The objects of this Standard on Surface Texture are to provide firstly, a definite basis for a simple numerical assessment of the texture or roughness of a surface under conditions which will ensure reasonable consistency between the results obtained from different instruments purporting to measure the same characteristics of the surface; and secondly, a series of recommendations which it is hoped may help to prevent an undesirable growth of conflicting practices in the use of terms and symbols.
The study of surface texture is relatively new and, as yet, there is little established knowledge of the surface phenomena in engineering practice. For this reason, the present standard has been expressed in the simplest possible terms consistent with serving an immediately useful purpose. As knowledge and experience accumulate, it may be deemed advisable to further revise the standard and extend its scope.
This standard is one of a series of Unified ABC Engineering Standards, and has been prepared as the first Canadian Standard on Surface Texture to correspond with ASA B46.1-1962, American Standard on Surface Texture and BS 1134-1961, The Assessment of Surface Texture. Previous standards published by the other members of the ABC group were ASA B46.1 published February 5, 1947, and revised and re-published January 11, 1955,and BS 1134 published in 1950, and these have been the only guidance available to Canadian Industry.
In 1955, Canadian delegates met with delegates from the United States and Great Britain to continue discussions which had originated earlier and which were aimed at achieving accord between the surface quality standards of the United States and Great Britain. This meeting led to the decision to issue a Canadian Standard and, in November 1958, a Committee was set up for this purpose.
In June, 1960, the ABC Committee delegates met in Chicago and reached substantial agreement on issues. A further meeting between the United States and Canadian delegates took place in November 1960 in New York City where further agreement in the surface texture standards of the respective countries was reached.
This Standard is concerned with the geometric irregularities of surfaces of solid materials. It establishes definite classifications for roughness, waviness, lay, and a set of symbols for drawings, specifications, and reports, and makes reference to requirements for Tracer Type Instruments, and specifications for Precision Reference Standards and Texture Comparison Specimens. This Standard is not concerned with luster, appearance, colour, corrosion resistance, wear resistance, hardness, micro-structure, 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, not 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 Appendices A, B, and C, which are not an integral part of this Standard.
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.
Terms and ratings in this Standard relate to surfaces produced by such means as machining, abrading, extruding, casting, molding, forging, rolling, coating, plating, blasting, or burnishing.