How to choose extreme pressure additives and emulsifiers in stainless steel rolling oil?

The cold rolling process conditions for stainless steel are harsh, and the deformation heat and high rolling force generated during the rolling process require stainless steel rolling oil to have good extreme pressure performance. Due to the fact that oily agents are only suitable for environments below 150 ℃, while phosphorus containing extreme pressure agents are suitable for temperatures ranging from 150 to 250 ℃, and sulfur containing extreme pressure agents are suitable for temperatures ranging from about 300 to 800 ℃. In order to meet the reduction requirements of customers under various rolling procedures and ensure that stainless steel rolling oil has good lubrication performance in various temperature ranges, various sulfurized fats and phosphate ester extreme pressure agents were screened.

Add different proportions of sulfur containing extreme pressure agents A (non active sulfur), B (active sulfur), and C (active sulfur) separately or in a certain proportion to the basic formula composed of Base Oil and oiliness agent to prepare small samples.

The anti wear performance of the sample is not ideal when a certain sulfur containing extreme pressure agent is added alone; The combination of two sulfur-containing extreme pressure agents can significantly improve the extreme pressure and wear resistance of the oil.

After comprehensive consideration, select the sample with the best extreme pressure and wear resistance performance and good copper corrosion results, which is the combination of sulfur containing extreme pressure agents B and C.

To improve the anti wear and friction reduction performance of stainless steel rolling oil, sulfur containing extreme pressure agents B and C, as well as phosphorus containing extreme pressure agents D and E, are added to the basic formula composed of base oil and oiliness agents.

Finally, a composite of sulfur containing extreme pressure agent B, sulfur containing extreme pressure agent C, and phosphorus containing extreme pressure agent E was selected as the extreme pressure and anti wear additive for the development formula.

Emulsifier selection
The emulsification state and particle size distribution of the emulsion directly affect its lubricity. Research has found that the poorer the stability and larger the particle size of the emulsion, the better its water dispersibility and lubricity; However, unstable emulsion can bring some problems to the emulsion circulation system, such as thick floating oil and soap on the surface of the emulsion tank. If stirred unevenly, it will affect the uniformity of the emulsion sprayed onto the surface of the stainless steel plate and strip; Moreover, the particle size of the emulsion is too large, making it easy to adhere to the board surface and difficult to blow, resulting in too much residual oil on the board surface, which can affect the annealing cleanliness of the oil product. Therefore, while ensuring lubrication performance, the emulsion should be kept as stable as possible.

The type and dosage of emulsifiers can affect the stability of the emulsion and the size of particles in the emulsion. By controlling the total dosage of emulsifiers and the proportion between different emulsifiers, the stability of the emulsion can be adjusted, that is, the dispersion state of the oil and the oil-water separation speed. This is the technical core of the stainless steel rolling oil emulsion dispersion system.

ESI is the stability index of the emulsion. By testing the ESI value, the stability of the emulsion can be determined. Among them, the higher the ESI value, the better the uniformity of the emulsion; On the contrary, the smaller the ESI, the worse the uniformity of the emulsion.

Due to the different optimal lipophilic hydrophilicity equilibrium (HLB) values required for emulsification of each oil product, the emulsification system corresponding to the optimal emulsification state varies depending on the formulation system. A variety of non ionic emulsifiers were screened in the laboratory for the basic formula system with a 50% (mass fraction) dosage of oily additives.