The 50 plus scaffolders, who are members of the construction union Unite, are responsible for the maintenance of over 500 scaffolding structures at the Scunthorpe site.
The dispute is over pay and began in 2019. The workers are seeking to be paid in line with the National Agreement for the Engineering Construction Industry (NAECI).
There is a difference of £2.00 an hour between their current pay rates and the established NAECI pay rates.
The dispute over pay rates has been rumbling since 2019 with Brand Energy.
Six days of strikes are planned over the coming weeks, with the first 48-hour strike beginning on Monday 25 January.
The dispute is made more complex as Brand Energy will lose the scaffolding contract on 15 February when it will transfer to Activo.
If the matter is not resolved before the contract is transferred, Unite said it would begin balloting for fresh industrial action with Activo, once the contract transfers.
Unite regional officer John McIntyre said: “Our members have been left with no choice but to take strike action due to the refusal of Brand Energy to even engage with Unite on the pay issue.
“There are clear pay rates established for this type of highly skilled work and Brand Energy are deliberately undermining them.”
A British Steel spokesman said: “This matter involves employees of a contract company on our site. We have contingencies in place, and it will not impact on production.”