--- title: "823M30 Forgings | 30CrNiMo8 1.6580 Steel | Jiangnan Metal" description: "823M30 (30CrNiMo8 / 1.6580) open-die forgings from Jiangyin Jiangnan Metal: rolled rings, shafts, discs, flanges, bars. Chemistry, +QT data, EN 10204 certs." canonical: https://www.steelforgepieces.com/Alloy-Steel/823M30.html author: Jiangyin Jiangnan Metal Co., Ltd. published: 2016-05-18 updated: 2026-09-12 --- # 823M30 Forgings BS 970 823M30 · EN 30CrNiMo8 · W.Nr. 1.6580 · AFNOR 30CND8 · JIS SNCM431 · GB 30Cr2Ni2Mo **823M30 is the British Standard BS 970 designation for a chromium-nickel-molybdenum quenched and tempered alloy steel containing 0.26 to 0.34 % carbon with 1.80 to 2.20 % chromium, 1.80 to 2.20 % nickel and 0.30 to 0.50 % molybdenum. It is identical in chemistry to the European grade 30CrNiMo8, Werkstoff 1.6580.** Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges 823M30 into seamless rolled rings, shafts, discs, flanges, sleeves, blocks and round bars to BS 970-3 and EN 10250-3, supplied quenched and tempered with EN 10204 3.1 or 3.2 mill test certificates. | | | |---|---| | Werkstoff | 1.6580 | | Density | 7.76 g/cm³ | | Tensile, +QT | 900 to 1450 MPa | | Forge window | 1150 to 850 °C | | Max section, +QT | 250 mm | | Certification | EN 10204 3.1 / 3.2 | Contact: [0086-189-2135-9659](tel:+8618921359659) · [sales@steelforgepieces.com](mailto:sales@steelforgepieces.com) --- ## What is 823M30 steel? 823M30 is a chromium-nickel-molybdenum through-hardening alloy steel specified in BS 970 Part 3, containing 0.26 to 0.34 % carbon, 1.80 to 2.20 % chromium, 1.80 to 2.20 % nickel and 0.30 to 0.50 % molybdenum. It is the same steel as 30CrNiMo8 (W.Nr. 1.6580) in EN 10083-3. Its defining property is very deep hardenability: heavy forged sections can be quenched and tempered right through to a uniform strength, rather than hardening only near the surface. The designation follows the BS 970 coding system. The leading **8** places the steel in the nickel-chromium-molybdenum family, and **23** identifies the specific alloy within that family. The letter **M** indicates that the steel is bought to a chemical composition specification rather than to a hardenability or mechanical property requirement. The final **30** is the mean carbon content in hundredths of a percent, that is 0.30 %. The main effect of the chemistry is hardenability. Nickel and chromium at approximately two percent each, together with molybdenum, move the nose of the transformation curve far enough to the right that a thick section can cool slowly and still transform to martensite at the core. Molybdenum also suppresses temper embrittlement, which allows the steel to be tempered high, in the 540 to 680 °C range, to recover toughness without losing the strength developed by the quench. For this reason 823M30 is normally specified for large shafts, rotors and rings. On smaller parts a less heavily alloyed grade such as 42CrMo4 will usually meet the same requirement at lower cost. The same alloy content produces a high carbon equivalent, so the heat affected zone of a weld hardens and becomes liable to cold cracking. 823M30 is therefore treated as a single piece forged material. The part is forged to shape, heat treated as one body and then machined, instead of being fabricated from welded sections. Jiangyin Jiangnan Metal supplies this grade as forged product only, meaning open-die forgings and seamless rolled rings. Forging closes the porosity present in cast stock and aligns grain flow with the principal stress direction, along the hoop in a rolled ring and along the axis in a shaft. --- ## 823M30 equivalents and cross-reference 823M30 is equivalent to 30CrNiMo8 (EN 10083-3 and DIN 17200), Werkstoff number 1.6580, 30CND8 or 30NCD8 (AFNOR NF A 35-552), SNCM431 (JIS), 30Cr2Ni2Mo (GB) and 31CrNiMo8 (ISO 683). It is frequently cross-referenced to AISI 4340, but that comparison is approximate only. **Table 1. 