Both firms are part of Tata Steel.
"The effective date of amalgamation of Tata Metaliks DI Pipes Ltd with the company is December 22, 2016," Tata Metaliks Ltd said in a filing to BSE.
The company had said last month that Calcutta High Court had approved the scheme of amalgamation of Tata Metaliks DI Pipes Ltd with Tata Metaliks Ltd on November 7.
Tata Steel had said in May that it has dropped plans to merge group firms Tata Metaliks and Tata Metaliks DI Pipes with it due to delay in regulatory and statutory approvals among other factors.