1.6582 (34CrNiMo6) forged parts, rolled rings, shafts and flanges

What 1.6582 (34CrNiMo6) is

1.6582 is an alloy steel for quenching and tempering, listed in EN 10083-3:2006. The nickel content raises toughness, chromium and molybdenum provide hardenability and reduce sensitivity to temper embrittlement, and the carbon range of 0.30 to 0.38 per cent keeps the steel workable in heavy forged sections.

The grade is normally specified when a section is too large or too highly stressed for 42CrMo4 (1.7225). 1.6582 hardens through thick sections, so a forged shaft of 200 mm diameter can be tempered to a comparable structure at the core and at the surface. This is the main reason it is used for rotating parts under fatigue loading.

In the United Kingdom the grade is designated 817M40 or EN24. Enquiries from North America often quote AISI 4340 against it. The equivalent grade table gives the full cross-reference and the difference between 1.6582 and 4340.

Forged compared with machined from bar

• Grain flow follows the contour of the part, which raises fatigue and impact strength in the loaded direction.
• Near net shape forging reduces material removal and machining time on large rings and discs.
• Open-die forging covers sizes and weights that are not available in rolled bar.
• Forging breaks down the as-cast structure and closes internal porosity, which improves ultrasonic response.

Chemical composition of 1.6582 / 34CrNiMo6

The table gives the cast analysis limits of EN 10083-3:2006 in weight per cent. Each heat is analysed and the result is reported on the mill certificate.

Tighter limits on sulphur and phosphorus, restricted residual elements such as Cu, Sn and As, or a controlled J-factor for service sensitive to temper embrittlement can be agreed at order stage.

Mechanical properties of 34CrNiMo6 in the +QT condition

Properties of 1.6582 depend on ruling section, because the cooling rate at the core falls as the section increases. The table gives the EN 10083-3 requirements for the quenched and tempered condition, measured on the reference test piece.

In imperial units the 40 to 100 mm band corresponds to approximately 145 to 174 ksi tensile strength, with a minimum yield of about 116 ksi. In the soft annealed condition (+A) hardness is 248 HB maximum. This is the usual delivery condition when the customer will machine and heat treat the forging.

1.6582 equivalent grades in other standards

The cross-references below are near equivalents, given for enquiry matching. Chemistry limits differ between standards, so the specification should be confirmed on the order before one grade is substituted for another.

1.6582 and AISI 4340

The two grades are often treated as interchangeable. The main difference is nickel. AISI 4340 is specified at approximately 1.65 to 2.00 per cent nickel, against 1.30 to 1.70 per cent for 1.6582, so 4340 has slightly deeper hardenability and slightly better low temperature toughness in very heavy sections. For forged shafts, rings and flanges below about 400 mm the two grades perform in a similar way. We quote either grade, see the AISI 4340 forgings page.

Heat treatment and forging temperatures for 1.6582

The values below are the normal starting points for 34CrNiMo6. Soak times and quench media are set for each part, since section thickness governs both.

Working notes

• 1.6582 is sensitive to hydrogen flaking in heavy sections. Vacuum degassing and controlled cooling after forging are applied to every heat.
• Finish forging above approximately 900 °C. Working below this temperature can cause cracking and leaves an uneven grain structure.
• Avoid holding in the range 375 to 575 °C during slow cooling after tempering, to limit temper embrittlement.
• Where a hardness band is specified instead of a tensile band, the tempering temperature is set to meet the band and both results are reported.

1.6582 forged shapes produced

The shapes below are made to drawing or to a dimensional sketch. Open-die forging is a made to order process, so there is no fixed catalogue.

• Seamless rolled rings and forged rings
• Forged shafts, stepped shafts and eccentric shafts
• Forged flanges and flange blanks
• Forged discs, disks and blanks
• Forged round bars and rectangular bars
• Forged blocks and slabs
• Forged sleeves and bushings
• Hollow forged pipes and tubes
• Forged tube sheets
• Gear blanks and pinion blanks
• Forged spindles
• Crankshafts and forged manifolds
• Forged wheels and hubs
• Forging rolls and mill rolls
• Forged nozzles
• Valve bodies and valve blocks
• Forged valve stems and seat rings
• Forged cylinders and pump bodies

Where 1.6582 forgings are used

1.6582 is specified where high strength has to be combined with resistance to shock and fatigue loading in heavy sections. Typical applications by industry:

Manufacturing capability for 1.6582 forgings

Jiangyin Jiangnan Metal controls the route from steel making to final inspection, which keeps the heat number traceable to the finished forging.

Size and weight

Ring outside diameter, shaft length and single piece weight vary with the shape. Send the drawing and we will confirm feasibility, forging ratio and weight before quoting. Single prototype pieces and small trial quantities are accepted alongside series work.

Testing and certification for 1.6582 forged parts

Ultrasonic examination

Each 1.6582 forging is ultrasonically tested to the standard nominated on the order. The acceptance standards in routine use are:

• EN 10228-3, ultrasonic testing of ferritic or martensitic steel forgings, quality classes 1 to 4.
• SEP 1921, German ultrasonic acceptance classes, commonly class C/c or D/d for shafts and rings.
• ASTM A388 / ASME SA-388, ultrasonic examination of heavy steel forgings for North American and ASME code work.

Documentation

Standard release is an EN 10204 3.1 certificate issued by the works inspection department. It lists the heat number, cast analysis, heat treatment record, mechanical test results and the ultrasonic report. An EN 10204 3.2 certificate can be issued with a third party inspection body such as TUV, SGS, BV or Lloyd's Register witnessing the tests. Material traceability records, hardness maps, dimensional reports and NDT operator qualification certificates are available on request.

Related alloy steel grades

• 1.6565 forgings
• 1.6587 forgings
• AISI 4340 forgings
• 42CrMo4 forgings
• 1.7225 forgings
• AISI 4140 forgings
• 17CrNiMo6 forgings
• 18CrNiMo7-6 forgings

Last reviewed 6 September 2026 by the technical sales department of Jiangyin Jiangnan Metal Co., Ltd. Composition and property data are quoted from EN 10083-3:2006 and are given for guidance. The mill certificate supplied with the delivered forging is the binding document.