Jiangyin Jiangnan Metal Co., Ltd.
20Mn5 open-die forgings
Material number 1.1133, manganese engineering steel, normalized (+N)
20Mn5 (material number 1.1133, also written 20M5) is a manganese alloyed engineering steel containing 0.17 to 0.23 % carbon and 1.0 to 1.5 % manganese. In the normalized condition it reaches a tensile strength of 530 MPa in sections up to 100 mm, falling to 490 MPa at 750 mm, with 55 J of impact energy at +20 °C. The grade is used for forgings that need toughness and good weldability at moderate strength.
Jiangyin Jiangnan Metal Co., Ltd. forges 20Mn5 to customer drawing at its works in Jiangyin, Jiangsu, China, as bars, seamless rolled rings, hollow bars, discs, blocks and gear shafts, released with an EN 10204 3.1 certificate.
- Grade
- 20Mn5
- Material no.
- 1.1133
- Also called
- 20M5
- Steel group
- Manganese engineering steel
- Condition
- +N (normalized)
- Section range
- to 750 mm
- Rm (≤100 mm)
- 530 MPa
- Re (≤100 mm)
- 300 MPa
- KV at +20 °C
- 55 J
- Certificate
- EN 10204 3.1 / 3.2
Key facts about 20Mn5 (1.1133)
- 20Mn5 carries the material number 1.1133 and the French designation 20M5.
- Its composition is 0.17 to 0.23 % C and 1.0 to 1.5 % Mn, with Cr + Mo + Ni held below 0.63 %.
- Normalized tensile strength is 530 MPa to 100 mm section and 490 MPa at 500 to 750 mm.
- Minimum elongation is 22 % longitudinal and 20 % transverse; reduction of area is 55 %.
- Impact energy is 55 J (KV) at +20 °C in the normalized condition.
- The grade is weldable, and the low carbon content also allows carburizing for gear applications.
- Jiangyin Jiangnan Metal Co., Ltd. produces 20Mn5 open-die forgings in Jiangyin, Jiangsu Province, China.
Chemical composition of 20Mn5
The heat analysis limits below apply to 20Mn5 forgings supplied by Jiangyin Jiangnan Metal. The balance is iron with residual elements. Product analysis tolerances apply per the ordering standard.
| C | Si | Mn | Ni | P | S | Cr | Mo | Al | Combined |
|---|---|---|---|---|---|---|---|---|---|
| 0.17-0.23 | max 0.40 | 1.00-1.50 | max 0.40 | max 0.035 | max 0.035 | max 0.40 | max 0.10 | min 0.020 | Cr+Mo+Ni < 0.63 |
Manganese at 1.0 to 1.5 % raises hardenability and strength without the alloy cost of chromium or molybdenum. The minimum 0.020 % aluminium refines grain size and fixes free nitrogen.
Mechanical properties of 20Mn5
Values are for the normalized (+N) delivery condition, quoted against nominal section thickness. Strength falls as section increases because the cooling rate through the centre of a heavy forging is slower.
| Property | to 100 mm | 100-250 mm | 250-500 mm | 500-750 mm |
|---|---|---|---|---|
| Tensile strength Rm (MPa) | 530 | 520 | 500 | 490 |
| Upper yield strength Re (MPa) | 300 | 280 | 260 | 250 |
| Property | Value | Condition |
|---|---|---|
| Elongation at fracture A, longitudinal | min 22 % | +N |
| Elongation at fracture A, transverse | min 20 % | +N |
| Reduction of area at fracture Z | 55 % | +N |
| Notch impact energy KV | 55 J | +N, tested at +20 °C |
Transverse elongation is set 2 % lower than longitudinal because forging elongates inclusions along the grain flow. State the required test direction on the enquiry where the part is loaded across the grain flow, as with ring segments and flanged hubs.
Physical properties of 20Mn5
Indicative room-temperature values for 20Mn5, typical of low-alloy manganese steels. Use them for design estimates and request measured values where a calculation is safety critical.
| Property | Value | Unit |
|---|---|---|
| Density | 7.85 | g/cm³ |
| Modulus of elasticity | 210 | GPa |
| Thermal conductivity | approx. 48 | W/(m·K) |
| Specific heat capacity | approx. 460 | J/(kg·K) |
| Mean thermal expansion, 20 to 200 °C | approx. 12.1 | 10⁻⁶/K |
| Electrical resistivity | approx. 0.19 | µΩ·m |
Heat treatment of 20Mn5
Typical furnace practice for 20Mn5 forgings. Soak times depend on section, and roughly one hour per 25 mm of ruling section is a common starting point, adjusted to the part and the furnace load.
| Operation | Temperature | Cooling and notes |
|---|---|---|
| Forging | 1100-1250 °C | Finish above 850 °C, then cool slowly in still air or in the furnace for heavy sections |
| Normalizing | 880-920 °C | Air cool. Standard delivery condition (+N) |
| Soft annealing | 650-700 °C | Furnace cool, for improved machinability |
| Stress relieving | 550-650 °C | Slow cool. Used after rough machining or welding |
| Hardening | 870-900 °C | Quench in water or oil according to section and geometry |
| Tempering | 550-660 °C | Air cool, for the quenched and tempered condition (+QT) |
| Carburizing | 880-930 °C | Direct or reheat quench, then temper at 150 to 200 °C for a hard case on a tough core |
20Mn5 is delivered normalized unless the order says otherwise. If the drawing calls for quenched and tempered properties, or for a carburized case depth, state it at enquiry, since it affects the forging allowance and the test piece location.
