20MnMoNi4-5 is a weldable fine grained steel for higher temperature
service. It is characterised by high 0.2% proof stress at elevated
temperatures. 20MnMoNi4-5 is produced using basic oxygen
steelmaking process. Its properties are achieved by water quenching
and tempering.
20MnMoNi4-5 is applied as plate or formed part for boilers and
pressure vessels operating at temperatures of - 20 °C to 400 °C.
Product description
Range of application
20MnMoNi4-5 pressure vessel steel, Material No. 1.6311, is
standardized in EN 10028, part 2 and approved in accordance with
VdTÜV-material data sheet 440/1 for supervised installations in
thicknesses of 30 up to 250 mm.
Applications:
• Boiler installations in accordance with Technical Rules TRD 101,
EN 12952 etc. for temperatures up to 375 °C.
• Pressure vessel installations in accordance with the AD
2000-Merkblätter series W and HP for temperatures of - 10 °C to 375
°C.
This material data sheet applies to heavy plates with thicknesses
from 30 to 250 mm.
Chemical analysis in %
For the chemical analysis the following limiting values are
applicable, max.:
| C | Si | Mn | P | S | N | Al | Ni | Mo | Cr | Cu | V |
| 0.13-0.25 | 0.10-0.46 | 0.95-1.60 | 0.025 | 0.013 | 0.014 | 0.010-0.055 | 0.35-0.85 | 0.41-0.64 | 0.25 | 0.25 | 0.02 |
Fully killed steel with metallurgical treatment in the ladle and
vacuum degassing on tank degassing unit.
Delivery condition
Unless otherwise agreed: water quenched and tempered
If the heat treatment is to be performed during processing, the
plates can be delivered in the normalized condition, and in
exceptional cases in the as rolled condition by special agreement
before the order. In this case testing of the mechanical properties
is provided on the basis of separately heat treated specimens.
Mechanical properties in the delivery condition (water quenched +
tempered condition)
Tensile test at ambient temperature (transverse test specimens) in
accordance with EN 10002-1
| Plate thickness | Yield strength ReH | Tensile strength Rm | Elongation A5 |
| [mm] | [MPa], minimum | [MPa] | %, minimum |
| ≤ 40 | 470 | 590 - 750 | 18 |
| > 40 ≤ 60 | 460 | 590 - 730 | 18 |
| > 60 ≤ 100 | 450 | 570 - 710 | 18 |
| > 100 ≤ 150 | 440 | 570 - 710 | 18 |
| > 150 ≤ 250 | 400 | 560 - 700 | 18 |
The fulfilment of one of the three quality classes Z15, Z25 or Z35
in accordance with EN 10164 or similar standards can be stipulated
on the order.
Hot tensile test (transverse test specimens) in accordance with EN
10002-5
| Plate thickness | Minimum yield strength Rp0,2 [MPa] at test temperature |
| [mm] | 100 °C | 200 °C | 300 °C | 350 °C | 400 °C |
| ≤ 40 | 448 | 432 | 415 | 402 | 384 |
| > 40 ≤ 60 | 438 | 423 | 406 | 394 | 375 |
| > 60 ≤ 100 | 429 | 413 | 398 | 385 | 367 |
| > 100 ≤ 150 | 419 | 404 | 389 | 377 | 359 |
| > 150 ≤ 250 | 381 | 367 | 353 | 342 | 327 |
Unless otherwise agreed the test is performed at 300 °C.
Impact test with Charpy-V transverse specimens in accordance with
EN 10045-1
| Test temperature in °C | - 20 | 0 | + 20 |
Minimum impact value Av in J: Average/lowest individual value: | 27/19 | 40/28 | 50/35 |
Other test temperatures respectively minimum values can be agreed
upon inquiry.
Testing
Sampling, testing method and tests are in accordance with the
provisions in VdTÜV-material data sheet 440/1.
Unless otherwise agreed the following tests are performed:
| tests | acceptance unit |
• Tensile test at ambient temperature, transverse specimens, acc.
