Alloy Steel EN24 Round Bar
➡️ EN19 | UNS G43400 | EN 1.6582 | AISI 4340 | 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:
G43400
Wr. No.:
1.6582
MTC Available:
EN 10204 3.1
Product Description for Alloy Steel EN24 Round Bar
Alloy Steel EN24 Round Bar is a high-tensile nickel-chromium-molybdenum steel known in the British system as EN24 and in BS 970 as 817M40. It contains about 0.36–0.44% carbon, 1.30–1.70% nickel, 1.00–1.40% chromium and 0.20–0.35% molybdenum. Its closest European grade is 34CrNiMo6 (1.6582), and the nearest American grade is AISI 4340.
EN24 has very good hardenability and can reach high strength in large sections while keeping good ductility and shock resistance. It is usually supplied hardened and tempered to one of the BS 970 conditions, most often condition T (850–1000 MPa), and can be treated to much higher conditions up to Z.
The grade responds well to nitriding and induction hardening, which gives a hard, wear-resistant surface with a strong core.
EN24 bars are stocked hot rolled, forged, peeled or turned, annealed or hardened and tempered. EN24T is the common name for condition T material.
Common applications include heavy-duty shafts, crankshafts, gears, axles, connecting rods, landing gear parts, high-tensile bolts and studs, and oil and gas tools. Although BS 970 is withdrawn, EN24 remains a common trade name worldwide. EN24 is the grade UK and Indian engineers usually choose when EN19 cannot reach the required strength in a large section. UK stockists commonly quote condition T up to about 250 mm, much larger than for EN19. For the highest conditions, from X to Z, the steel is used in small sections for aerospace and motorsport parts, where very high strength must be combined with good shock resistance. Bright EN24T bars are also stocked.
Common Applications of Alloy Steel EN24 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 EN24 Round Bar
Standard
Country / Region
Grade
UNS
USA
UNS G43400
AISI / SAE / ASTM A29
USA
4340
BS 970
United Kingdom
817M40 / EN24 / EN24T
EN 10083-3 / DIN
Europe
EN 1.6582 (34CrNiMo6)
JIS G4103
Japan
SNCM439 / SNCM447
KS D 3867
South Korea
SNCM439
GB/T 3077
China
34Cr2Ni2Mo / 40CrNiMoA
AFNOR
France
35NCD6 / 34NiCrMo8
ISO 683-18
International
34CrNiMo6
IS
India
40NiCrMo7 / 40NiCrMo3
GOST
Russia
38XH2MA (38KhN2MA)
SIS
Sweden
14.2541
Technical Specification for Alloy Steel EN24 Round Bar
Specification
Value
Unit
Material
Alloy steel
-
Grade
EN24 / 817M40
-
Standard
BS 970-3 (817M40), nearest EN 10083-3 34CrNiMo6
-
Product Form
Round bar (hot rolled, forged or bright)
-
Diameter (supply range)
10–800 (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
Annealed or hardened and tempered (conditions T to Z)
-
Tolerance Standard
EN 10060 (hot rolled), EN 10278 (bright, h9-h11), or as agreed
-
Carbon Equivalent CEV (IIW, calculated from mid-range analysis)
≈ 0.89
-
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 EN24 Round Bar
EN24 Round Bar is ordered to BS 970 as 817M40 in a named condition, most often T. Because BS 970 is withdrawn, many buyers now order 34CrNiMo6 +QT to EN 10083-3. EN24 orders should say whether BS 970 817M40 or EN 10083-3 34CrNiMo6 governs.
Hardening is normally done from about 830–850°C with oil quenching, followed by tempering at about 550–660°C for conditions T to V. Higher conditions use lower tempering temperatures.
BS 970 conditions apply up to a limiting ruling section. The very high conditions (X, Y, Z) are only possible in smaller sections.
With its high carbon equivalent, EN24 should only be welded with preheat and post-weld heat treatment. Forged EN24 bars are usually ultrasonically tested.
The most common order is EN24T, which is machined directly into shafts, gears and bolts. For higher conditions, bars are often bought annealed, rough machined, then hardened and tempered by the customer to the required condition. Condition Z is reached by hardening and tempering at a low temperature, which gives very high strength but lower toughness. Such parts need careful grinding and plating to avoid cracking and hydrogen embrittlement. State the condition, bar size and whether the certificate should show 817M40 or 34CrNiMo6 on the order.
