OSP- Scrap

Hello

We have been sending Steel for OSP to a vendor. e.g. We have created a job for 10 ton of steel. The OSP vendor after completion sends back 9 ton finished item and 1 ton scrap. But when we receive the item on PO  stock in our books comes as 10 ton as finish good. We require  9 ton should go into Finish goods and 1 ton scrapped qty should go into a separate item code of scrap . How to achieve this

Thanks

Gobind