W.NR. 1.2738HH

VR400 is a high hard tool steel ideal to produce block with thickness up to 1300mm in large size with an high performance of trough hardening homogeneity. To be used for plastic injection moulds, compression moulds, big sizes moulds for automotive industry with texturing.

VR400 is designed to provide improved performance and offers the following advantages:
• uniform hardness across the full thickness up to 1300mm.
• high polishability.
• high machinability.
• excellent suitability for texturing.
• greatly increased thermal conductivity.
• improved weldability as W W.NR. 1.2738.
• good toughness.

Comparable standards

DIN	W.Nr	JIS
VR400	1.2738 HH	-

Chemical composition (typical; in weight %)

C	Si	Mn	P (max)	S (max)	Cr	Mo	Ni
0.27-0.30	0.03	1.50-1.60	0.010	0.001	1.20-1.40	0.45-0.60	1.05-1.20

Production technology

EAF – LF – VD - Forging – Heat treatment QT

US specification

In according to standard EN10228-3 Class 4 and standard SEP 1921 Class E/e

Delivery condition

VR400 is delivered in quenched and tempered condition, with hardness range 360 - 400 HB (39 - 43 HRC).

Through hardenability

The high performance of hardenability for thickness 1300 mm, is obtained by an optimized balance of chemical composition and a special manufacturing process.

Physical properties (reference values)

	20°C	100°C	250°C	500°C
Thermal expansion coefficient (10-6/K)	11.4	11.6	12.7	14.2
Thermal conductivity (W/mk)	36	36.7	38	34.3
Young modulus (Kn/mm2)	211	207	199	166

Heat treatment

TREATMENT		TEMPERATURE	HOLDING TIME (HT)	COOLING	COMMENTS
Annealing		Heat to 650 - 700 °C	Min. H.T. for 2 minute /mm	Air or furnace	In order to obtain hardness lower than 250 HB ( 24 HRC) to improve machinability
Stress relieving		Heat to 500 - 550 °C	Min. H.T. for 2 minute /mm	Air or furnace	To be carried out after machining, is recommended to eliminate the residual stresses induced by mechanical working
Hardening		Heat to 860-900°C	Min. H.T. for 1 minute /mm	Polymer	-
Tempering		Heat to 550 – 610°C	Min. H.T. for 3 minute /mm	Air or furnace	To be carried out after hardening. 2nd Tempering must be performed to max 30°C below tempering temperature

Texturing performed by Standex Mold-tech with patterns Standex MT 9086, MT 9055 and 9083