The chemical analysis provided in the material certification shows fewer elements than required by the standards
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The chemical analysis provided in the certificate of conformity for the sheet material shows that the levels of certain elements are lower than those required by the standards; is this material suitable? For example, the Q345R standard GB713-2014 specifies the chemical composition of 13 elements, whereas the material certificate lists only 8 of them. Is such a material certificate acceptable? Why didn’t the steel plant provide the composition of all elements according to the standards? How should this situation be handled? Is it necessary to retest the chemical composition?
Normal; even the overreported element contents are normal
This post was last edited by qugd on 2016-4-13 at 21:42. In material certification, only the main or key elements are usually listed; if it is necessary to analyze some unconventional or trace elements, an additional fee will apply. Material certificates resulting from such elemental composition analysis are mostly for alloy steel or stainless steel; if a full analysis is not required, it is normal for the material certificate to provide analysis results for the main or key elements. Furthermore, if the composition of one or several elements is within a certain range, even the minimum value obtained from the analysis does not constitute a violation; as long as it falls within the specified range in the standards, it is considered acceptable. Unless the user specifically requests that the content of one or more elements in the specified material be no lower than a certain level before placing the order. For suppliers of materials for some world-famous brands, the intermediate values specified in the standards may be strictly followed, but the prices could be much higher than those for other brands.
In the material certificate, the main or critical elements are listed; any trace elements that are added must also be indicated in the material document, as the standards set clear requirements, and large steel manufacturers follow these standards.
Some elements are normally controllable and do not affect the material properties; generally, as long as those key indicators remain within the specified range, it’s fine. Special attention should be paid to the materials used for pressure vessels, but other aspects are not subject to such strict requirements.