With the exception of the final inspection of a finished component, it is the incoming material inspection that is, in my opinion, the most important inspection criteria. Incorrect material that is issued to the shop for manufacturing and machining is doomed for failure and added cost before it has started its manufacture.

But if we are unable to determine the chemistry of the steel, aluminum, stainless steel, copper, titanium alloy or whatever the choice of material is for the manufacturing procedure, what can we do then to identify and confirm that the material is what the test certificate says that it is?

The test certificate will state the following values: specification analysis, actual analysis, hardness, grain size, surface decarburization (if hot-rolled steel), surface oxidation depth (if steel) and hardenability.

Any of the above values can be checked prior to issuance of the material for manufacture. If the material checks out to the test certificate, it is suitable for issuance for the manufacturing of that component. A simple hardness test can be all that might be necessary to identify and confirm a material for issuance for manufacturing. The hardenability test is another very simple test that can be applied to incoming material (steel) to add to the confirmation of the steel’s identity.

In your Standard Operating Procedures, write up a control and report sheet that will accompany the component through its manufacturing operations, showing the results of the pre-issuance tests prior to manufacturing.

It is always best to “do it right the first time, because the second time will cost you money.” That is to say, if the incorrect material has been issued, then it will manifest itself at the heat-treatment procedure when it does not respond appropriately. Good incoming material inspection procedures are as important to the manufacturing sequence as good engineering and design practices.

The material “‘as delivered” data is readily available on the test certificate for verification by the incoming material inspection department. Make good use of that available information so that the component can be manufactured as per the drawing requirements with the appropriate material, and obtain the appropriate thermal response when heat treated.