Metal fabricators use several methods to verify the material they receive meets the required specifications. Here are some of the common methods:

1. Material test reports: Metal fabricators will typically require material test reports (MTRs) from their suppliers to verify the material's properties, including the chemical composition, mechanical properties, and dimensions. MTRs provide a detailed analysis of the material's composition and physical properties and can help to ensure that the material meets the required specifications.
2. Visual inspection: Metal fabricators may perform a visual inspection of the material to check for any defects or irregularities, such as cracks, warping, or surface imperfections. Visual inspection can be a useful method to quickly identify any potential issues with the material.
3. Non-destructive testing: Non-destructive testing (NDT) methods, such as ultrasonic testing, magnetic particle inspection, or dye penetrant inspection, can help to detect any hidden defects or inconsistencies in the material without damaging it. NDT methods are typically used for critical applications where the material's integrity is of utmost importance.
4. Mechanical testing: Mechanical testing involves subjecting the material to specific tests to measure its strength, hardness, and other physical properties. These tests can include tensile testing, hardness testing, and impact testing, among others. Mechanical testing can help to ensure that the material meets the required strength and performance specifications.

Overall, metal fabricators use a range of methods to verify the material they receive meets the required specifications. By verifying the material's properties and integrity, metal fabricators can ensure that the finished products they produce meet the required standards and are safe and reliable for their intended use.