1.6562 (40NiCrMo8-4) Forgings: Bars, Hollow Bars, Rolled Rings, Discs, Blocks and Gear Shafts

By Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, China. Published 10 March 2016. Reviewed 5 September 2026.

1.6562 key data at a glance

Chemical composition of 1.6562

The analysis below is the composition Jiangyin Jiangnan Metal Co., Ltd. melts to for 1.6562 forgings. Phosphorus and sulfur are held below the standard maximum. Vacuum degassing reduces residual gas and non-metallic inclusion content, which supports the ultrasonic acceptance levels applied to heavy rings and shafts.

Heat analysis and product analysis are both reported on the mill test certificate. Tighter residual limits for copper, tin, arsenic and antimony can be agreed at order stage for rotor and pressure-retaining components.

International equivalents of 1.6562

1.6562 carries a different designation in most national standards, and many buyers search for 4340 or EN24 rather than the material number. The table lists the designations cross-referenced to 40NiCrMo8-4.

Equivalents are close but rarely identical. Where a design code, customer specification or pressure-equipment approval names one grade, order that grade rather than a substitute and check the acceptance criteria against the certificate. Jiangyin Jiangnan Metal Co., Ltd. states on the certificate which specification the forging was made and tested to.

Mechanical properties after quenching and tempering

The properties of 1.6562 are developed by heat treatment. Strength is set by the tempering temperature, and the class that can be achieved depends on the ruling section. A 200 mm shaft will not reach the same core properties as a 60 mm shaft on the same tempering cycle. The classes below follow the EN24 / 817M40 condition lettering that the grade is normally ordered against.

These values are indicative and intended for design guidance. Contractual properties are those tested on prolongations from the actual forging and recorded on the EN 10204 3.1 or 3.2 certificate.

Heat treatment of 1.6562

1.6562 is a through-hardening steel. At 0.37 to 0.44 percent carbon it develops its properties by quenching and tempering the full section rather than by forming a surface case. The nickel and molybdenum content allows the core of a heavy section to transform on quenching, which is the reason the grade is specified in place of 42CrMo4. The parameters below are those used in production by Jiangyin Jiangnan Metal Co., Ltd.

Forging

Preheat, then heat to 1150 to 1200 °C and hold until the temperature is uniform throughout the section. Do not forge below 850 °C. After forging, cool slowly under cover or in a furnace. 1.6562 air-hardens readily in heavy sections and an unprotected forging left to cool in the open is liable to crack.

Normalising

Heat to 850 to 880 °C, soak for 30 minutes plus approximately 30 minutes per 25 mm of section, and cool in still air. Normalising refines the coarse as-forged grain and provides a uniform starting structure for hardening.

Annealing

For machining stock, subcritical anneal at 650 to 700 °C, soak for one hour per 25 mm of section and cool in the furnace to approximately 500 °C before air cooling. This normally brings 1.6562 to 220 to 250 HB. Full annealing from 830 to 850 °C with a slow furnace cool is used where the softest condition is required.

Hardening

Heat to 810 to 840 °C, hold until the temperature is uniform throughout the section, soak for 10 to 15 minutes per 25 mm and quench in oil. Water quenching is not used on this grade. The hardenability is high enough that oil is sufficient, and water increases the risk of quench cracking in complex shapes. As-quenched hardness is approximately 55 to 58 HRC. Temper immediately while the part is still hand warm.

Tempering

Reheat to 540 to 660 °C depending on the strength class required, hold until the temperature is uniform, soak for one hour per 25 mm of section and cool in still air. Higher tempering temperatures give lower strength and higher impact toughness.

Tempering between approximately 250 and 450 °C should be avoided. This range produces tempered martensite embrittlement, which reduces Charpy impact energy without a corresponding change in the hardness reading. Where a low tempering temperature is required to meet a hardness target, raise it at enquiry stage.

