---
title: "EN24 Round Bar, 16 to 125 mm | Laxcon Steels"
source: "https://www.laxconsteels.com/products/hot-rolled-round-bars/en-24/"
description: "EN 24 alloy steel hot rolled round bar, made to order by Laxcon Steels, India: composition, equivalents, weight per metre and tolerances."
---
# EN 24 Round Bars

*[Home](https://www.laxconsteels.com/) > [Products](https://www.laxconsteels.com/products/) > [Hot Rolled Round Bars](https://www.laxconsteels.com/products/hot-rolled-round-bars/) > EN 24*

EN 24 hot rolled round bar is a nickel chromium molybdenum alloy steel bar used for shafts, axles and gears in heavy sections.

16 to 125 mm Alloy steel Made to order

## EN 24 hot rolled round bar

EN 24 hot rolled round bar is an alloy steel bar rolled from a nickel chromium molybdenum engineering steel that hardens right through its section when it is quenched and tempered. The same steel is written EN24, and appears as 817M40 in BS 970, as 34CrNiMo6 in the German designations, as 1.6582 in the European material numbers and as 4340 in the American system. Carbon near 0.4 percent sets the hardness the bar can reach. Nickel of 1.3 to 1.8 percent, with the chromium and the molybdenum beside it, carries that hardness deep into a thick bar. EN 19 one step down holds no nickel and softens toward the centre of a large diameter. EN 30B holds more nickel again and is kept for sections heavier still.

The bar is supplied annealed, normalised, or hardened and tempered to a BS 970 condition, T, U, V or above, each letter naming a band of tensile strength. Annealed or normalised bar machines cleanly and suits a part that is heat treated after cutting; bar bought hardened and tempered is cut to size and used as it is. Quenching is done in oil for most diameters, which is gentler than water on a steel of this carbon level, and tempering follows at once. The steel has no corrosion resistance, so finished parts are painted, plated or oiled. Round bar in this grade becomes transmission shafts and axles, gear and pinion blanks, high tensile bolts and studs, and forging stock for crankshafts.

Composition limits in weight percent are carbon 0.35 to 0.45, manganese 0.45 to 0.7, sulphur 0.05 maximum, phosphorus 0.05 maximum, silicon 0.1 to 0.35, chromium 0.9 to 1.4, nickel 1.3 to 1.8 and molybdenum 0.2 to 0.35.

## EN 24 hot rolled round bar supply conditions

| Property | Value |
| --- | --- |
| Size range | 16 mm - 125 mm (5/8" - 5") |
| Length | Up to 8 metres |
| Tolerances | EN10060 |
| Heat treatment | Soft annealing or normalising; oil or water quenching and tempering |
| Grade | EN 24 (EN24, 817M40, 34CrNiMo6, 4340) |
| Family | Alloy steel |
| Supply | Made to order in this grade; every published size of the form |

## Composition of EN 24

| Element | Symbol | Minimum % | Maximum % |
| --- | --- | --- | --- |
| Carbon | C | 0.35 | 0.45 |
| Manganese | Mn | 0.45 | 0.7 |
| Sulphur | S |  | 0.05 |
| Phosphorus | P |  | 0.05 |
| Silicon | Si | 0.1 | 0.35 |
| Chromium | Cr | 0.9 | 1.4 |
| Nickel | Ni | 1.3 | 1.8 |
| Molybdenum | Mo | 0.2 | 0.35 |

Composition, weight percent, balance iron. From the Laxcon Steels grade reference.

## Equivalents of EN 24

| Standard | Designation |
| --- | --- |
| SAE | 4340 |
| DIN | 34CrNiMo6 |

Equivalence means nearest counterpart, not identity: each standards body sets its own composition window, so the limits of the standard named on the order govern.

## Governing standards

| Property | Value |
| --- | --- |
| EN 10083-1 | Steels for quenching and tempering, part 1: general technical delivery conditions for the bars, rods and sections supplied for heat treatment. |
| EN 10083-3 | Steels for quenching and tempering, part 3: technical delivery conditions for alloy steels, 42CrMo4 and 34CrNiMo6 among them. |
| BS 970-1 | Wrought steels for mechanical and allied engineering purposes, part 1: the British numbering behind the EN and M designations and the R to Z heat treatment conditions. |
| ASTM A29/A29M | Steel bars, carbon and alloy, hot-wrought: general requirements for delivery, the base every carbon and alloy bar order inherits. |
| ASTM A322 | Steel bars, alloy, standard grades: the composition tables for the SAE alloy grades supplied as bar. |
| EN 10060 | Hot rolled round steel bars for general purposes: dimensions and tolerances on shape and dimensions. |
| NACE MR0175 / ISO 15156 | Materials for use in H2S-containing environments in oil and gas production: the sour-service limits on hardness and condition. |
| EN 10204 | Metallic products, types of inspection documents: the 2.2 test report and the 3.1 and 3.2 inspection certificates a purchase order can call for. |