823M30 international cross-reference** | Standard / country | Designation | Relationship | |---|---|---| | BS 970 (UK) | 823M30 | Base designation | | EN 10083-3 / DIN 17200 (Europe) | 30CrNiMo8 | Identical chemistry | | Werkstoff number | 1.6580 | Identical chemistry | | AFNOR NF A 35-552 (France) | 30CND8 / 30NCD8 | Identical chemistry | | JIS (Japan) | SNCM431 | Nearest equivalent | | GB (China) | 30Cr2Ni2Mo | Identical chemistry | | ISO 683 | 31CrNiMo8 | Nearest equivalent | | UNI (Italy) | 30NiCrMo8 / 30CrNiMo8 | Nearest equivalent | | PN (Poland) | 30H2N2M | Nearest equivalent | | SS (Sweden) | 2534 | Nearest equivalent | | AISI / SAE (USA) | 4340 / 4337 | Approximate only, see note below | Table compiled by Jiangyin Jiangnan Metal Co., Ltd. from published national standards. Cross-references indicate the closest known equivalent grade and are not a statement of interchangeability. ### Why 823M30 is not a drop-in replacement for AISI 4340 Many cross-reference tables list 823M30 against AISI 4340, and buyers sometimes quote the two interchangeably. The chemistry should be checked before that substitution is accepted. AISI 4340 contains approximately 0.70 to 0.90 % chromium and 0.20 to 0.30 % molybdenum, while 823M30 contains 1.80 to 2.20 % chromium and 0.30 to 0.50 % molybdenum, so the chromium content is more than double. Carbon also differs, at approximately 0.40 % for 4340 against 0.30 % for 823M30. In practice 823M30 hardens deeper and shows better resistance to temper embrittlement, while 4340 reaches a higher peak hardness. On a lightly loaded part the substitution is often acceptable. On a rotating part supported by a fatigue life calculation it usually is not. Jiangyin Jiangnan Metal forges to whichever designation the drawing names and issues a material certificate listing every specification the heat satisfies. Substitution between these two grades should be approved by the design authority before the order is placed. --- ## Chemical composition of 823M30 The table below is the specification range Jiangyin Jiangnan Metal forges to. Every heat is supplied with a ladle analysis on the mill certificate; a product analysis taken from the forging itself can be added on request. **Table 2. 823M30 / 30CrNiMo8 / 1.6580 chemical composition, weight percent** | Element | Symbol | Weight % | Function in this steel | |---|---|---|---| | Carbon | C | 0.26–0.34 | Sets attainable hardness and strength after quenching | | Silicon | Si | 0.40 max | Deoxidation; raises tempering resistance | | Manganese | Mn | 0.50–0.80 | Hardenability; combines residual sulphur | | Chromium | Cr | 1.80–2.20 | Principal hardenability addition; carbide former | | Nickel | Ni | 1.80–2.20 | Toughness, particularly at low temperature; hardenability | | Molybdenum | Mo | 0.30–0.50 | Deep hardening; suppresses temper embrittlement | | Phosphorus | P | 0.025 max | Impurity limit, promotes temper embrittlement | | Sulphur | S | 0.035 max | Impurity limit, reduces transverse ductility | | Copper | Cu | 0.40 max | Residual from scrap | | Iron | Fe | Balance | Matrix | Source: Jiangyin Jiangnan Metal Co., Ltd., 823M30 forging specification, consistent with BS 970-3 and EN 10083-3. Tighter residual limits, including a reduced phosphorus maximum for sour or low-temperature service, can be agreed at order. Melting practice is stated on the enquiry. Electric arc furnace steel with vacuum oxygen decarburisation (EAF + VOD) is standard. Electroslag remelted (ESR) stock is used where the drawing calls for improved cleanliness and reduced segregation, normally on rotating parts, large discs and components subject to a demanding ultrasonic acceptance class. --- ## Mechanical properties of 823M30 in the quenched and tempered condition Quenched and tempered 823M30 develops a 0.2 % proof strength of at least 1050 MPa and a tensile strength of 1250 to 1450 MPa in ruling sections up to 40 mm. Properties fall as section size rises: 900 MPa proof and 1100 to 1300 MPa tensile at 40 to 100 mm, 800 and 1000 to 1200 MPa at 100 to 160 mm, and 700 and 900 to 1100 MPa at 160 to 250 mm. State your ruling section on the enquiry, because it determines which row applies. **Table 3. 823M30 / 30CrNiMo8 mechanical minima, quenched and tempered (+QT), room temperature** | Ruling section | Rp0.2 min | Rm | A min | Z min | KV min | |---|---|---|---|---|---| | d ≤ 16 mm | 1050 MPa | 1250–1450 MPa | 9 % | 40 % | not specified | | 16 < d ≤ 40 mm | 1050 MPa | 1250–1450 MPa | 9 % | 40 % | 30 J | | 40 < d ≤ 100 mm | 900 MPa | 1100–1300 MPa | 10 % | 45 % | 35 J | | 100 < d ≤ 160 mm | 800 MPa | 1000–1200 MPa | 11 % | 50 % | 45 J | | 160 < d ≤ 250 mm | 700 MPa | 900–1100 MPa | 12 % | 50 % | 45 J | Source: Jiangyin Jiangnan Metal Co., Ltd., compiled from EN 10083-3 for the equivalent grade 30CrNiMo8 in the +QT condition. Rp0.2 = 0.2 % proof strength; Rm = tensile strength; A = elongation; Z = reduction of area; KV = Charpy V-notch impact energy. Test pieces are taken from integral or separately forged prolongations. Certified results are typically 5 to 10 % above these minima. **Table 4. 