Material number

The material number uniquely identifies a technical material, replacing inconsistent trade and brand names. It consists of a main group digit, a decimal point and four additional digits, for example 1.4404 or 2.4819. For steels, the numbering system is defined in EN 10027-2; the numbers are assigned by the German Steel Institute VDEh. Material numbers for non-ferrous metals follow the system specified in DIN 17007. In addition, EN 10027-1 defines the abbreviated material designation, which reflects the chemical composition—for example, X2CrNiMo17-12-2 for 1.4404. In the context of sampling bulk solids, the material number is the binding specification for all product-contact components, as designations such as “stainless steel”, “316L” or “Hastelloy” remain ambiguous.

Structure and meaning of the digits

The first digit identifies the main material group, the next two digits the material or steel group, and the final two digits the sequential number within that group:

• 1.xxxx – Steels. Group 1.4xxx comprises stainless steels.
• 2.xxxx – Heavy non-ferrous metals. Group 2.4xxx comprises nickel and cobalt alloys.
• 3.xxxx – Light metals.

The following materials are particularly relevant for sampling applications:

• 1.4301 (X5CrNi18-10, AISI 304) – the standard austenitic stainless steel for non-critical applications.
• 1.4404 (X2CrNiMo17-12-2, AISI 316L) – a molybdenum-alloyed stainless steel with a low carbon content, widely used as the standard material for product-contact components.
• 1.4571 (X6CrNiMoTi17-12-2, AISI 316Ti) – a titanium-stabilised stainless steel with a special alloying addition.
• 2.4819 (UNS N10276) – the nickel-based alloy Hastelloy C-276, designed for aggressive media.
• 2.4602 (UNS N06022) – Hastelloy C-22, with a higher chromium content for oxidising media.

An important point when preparing specifications: the material number identifies the alloy, not the condition of the component. Surface finish, heat treatment and semi-finished product form are not included and must be specified separately.

Use in bulk solids sampling

The material number should be used consistently in quotations, purchase orders, drawings and inspection certificates—not the trade name. This is the only way to define the alloy to be supplied unambiguously and verify it against the material certificate in accordance with EN 10204. The material number therefore provides the link between the design specification and documentary evidence. It applies to all product-contact components, including probes, screws, pistons, nozzles, sample chambers and valve components, as well as accessories such as bottle adapters, bag holders and transfer tubes.

Material selection is governed by the process requirements. Grades 1.4404 and 1.4571 cover the vast majority of applications. Nickel-based alloys such as 2.4819 or 2.4602 are used for media containing chlorides or acids, at high temperatures or where aggressive cleaning procedures are employed. The decisive factors are the material properties and constituents of the bulk solid to be sampled.

Relevant industries

The material number is the standard designation across industries. Its importance for traceability is particularly high in the pharmaceutical and fine chemicals industries, the chemical industry and the food industry, where the relationship between material grade and production batch must be documented. In metals and plastics and mining and quarrying, by contrast, wear resistance is generally the primary consideration.

Regulations and standards

The principal designation systems are EN 10027-1 for abbreviated material designations and EN 10027-2 for the steel numbering system, supplemented by DIN EN 10020 for the classification of steel grades and the DIN 17007 system for non-ferrous metals. The EN 10088 series applies to stainless steels. Material data sheets are also consulted, such as VdTÜV Material Data Sheet 479 for 2.4602. Compliance of the material actually supplied is documented in accordance with EN 10204. The Pressure Equipment Directive 2014/68/EU applies to pressure equipment, while the ATEX requirements apply in ATEX-relevant environments. The applicable standards and directives vary depending on the industry, country and type of bulk solid.