ASTM E1338-09(2015)

4.1 This guide describes the types of information that are indispensable for uniquely identifying a metal or alloy in a computerized database. The purpose is to facilitate standardized storage and retrieval of the information with a computer, and allow meaningful comparison of data from different sources.

4.2 Many numbering systems for metals and alloys have been developed which are based on their chemical compositions. Separate systems have also evolved to describe the thermomechanical condition of metals and alloys in order to narrow their description. It is the separation into logical data elements from these complex, historically significant, and overlapping systems of identification that is the challenge in the identification of metals and alloys within computerized databases.

4.3 This guide is intended to provide a common starting point for designers and builders of materials property databases. This guide generally identifies the contents of the database in terms of data elements, but does not recommend any particular logical or physical database design. A database builder has considerable flexibility in designing a database schema, and it is intended that this guide support that flexibility.

4.4 It is recognized that material property databases will be designed for different levels of material information and for different purposes. For example, a database developed by an industry trade group might only identify typical properties generally representative of those for a particular metal or alloy, and not actual values measured on a specific sample. On the other hand, a business might desire to manage data on specific lots it procures, or even properties of a specific piece or sample from a lot. Consequently, some of the data elements identified in this guide might not be applicable in every database instance.

4.5 The extent of material identification implemented in a particular database depends on its specific purpose. A single organization may include substantial detail in its database. Less detail may be included in a common database used by several organizations because of commercial and other considerations. Since metals and alloys are diverse and the technologies are always changing, recommendations should not be regarded as exclusive of additional data elements for material identification. The recommended data elements should be expanded if additional detailed information which serves to identify materials is to be recorded.

4.6 A number of data elements are considered essential to any database and need to exist in the database. Data elements are considered essential if they are required for users to have sufficient information to interpret the data and be confident of their ability to compare sets of data for materials from different sources. Failure to complete an essential data element may render the record unusable in a database or in data exchange. Essential refers to the quality or completeness of recorded data, and does not necessarily have direct meaning relative to database structure. In some cases, the identified data element might be accommodated within a particular database without explicitly including a field just for the essential data element. Additionally, a database schema may require additional data fields to be not null to maintain data record integrity or to implement a mandatory data relationship. These additional fields are beyond the scope of this guide. Finally, it is also noted that a data element identified as essential in this guide might not be relevant for a database created for a specific application of limited scope.

4.7 This guide presents a listing of the data elements and does not intend to define any single organization of the data elements to be used in either a logical or physical model for the database. The data element lists are divided by group headings for discussion purposes only. The group headings are not intended to identify normalization of the database model; this is left to the database designer.

4.8 Numerous data elements listed in this guide may need to be repeated to identify even a single material. Depending on the database purpose or design, it may be appropriate to design the database to enable additional repeatable data elements. How the database should accommodate multiple values for a given data element is another question left to the database designer.

1.1 This guide covers the identification of metals and alloys in computerized material property databases. It establishes essential and desirable data elements that serve to uniquely identify and describe a particular metal or alloy sample as well as properties that identify a given metal or alloy in general.