Material Type in SAP

Material Type:
            Materials which are having same attributes are grouped together and assigned to one material type.
(OR) Classification of materials into different material types based on material attributes.

            Material type is a controlling function in SAP. Material type controls.......
1. Number assignment
        i.e. external number assignment or internal number assignment
2. Field selection
        i.e. which fields to be hidden, which fields to be displayed, which fields are mandatory, which fields are optional
3. Procurement
       i.e. external procurement or in-house production
4.Valuation class
       i.e. which valuation classes to be allowed and which valuation classes not to be allowed
5. Department views
       i.e. which department views to be appeared in user department selection view
6. Inventory update 
       i.e. inventory update is required on quantity basis or value basis or both

Important Material Types:
ROH  - Raw materials
HALB- Semi finished goods
FERT - Finished goods
HAWA - Trading goods
ERSA - Spare parts
LEIH - Returnable transport packaging (RTP)
PIPE - Pipe line materials
NLAG - Non-stock materials
UNBW - Non-valuated materials
FRIP - Perishable materials
KMAT - Configurable materials