THERMISOL 251

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THERMISOL 251

Polymer Quenching Oil

Diagram

Heat Treatment of Steels and Non-ferrous Alloys.

THERMISOL 251 was developed with the objective of having one product to satisfy various quenching speeds. This is achieved by adjusting the application concentration. Low concentrations offer more rapid cooling than water alone while higher concentrations offer quenching speeds similar to oils. The most important feature of this water-based Quenching Oil is minimal warping.

Benefits of using THERMISOL 251

Allows quenching speed to be adjusted

Ensures consistent hardness

Non-flammable Components remain clean after quenching

High performance without the danger of overheating

Easily washed-off workshop floors etc.

Typical Physical & Chemical Characteristics:

Properties	Unit	Value	Norm Test
Density at 15 °C	kg/l	1.088	ASTM D 1298
Colour		5.0	ASTM D 1500
Viscosity at 20 °C	mm²/s	562	ASTM D 445
Viscosity at 40 °C	mm²/s	324	ASTM D 445
pH-value of the solution DIN water 10%		8.3	DIN 51 369
Reserve Alkalinity up to pH = 7	ml 0,1 n HCl	25	FLP*
Refractometer / Fluid Tester factor		2.05	FLP*

FLP*= FUCHS Laboratory Procedure

Application:
THERMISOL 251 should be diluted with water to concentrations ranging from 2 to 25 %.
Depending on the process and the materials involved, concentrations of up to 50 % are possible.
Recommended concentrations are:

Induction hardening	2 to 8 %
Hardening structural steels	8 to 15 %
Hardening alloyed steels	10 to 25 %
Special alloys	20 to 30 %
Nonferrous metals and their alloys	30 to 45 %

Quenching Oil mixing:

Tanks which have previously contained quenching oils should be thoroughly cleaned, proceeding with scouring and rinsing to avoid excessive contamination. Fill the tank with 3 parts of water if the concentration is 25 % and immediately add 1 part THERMISOL 251. Stir the solution, check the
concentration and adjust by adding small amounts of product or water. For optimum mixing, heat the solution to 40 - 60 °C and stir thoroughly.Quenching operations can now begin.

Caution!

Clean parts that have been heated in bath salts prior to quenching.

Do not quench tool steels.

The temperature of the bath should not exceed 65 °C.

If complex-shaped parts with difficult cooling characteristics are being quenched, adjust the THERMISOL 251 concentration accordingly.

THERMISOL 251 bath (concentration) control:

Hand refractometer.Since the refraction index of solution varies with concentration, this is a useful means of measurement.Filter a solution sample and place a drop on the lens, close the cover and look through the eye-piece with the instrument pointing at a light. Having determined the reading which corresponds to the shaded area observed in the eye piece, multiply by a factor of 2.05 and this will give the direct concentration of the bath, e.g.
Refractometer reading = 7;
Calculation: 2.05 x 7 = 14.35 % of THERMISOL 251.

Another simple procedure consists of heating a defined quantity of the Quenching Oil in a graduated test tube. A film will then separate and float to the top of the solution. This film is then measured and compared to the results of similar tests on standard solutions.

Use ASTM D 445 to determine kinematic viscosity and thus concentration at a constant temperature.

Viscosity /Concentration values (at 40 °C):

Concentration, %	Viscosity, mm²/s
2	0.75
5	0.90
8	1.20
10	1.45
12	1.70
15	2.15
18	2.75
20	3.30
22	3.90
25	4.80
30	6.70
35	9.90

Further information:

Handling: No special precautions need to be taken when handling THERMISOL 251.
It is advisable to test bacteria levels regularly because microbiological growth in aqueous solutions has a direct bearing on corrosion problems.

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