823M30 hardness by delivery condition** | Condition | Code | Hardness | Notes | |---|---|---|---| | Soft annealed | +A | 248 HB max | Supply condition for customers doing their own heat treatment | | Normalised | +N | Typically 220–280 HB | Grain refinement after forging; intermediate condition | | Quenched and tempered | +QT | Up to approx. 41 HRC | Hardness set by tempering temperature, see Table 6 | | Stress relieved | +SR | Unchanged | After rough machining, 50 °C below tempering temperature | Source: Jiangyin Jiangnan Metal Co., Ltd. Delivery condition is stated on the order and recorded on the mill certificate. Ruling section governs which values apply. A tensile figure of 1250 MPa quoted from a datasheet applies to a 40 mm test piece and not to a 600 mm diameter rotor, and referring to the wrong row is a frequent cause of dispute on this grade. Test position affects the result as well. Unless the drawing states otherwise, longitudinal test pieces are taken from the core for diameters up to 25 mm, and from a point 12.5 mm below the surface on larger sections. Where a specification requires mid-radius or centre-line testing on a heavy forging, this should be stated at enquiry, since it affects both the achievable minima and the price. --- ## Physical and thermal properties **Table 5. 823M30 / 1.6580 physical and thermal data** | Property | Metric | Imperial | |---|---|---| | Density | 7.76 g/cm³ | 0.280 lb/in³ | | Modulus of elasticity, 20 °C | 210 GPa | 30 500 ksi | | Thermal conductivity, 20 °C | 38.0 W/m·K | 264 BTU·in/hr·ft²·°F | | Specific heat capacity, 20 °C | 430 J/kg·K | 0.103 BTU/lb·°F | | Electrical resistivity, 20 °C | 0.19 Ω·mm²/m | 0.19 µΩ·m | | Poisson's ratio | 0.30 | 0.30 | | Magnetic response | Ferromagnetic | Ferromagnetic | | Lowest recommended working temperature | −40 °C | −40 °F | Source: Jiangyin Jiangnan Metal Co., Ltd., consolidated from published 30CrNiMo8 / 1.6580 datasheets. Values are for the quenched and tempered condition at room temperature unless stated. Use 7.76 g/cm³ when estimating forging weight. A rolled ring of 900 mm OD, 700 mm ID and 200 mm height contains about 0.050 m³ of steel, so approximately 390 kg finished, before machining allowance is added. Send the finished dimensions and we will return the rough forging weight that the quotation is based on. --- ## Heat treatment of 823M30 forgings Forging stock is heated to 1050 to 1150 °C and forging is finished above 850 °C, then cooled slowly in the furnace or in sand, because this grade cracks readily if cooled fast from the forging heat. Normalising is 850 to 880 °C, air cool. Soft annealing is 650 to 700 °C with furnace cooling at about 10 °C per hour, giving 248 HB maximum. Hardening is from 830 to 860 °C with an oil or polymer quench, followed immediately by tempering at 540 to 680 °C and air cooling. **Table 6. Heat-treatment and forging windows for 823M30** | Operation | Code | Temperature | Cooling | Notes | |---|---|---|---|---| | Heating for forging | not applicable | 1050–1150 °C | not applicable | Soak to a uniform through-temperature before the first blow | | Finish forging | not applicable | above 850 °C | Furnace or sand, slow | Reheat if the piece drops below 850 °C; fast cooling causes cracks | | Normalising | +N | 850–880 °C | Air | Refines forged grain; tempering may follow on heavy sections | | Soft annealing | +A | 650–700 °C | Furnace, approx. 10 °C/h | For machining or customer heat treatment; 248 HB max | | Hardening | +Q | 830–860 °C | Oil or polymer quench | 840–850 °C with water quench on selected sections | | Tempering | +T | 540–680 °C | Air | Start immediately after quenching to avoid quench cracks | | Stress relieving | +SR | 50 °C below tempering | Furnace to 300 °C, then air | After rough machining, to release machining stresses | Source: Jiangyin Jiangnan Metal Co., Ltd. Calibrated furnaces with recorded time and temperature charts for the whole load; charts are issued with the mill certificate. ### Selecting the tempering temperature Tempering temperature controls the delivered strength and should be stated on the drawing wherever the application allows it. Tempering at the low end of the range, near 540 °C, retains the most strength and gives the highest hardness. Tempering near 660 to 680 °C reduces strength in exchange for impact toughness, and is the usual choice for heavy sections and for parts carrying a low temperature Charpy requirement. One point applies to this family of steels in particular. Extended holding in the 350 to 550 °C range should be avoided where practicable, and cooling