The SOLO solution:

- Gas-carburizinq atmosphere

Gas-carburizing and hardening of camshaftsfor 6 cylinder diesel motors in 16MnCr5 steel.

- Carburizing gas: propaneregulated by atmospherecontrol and supervisionsystem

Exampl e of load

- carrier gas: producedby direct injection ofmethanol into the furnace

- Parameters of time-temperatures-atmospheres, adapted to requirements

- oil quenching at80·C

Problem:

- Weight of one load approx.455 kg net (35 parts)

Requirements: Surface hardness: 58-60 HRCEffective gas-car-burising depth: (E550) 1.5 - 1.6 mm% C at depthof 0.70 mm: 0.75/0.85 % CDistortion: VTC ~O. 50 mm

- Total duration of cycle: 11 hours

- Gas-carburizing/hardening/tempering in a multi-purpose bell-type furnace:SOLO-202-60/60/100

- Loading on supports,suspension of parts

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Surface hardness:

Results

1.50 mm / 1.60 mm

HRC = 60/62 on aIl controlled parts

1 part is taken at random and cut intopieces.

aIl parts are taken between centres andare controlled by comparator

(maximum and minimum values found on 4 loads)

E550:

VTC:

E550:

Carbon profiles:

6 test parts are distributed inthe load as shown on the diagramand are submitted to carboncontrol after heat treatment.

Surface hardness:

5 parts are chosen, one in the centre and the other4 at each corner of the load.Hardness measurements are made on each level.

2. Results:

1. Checkinq methods:

- parameters of quenching-washing-tempering cycles

- time-temperature-atmosphere profiles in gas-carburizing element

- planning and load transfer functions on furnace-line

Computerised management of:

- alarms, diagnostics and protocols

Control and supervision of treatment

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Dispersion carbon profile controlled on 60 samples heat treated in 10 loads

Carbon profiles: surface carbon content: max. 0.82 %Cmin. 0.75 %C

% C at 0,70 mm: max. 0.77 %Cmin. 0.72 %C

% C at 1,6 mm: max. 0.39 %Cmin. 0.37 %C

i !1 11 i

!

1 r- I

111

of surface hardness valuesof carbone profilesof values E550

upon aIl parts <0.50 mm

% Carbone

Advantages of the SOLO method:

VTC:

- a temperature dispersion of max. ± 5°C in the load

Reproducible results at aIl times due to:

The carbon profile curve is included further on.

Small dispersion:

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a rapid atmosphere balance due to a casing made ofheat-resistant steel

- a forced and homogeneous circulation of the atmosphere

- a very precise control of the carbon potential due to themeasurement of partial oxygen (02) pressure by means of a newgeneration of Zirconium probes

an automation of the control and supervision of the processand follow-up of the load, for an accurate reproduction ofthe time-temperature-atmosphere profile and of the transferfunctions

- small distortion values resulting from the possibility ofvarying the quenchant flow supply.

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