What is a Certified Mill Test Report?
The Certified Mill Test Report is a tool used to ensure that received raw material matches the engineering and purchase order requirements. It is a quality assurance document generated by the raw material manufacturer and provided with the material to intermediate suppliers and ultimately to a finished goods manufacturer. Whether it’s called a CMTR, Mill Test Report (MTR), Mill Certification, Metallurgical Test Report, or similar name, this document provides the end user of the raw material verification that the material received matches the requirements of their order. CMTRs are also used to maintain traceability of the material from its initial inception to its inclusion in a finished part as in the execution of construction works.
How to review Certified Mill Test Report in Construction Project?
At the Construction site, it is the Receiving Department such as Procurement/Purchasing Department responsibility to match received goods to supporting CMTRs and forward that information to the Store/Logistic Department and QA/QC Department. The Procurement/Purchasing Engineer and QA/QC Engineer are responsible for the review of the CMTR to ensure it meets the engineering and order requirements. Below is the summarized what the engineers are reviewing so that only the correct materials are received and issued to the construction site for use or fabrication. This being the way to implement the project risk reduction and achieve the guaranteed quality of ownership for the client such as prescribed in the project specifications.
Procurement/Purchasing Engineers, QA/QC Engineers, and material manufacturers can identify raw material in different ways, using a lot, coil or other identifying numbers, but ultimately all CMTRs will identify the material with a Heat Number. The heat number is used to maintain traceability of the material. When matching a CMTR to its raw material all accompanying paperwork and in many cases, markings on the raw material itself must match the heat number on the CMTR. See Figure 1, circled #1.
Metal materials are produced in various grades. The CMTR identifies the grade of the material. See Figure 1, circled #2.
For example, depending on the specifications and codes used, CMTRs certify that the raw material meets the appropriate American Society for Testing and Materials (ASTM) or American Society of Mechanical Engineers (ASME) material product specification. ASME material specifications are required when fabricating Pressure or Vacuum Vessels to the ASME Boiler and Pressure Vessel Code. ASTM specifications are prefixed by an “A”, e.g. A240, while ASME specifications are prefixed by an “SA”, e.g. SA240. Often but not always the ASTM and ASME specification are identical. The product specifications that the raw material meets are listed on the CMTR. See Figure 1, circled #3.
The CMTR identifies the applicable dimensions of the raw material. In the case of the plate material, this would be the thickness, round bar the diameter, or flat bar the thickness and width. This information must match the order requirements. See Figure 1, circled #4.
The product specification lists the detailed requirements that the raw material must meet to be certified to that product specification and grade. The actual measured properties of the raw material are recorded on the CMTR for the identified heat number. These properties typically consist of the Mechanical Properties (see Figure 1, circled #5) and Chemical Analysis (see Figure 1, circled #6). The values listed on the CMTR must fall within the range or limits of the product specification for the raw material to be accepted for use.
Depending on the raw material, there may be other requirements in the product specification. For example, 300 series stainless steel requires a specific heat treatment which must be recorded on the CMTR. See Figure 1, circled #7. The reviewer must identify all special processes in the product specification and confirm they are properly recorded on the CMTR.
Finally, the CMTR must be certified with the signature of a responsible employee of the foundry or mill producing the raw material. See Figure 1, circled #8.
Certified Mill Test Reports provide a record of traceability and properties of a raw material, ensuring that the material will perform in the way it was designed to. Deviations from product specification values can have large consequences, even causing a component failure. The ability to effectively review a Certified Mill Test Report to avoid such consequences is just one-way Procurement/Purchasing Engineer and QA/QC Engineer reduces Project Risk and achieves the guaranteed quality of ownership for the client such as prescribed in the project specifications.