through that range after the high temper should not be unduly slow. The molybdenum content is present to resist temper embrittlement, but on very heavy forgings the centre cools slowly through that range regardless of the furnace setting, so the step cooling and impact testing regime should be agreed with us before the order is placed. If the drawing specifies a target hardness or a tensile band instead of a tempering temperature, send that band and the ruling section, and our metallurgical team will set the cycle to meet it and record the actual temperature on the certificate. --- ## 823M30 compared with 817M40 and 42CrMo4 These three grades cover most heavy through-hardening forging work and are routinely compared against one another at enquiry stage. 42CrMo4 is the general purpose grade and the least expensive. 817M40 adds nickel for improved toughness. 823M30 carries the highest alloy content of the three and is used for the heaviest sections. **Table 7. 823M30 compared with 817M40 and 42CrMo4** | Attribute | 823M30 | 817M40 | 42CrMo4 | |---|---|---|---| | EN designation | 30CrNiMo8 | 34CrNiMo6 | 42CrMo4 | | Werkstoff number | 1.6580 | 1.6582 | 1.7225 | | Carbon | 0.26–0.34 % | 0.30–0.38 % | 0.38–0.45 % | | Chromium | 1.80–2.20 % | 1.30–1.70 % | 0.90–1.20 % | | Nickel | 1.80–2.20 % | 1.30–1.70 % | none specified | | Molybdenum | 0.30–0.50 % | 0.15–0.30 % | 0.15–0.30 % | | Hardenability | Highest of the three | High | Moderate | | Practical +QT section | to 250 mm | to 250 mm | to 160 mm | | Low-temperature toughness | Best | Good | Moderate | | Weldability | Difficult | Difficult | Difficult, but most tolerant | | Relative cost | Highest | Medium | Lowest | | Typical use | Very heavy rotors, rings, rotating shafts | General heavy shafts, gears, couplings | General shafts, pinions, flanges | Table compiled by Jiangyin Jiangnan Metal Co., Ltd. from published national standards. 823M30 is the correct choice where the ruling section is large enough that a lower alloy grade would not harden to the core, where the part is rotating and fatigue critical, or where a low temperature impact requirement has to be met in a heavy section. Below approximately 100 mm the additional alloy content rarely justifies its cost, and 42CrMo4 or 817M40 will normally meet the specification at a lower price. --- ## How Jiangyin Jiangnan Metal forges 823M30 The route below runs on every 823M30 order. Each stage produces a record that goes into the documentation pack shipped with the forging. 1. **Billet sourcing and melt route.** Ingot or billet is bought against documented EAF + VOD practice as standard, or ESR where the drawing calls for improved cleanliness and reduced centre segregation. Mill certificates for the incoming stock are retained and referenced on the final certificate. 2. **Billet preparation and soak.** Surfaces are conditioned to remove seams and decarburised skin, then the billet is soaked to a uniform through-temperature of 1050 to 1150 °C. Insufficiently soaked alloy steel will crack on the first blow, and on this grade such cracks penetrate deeply. 3. **Open-die forging, finishing above 850 °C.** Forged on 1, 3, 5 and 9 tonne hammers and a 5000 tonne hydraulic press, with controlled reduction ratios and reheats. Grain flow is directed along the hoop for rings and along the axis for shafts. Material that falls below 850 °C is returned to the furnace before forging continues. 4. **Ring rolling or upsetting to shape.** Seamless rings are pierced and rolled to the finished envelope; discs are upset and punched. Both routes give continuous grain flow with no cut fibres at the bore. 5. **Slow cool and normalise.** Forgings are cooled in the furnace or buried in sand, and not in still air on heavy sections, then normalised at 850 to 880 °C to refine the forged grain structure before hardening. 6. **Quench and temper.** Austenitised at 830 to 860 °C, quenched into oil or polymer, and tempered at 540 to 680 °C to the strength band on the drawing. Tempering starts immediately after the quench. Time and temperature charts are recorded for the whole furnace load. 7. **Rough or finish machining.** Supplied as-forged, rough machined to an agreed allowance, or finish machined to drawing tolerance. A stress relief 50 °C below the tempering temperature is inserted after rough machining where dimensional stability matters. 8. **Non-destructive and mechanical testing.** Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388. Magnetic particle or penetrant inspection as specified. Tensile, impact and hardness testing from integral or separately forged prolongations. 