Negative deviation for Q235B steel plates
Thread Content
When the main material of the equipment is Q235B, should the negative deviation for Q235B steel plates be specified in the drawings? It seems that the standards do not specify a negative deviation for Q235B steel plates
In equipment design, if the main material is Q235B steel plate, it is recommended to specify its negative tolerance in the drawings. Although the standard does not specify a negative deviation for Q235B, specifying it helps ensure precision in processing and assembly, which is beneficial for subsequent quality control and inspection. .
Follow the execution standard; only indicate it if the required negative deviation is smaller than the standard
It is present in 709; for Class B steel plates, it is -0.3
The standard does not specify which level it is
The standard does not specify that it should be classified as Category B; GB713 clearly states that it should be classified as Category B, but GB3274 does not mention this
The standards specify that the tolerances for steel plates shall comply with GB/T709; if no precision grade is indicated, they shall be supplied at ordinary precision.
Where can I find information on products that are supplied with standard precision, as no precision grade is specified?