The influence of soak temperature and forging lubricant on surface properties of steel forgings

Research output: Contribution to journalArticlepeer-review


Colleges, School and Institutes

External organisations

  • W.H. Tildesley Ltd
  • University of Wolverhampton


A small series of ring compression tests were performed on BS970:708M40 alloy steel. The samples were tested using a 2-factor temperature variable, and a 4-factor lubricant variable, as the design parameters. Two differing soak temperatures were used, namely 1030 °C and 1300 °C respectively. The lubricants applied at the billet to tooling interface were synthetic water–based, graphite water–based, graphite and molybdenum disulphide viscous grease, and finally, unlubricated samples were tested. The ring compression tests were performed using a traditional drop forging hammer and induction heating to minimise any unintentional process variability. The impact that the two varying process parameters have upon the compression sample was then assessed by measuring each sample’s surface hardness and surface roughness prior to and post forging with fully calibrated equipment. It was demonstrated that the higher soak temperature of 1300 °C yielded a lower surface hardness value and higher surface roughness than the lower soak temperature, 1030 °C. The two water-based lubricants offered negligible change in results compared with the unlubricated forging, strongly suggesting that the lubricants were evaporated off the surface prior to forging. However, the results from the graphite–molybdenum disulphate grease do indicate in particular higher surface roughness than other lubricants, and a non-symmetric distortion pattern.

Bibliographic note

Funding Information: The authors were financially supported by WH Tildesley Ltd. Publisher Copyright: © 2020, The Author(s).


Original languageEnglish
Pages (from-to)1133–1144
JournalInternational Journal of Advanced Manufacturing Technology
Early online date28 Dec 2020
Publication statusPublished - 1 Jan 2021


  • Forging, Ring compression test, Lubricant, Surface hardness, Surface roughness, Deformation, Friction