9. **Marking, certification and packing.** Hard stamped heat number and part identification, an EN 10204 3.1 certificate, or 3.2 counter-signed by a third party such as TUV, BV, SGS or Lloyd's Register, followed by seaworthy packing for export. --- ## 823M30 forged forms and size capability All parts are made to customer drawing or dimensional sketch. There is no fixed catalogue and no stock list. The range below covers what Jiangyin Jiangnan Metal forges regularly in 823M30 and its equivalent designations. **Table 8. 823M30 product forms and size range** | Forged form | Size range | Common uses in this grade | |---|---|---| | Seamless rolled rings | OD 200–4000 mm, H to 1000 mm | Gear rims, bearing races, spacer and casing rings, flange blanks | | Forged discs | Dia. 150–2500 mm | Rotor and turbine discs, blind flanges, tube sheets | | Forged shafts and spindles | Dia. 80–1200 mm, L to 8000 mm | Propeller and transmission shafts, drive spindles, stub shafts | | Round bars | Dia. 20–800 mm | Machining stock, valve stems, heavy fasteners, pins | | Forged flanges | DN 15–1500, ASME B16.5 / B16.47 / EN 1092-1 | Pressure vessels, piping, exchangers | | Sleeves, bushings, hollow bars | OD 100–1200 mm | Bearing housings, wear sleeves, liners | | Forged blocks and rectangles | to 800 × 1500 mm section | Valve bodies, die blocks, manifolds | | Tube sheets and nozzles | Dia. to 3000 mm | Shell and tube heat exchangers, pressure vessels | | Crankshafts and eccentric shafts | to 6000 mm long | Compressors, presses, crushers, mill drives | | Single-piece weight | 10 kg to 15 000 kg | Heavier pieces quoted case by case | Source: Jiangyin Jiangnan Metal Co., Ltd. Equipment: 1, 3, 5 and 9 tonne open-die forging hammers and a 5000 tonne hydraulic press, with ring rolling, heat treatment, machining and testing on site. Delivery conditions: as-forged, normalised, quenched and tempered, rough machined or finish machined. --- ## Where 823M30 forgings are used 823M30 is specified where a large section has to carry a high load, withstand reversed stress and retain toughness. The typical application is a rotating or pressure containing part that could not be made from a lower alloy grade without increasing the section size. **Power transmission and rotating machinery.** The largest single application. Deep hardenability allows a heavy shaft to reach its specified strength at the core, which is where fatigue cracks normally initiate. Transmission shafts, propeller shafts, drive and steering axles, gear blanks, pinions, forged gears, couplings, spindles. **Turbines, compressors and gearboxes.** Rotors, discs and rolled rings for steam and gas turbines, industrial air compressors, nitrogen generators and heavy gearboxes. Rotor discs, turbine shafts, forged rings, spacer rings, casing rings, compressor shafts. **Pressure vessels and heat exchangers.** Forged flanges, tube sheets and nozzles for shell and tube exchangers, air receivers, columns, towers, silos and preheaters. Forged flanges, tube sheets, nozzles, shell rings, heads, forged pipes, forged tubes. **Valves and flow control.** Pressure-containing and stem components for ball, gate, globe, check and plug valves, and for strainers. Valve bodies, bonnets, seat rings, valve stems, valve blocks, hubs. **Oil, gas and offshore.** Subsea and deepwater production hardware, wellhead and Christmas tree components, and drilling equipment where impact toughness is specified down to −40 °C. Connectors, blocks, mandrels, bushings, sleeves, hollow bars, crossovers. **Heavy plant, mining and mills.** Crusher and mill components, cement, sugar and concrete mill drives, mixers, and mill rolls where wear and shock load run together. Crankshafts, eccentric shafts, forged rolls, forged wheels, pinion shafts, manifolds. **Marine, chemical and process industry.** Shipbuilding, pulp and paper, pharmaceutical and biochemical plant, covering chemical pumps, plunger pumps, process modules and crystalliser equipment. Pump shafts, plungers, forged discs, forged bars, rudder stocks, process modules. **Fasteners and structural connections.