A comparative study on the performance of boric acid with several conventional lubricants in metal forming processes

During metal forming, lubricants are necessary to prevent direct contact, adhesion, transfer, and scuffing of workpiece materials and tools. The lubricating action of boric acid is due to its layered crystalline structure, and is similar to the structure of MoS ₂ and graphite. However, boric acid lubrication could offer distinct advantages in terms of its application prior to forming and removal after a forming operation since it can be dispensed using water and alcohol solutions, raising the possibility of being environmentally friendly. Its effectiveness under actual conditions of metal forming operations such as rolling, forging, and sheet metal drawing and stretching has been evaluated in this study with both ferrous and non-ferrous work materials. It was found that boric acid provided lowest friction in sheet drawing and stretching operations, which is attributed to its lattice layer structure that facilitates easy sliding between molecular layers. Under predominantly compressive conditions of forming, liquid or semi-solid lubricants have performed better as they could squeeze out along with forwarding workpiece surfaces. The findings presented in this paper increase the prospect for developing boric acid as an effective lubricant in the cold forming of materials under certain conditions. © 2005 Elsevier Ltd. All rights reserved.