Welding and machining 20Mn5
20Mn5 is a weldable grade. With carbon capped at 0.23 % and manganese at 1.5 %, the carbon equivalent (CEV, IIW formula) typically falls between 0.41 and 0.52. Welding is routine at that level, although heavy sections need care.
- Preheat of roughly 100 to 200 °C is usual for thick forged sections, rising with restraint and section size.
- Low-hydrogen consumables and dried electrodes reduce the risk of hydrogen-assisted cracking.
- Post-weld stress relief at 550 to 650 °C is normal practice on welded assemblies.
- In the normalized condition the steel machines predictably. A soft anneal at 650 to 700 °C helps where heavy stock removal is planned.
Calculate the CEV from the actual heat analysis on the mill certificate rather than from the specification maxima. The real figure is usually well below the worst case.
20Mn5 equivalent grades
Grades close to 20Mn5 in composition. Limits, test conditions and delivery states differ between standards, so treat these as starting points for a substitution enquiry rather than certified interchangeable materials.
| Country or region | Standard | Designation |
|---|---|---|
| Germany | DIN / EN, Werkstoff-Nr. | 20Mn5, 1.1133 |
| France | AFNOR NF | 20M5 |
| Japan | JIS G4053 | SMn420 |
| United States | SAE / ASTM | SAE 1524 (near 1522) |
| United Kingdom | BS 970 | 150M19 |
| China | GB/T | 20Mn2 |
| Russia | GOST | 20G2 |
Send us the drawing and the governing specification and we will confirm in writing whether a given equivalent can be certified against it before you place the order.
20Mn5 forged forms and size range
Jiangyin Jiangnan Metal supplies 20Mn5 as open-die forgings and seamless rolled rings, rough forged, rough machined or finish machined to drawing. Sizes below are indicative. Send your drawing for confirmation.
| Product form | Indicative size range | Typical use |
|---|---|---|
| Forged round bars and rods | Ø 80-1200 mm, length to 12 000 mm | Shaft and pin blanks |
| Square, rectangular, flat and hex bars | Thickness 40-800 mm, width to 1500 mm | Machined blocks, tooling bases |
| Seamless rolled rings | OD 200-4000 mm, height to 1500 mm | Bearing races, slewing rings, flanges |
| Forged rings and flanges | OD 150-3000 mm | Pressure and structural flanges |
| Hollow bars, sleeves, bushings, cylinders | OD 150-2500 mm, ID from 80 mm | Housings, casings, shells, hubs |
| Discs, blocks and plates | Ø or width to 2500 mm, thickness 30-1000 mm | End covers, tube sheets, die blocks |
| Gear shafts, pinion shafts, spindles | Single piece to 20 t | Gearbox and drive components |
How 20Mn5 forgings are made and inspected
Melting and forging
20Mn5 is supplied from electric arc furnace steel with ladle refining, and vacuum degassing where the specification calls for it. Ingots or continuous cast blooms are upset and drawn on the open-die press to break down the as-cast structure. A forging reduction ratio of at least 3:1 is normal, and a higher ratio is used where the specification sets one.
Heat treatment
Parts are normalized at 880 to 920 °C as standard, with quenching and tempering or carburizing available to order. Furnace charts are recorded and issued with the certificate.
Testing and certification
- Chemical analysis by spectrometer, reported as heat analysis and, on request, product analysis.
- Mechanical testing: tensile, notch impact (Charpy V) and hardness, from prolongations or sacrificial test pieces.
- Ultrasonic examination to EN 10228-3, SEP 1921 or ASTM A388 as specified.
- Magnetic particle or dye penetrant examination on machined surfaces where required.
- Dimensional report against the customer drawing.
- EN 10204 3.1 certificate as standard, 3.2 with third-party witness (TÜV, SGS, BV, Lloyd's Register) to order.
Applications of 20Mn5 forgings
20Mn5 suits parts that are welded into larger fabrications, or that are carburized for wear resistance, where a quenched and tempered alloy steel would exceed the duty required.
- Chain links and lifting components, where toughness matters more than peak strength.
- Gear blanks and pinion shafts intended for carburizing.
- Welded machine frames, hubs and housings in construction and mining equipment.
- Shafts, couplings and spindles in general power transmission.
