This key determines which conditions are valid for quality management in
procurement.
If you activate the indicator for QM in procurement in the material master
record at the client level , you must also store a control key at the plant
level for quality management in procurement.
Depending on the control indicators in the control key, you may have to
maintain additional data.
SAP transaction code to maintain the Control key
SM30 - V_TQ08
You can set the Message Control for Lock as :
I - Information
W - Warming
E - Defects
You can also indicate that a Quality Certificate is required or not.