Is it possible to maintain the same material master with same code in all plants in a company. Our client is using same materials in all their four plants?
Material numbers are always maintained at Company code level. If you look at the Material master data, some data is maintained at Company code level, some at Plant level and some at Storage location level. If you have all the 4 plants attached to one company code, they should have the same material number. What you need to do is to extend the material to all the 4 plants if thats your requirement. Also, if you have your valuation area as your Plant, then you have the flexibility to maintain Plant specific pricing for the same material.
You can use MM01 T code to copy material from old plant to new plant. But check for the required details in your new plant and make changes accordingly.