1 Scope
This standard stipulates dimension (linear dimension and angular dimension) tolerance of the welded construction as well as geometric tolerance, these tolerances can be classified into four grades, and they are applicable to common manufacturing accuracy. Selection of tolerance grade shall be in accordance with the practical requirement.
General dimensional tolerance and geometric tolerance stipulated in this standard are applicable to weldment, welding assembly parts, and welded construction. Complicated structure may be made with special stipulation as required.
These technical requirements stipulated in this standard shall base upon the independent principle stipulated in GB/T 4249, that is, each dimension, shape and status requirement is independent, they shall meet the requirements independently.
Technological documents shall only be labeled with linear dimension and angular dimension or geometric illustration, but not solely labeled with tolerance shall be regarded as unsoundness if there is no general tolerance referring instructions, excluding the temporary dimension.
2 Normative documents
The following normative documents contain provision which, through reference in this text, constitute provisions of this national standard. For dated reference, subsequent amendments to, or revisions of, any of these publications do not apply. However, the Parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 19804-2005 The following standards are cited：