Stress relieving

Heat to 550 to 600 °C, soak for 30 minutes plus one hour per 25 mm and cool slowly in the furnace to 300 °C. The stress-relieving temperature must be at least 30 °C below the tempering temperature used, otherwise the part will lose strength.

Stress relieving following welding

Heat the weld area to 600 to 650 °C, soak for 30 minutes plus one hour per 25 mm of section and cool in the furnace or in still air. The post-weld temperature must also stay below the original tempering temperature. 1.6562 has a high carbon equivalent, so welding additionally requires low-hydrogen consumables, preheat to 250 to 350 °C and a maintained interpass temperature.

Induction and flame hardening

1.6562 responds well to localised surface hardening on journals, splines and bearing seats. Machine off any decarburised layer first, then heat the surface into the austenitic range at 850 to 880 °C and quench immediately in oil or a water spray as required. Typical surface hardness is 50 to 55 HRC. Temper immediately at 150 to 200 °C to relieve stress and improve the toughness of the case. The feed material can be in the as-supplied condition or pre-hardened and tempered where a higher core strength is required.

Nitriding

1.6562 nitrides successfully because of its chromium and molybdenum content. Nitride at 490 to 530 °C followed by slow cooling with no quench, which keeps distortion low enough for parts to be machined to near-final size with only a grinding tolerance left. Typical case hardness is 50 to 55 HRC. Where pre-hardened and tempered stock is used, ensure the tempering temperature was at least 30 °C above the nitriding temperature. With 1.6562 tempered at 540 °C or higher this condition is normally satisfied.

Carburising and carbonitriding are not applicable to 1.6562

1.6562 is not a case-hardening grade and should not be carburised or carbonitrided. Those processes are intended for low-carbon steels of approximately 0.10 to 0.25 percent carbon, where a hard case is formed over a softer and tougher core. At 0.37 to 0.44 percent carbon the core of a 1.6562 component hardens together with the case and the core toughness is lost. Where only a hard surface is required on 1.6562, use induction or flame hardening or nitriding as described above. Where a carburised case is required, Jiangyin Jiangnan Metal Co., Ltd. supplies case-hardening grades including 18CrNiMo7-6, 17CrNiMo6 and AISI 8620.

Notes on heat treatment

The temperatures, heating rates, soaking times and cooling rates given above are indicative. The cycle for a given component depends on its size and shape, the furnace and quenching equipment used, the transfer time from furnace to quench, and the properties specified on the drawing. Section thickness has the largest effect: a 500 mm shaft and a 60 mm bar tempered on the same cycle will not reach the same condition. Jiangyin Jiangnan Metal Co., Ltd. confirms the cycle against the drawing before production and supplies a charted furnace record with the certificate.

Machining and grinding 1.6562

1.6562 machines predictably but is not a free-cutting steel. Sulfur is held at or below 0.015 percent for ultrasonic cleanliness and transverse toughness, and the low sulfur content reduces chip breaking. Machinability is approximately 55 to 60 percent of the AISI 1212 free-cutting reference in the annealed condition.

• Best machining condition. Annealed at 220 to 250 HB, or quenched and tempered to condition T at 248 to 302 HB. Most customers order 1.6562 pre-hardened to condition T or U and machine it in that state.
• Above approximately 350 HB. Use coated carbide or CBN tooling, rigid setups and reduced feeds. Above 400 HB, grinding is normally more economical than turning.
• Deep holes and trepanning. Jiangyin Jiangnan Metal Co., Ltd. bores hollow bars and sleeves in house before final heat treatment, which removes most of the deep-drilling work from the customer.
• Stress relief between operations. For parts with heavy stock removal or asymmetric sections, a stress relief at 550 to 600 °C after roughing keeps distortion within tolerance at finishing.
• Grinding. Keep the wheel dressed and the coolant flowing. Hardened 1.6562 is sensitive to grinding burn, which can appear later as surface cracking in service.

