Boards at both companies were expected to decide on the venture by the end of June, Thyssenkrupp said, adding that the signing was planned to take place afterwards. The group had previously aimed to sign the deal in the beginning of 2018.
Tata Steel is still due to deliver labour agreements with its staff at its Port Talbot plant in Britain and IJmuiden in the Netherlands. Thyssenkrupp, meantime, has already secured approval from German workers.
Thyssenkrupp and Tata Steel in September agreed in principle to combine their European steel activities to create the continent's second-largest steelmaker after ArcelorMittal in quest to slash overcapacity in the sector.
Following the deal's signing Thyssenkrupp's management, led by Chief Executive Heinrich Hiesinger, will present a refined strategy to the group's supervisory board, Thyssenkrupp said.
"With the planned joint venture Thyssenkrupp achieves a key prerequisite for a sharpening of the group's strategic target and subsequently also the financial targets," Thyssenkrupp said in a statement.