What is the purpose of material spec. QS61 master data in QM Module?

They allow the transfer of the batch class characteristic spec values to transfer from the assigned class and populate into the inspection plan. Without this, you must maintain the spec in the inspection plan. With this, you only need to maintain them in the class. Because many materials can be assigned to class, a lot of maintenance can be saved.

You also need this to transfer results from the inspection lot back to the class unless the indicator of "Batch results transfer without material spec" in plant config is selected on.

In simple terms:

It is an option to that of Inspection plan. Inspection plan is defined & created at plant level for the material.  But Material specs are created for a material can be used for all the plants. This means it is created at client level.  You can only use MIC in the materials specs.  You cannot use DMR & Inspection points in material specs.
So it simply meant, once used material specs. for a material can be used at any plant.
 

Which T.code we can maintain the material specification?

QS61    Maintain material specification
QS62    Display material specification
QS63    Maintain material spec: Planning
QS64    Display material spec: For key date
QS65    Activate material specification
QS66    Plan activation of material spec.

Have a SAP QM Problems?
SAP QM Forum - Do you have a SAP QM Question?

SAP QM Books
SAP Quality Management Certification, Interview Questions and Configuration Reference Books

SAP QM Tips
SAP QM Tips and Quality Management Discussion Forum

Best regards,
SAP Basis, ABAP Programming and Other IMG Stuff
http://www.erpgreat.com