** High-strength bolting stock and heavily loaded connecting elements, where the grade is used for its combination of strength and notch toughness. Bolting stock, studs, connecting rods, tie rods, pins, clevises. --- ## Testing, inspection and certification Every 823M30 forging is shipped with a documentation pack. Its content is agreed before production starts. - **Chemical analysis:** ladle analysis on every heat; product analysis taken from the forging on request. - **Mechanical testing:** tensile, 0.2 % proof, elongation, reduction of area, Charpy V-notch impact and hardness, taken from integral or separately forged prolongations at the test position the drawing specifies. - **Ultrasonic testing:** to EN 10228-3, SEP 1921 class C, D or E, ASTM A388, or a customer-specified acceptance class. - **Surface NDT:** magnetic particle to ASTM E709 (this grade is ferromagnetic, so magnetic particle inspection is normally suitable), or liquid penetrant to ASTM E165. - **Grain size and microstructure:** to ASTM E112, with photomicrographs where the order calls for them. - **Jominy end-quench hardenability test:** available where the drawing specifies a hardenability band rather than a composition. - **Dimensional report:** against the drawing, including machining allowance where supplied rough machined. - **Certification:** EN 10204 3.1 as standard, or 3.2 witnessed and counter-signed by TUV, BV, SGS, Lloyd's Register or your own inspector. - **Additional documentation:** NACE MR0175 / ISO 15156 hardness records and PED 2014/68/EU documentation where the end use requires it. In-house equipment includes a universal testing machine, impact testing machine, hardness testers, magnetic particle flaw detector, ultrasonic flaw detection and a metallographic microscope. Third-party inspectors and customer QA representatives are welcome at the works, and witnessing any production stage, including chemistry, forging, heat-treatment cycles, mechanical testing and NDE, is arranged at no charge. The same material is shipped under the designations 30CrNiMo8, 1.6580, 30CND8, 30NCD8, SNCM431 and 30Cr2Ni2Mo where a specification calls the grade by a different name. The certificate lists every specification the heat satisfies. --- ## How to request an 823M30 quotation Send a drawing or a dimensional sketch to sales@steelforgepieces.com. Quotations are normally returned within one working day when the following points are supplied. 1. **Grade and standard:** 823M30, 30CrNiMo8 or 1.6580, and which specification governs: BS 970-3, EN 10083-3, EN 10250-3 or your own drawing. 2. **Product form:** ring, disc, shaft, bar, flange, sleeve, block or custom shape. 3. **Dimensions:** OD, ID and height for rings; diameter and length for bars and shafts; plus an estimated finished weight. 4. **Ruling section:** the governing thickness, because it determines which row of Table 3 applies. 5. **Delivery condition:** as-forged, normalised, quenched and tempered, rough machined or finish machined. 6. **Mechanical requirement:** target tensile band or hardness range, and any Charpy requirement including test temperature. 7. **Certification:** EN 10204 3.1 or 3.2, and which third party if 3.2. 8. **NDT requirements:** ultrasonic acceptance class, MPI or PT requirements, and any special acceptance criteria. 9. **Quantity and required delivery date.** Lead time for 823M30 forgings is normally 30 to 60 days depending on size, heat-treatment route and machining scope. There is no minimum order quantity, and single prototype pieces are accepted. --- ## Frequently asked questions about 823M30 ### What is 823M30 steel? 823M30 is the British Standard BS 970 designation for a chromium-nickel-molybdenum quenched and tempered alloy steel containing 0.26 to 0.34 percent carbon, 1.80 to 2.20 percent chromium, 1.80 to 2.20 percent nickel and 0.30 to 0.50 percent molybdenum. It is the same chemistry as the European grade 30CrNiMo8, Werkstoff number 1.6580. The combination of chromium, nickel and molybdenum gives very deep hardenability, so large forged sections can be through-hardened to a uniform strength and toughness. ### What is 823M30 equivalent to? 823M30 is equivalent to 30CrNiMo8 under EN 10083-3 and DIN 17200, to Werkstoff number 1.6580, to 30CND8 or 30NCD8 under AFNOR NF A 35-552, to SNCM431 under JIS, to 30Cr2Ni2Mo under Chinese GB, and to 31CrNiMo8 under ISO 683. It is often cross-referenced to AISI 4340 or 4337, but that comparison is approximate only: 823M30 carries roughly twice the chromium and molybdenum of 4340, so the two are not interchangeable without approval from the design authority. ### What is the chemical composition of 823M30? The specification range Jiangyin Jiangnan Metal Co., Ltd. forges to is carbon 0.26 to 0.34 percent, silicon 0.40 percent maximum, manganese 0.50 to 0.80 percent, phosphorus 0.025 percent maximum, sulphur 0.035 percent