Chemical Composition for Alloy Steel EN24 Round Bar
Element
Symbol
Min
Max
Unit
Carbon
C
0.36
0.44
%
Silicon
Si
0.10
0.35
%
Manganese
Mn
0.45
0.70
%
Phosphorus
P
-
0.035
%
Sulfur
S
-
0.040
%
Chromium
Cr
1.00
1.40
%
Molybdenum
Mo
0.20
0.35
%
Nickel
Ni
1.30
1.70
%
Chemical Composition
View the chemical composition and applicable material limits for EN24 Round Bar
The table shows BS 970 limits for 817M40 (EN24). The nearest EN grade, 34CrNiMo6, has slightly lower carbon and different chromium limits.
Carbon at 0.36–0.44% allows high strength after hardening. Nickel at 1.30–1.70% improves toughness and hardenability, especially in large sections.
Chromium at 1.00–1.40% raises hardenability and wear resistance. Molybdenum at 0.20–0.35% improves hardenability and reduces temper embrittlement.
Manganese and silicon act as deoxidisers and add some strength. 817M40 has more carbon than 34CrNiMo6, at 0.36–0.44% against 0.30–0.38%, and a slightly lower chromium range. The higher carbon allows the very high conditions up to Z. Manganese at 0.45–0.70% is kept moderate, because the steel gets its hardenability mainly from nickel, chromium and molybdenum. The chemistry is also close to AISI 4340, which has nickel of 1.65–2.00% and chromium of 0.70–0.90%. For the best toughness and fatigue life at high strength, many buyers ask for vacuum-degassed steel with low sulfur and phosphorus, especially for aerospace and motorsport parts.
Phosphorus and sulfur are kept low to protect toughness and fatigue strength, which matter most in the high conditions. Low sulfur also improves transverse toughness in forged shafts.
Mechanical Properties for Alloy Steel EN24 Round Bar
Mechanical Property
Value
Unit
Tensile Strength (condition T)
850–1000
MPa
Hardness (condition T)
248–302
HB
Tensile Strength (condition U)
925–1075
MPa
Hardness (condition U)
269–331
HB
Tensile Strength (condition V)
1000–1150
MPa
Hardness (condition V)
293–352
HB
Tensile Strength (condition W)
1075–1225
MPa
Hardness (condition W)
311–375
HB
Tensile Strength (condition X)
1150–1300
MPa
Hardness (condition X)
341–401
HB
Tensile Strength (condition Y)
1225–1375
MPa
Hardness (condition Y)
363–429
HB
Tensile Strength (condition Z)
≥ 1550
MPa
Hardness (condition Z)
≥ 444
HB
Mechanical Properties
Check the key mechanical properties and performance requirements of EN24 Round Bar
The values shown are BS 970 tensile and hardness ranges for EN24 in the hardened and tempered conditions T to Z. Every EN24 condition has its own ruling section limit, with yield, elongation and impact minimums set for each.
Condition T is the most common supply condition. Higher conditions give very high strength for aerospace and heavy-duty parts but lower ductility.
For design, use the values for the ordered condition and section, and confirm results on the mill certificate. BS 970 gives EN24 a set of tensile conditions from T (850–1000 MPa) up to Z (1550 MPa minimum), each with a hardness range and a limiting ruling section. Yield strength, elongation and impact minimums also apply to each condition, and they fall as strength rises. Condition T gives good toughness and is easy to machine. Conditions W to Y give higher strength with reduced ductility and are limited to smaller sections. For fatigue-critical parts, surface finish and residual stress have a strong effect, so shot peening or nitriding is often added.
Impact tests are useful for cold-climate parts, and they should be ordered at the lowest service temperature with the notch type stated.
Dimension / Sizes for Alloy Steel EN24 Round Bar
Dimension / Size
Value
Unit
Available Diameter Range (supply capability)
10–800 (forged, larger on request)
mm
Standard Length (random)
3–6
m
Custom / Cut-to-Length
Available on request
-
Diameter Tolerance
EN 10060 (hot rolled), EN 10278 (bright, 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 EN24 Round Bar
Pricing for Alloy Steel EN24 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 EN24 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 EN24 or EN19?
What does EN24T mean?
What is the highest strength EN24 can reach?
Is EN24 the same as 34CrNiMo6 or AISI 4340?
How is EN24 heat treated, welded and machined?
What are the limits of EN24?
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