Alloy Steel 20CrMo Round Bar
➡️ UNS G41180 | EN 1.7243 | AISI 4118 | 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:
G41180 / G41200
Wr. No.:
1.7218 / 1.7243
MTC Available:
EN 10204 3.1
Product Description for Alloy Steel 20CrMo Round Bar
Alloy Steel 20CrMo Round Bar is a low-carbon chromium-molybdenum alloy structural steel to the Chinese standard GB/T 3077. It contains about 0.17–0.24% carbon, 0.80–1.10% chromium and 0.15–0.25% molybdenum.
The steel is used both as a quenched and tempered structural steel and as a case-hardening steel. After quenching and tempering, it gives good strength with high toughness. After carburising, it gives a hard, wear-resistant surface with a tough core.
In 20CrMo, molybdenum also helps the core harden evenly and resist temper embrittlement. The low carbon content gives good weldability and good cold formability.
20CrMo bars are sold hot rolled or forged, annealed or quenched and tempered, with black, peeled or turned surfaces.
Common applications include gears, shafts, spindles, fasteners, high-pressure pipe fittings, valve parts, and carburised machine parts. It is also used for parts that operate at moderately high temperatures. It is similar to the Japanese SCM420, the American 4118 and the European 18CrMo4 (1.7243), though chemistry ranges differ slightly. 20CrMo is a practical grade for parts that must be both carburised and welded, or for small quenched and tempered parts that need high toughness. Its GB/T 3077 test uses a small 15 mm blank, which reflects its moderate hardenability. In Chinese industry it is widely used for gear shafts, hydraulic fittings, high-pressure pipe joints and fasteners, and it is easy to source in bar sizes from small to medium diameters, both hot rolled and bright. It is also a common grade for high-strength bolts that are carburised or quenched and tempered.
Common Applications of Alloy Steel 20CrMo 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 20CrMo Round Bar
Standard
Country / Region
Grade
UNS
USA
UNS G41180 / UNS G41200
ASTM / AISI / SAE
USA
4118 / 4120
EN 10084
Europe
1.7218 / 1.7243
GB/T 3077
China
20CrMo
EN / DIN
Europe
25CrMo4 / 18CrMo4
JIS
Japan
SCM420 / SCM420H
KS
South Korea
SCM420
GOST
Russia
20KHM (20ХМ)
BS
United Kingdom
BS 708M20
AFNOR
France
18CD4
ISO
International
18CrMo4
Technical Specification for Alloy Steel 20CrMo Round Bar
Specification
Value
Unit
Material
Alloy steel
-
Grade
20CrMo
-
Standard
GB/T 3077
-
Product Form
Round bar (hot rolled, forged or bright)
-
Diameter (supply range)
10–500
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
Annealed or quenched and tempered as ordered
-
Tolerance Standard
GB/T 702 (hot rolled bars) or GB/T 908 (forged bars), or as agreed
-
Carbon Equivalent CEV (IIW, calculated from mid-range analysis)
≈ 0.53
-
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 20CrMo Round Bar
Alloy Steel 20CrMo Round Bar is ordered to GB/T 3077, with tolerances in GB/T 702 or GB/T 908.
The standard mechanical properties are measured on a 15 mm test blank after quenching at about 880°C in water or oil and tempering at about 500°C. For carburised parts, case depth and hardness should be specified separately.
The carbon equivalent is moderate, so welding is possible with preheat.
Physical data for 20CrMo are reference values. UT, grain size and third-party inspection can be ordered.
GB/T 3077 sets the table values for bars up to 80 mm, with allowed reductions in elongation, reduction of area and impact energy for larger sizes. Because the test blank is only 15 mm, a large 20CrMo bar will not reach the table strength at its centre after quenching. If the part is carburised, the order should also state case depth, surface hardness and core hardness, because GB/T 3077 does not cover carburised properties. For high-pressure fittings, check whether a pressure standard such as a fitting specification applies in addition to GB/T 3077.
Annealed bar is limited to 197 HBW for machining.
