Selection of extreme pressure agent and emulsifier in stainless steel rolling oil design
August 20, 2022
Extreme pressure agent selection Stainless steel cold rolling process conditions are harsh, and the deformation heat and high rolling force generated in the rolling process require stainless steel rolling oil to have good extreme pressure properties. Since the oil-based agent is only suitable for the environment below 150 ℃, the suitable temperature range of the phosphorus-containing extreme pressure agent is 150-250 ℃, and the suitable temperature range of the sulfur-containing extreme pressure agent is about 300-800 ℃. In order to meet the customer's reduction requirements under various rolling schedules and ensure that the stainless steel rolling oil has good lubricating properties in each temperature section, a variety of sulfurized fats and phosphate extreme pressure agents were screened. The sulfur-containing extreme pressure agents A (inactive sulfur), B (active sulfur) and C (active sulfur) in different proportions are added to the basic formula composed of Base Oil and oily agent individually or in a certain proportion to prepare a small sample. When a certain sulfur-containing extreme pressure agent is added alone, the anti-wear performance of the sample is not ideal; while the combination of two sulfur-containing extreme pressure agents can significantly improve the extreme pressure and anti-wear performance of the oil. Comprehensive consideration, select the sample with the best extreme pressure and anti-wear performance and better copper corrosion results, that is, the sulfur-containing extreme pressure agent B and C are compounded. In order to improve the anti-wear and anti-friction properties of stainless steel rolling oil, sulfur-containing extreme pressure agents B and C and phosphorus-containing extreme pressure agents D and E are added to the basic formula composed of base oil and oily agent. Finally, the compound 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 of the developed formula.
Emulsifier selection The emulsification state and particle size distribution of the emulsion directly affect the lubricity of the emulsion. The study found that the worse the stability of the emulsion, the larger the particle size, the better its water-free spreadability, and the better the lubricity of the emulsion; but the instability of the emulsion will bring some problems to the emulsion circulation system. For example, there will be thick oil slicks and soap slicks on the surface of the emulsion tank. If the stirring is not uniform, it will affect the uniformity of the emulsion sprayed on the surface of the stainless steel strip; and the particle size of the emulsion is too large, and it is easy to adhere to the plate surface. , It is not easy to purge, resulting in too much residual oil on the board surface, which will affect the annealing cleanliness of the oil. Therefore, on the basis of ensuring lubricating performance, the emulsion should be kept as stable as possible. The type and amount of emulsifier added will affect the stability of the emulsion and the size of the particles in the emulsion. By controlling the total amount of emulsifier and the ratio between different emulsifiers, the stability of the emulsion, that is, the dispersion state of the oil and the speed of oil-water separation, can be adjusted, which is the technical core of the stainless steel rolling oil emulsification and dispersion system. ESI is the emulsion stability index. By testing the ESI value, the stability of the emulsion can be judged. The larger the ESI value, the better the homogeneity of the emulsion; on the contrary, the smaller the ESI, the worse the homogeneity of the emulsion. Since the optimal lipophilic and hydrophilic balance (HLB value) required for each oil to be emulsified is different, the emulsification system of the optimal emulsification state corresponding to different formulation systems is also different. For the basic formula system with an oily agent dosage of 50% (mass fraction), a variety of non-ionic emulsifiers were screened in the laboratory.