maximum, chromium 1.80 to 2.20 percent, nickel 1.80 to 2.20 percent, molybdenum 0.30 to 0.50 percent and copper 0.40 percent maximum, with iron as the balance. Every heat is supplied with a ladle analysis on the mill certificate, and a product analysis can be added on request. ### What are the mechanical properties of 823M30 in the quenched and tempered condition? In the quenched and tempered condition to EN 10083-3, 823M30 develops a 0.2 percent proof strength of at least 1050 MPa and a tensile strength of 1250 to 1450 MPa in ruling sections up to 40 mm. From 40 to 100 mm the minima are 900 MPa proof and 1100 to 1300 MPa tensile. From 100 to 160 mm they are 800 MPa proof and 1000 to 1200 MPa tensile. From 160 to 250 mm they are 700 MPa proof and 900 to 1100 MPa tensile. Elongation rises from 9 percent to 12 percent as section size increases. Because properties fall with ruling section, the section size must be stated on the enquiry. ### What is the correct heat treatment for 823M30 forgings? Forging stock is heated to 1050 to 1150 degrees Celsius and forging is finished above 850 degrees Celsius, followed by slow cooling in the furnace or in sand, because this grade is sensitive to cooling cracks. Normalising is carried out at 850 to 880 degrees Celsius with air cooling. Soft annealing is 650 to 700 degrees Celsius with furnace cooling at about 10 degrees Celsius per hour, giving a maximum of 248 HB. Hardening is from 830 to 860 degrees Celsius with an oil or polymer quench, and tempering follows immediately at 540 to 680 degrees Celsius with air cooling. Stress relieving is carried out about 50 degrees Celsius below the tempering temperature. ### Is 823M30 weldable? 823M30 is difficult to weld and is not recommended for welded structures. The carbon and alloy content give a high carbon equivalent, so the heat-affected zone hardens and is prone to cold cracking. Where welding cannot be avoided, preheat, a low-hydrogen process, controlled interpass temperature and a post-weld heat treatment below the tempering temperature are all required, and the welding procedure should be qualified for the specific section. Components are normally used in the quenched and tempered condition as a single forged piece instead. ### What is the density of 823M30? The density of 823M30, also known as 30CrNiMo8 and 1.6580, is 7.76 grams per cubic centimetre, or about 0.280 pounds per cubic inch. Its modulus of elasticity is about 210 GPa, thermal conductivity at 20 degrees Celsius is about 38 watts per metre kelvin, and specific heat capacity at 20 degrees Celsius is about 430 joules per kilogram kelvin. ### What forged shapes can be made in 823M30? Jiangyin Jiangnan Metal Co., Ltd. produces 823M30 as seamless rolled rings with outside diameters from 200 to 4000 mm, forged discs from 150 to 2500 mm diameter, shafts and spindles from 80 to 1200 mm diameter and up to 8000 mm long, round bars from 20 to 800 mm diameter, forged flanges, sleeves, bushings, hollow bars, blocks, tube sheets, gear blanks and crankshafts, in single-piece weights from 10 kg to 15 000 kg. All parts are made to customer drawing; there is no fixed catalogue. ### What is 823M30 used for? 823M30 is used where a large section has to carry a high load and stay tough. Typical parts are heavy-duty transmission and propeller shafts, drive and steering axles, crankshafts, connecting rods, turbine and compressor rotors, gear blanks and pinions, rolled rings and spacers, pressure-vessel flanges and tube sheets, valve bodies and seat rings, wellhead and Christmas tree components, mill rolls, and heavy fasteners. Its lowest recommended working temperature is about minus 40 degrees Celsius. ### Which standards cover 823M30 forgings? The designation 823M30 comes from BS 970 Part 3. The identical chemistry is specified as 30CrNiMo8 in EN 10083-3, which covers steels for quenching and tempering. For forgings specifically the governing standard is EN 10250-3, open die steel forgings for general engineering purposes, part 3 alloy special steels. Ultrasonic acceptance is normally to EN 10228-3, SEP 1921 or ASTM A388, and certification to EN 10204 3.1 or 3.2. ### What is the difference between 823M30 and 817M40? Both are British Standard chromium-nickel-molybdenum through-hardening steels, but 817M40, equivalent to 34CrNiMo6 and 1.6582, contains about 0.40 percent carbon with 1.30 to 1.70 percent chromium and 1.30 to 1.70 percent nickel, while 823M30 contains about 0.30 percent carbon with 1.80 to 2.20 percent chromium and 1.80 to 2.20 percent nickel. The higher alloy content of 823M30 gives deeper hardenability, so it holds its properties better in very heavy sections, while its lower carbon gives slightly better toughness and a slightly lower attainable peak hardness. 