- Structural forgings for wind energy nacelles and towers.
- Flanges, end covers and cylinders in general pressure and process equipment.
Ordering 20Mn5 forgings
Send a drawing or a sketch with dimensions. To quote accurately we need the finished weight and machining allowance, the delivery condition (+N, +QT or carburized), the governing standard, the test and certificate level, and the quantity.
Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
- Address
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone
- +86 189 2135 9659 (0086-189-2135-9659)
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
- Supplies
- Open-die forgings and seamless rolled rings in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys
20Mn5 questions and answers
What is 20Mn5 steel?
20Mn5 is a manganese alloyed engineering steel with material number 1.1133, containing 0.17 to 0.23 % carbon and 1.0 to 1.5 % manganese. It is normally supplied normalized (+N) and is used for forged bars, rings, shafts and blocks where good toughness and weldability are needed at moderate strength. Jiangyin Jiangnan Metal Co., Ltd. forges 20Mn5 to order in Jiangyin, Jiangsu, China.
What is the material number of 20Mn5?
The material number (Werkstoffnummer) of 20Mn5 is 1.1133. The grade is also written 20M5 in French AFNOR practice. Both designations refer to the same manganese engineering steel.
What is the chemical composition of 20Mn5?
20Mn5 contains C 0.17 to 0.23 %, Si max 0.40 %, Mn 1.00 to 1.50 %, Ni max 0.40 %, P max 0.035 %, S max 0.035 %, Cr max 0.40 %, Mo max 0.10 % and Al min 0.020 %, with combined Cr+Mo+Ni limited to 0.63 %. The balance is iron.
What is the tensile strength of 20Mn5?
In the normalized (+N) condition, 20Mn5 has a tensile strength of 530 MPa for sections up to 100 mm, 520 MPa for 100 to 250 mm, 500 MPa for 250 to 500 mm and 490 MPa for 500 to 750 mm. Upper yield strength over the same ranges is 300, 280, 260 and 250 MPa.
Is 20Mn5 weldable?
Yes. With carbon limited to 0.23 % and a carbon equivalent typically around 0.41 to 0.52, 20Mn5 is regarded as a weldable engineering steel. Preheating of roughly 100 to 200 °C and controlled interpass temperature are usual for heavy forged sections, with post-weld stress relief at 550-650 °C.
What is the equivalent grade of 20Mn5?
The nearest equivalents to 20Mn5 (1.1133) are 20M5 in French AFNOR, SMn420 in JIS G4053, SAE 1524 in the United States, 150M19 in British BS 970 and 20Mn2 in Chinese GB/T. These are close matches on composition, not certified drop-in substitutes, and the ordering standard should always be confirmed.
Can 20Mn5 be case hardened?
Yes. The low carbon content and 1.0 to 1.5 % manganese make 20Mn5 suitable for carburizing at about 880 to 930 °C, followed by direct or reheat quenching and low tempering at 150 to 200 °C. This gives a hard wear-resistant case over a tough core, which suits gear blanks and pinion shafts.
In what forms are 20Mn5 forgings supplied?
Jiangyin Jiangnan Metal Co., Ltd. supplies 20Mn5 as forged round, square, flat and hexagonal bars; seamless rolled rings and forged rings; hollow bars, sleeves, bushings and cylinders; discs, blocks and plates; and gear shafts, pinion shafts and spindles. Parts are supplied rough forged, rough machined or finish machined.
Who supplies 20Mn5 open-die forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, that manufactures 20Mn5 (1.1133) forgings to customer drawing. Enquiries: sales@steelforgepieces.com, telephone +86 189 2135 9659.
What test certificate is issued with 20Mn5 forgings?
20Mn5 forgings are normally released with an EN 10204 3.1 inspection certificate covering heat analysis, mechanical test results and the heat treatment record. An EN 10204 3.2 certificate countersigned by a third party such as TÜV, SGS, BV or Lloyd's Register can be arranged when specified at order.
Standards referenced and how to cite this page
- EN 10250-2, open die steel forgings for general engineering purposes: non-alloy quality and special steels.
- DIN 17115, steels for chains, in which 20Mn5 (1.1133) appears.
- EN 10204, types of inspection document for metallic products.
- EN 10228-3, non-destructive testing of steel forgings, ultrasonic testing of ferritic or martensitic forgings.
- JIS G4053, BS 970, GB/T 3077, GOST 4543, sources for the equivalent designations listed above.
Jiangyin Jiangnan Metal Co., Ltd. (2026). 20Mn5 (1.1133) open-die forgings: composition, mechanical properties and equivalents. https://www.steelforgepieces.com/Alloy-Steel/20Mn5.html
Composition and mechanical property data on this page is compiled by the technical team at
Jiangyin Jiangnan Metal Co., Ltd. from the applicable European standards and from our own mill
certificates.
Values are given in good faith for guidance. The certified values for any specific order
are those on the EN 10204 certificate issued with that consignment.
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