1.2842 (90 MnCrV 8)

AISI O2, BS BO2, AFNOR 90 M V 8

Chemical composition % C Si Mn Cr V
0.90 0.20 2.00 0.40 0.10

Cold working tool steel for the manufacture of tools, gauges, jigs, templates, guideways and components of all kinds.

This material can also be obtained from us to your individual specifications as standard material for machine components and hardened guideways under 40 mm thick.

When heat treating, it must be borne in mind that 1.2842 is a through-hardener which undergoes a volume change of approx. 1 ‰ yet exhibits very low-distortion behaviour. Work piece cross-sections over 40 mm thick can result in partial lower hardnesses than 58 - 62 HRc. For larger guideway component cross sections we recommend 1.2363 or the cementing in of hardened ways, for machine parts even1.2379.

It machines well and is not problematic.

Tempering diagram
Hardening temperature: 810°C
Sample cross section: rect. 20 mm

1.2842-1a

Heat treatment diagram

1.2842-1b

Repair welding
There is the danger of fracture during welding work, as is general with tool steels.

TTT diagram for continuous cool down

Microstructure components: 820°C
Dwell time: 15 minutes

Hardness in HV
5...100 Austenitisation temperature in %
0.03...7.18 Cool down parameters, i.e. cooling duration from 800 - 500°C
in seconds x 10 (power -2)
B...Bainite

1.2842-2c

Microstructure mass diagram
B...Bainite

1.2842-2d

Isothermic TTT diagram

Austenitisation temperature: 820°C
Dwell time: 15 minutes

lexi1

Dependence of grain hardness and hardening depth on the work piece diameter
Hardness temperature: 820°C
Hardening medium: oil

lexi2
 

Obtainable as the following products:

 

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1.2842 O 2/BO 2

Cold work tool steel for the manufacture of tools, measuring instruments, devices, templates, guide bars and components of all kind