The definitions and procedures for measuring flatness characteristics of steel sheet products are provided so that purchasers and suppliers have common definitions and measuring procedures for flatness characteristics. The intention of these definitions and measuring methods is not to provide a dimensional specification for flatness characteristics, but rather common procedure(s) for quantifying flatness anomalies. For determining compliance with flatness specifications, references are provided to appropriate ASTM standards.

1.1 Flatness is a significant quality characteristic of steel sheet products. Sheet flatness is affected by mill process factors plus the grade, thickness and width of the material supplied. It is the purpose of this practice to define the different flatness characteristics and to describe the method(s) most commonly used to measure particular characteristics. The methods described are designed and intended to be used in mill situations and environments.

1.2 The substrate shall conform to all the requirements of the appropriate specifications as follows: Specifications A568/A568M or A924/A924M.

1.3 Quantitative limits are not addressed and are established in the general requirements, or individual product specifications, or both; or when applicable, as agreed to between supplier and user.

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.