Role and application of triethanolamine in metal working fluids

December 13, 2023

Role and application of triethanolamine in metal working fluids

Triethanolamine is an important additive in water-based cutting fluid, most of the cutting fluid will be used in triethanolamine, visible triethanolamine in the importance of cutting fluid, but triethanolamine in the cutting fluid in the end what role does it play?

The role of triethanolamine in water-based cutting fluid

Synthetic water-soluble oil agent

At present, most of the oil agents with good lubrication performance are long carbon chain substances, and most of these substances are water-soluble. To add them to water-based cutting fluid, it is necessary to introduce hydrophilic groups in their molecular chains. Triethanolamine has three -OH, which is water-soluble. By controlling the ratio of raw materials, one OH in triethanolamine molecule reacts with oiliness agent to produce water-soluble oiliness agent.

Oleic acid is one of the important fatty acids, but it is insoluble in water. The chemical reaction between triethanolamine and oleic acid (about 65℃) can produce triethanolamine oleate. It is a commonly used water-soluble oil agent, and the higher the proportion of triethanolamine contained, the better the water solubility. The maximum stickless PB value of aqueous solution of triethanolamine oleate (5%) was measured by four-ball testing machine, and the friction coefficient was 0.071 by friction and wear testing machine. Oleic acid triethanolamine is added to the cutting fluid as an oil agent, which is easy to form a physical adsorption film between the tool and the chip (workpiece), and plays a lubricating role under low load. The results show that triethanolamine oleate and Ep Additive also have good synergistic anti-wear effect. In addition to chlorinated paraffin S52, borate and phosphate, triethanolamine oleate can significantly improve its polar lubrication performance, so as to further improve the cutting performance.

Antirust agent

Triethanolamine itself is a water-soluble rust inhibitor. Using it alone can effectively prevent steel rust in the short term, and the general use concentration is 0.5% to 2%. Triethanolamine and L190plus, sebacic acid, boric acid and other water-soluble anti-rust agents have synergistic anti-rust effect, and the combined use can significantly improve the anti-rust ability of water-based cutting fluid. The addition of 0.1-0.3% BASF aqueous metal active agent Irgamet 42 can solve the corrosion of copper. Oleate triethanolamine is also a rust inhibitor, which is suitable for the rust prevention of ferrous metals and aluminum alloys

surfactant

Surfactants play the role of penetration, diffusion, stability and cleaning in water-based cutting fluid, and are essential additives for the synthesis of cutting fluid and emulsion. An anionic surfactant can be synthesized by triethanolamine and fatty acid. The HLB value of surfactants with different ratio and different fatty acid synthesis is different, which can be suitable for different water-based cutting fluids. These surfactants have good emulsifying ability, and the emulsifying effect is better when combined with non-ionic surfactants alkyl phenol polyoxyethylene ether or fatty alcohol polyoxyethylene ether. Triethanolamine itself is also a non-ionic surfactant, adding it to water can significantly reduce the surface tension of water. The addition of triethanolamine in the water-based cutting fluid will help the cutting fluid to infiltrate and penetrate the cutting (grinding) interface, so as to give full play to the cooling and cleaning role of the water-based cutting fluid.

stabilizer

The oil agent and extreme pressure agent added in the water-based cutting fluid are resolved to reduce the role of the cutting fluid. Adding a small amount of triethanolamine can play a stabilizing role. For example, organic borate is a new type of extreme pressure antiwear agent, which is formed by the reaction of hydroxyl substances with boric acid or its compounds. The main disadvantage of borate is easy hydrolysis, which can be inhibited by adding a small amount of triethanolamine when synthesizing borate.

Application of triethanolamine cutting fluid

The oil agent (triethanolamine oleate), extreme pressure agent (S52, phosphate, etc.), anti-rust additives (triethanolamine, L190plus, BASF 42, sebacic acid, boric acid, etc.), fungicide (Dantogard,BIT,IPBC,BBIT) and other additives are combined to prepare water-based cutting fluid. Qualified according to GB6144-85 synthetic cutting fluid standard (IV). The lubrication and anti-rust properties are better than the national standard. After being used for a long time in the factory, the cutting fluid has excellent performance, can significantly improve the cutting efficiency and processing quality, extend the service life of the tool, reduce the processing cost, and is harmless to the operator and has a long service cycle.

Precautions for use of triethanolamine

Triethanolamine is easy to react with nitrous acid to produce harmful substances. Therefore, sodium nitrite should be carefully used as an anti-rust agent in triethanolamine cutting fluids.

When using triethanolamine cutting fluid as grinding fluid, it will produce a slight unpleasant odor. In order to overcome this shortcoming, the amount of triethanolamine can be reduced, and trace food flavor can also be added.

When grinding carbide tools, it is not easy to use cutting fluids containing triethanolamine. Because the triethanolamine solution will make the cobalt in the cemented carbide tool leaching, thus affecting the performance and service life of the tool.

Author:

Mr. James

E-mail:

sales@cn-lubricantadditive.com

Phone/WhatsApp:

+86 13783582233