Under New Section 115BAB

1. The new provision will be applicable only for Companies setting up manufacturing unit on or after 01.10.2019 and commences production before 31.03.2023. 
2. The tax rate would be 15% and effectively it will be 17.01% provided no exemption or incentive. 
3. They are also excluded from the payment of MAT. 
4. In your case it is a partnership firm and converting it into a company would not be considered as a new domestic company. Hence, 15% tax rate will not be applicable in your case. 
Please correct me if the above solution has an alternative view.