scope:

GENERAL

This standard is concerned with the geometric irregularities of surfaces of solid materials, physical specimens for gaging roughness, and the characteristics of stylus instrumentation for measuring roughness. It defmes surface texture and its constituents: roughness, waviness, lay and flaws. A set of symbols for drawings, specifications and reports is established. In order to assure a unifonn basis for measurement, it also provides specifications for Precision Reference Specimens, and Roughness Comparison Specimens, and establishes requirements for stylus type instruments. This standard is not concerned with luster, appearance, color, corrosion resistance, wear resistance, hardness, subsurface micro-structure, surface integrity and many other characteristics which may be governing considerations in specific applications.

This standard does not define the degrees of surface roughness and waviness or type of lay suitable for specific purposes, nor does it specify the means by which any degree of such irregularities may be obtained or produced. However, criteria for selection of surface qualities and information on instrument techniques and methods of producing, controlling and inspecting surfaces are included in Appendixes attached to this standard. The Appendix sections shall not be considered a part of this standard. They are included for clarification or information purposes only.

Surfaces, in general, are very complex in character. This standard deals only with the height, width, and direction of surface irregularities since these are of practical importance in specific applications.

Surface texture designations as delineated in this standard may not be a sufficient index to performance. Other part characteristics such as dimensional and geometrical relationships, material, metallurgy, and stress must also be controlled.

The values stated in the S.I.¹ (metric) system are to be regarded as standard. Approximate non-metric equivalents are shown for reference.

¹ Le Systeme International d'Unites.