817M40 is the more widely stocked of the two. ### Who supplies 823M30 open-die forgings in China? Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China, producing 823M30 forged rings, discs, shafts, flanges and bars to drawing. Enquiries go to sales@steelforgepieces.com or 0086-189-2135-9659. Jiangyin sits in the Yangtze River Delta within about two hours of Shanghai port, which keeps export logistics short for heavy forgings. ### What certificates are supplied with 823M30 forgings? EN 10204 3.1 mill test certificates are standard and cover chemical analysis, mechanical test results, heat-treatment charts, non-destructive test reports and dimensional records. EN 10204 3.2 certificates counter-signed by TUV, BV, SGS or Lloyd's Register are available on request. Ultrasonic testing is reported to EN 10228-3, SEP 1921 class C, D or E, or ASTM A388, to whichever acceptance class the order specifies. ### Is there a minimum order quantity for 823M30 forgings? There is no fixed minimum order quantity and single prototype pieces are accepted, although the price per piece falls with quantity because tooling, set-up and furnace charges are shared across the batch. Lead time for 823M30 forgings is normally 30 to 60 days depending on size, heat-treatment route and machining scope. --- ## About the manufacturer Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China. The works produces forged rings, seamless rolled rings, discs, shafts, flanges, bars, sleeves and bushings in carbon steel, alloy steel, tool steel, stainless steel and nickel-based superalloys. Raw material handling, forging, heat treatment, machining, testing and inspection are all on one site. The company employs approximately 460 people, including 9 senior engineers and 32 intermediate engineers. Work is made to customer drawing and certified to EN 10204 3.1 or 3.2. | | | |---|---| | Company | Jiangyin Jiangnan Metal Co., Ltd. | | Address | No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China | | Telephone | 0086-189-2135-9659 | | Email | sales@steelforgepieces.com | | Website | https://www.steelforgepieces.com/ | | Business | Open-die forging, ring rolling, heat treatment, machining, testing | ### Data source and citation The technical data on this page is published by Jiangyin Jiangnan Metal Co., Ltd. and may be quoted, reproduced or cited with attribution. Suggested citation: > Jiangyin Jiangnan Metal Co., Ltd. *823M30 Forgings: 30CrNiMo8 / 1.6580 Technical Datasheet.* Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Alloy-Steel/823M30.html ### Related alloy steel grades we forge - [30CrNiMo8](https://www.steelforgepieces.com/Alloy-Steel/30CrNiMo8.html): the EN designation for this same steel - [1.6580](https://www.steelforgepieces.com/Alloy-Steel/1.6580.html): the Werkstoff number for this same steel - [30CND8](https://www.steelforgepieces.com/Alloy-Steel/30CND8.html): the AFNOR designation for this same steel - [817M40](https://www.steelforgepieces.com/Alloy-Steel/817M40.html) and [34CrNiMo6](https://www.steelforgepieces.com/Alloy-Steel/34CrNiMo6.html): lower-alloy Cr-Ni-Mo alternative - [42CrMo4](https://www.steelforgepieces.com/Alloy-Steel/42CrMo4.html), [AISI 4140](https://www.steelforgepieces.com/Alloy-Steel/AISI-4140.html), [708M40](https://www.steelforgepieces.com/Alloy-Steel/708M40.html), [SCM440](https://www.steelforgepieces.com/Alloy-Steel/SCM440.html) - [AISI 4340](https://www.steelforgepieces.com/Alloy-Steel/AISI-4340.html), [40NiCrMo6](https://www.steelforgepieces.com/Alloy-Steel/40NiCrMo6.html), [34CrNiMo6V](https://www.steelforgepieces.com/Alloy-Steel/34CRNIMO6V.html) - [18CrNiMo7-6](https://www.steelforgepieces.com/Alloy-Steel/18CrNiMo7-6.html), [17CrNiMo6](https://www.steelforgepieces.com/Alloy-Steel/17CrNiMo6.html), [822M17](https://www.steelforgepieces.com/Alloy-Steel/822M17.html): case-hardening gear grades - [All alloy steel grades we forge](https://www.steelforgepieces.com/Alloy-Steel/) --- Published 18 May 2016. Last updated 12 September 2026. Reviewed by the metallurgical engineering team, Jiangyin Jiangnan Metal Co., Ltd. © 2026 Jiangyin Jiangnan Metal Co., Ltd. All rights reserved. 823M30 is a designation of BS 970; 30CrNiMo8 and 1.6580 are designations of EN 10083-3 and the Stahl-Eisen-Liste, used here only to identify the steel grade.