1.6562 product forms and size capability

1.6562 is produced to order rather than supplied from stock sections, so most solid and hollow sections can be forged from the same heat. The table groups the forms Jiangyin Jiangnan Metal Co., Ltd. produces most often in this grade.

Hollow forms in 1.6562 are forged solid and then bored or trepanned rather than pierced. Grain flow remains continuous around the bore and the full wall thickness can be ultrasonically inspected. All forms can be supplied black, rough machined or proof machined, in the annealed, normalised or quenched and tempered condition, with the machining allowance agreed on the drawing. Minimum order is one piece for large forgings. Small bars, sleeves and rings are normally batched.

Production route for 1.6562 forgings

1. Steelmaking, EAF + LF + VDElectric arc melting, ladle refining and vacuum degassing to control hydrogen, oxygen and inclusion cleanliness.
2. Ingot castingIngot sized to give the reduction ratio the drawing requires, then surface conditioned and inspected.
3. Open-die forging or ring rollingHeated to 1150 to 1200 °C and worked on hydraulic presses or the ring mill, finishing above 850 °C at a reduction ratio of 3:1 or better.
4. Heat treatmentNormalise, harden from 810 to 840 °C in oil and temper at 540 to 660 °C to the ordered strength class, with a charted furnace record.
5. Machining and boringMachined to the ultrasonic testing condition and to the ordered rough dimensions. Hollow forms are bored or trepanned from solid.
6. Non-destructive testingUltrasonic to EN 10228-3, SEP 1921 or ASTM A388, with magnetic particle inspection to ASTM E709 where specified.
7. Mechanical testingTensile, Charpy impact and hardness on prolongations, tested in the delivery condition.
8. Certification and dispatchEN 10204 3.1 certificate, or 3.2 countersigned by a third party, then hard stamping, preservation and export packing.

Where 1.6562 forgings are used

1.6562 is specified for components that are both large and highly stressed, where a chromium-molybdenum steel such as 42CrMo4 does not have sufficient hardenability. The table lists the applications Jiangyin Jiangnan Metal Co., Ltd. supplies the grade for most often.

1.6562 compared with 42CrMo4 and 34CrNiMo6

Section size is normally the deciding factor when choosing between the three grades. Nickel content determines whether the core of a thick forging will transform on quenching.

Testing, inspection and certification

Non-destructive testing

• Ultrasonic testing to EN 10228-3 for ferritic and martensitic steel forgings, quality classes 1 to 4.
• Ultrasonic testing to SEP 1921 or ASTM A388 where the customer specification requires it.
• Magnetic particle inspection to ASTM E709 or EN 10228-1 on machined surfaces.
• Dimensional inspection against the drawing, with a report issued for each piece.

Mechanical and chemical testing

• Tensile test in the delivery condition, on prolongations taken from the forging.
• Charpy V-notch impact testing at room temperature or down to −46 °C for low-temperature service.
• Brinell hardness survey, with Jominy hardenability testing on request.
• Spectrographic heat analysis and product analysis.
• Grain size, macro-etch and inclusion rating on request.

Certification

EN 10204 3.1 is issued as standard with every 1.6562 forging. EN 10204 3.2 countersigned by TUV, SGS, BV, Lloyd's Register or the customer's own inspector is available on request. Witnessed inspection and hold points at the works can be arranged before production starts.

Frequently asked questions about 1.6562

Related nickel-chromium-molybdenum forging grades

• AISI 4340 forgings
• 34CrNiMo6 forgings
• 817M40 / EN24 forgings
• SNCM439 forgings
• 1.6565 (40NiCrMo6)
• 1.6582
• 1.6580 (30CrNiMo8)
• 40NiCrMo6
• 42CrMo4 forgings
• All alloy steel forging grades

1.6562 forged product pages

• Forged rings
• Forged shafts
• Forged discs
• Forged spindles
• Forging rolls
• Forged flanges