at 1.40–1.70% improves core toughness and fatigue strength, which is why this steel is preferred for large, highly loaded gears. Chromium at 1.50–1.80% and molybdenum at 0.25–0.35% give high hardenability, so even large parts harden well in the core after carburising and oil quenching. Carbon at 0.15–0.21% keeps the core tough. Manganese is kept at a moderate 0.50–0.90%. Phosphorus and sulfur are limited to protect toughness and cleanliness, and many buyers order lower residual limits for critical gears.
Mechanical Properties for Alloy Steel 18CrNiMo7-6 Round Bar
Mechanical Property
Value
Unit
Hardness (+A, soft annealed)
≤ 229
HB
Hardness (+FP, ferrite-pearlite)
159–207
HB
Core Tensile Strength (blank-hardened 30 mm)
1080–1320
MPa
Core Yield Strength (blank-hardened 30 mm)
≥ 785
MPa
Core Elongation (blank-hardened 30 mm)
≥ 8
%
Case Hardness after carburising
58–62
HRC
Mechanical Properties
Check the key mechanical properties and performance requirements of 18CrNiMo7-6 Round Bar
EN 10084 sets delivery hardness for 18CrNiMo7-6, while finished-part strength depends on the heat treatment. The +A and +FP hardness limits shown for 18CrNiMo7-6 are EN 10084 requirements for bars as delivered.
The core tensile values are reference figures for a 30 mm blank-hardened test piece, based on former DIN 17210 data for 17CrNiMo6. They show the high core strength this grade can reach and are not mandatory EN 10084 limits.
Carburised 18CrNiMo7-6 gears normally reach about 58–62 HRC at the surface with a strong core underneath. The main advantage of this grade is that core strength and toughness stay high even in large sections. For gears, buyers should specify case depth, surface and core hardness, and cleanliness requirements. After carburising and hardening, 18CrNiMo7-6 keeps a high core strength even in large sections. This is the main reason it is chosen over 20MnCr5 for big gears. For design, use core hardness at the tooth root position and fatigue data from gear standards such as ISO 6336. Ask for Jominy results when ordering hardenability bands, and check that grain size stays fine after long carburising cycles.
Plan heat treatment trials for new gear sizes.
Dimension / Sizes for Alloy Steel 18CrNiMo7-6 Round Bar
Dimension / Size
Value
Unit
Available Diameter Range (supply capability)
20–800 (forged, larger on request)
mm
Standard Length (random)
3–6
m
Custom / Cut-to-Length
Available on request
-
Diameter Tolerance
Hot rolled: EN 10060 or ASTM A29. Bright: EN 10278 (h9-h11) or as agreed
-
Length Tolerance
Per ordered standard or as agreed (commonly +50 / -0 mm for cut lengths)
-
Straightness Tolerance
Per EN 10060 / EN 10278 or as agreed
-
End Condition
Saw cut square, chamfered or as ordered
-
Surface Finish
Black (as rolled or forged), shot blasted, peeled, rough turned, cold drawn, centreless ground
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for 18CrNiMo7-6 Round Bar
Pricing for Alloy Steel 18CrNiMo7-6 Round Bar
Round Bar Prices are generally quoted per kilograms or meters tonnes and can fluctuate with the global raw material and market prices. The final price will depend on a variety of factors, including the grade size, diameter, length, surface finish, the quantity and whether the bars are cut to length or in standard lengths.
For smaller quantities, we can also quote per metre or per piece basis once the required dimensions have been confirmed. Container-loads or orders that are larger in size are typically priced per tonne, based upon the specifications required and the supply conditions.
Please provide your desired dimensions, grades, length number, and end for a current quote including the lead time applicable and details for certification.
Pricing
Get current Alloy Steel 18CrNiMo7-6 Round Bar pricing based on size, quantity, grade, finish, and delivery requirements.
Why Choose Us
Euro Steel Bars is an international distributor, stockist and exporter of stainless round steel bars that cover carbon, stainless alloy, special grades. We stock a variety of sizes and grades. We guarantee every order with mill test certificates as well as full quality-assurance documentation. Our name speaks to our roots: European-sourced materials that is backed by the certificates and rigor that buyers from Asia as well as the Gulf and Africa are looking for.
Each bar we deliver is accompanied by EN 10204 3.1 mill test certificates as well as complete documentation of quality, so what you receive corresponds to what’s written in the documents. We carry a selection of sizes and grades ready for transport, and cut length upon the request of customers, which results in quicker lead times, whether you’re ordering just a one-off spec or a complete project tonnage.
We operate an actual wholesale business that is that is supported with an internationally-operated supply chain therefore we are able to serve fabricators sourcing one grade the same way in the same way as an EPC contractor who is placing a large order. Our clients include manufacturers, fabricators EPC construction companies, engineers oil and gas projects as well as construction companies. we design our inventory as well as documentation to show what buyers need to bring projects forward.
Our customers trust us across Qatar, Oman, Bahrain, Kuwait, Jordan, Malaysia, Singapore, Thailand, Taiwan, Turkey, Italy and South Africa. If you’re looking to source an Gulf energy project, or a construction project within Southeast Asia, you get the same quality of certified material, the exact documentation, and the exact delivery procedure.
Frequently Asked Questions
When should I choose 18CrNiMo7-6 over 20MnCr5?
Why is 18CrNiMo7-6 used for wind turbine gearboxes?
Is 18CrNiMo7-6 the same as 17CrNiMo6?
What extra tests should I order for large 18CrNiMo7-6 bars?
How is 18CrNiMo7-6 heat treated, welded and machined?
What are the limits of 18CrNiMo7-6?
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