can any body expalin how to design a hydraulic press for 850 tons? what will be the cylinder size? what will be the power pasc specification? please explain i need
So that with what you give it is impossible to fully answer your question.
I would suggest if you ask such a question to better either buy the press or ask for a SERIOUS consulting from specialised people. You do not give the feeling that you are aware of the project complexity.
Any for FREE you cannot get such a project done and this forum although visited by high skilled persons is not a guaranty for the final result. If wrong the press can kill many people and you will be the convicted one.
How many years do you want to risk to spend in jail?