Page 9 - Dycert_Havryluk

9

with new surface after machining in LCL are presented.

Gravimetric studies has shown that in 3% LCL based on sunflower (LCLs) and

rapeseed (LCLr) oils in comparison with mineralized water, the corrosion rate of

38KhN3МFА steel with polished surface reduces by an order of magnitude and the

degree of corrosion protection exceeds 90%. Enlargement of LCLs and LCLr

concentrations from 1% to 3% increases the protection effectiveness but further increase

of concentration up to 5% practically does not affect the corrosion process.

Electrochemical studies of polished steel samples and newly formed specimens

surface were performed to determine the LCL ability to protect against corrosion the

surface of machined parts. Newly formed surface is a result of machining in the

corresponding LCL. It was found that after machining in the investigated environments

the repassivation (increase of potential from -331 ... -340 up to 30 ... 40 mV) for

12Kh18АG18Sh steel was observed, and for 38KhN3МFА steel in water the potential

falls by 30% while in LCLs, LCLr and LCLo increases by 33%, 17% and 7%

respectively.
The character of corrosion potentials and currents changes of 12Kh18АG18Sh and

38KhN3МFА samples with mechanically treated surfaces in the environments of the
investigated LCL is similar to corrosion potentials and currents changes of samples with

polished surface. However, after machining the samples surface in LCL, the corrosion
currents of both steels in the environment with 3% LCL is by order larger than the

corrosion currents of the polished samples. Such an increase in currents is associated
with an increase in the surface area of samples.

The addition of 1% LCLs to water reduces the corrosion current of 38KhN3МFА

steel by 3,9 times, and the addition of 3% LCLs by 4,4 times in comparison with water

and increases the Taffel constants, which testifies to high corrosion protection of new

developed LCL.

The postoperative protective LCL effect is evaluated according to the appearance

of the shavings (the "indicator") after 100 h after sharpening. This effect confirms the

protective action of LCL. The effect of the LCL aftereffect due to the adsorption of their

components is confirmed by the results of the LCL surface tension investigations and