AR400 quenched and tempered high strength bullet resistant armoured
steel plate
High strength armoured steel
AR400 ARMOURED STEEL is an alloyed, high strength quenched and
tempered steel with a resistance against bullet impacts and the
effects of blast waves. It is preferably used for light weight
armoured vehicles. Due to its performance the steel is used by the
customers for civil and military protection systems.
Product description
Range of application
AR400 ARMOURED STEEL is an alloyed, high strength quenched and
tempered steel, with a hardness range of 380 – 430HBW in the
delivery condition.
AR400 ARMOURED STEEL can be supplied in the following dimensions:
| Thickness | ≥ 6mm ≤ 25mm |
| Width | ≥ 1,000mm ≤ 2,500mm |
| Length | ≥ 3,000mm ≤ 8,000mm |
On request, other dimensions can be agreed.
Chemical composition
For the ladle analysis, the following max. values in % are
applicable:
| C | Si | Mn | P | S | Cr | Ni | Mo |
| 0.32 | 0.50 | 1.20 | 0.015 | 0.005 | 2.00 | 2.00 | 0.70 |
Delivery condition
The plates are delivered in the quenched and tempered condition.
Mechanical and ballistic properties
Hardness
Brinell surface hardness at room temperature: 380 – 430 HBW
Tensile testing on transverse specimens at room temperature
Minimum tensile strength Rm [MPa] | Minimim yield strength ReH [MPa] | Minimum elongation A5 % |
| 1,150 | 950 | 10 |
Charpy-V impact test
AR400 ARMOURED STEEL offers impact energy values KV2 of 27 J at -40
°C (longitudinal and transverse to the rolling direction).
The specified minimum value is the average of 3 tests. Only one
individual value may be below the minimum average value specified,
provided that it is not less than 80 % of that value.
For plate thickness below 12 mm the Charpy-V-notch test can be
carried out on Charpy-V-test pieces with reduced width, the minimum
size of the sample shall not be less than 5 mm. The minimum
specified value decreases proportional to the reduction of the
section.
Properties under ballistic impacts
The properties under ballistic impacts have to be agreed.
Testing and documentation
Determination of the mechanical properties in the delivery
condition per plate as rolled in ¼ plate width in accordance with
ISO 404. The hardness test is carried out in accordance with ISO
6506-1. The tensile test is carried out on flat rectangular,
transverse specimens in accordance with EN ISO 6892-1.
The impact test will be carried out on Charpy-V-longitudinal and
transverse specimens in accordance with EN ISO 148-1.
The test results are documented in a certificate 3.1 in accordance
with EN 10204. A bullet resistance test can be agreed upon.
Identification of plates
Unless otherwise agreed the marking is carried out via perforated
steel stamps with at least the following information:
• steel grade (AR400 ARMOURED STEEL)
• heat number
• number of mother plate and individual plate
• the manufacturer’s symbol
• inspector’s sign
Processing
The entire processing 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 are
suitable for the intended use. The customer is responsible for the
selection of the material. The recommendations in accordance with
EN 1011 should be observed. The much higher tensile properties of
the armoured steel comparing to other steels covered by the
standard can lead to a higher crack probability while processing.
Welding and flame cutting
The heat input during welding and flame cutting can lead to a
decrease in hardness in a small area adjacent to or in the weld
seam. This can have an impact on the bullet resistance properties
of AR400 ARMOURED STEEL. The manufacturer is advised to take this
into account in his design.
Forming
The material can be formed by cold bending, in spite of its high
hardness. It is recommended that the flame cutting or shearing
edges in the area of the bend should be grinded. The bending speed
must be adjusted by the fabricator to the geometry of the processed
parts.
Due to the high strength values of AR400 ARMOURED STEEL in the
quenched and tempered condition the spring-back phenomenon has to
be taken into account while cold forming. During the processing,
the necessary safety measures have to be taken, so that nobody will
be exposed to a danger by a possible fracture of the work piece
during the forming process.
Heat treatment
AR400 ARMOURED STEEL is delivered in a heat treatment condition
which is ready for assembly. Subsequent heat treatment above 200 °C
impairs its ballistic properties and is therefore not permissible.
Machining
AR400 ARMOURED STEEL is suitable for machining. In view of its high
delivery hardness a lower cutting speed must be anticipated.
Tolerances
Unless otherwise agreed the following tolerances apply:
For the thickness in the range of -0 / +0.8 mm, for the width in
the range -0 / +12 mm.
Tolerances for the lengths are as follow, values in mm:
| Length | < 4,000 | ≥ 4,000 < 6,000 | ≥ 6,000 ≤ 8,000 |
| Tolerance | -0 / +10 | -0 / +20 | -0 / +25 |
Unless otherwise agreed, the flatness tolerances will be in
accordance with EN 10029, table 4, steel group H.
Smaller flatness tolerances may be agreed upon request.
Surface quality
Unless otherwise agreed, the indications in accordance with EN
10163-2, class A3, apply. Higher requirements may be agreed upon
request.
Surface protection
Upon request the plates can be shot blasted and / or primer coated
with a product at the manufacturer’s choice.
Ultrasonic testing
Unless otherwise agreed, indications be in accordance with EN
10160, class S2/E2 apply.
Production process