EN 10002-1 • Impact test Charpy-V, transverse specimens, at 0 °C acc. EN
10045-1 | per rolled plate ≤ 15 m at one end, ¼ width > 15 m at both ends, ¼ width |
| • Hot tensile test at elevated temperatures, transverse specimens,
at 300 °C acc. EN 10002-5 | per heat at one end, ¼ width; for orders in accordance with AD 2000
W1 per heat and dimensional range |
| • material identity test per rolled plate | per rolled plate |
| • upon request: product analysis per heat | per heat |
Type/location of specimen:
| Tensile test at ambient temperature | Hot tensile test | Impact test |
| plate thickness 30 mm: flat tensile test specimens with both rolled
surfaces plate thickness > 30 mm: flat tensile test specimens
with at least one rolled surface or cylindrical tensile test
specimens with axis in ¼ plate thickness | plate thickness 30 mm: flat tensile test specimens with both rolled
surfaces plate thickness > 30 mm: cylindrical tensile test
specimens with axis in ¼ plate thickness | Plate thickness ≤ 40 mm: Charpy-V test specimens near surface Plate thickness > 40 mm: Charpy-V test specimens in ¼ plate
thickness |
Sampling, testing method and tests are in accordance with the
provisions in EN 10028 and VdTÜV material data sheet 440/1. The
plates are delivered with inspection certificate 3.1 or 3.2 in
accordance with EN 10204. The document type and, in case of
inspection certificate 3.2, the inspection representative are to be
stated on the order.
Identification of plates
Unless otherwise agreed the marking is carried out via steel stamps
with at least the following information:
• steel grade (DIWA 393 and/or 20MnMoNi45)
• heat number
• number of mother plate and individual plate
• the manufacturer's symbol
• inspectors' sign
Fabrication properties
The entire fabrication and application techniques are of
fundamental importance to the reliability of the products made from
this steel. The user should ensure that his design, construction
and processing methods are aligned with the material, correspond to
the state-of-the-art that the fabricator has to comply with and
suitable for the intended use. The customer is responsible for the
selection of the material. The recommendations in accordance with
EN 1011-2 should be observed.
Forming properties and weldability
20MnMoNi4-5 pressure vessel steel can be hot or cold formed and can
be welded and flame cut according to the general procedures. The
guidelines according to EN 1011 and VdTÜV-material data sheet 440/1
shall be observed. For the fabrication of pressure vessels in
accordance with AD 2000 Merkblatt in the context of PED qualified
welding consumables have to be applied. For other applications the
use of qualified welding consumables is recommended.
Heat treatment
| Quenching and tempering | Stress relieving |
Austenitizing + quenching 870 to 940 °C After temperature achievement over the whole section cooling in
water | Tempering 610 to 690 °C Holding time after temperature achievement over the whole section: 30 min, cooling in still air | 580 - 620 °C |
thickness mm | time 1) min |
30 > 30 ≤ 250 | ≥ 30 ≥ 60 |
- Heating and soaking in the temperature range between 580 and 620
°C. Temperature measurement at the part’s surface.
Generally the maximum stress relieving time shall be restricted to
150 min. If it exceeds 90 min or in case of repeated heat treatment
the lower range of recommended temperatures shall apply. If stress
relieving and tempering are joined together in one process, the
tempering conditions apply.
The stress relieving temperature must not be higher than the
tempering temperature applied at VANFORGE. It should rather be
situated in a sufficient distance of at least 30 °C below the
tempering temperature in order to avoid a decrease of the
mechanical properties. In many cases the stress relieving
temperature during processing is determined by other influencing
factors and therefore can not always be 30 °C below the tempering
temperature applied at VANFORGE. Therefore we recommend to consult
us so that we can check the scheduled stress relieving conditions.
Temperatures and holding times are determined by the steel
manufacturer as a function of the plate thickness and the chemical
composition. In order to preserve the mechanical properties the
fabricator should ensure that the subsequent heat treatments
correspond to those applied by the manufacturer (indicated in the
plate inspection document).
General technical delivery requirements
Unless otherwise agreed, the general technical delivery
requirements in accordance with EN 10021 apply.
Tolerances
Unless otherwise agreed, tolerances are in accordance with EN
10029, with class B for the thickness and class N for the flatness.
Surface condition
Unless otherwise agreed, the provisions in accordance with class B2
of EN 10163 are applicable.
General notes
If special requirements, which are not listed in this material
specification, are to be met by the steel due to its intended use
or processing, these requirements are to be agreed before the
order.
Production process
