2378 Durable Hardened CrMnNiMo Alloy Tool Steel Plate , Steel Surface Plate

Product Specification

2378 MOULD STEEL is a prehardened CrMnNiMo-alloyed tool steel for the construction of plastic molds with superior surface requirements on molds. It is characterized by excellent polishability, photoetchability, spark erosion behaviour and dimensional stability as well as good machinability. 2378 MOULD STEEL shows a better through-hardening compared to 2311 mould steel.
 
Product description
Designation and range of application
2378 MOULD STEEL is a modified version of 1.2738 according to Stahl-Eisen-Liste and of 40CrMnNiMo8-6-4 according to EN ISO 4957. 2378 MOULD STEEL differs from 1.2311 and from 40CMD8 according to NF A 35590 by a higher Ni-content of approximate 1 %.
 
2738 MOULD STEEL is available as plate with sheared or flame cut edges in the following dimensions:

(1) Widths < 1250 mm (49 in) have to be ordered with an even number of plates
Other dimensions available upon request.
 
Production
The 2738 MOULD STEEL production route is designed to achieve the excellent properties of this mold steel type with superior surface requirements. 2738 MOULD STEEL is characterized by high dimensional stability. The 2738 MOULD STEEL production route provides excellent polishability, photoetchability and spark erosion properties. Therefore 2738 MOULD STEEL is particularly suitable for molds with superior surface requirements if suitable manufacturing processes are employed.
 
The good sulfidic and oxidic cleanliness and the modification of the few remaining inclusions by the calcium treatment lead to good machinability and minimize the tool wear.
 
These properties can only be achieved by the combination of the following 2738 MOULD STEEL-production steps:
· desulphurization to S ≤ 0.002 % for high sulfidic cleanliness
· chemical analysis in dependence of dimensions
· vacuum degassing
· argon stirring for high sulfidic and oxidic cleanliness
· calcium treatment for inclusion shape control
· special casting conditions to assure the high cleanliness and homogenity
· High Shape Factor Rolling (high thickness reduction) to realize a closely packed structure
· appropriate heat treatment parameters according to analysis and dimensions to assure homogeneous hardness distribution over the plate and to minimize residual stresses
 
Chemical composition

(1) alloyed depending on dimensions
 
Delivery condition
2738 MOULD STEEL is supplied in the prehardened (air hardened + tempered) condition.
 
Mechanical and technological properties in the delivery condition
Hardness
Unless otherwise agreed the hardness at the surface in the delivery condition is 280 - 325 HB. According to EN 18265, table B2, this corresponds to a tensile strength of approximately 890 - 1030 MPa (128 - 148 ksi).
 
Testing
· Heat analysis
· Dimension control
· Surface inspection
· Hardness
The hardness (HB) is tested on surface of each rolled mother plate.
· Ultrasonic testing
Unless otherwise agreed, 100 % ultrasonic testing is performed on each plate in the delivery condition in accordance with EN 10160. As admissible limit applies quality class 4 in table 5 of EN 10228-3.
Upon request, an ultrasonic testing in accordance with ASTM A 578, Level C, supplementary requirements S1 and S9 is possible. In this case the desired testing type has to be indicatd on the order.
 
Unless otherwise agreed, the results are documented in an inspection certificate 3.1 in accordance with EN 10204.
 
Identification of plates
Unless otherwise agreed the marking is carried out via steel stamps with at least the following information:
· steel grade (2738 MOULD STEEL)
· heat number
· number of mother plate and individual plate
· the manufacturer’s symbol
· inspector’s sign
 
Processing
Heat treatment
2738 MOULD STEEL is delivered in the prehardened condition; therefore further heat treatment is generally not necessary. This avoids the risks and costs involved by the hardening and tempering of a mold after processing. Should a heat treatment become necessary, the following data are recommended:

 
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 / ASTM A 6 with the following restrictions:

Unless otherwise agreed, short lengths ≥2 m (79 in) are part of the delivery.
 
Surface quality
Unless otherwise agreed, the specifications will be in accordance with EN 10163-2 class A, subclass 3. Shot blasting of upper and lower surface of the plate and shop priming are possible on request.
 
General note
If special requirements, which are not listed in this specification, are to be met by the steel due to its intended use or processing, these requirements are to be agreed before placing the order.
 
 
Production process