What Is a Material Certificate?

A material certificate (also called a mill certificate, mill test report, or material test report) is a document issued by a metal manufacturer or distributor that certifies the chemical composition, mechanical properties, and heat treatment of a specific lot of metal, used in vibratory screening to verify that screen wire and equipment components meet the required alloy specification. In the vibratory screening industry, material certificates trace the stainless steel wire in your screen cloth back to the specific heat of steel at the wire mill, providing the documented traceability that cGMP, HACCP, and FSMA quality systems require.

Material certificates are classified by EN 10204 standards. The most common types are Type 2.2 (manufacturer's declaration of compliance), Type 3.1 (inspection certificate issued by the manufacturer with test results from the specific lot), and Type 3.2 (inspection certificate validated by an independent inspector). For screen wire in food and pharmaceutical applications, Type 3.1 certificates are the standard requirement, providing specific chemical analysis and mechanical test results for the heat of steel from which the wire was drawn.

Material Certificate Contents for Screen Wire

Why This Matters in Vibratory Screening

Material certificates are the documented proof that your screen wire is what it claims to be. In regulated industries, this documentation is not optional.

• Food safety compliance — FSMA and HACCP programs require that food-contact equipment be constructed of materials suitable for the intended use. A material certificate proves that your screen wire is food-grade stainless steel with composition within specification limits — not an inferior alloy that could introduce contaminants or corrode in contact with your product.
• Pharmaceutical requirements — cGMP regulations require documented traceability of manufacturing materials. Pharmaceutical auditors expect material certificates for every screen cloth in contact with product. A missing certificate can result in a regulatory observation or batch rejection.
• Corrosion resistance verification — The difference between 304 SS and 316 SS is the molybdenum content (316 SS contains 2-3% Mo), which provides superior corrosion resistance in chloride environments. The material certificate is the only way to verify which alloy you actually received. Installing 304 SS screen wire in a chloride-rich application can lead to premature corrosion failure.
• Nickel-free verification — T430 (nickel-free) stainless steel is required for certain food products where nickel contamination is a concern (chocolate, citric acid products). The material certificate confirms that the nickel content is below the specified limit — typically under 0.50%.
• Audit documentation — Third-party auditors (SQF, BRC, FSSC 22000, ISO) expect material certificates on file for product-contact equipment. ScreenerKing provides material certificates with every screen order upon request, supporting your audit readiness.

Related Glossary Terms

• cGMP — Manufacturing practice regulations requiring material traceability
• HACCP — Food safety system requiring verified equipment materials
• FSMA — FDA regulation requiring food-grade equipment documentation
• Screen Cloth — The product-contact component requiring material certificates
• FDA Compliant — Material standards for food-contact equipment
• Woven Wire Cloth — Wire mesh specified by material grade and mesh size

Material Certificate FAQs

What is a material certificate?

A material certificate (also known as a mill certificate or MTR) is a document from a metal manufacturer certifying the chemical composition, mechanical properties, and manufacturing details of a specific lot of metal. For vibratory screening, it verifies that screen wire is the correct alloy — 304 SS, 316 SS, or T430 — and meets specification limits. This traceability is required by cGMP, HACCP, and FSMA quality systems.

Why do I need material certificates for my screen cloth?

Material certificates provide traceability from wire mill to installed screen, proving your screen wire is the specified alloy. This is critical for food safety (no harmful elements), corrosion resistance (correct grade for your product chemistry), and audit compliance. Without material certificates, you cannot verify that the screen in your separator meets quality system requirements.

What information is on a material certificate?

A certificate typically includes manufacturer name, heat or lot number, material specification (e.g., ASTM A240, AISI 304), chemical composition by element (carbon, chromium, nickel, molybdenum, etc.), mechanical properties (tensile strength, yield strength, elongation, hardness), wire dimensions, and quantity. The certificate traces the wire to a specific heat of steel at the mill.