GB/T 12767-1991Powder metallurgy products--Surface roughness--Parameters and their values (English PDF)

3 General rules

4 Parameters for the assessment of surface roughness and their series of values

5 Basic parameters of instruments for the assessment of surface roughness

Foreword

This document was issued on 22 March 1991 by the State Bureau of Technical Supervision, and has been in force since 1 May 1992.

It is the first edition of this standard.

Classification: ICS 77.040.30, CCS H72.

About this edition

GB/T 12767-1991 is the first edition of this standard. It was issued on 22 March 1991 and has been in force since 1 May 1992.

There is no earlier edition to compare it with, so a specification that has to refer to this subject can only cite GB/T 12767-1991 itself.

The interval between issue and effect is the transition period. It exists so that producers, laboratories and buyers can requalify products, revise procedures and use up documentation before the new text becomes the one that applies. The date on this page is the official one from the record of the Standardization Administration.

Classification and status

GB/T 12767-1991 is classified under ICS 77.040.30, in the field of metallurgy. ICS is the International Classification for Standards, the same scheme used by ISO and by the national bodies of most countries, which is what allows a Chinese standard to be placed beside its foreign counterparts on subject rather than on number.

Its Chinese Standard Classification code is CCS H72. CCS is the domestic scheme, a letter for the sector and two digits for the subject within it, and it is the code by which the standard is filed and searched in China.

The GB/T prefix marks a recommended national standard. It is not, in itself, law: it becomes binding when a contract names it, when a regulation or a mandatory standard refers to it, or when a producer declares conformity with it. In practice that covers most of the cases in which it will be read — a purchase specification, an inspection agreement or a certification scheme.