How can you determine the grade of steel without a material certificate? FILAB Laboratory

When a structure, frame, maintenance component or element identified through a PEMD assessment (beam, IPN …) no longer has a material certificate, uncertainty about the grade becomes a direct risk for your calculations, repair choices and documentary compliance.

In practice, it is impossible to seriously validate an assumption regarding mechanical strength, weldability or service performance based solely on visual appearance. Determining steel grade without a certificate is therefore a critical step in securing reuse, structural modification, post-incident investigation or characterization of old steel.

An old drawing, incomplete marking, a trade name or a visual resemblance do not make it possible to identify a steel grade with certainty. Two materials may look similar while having very different carbon, manganese, chromium, nickel or molybdenum contents, with major consequences for strength, ductility, weldability or corrosion resistance.

In a regulated environment or for structural calculations, this approximation is not sufficient.

The first step generally consists of establishing the elemental composition in order to guide the identification of a metal alloy. This data is then interpreted alongside metallographic analysis: matrix type, presence of characteristic phases, grain size, inclusions, carbides or signs of alteration. This approach is particularly useful for characterizing old steel, when the original references are no longer available or the material has undergone changes during service.

Analysis is a priority in the event of structural repair, strengthening, welding on existing structures, replacement of critical parts, post-fracture assessment, doubt about a batch of material, absence of a certificate for an old structure or a need for traceability as part of a PEMD assessment. It is also recommended when the grade determines a calculation, contractual compliance or a decision to retain metal elements.

FILAB supports maintenance managers, structural engineers, technical inspectors and construction professionals in metal alloy identification and old steel characterization. The approach is based on combining several levels of investigation: steel chemical analysis, metallographic observation, hardness measurement and, if necessary, laboratory tensile testing.

This work makes it possible to approach or confirm a material family, assess its consistency with a given use and produce results that can be used in a material expertise construction.

The laboratory can carry out a steel chemical analysis to determine the main and alloying elements, then complement it with microstructural observation to characterize the metallurgical condition of the material. Depending on the issues at stake, hardness testing, metallography with grain size measurement, inclusion rating or a laboratory tensile test can be performed.

The aim is to obtain an identification that is technically defensible and suited to your operational needs.

Depending on your issue, FILAB can supplement the study with mechanical tests and targeted examinations: laboratory tensile testing to assess mechanical behavior, hardness measurements, fractographic analysis in the event of fracture, or surface and treatment-layer investigation if the condition of the part justifies it. For some materials, standardized metallurgical tests such as grain size measurement, inclusion rating, carbide study or intergranular corrosion testing may also be relevant.

Laboratory characterization makes it possible to secure calculation assumptions, guide repair choices, reduce the risk of material error and build a solid technical basis for your discussions with the design office, technical inspector, insurer or project owner. Do not let uncertainty compromise your structural calculations: in the absence of a certificate, material verification becomes a risk-control step.

To begin the study, simply provide your application context, the nature of the part, the dimensions available for sampling, and the technical question to be resolved: grade identification, comparison with a reference, verification before calculation, or construction materials expertise.

The laboratory will guide you toward the appropriate test program and work with you to define the level of characterization required. You can then have a sample analyzed, have a material hypothesis confirmed, or book an appointment with an expert.