Chemical Composition for Alloy Steel 20CrMo Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
0.17
0.24
%
Silicon
Si
0.17
0.37
%
Manganese
Mn
0.40
0.70
%
Phosphorus
P
-
0.030
%
Sulfur
S
-
0.030
%
Chromium
Cr
0.80
1.10
%
Molybdenum
Mo
0.15
0.25
%
Chemical Composition
View the chemical composition and applicable material limits for 20CrMo Round Bar
The table shows the GB/T 3077 limits for 20CrMo in the high-quality grade.
Carbon at 0.17–0.24% gives good toughness and weldability while allowing moderate strength after hardening. It is also low enough for carburising.
Chromium at 0.80–1.10% raises hardenability and wear resistance. Molybdenum at 0.15–0.25% improves hardenability, strength at moderate temperatures and resistance to temper embrittlement.
Silicon and manganese in 20CrMo mainly deoxidise the steel. Impurities such as phosphorus and sulfur are limited in all 20CrMo qualities. Carbon at 0.17–0.24% puts 20CrMo on the border between a case-hardening steel and a low-carbon quenched and tempered steel, which is why it is used both ways. Manganese at 0.40–0.70% is lower than in European case-hardening grades such as 20MnCr5, so hardenability is more modest. Molybdenum at 0.15–0.25% helps the core respond evenly after carburising and quenching. The chemistry is close to JIS SCM420, which has carbon of 0.18–0.23% and higher manganese of 0.60–0.90%, and to the European 18CrMo4 (1.7243). These grades are similar in use but not identical, so hardenability and core properties should be checked when substituting.
Phosphorus and sulfur are held at 0.030% maximum in the standard quality, with lower limits in the A and E qualities. The lower levels are worth ordering for fatigue-critical gears.
Mechanical Properties for Alloy Steel 20CrMo Round Bar
Mechanical Property
Value
Unit
Tensile Strength Rm (GB/T 3077, Q&T)
≥ 885
MPa
Yield Strength ReL (GB/T 3077, Q&T)
≥ 685
MPa
Elongation A (GB/T 3077, Q&T)
≥ 12
%
Reduction of Area Z (GB/T 3077, Q&T)
≥ 50
%
Impact Energy KU2 (GB/T 3077, Q&T)
≥ 78
J
Hardness (annealed or high-temperature tempered)
≤ 197
HBW
Mechanical Properties
Check the key mechanical properties and performance requirements of 20CrMo Round Bar
The values shown are GB/T 3077 minimum requirements for 20CrMo after quenching at about 880°C and tempering at about 500°C on a small test blank. The 78 J impact value for 20CrMo comes from a KU2 U-notch specimen.
The steel reaches good strength with high toughness. Properties fall in larger sections because of limited hardenability.
In the annealed condition, hardness is limited to 197 HBW for machining. Confirm the required properties at the actual size with the mill. GB/T 3077 requires 20CrMo to reach tensile strength of at least 885 MPa, lower yield strength of at least 685 MPa, elongation of at least 12%, reduction of area of at least 50% and U-notch impact energy of at least 78 J, on a 15 mm blank quenched at about 880°C and tempered at about 500°C. These values apply to small sections only. In a 50 mm bar, the core will be noticeably softer. For carburised parts, case hardness of about 58–62 HRC is normal, and core hardness depends on the part size. Design with properties measured on the actual section.
Because the table values come from a 15 mm blank, a certificate for a large bar should say where its own test piece was taken.
Dimension / Sizes for Alloy Steel 20CrMo Round Bar
Dimension / Size
Value
Unit
Available Diameter Range (supply capability)
10–500 (forged sizes on request)
mm
Standard Length (random)
3–6
m
Custom / Cut-to-Length
Available on request
-
Diameter Tolerance
GB/T 702 (hot rolled bars) or GB/T 908 (forged bars), or as agreed
-
Length Tolerance
Per ordered standard or as agreed (commonly +50 / -0 mm for cut lengths)
-
Straightness Tolerance
Per GB/T 702 / GB/T 908 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 20CrMo Round Bar
Pricing for Alloy Steel 20CrMo 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 20CrMo 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
Should I choose 20CrMo or 42CrMo?
Can 20CrMo be carburised?
Is 20CrMo the same as SCM420 or 4118?
What size limits apply to 20CrMo properties?
How is 20CrMo heat treated, welded and machined?
What are the limits of 20CrMo?
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