## Weight per metre

| Diameter (mm) | kg per metre | Metres per tonne |
| --- | --- | --- |
| 16 | 1.58 | 633.5 |
| 17 | 1.78 | 561.2 |
| 18 | 2.00 | 500.6 |
| 19 | 2.23 | 449.3 |
| 20 | 2.47 | 405.5 |
| 21 | 2.72 | 367.8 |
| 22 | 2.98 | 335.1 |
| 23.2 | 3.32 | 301.3 |
| 24 | 3.55 | 281.6 |
| 25 | 3.85 | 259.5 |
| 26 | 4.17 | 239.9 |
| 27 | 4.49 | 222.5 |
| 28 | 4.83 | 206.9 |
| 30 | 5.55 | 180.2 |
| 32 | 6.31 | 158.4 |
| 34 | 7.13 | 140.3 |
| 36 | 7.99 | 125.1 |
| 37 | 8.44 | 118.5 |
| 38 | 8.90 | 112.3 |
| 40 | 9.87 | 101.4 |
| 42 | 10.88 | 91.9 |
| 45 | 12.49 | 80.1 |
| 47 | 13.62 | 73.4 |
| 48 | 14.21 | 70.4 |
| 50 | 15.41 | 64.9 |
| 53 | 17.32 | 57.7 |
| 56 | 19.34 | 51.7 |
| 57.5 | 20.39 | 49.1 |
| 60 | 22.20 | 45.1 |
| 63 | 24.47 | 40.9 |
| 66 | 26.86 | 37.2 |
| 67.5 | 28.09 | 35.6 |
| 70 | 30.21 | 33.1 |
| 73.5 | 33.31 | 30.0 |
| 75 | 34.68 | 28.8 |
| 77.5 | 37.03 | 27.0 |
| 80 | 39.46 | 25.3 |
| 83 | 42.48 | 23.5 |
| 85 | 44.55 | 22.4 |
| 88 | 47.75 | 20.9 |
| 90 | 49.94 | 20.0 |
| 93 | 53.33 | 18.8 |
| 95 | 55.65 | 18.0 |
| 98 | 59.22 | 16.9 |
| 100 | 61.66 | 16.2 |
| 105 | 67.98 | 14.7 |
| 106 | 69.28 | 14.4 |
| 110 | 74.61 | 13.4 |
| 115 | 81.54 | 12.3 |
| 120 | 88.79 | 11.3 |
| 125 | 96.34 | 10.4 |

Density 7.85 g/cm³, diameter squared x 0.006166. Sizes are the published range at the nominal diameters shown.

## Ordering EN 24 hot rolled round bar

An enquiry for EN 24 in this form states the grade with the standard it is bought to, BS 970, EN 10083-3 or ASTM A322, the condition wanted, the diameter with its tolerance to EN 10060, the surface as black, spot ground or fully ground, the cut length, the quantity, the EN 10204 certificate type, and any test called for, such as ultrasonic testing or PMI confirmation of the grade. Laxcon Steels rolls every size to order.

## Other grades in Round Bars

- [**AISI 304** The general purpose austenitic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-304/)
- [**AISI 316** The molybdenum-bearing austenitic grade](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-316/)
- [**EN 8** A medium-carbon unalloyed engineering steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/en-8/)
- [**Duplex 2205** The standard duplex stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/duplex-2205/)
- [**SAE 4140** The chromium-molybdenum through-hardening steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/sae-4140/)
- [**AISI 303** The free-machining austenitic grade](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-303/)
- [**AISI 316L** The low-carbon version of AISI 316](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-316l/)
- [**AISI 410** The basic martensitic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-410/)
- [**SAE 4340** The nickel-chromium-molybdenum through-hardening steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/sae-4340/)
- [**AISI 416** The free-machining martensitic grade](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-416/)
- [**17-4 PH** The precipitation hardening stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/17-4-ph/)
- [**AISI 420** A higher-carbon martensitic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-420/)
- [**AISI 431** A martensitic stainless steel with nickel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-431/)
- [**AISI 304L** The low-carbon version of AISI 304](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-304l/)
- [**AISI 430** The standard ferritic stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-430/)
- [**Super duplex 2507** A super duplex stainless steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/super-duplex-2507/)
- [**AISI 310S** A high-chromium, high-nickel austenitic grade for continuous service](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-310s/)
- [**AISI 321** AISI 304 stabilised with titanium](https://www.laxconsteels.com/products/hot-rolled-round-bars/aisi-321/)
- [**EN 19** A chromium-molybdenum engineering steel](https://www.laxconsteels.com/products/hot-rolled-round-bars/en-19/)

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