Guaranteed values are given for properties that are measured and controlled to be within defined limits. Products with properties outside of these limits will not be delivered. Since all properties have spread and variation, typical values indicate what value could most commonly be expected. Nominal values are convenient when describing a product in general, but cannot be used for engineering and design purposes.
The difference between guaranteed, typical, and nominal values lies in the level of certainty associated with each value. It's important to understand the difference between these values and to select the appropriate value based on the level of certainty required for a particular application.
Guaranteed values are the properties of a product that are measured and controlled to be within defined limits and are typically used as the basis for product specifications. These values are critical because products that do not meet these specifications will not be delivered to customers.
Typical values indicate what value could most commonly be expected based on a statistical analysis of a large number of measurements. While typical values are not guaranteed, they can be used as a guide to the expected properties of a product and the average process behavior of the material.
Nominal values are values that are specified as part of a product description, but do not necessarily reflect the actual properties of the product. Nominal values are often used as a convenient way to describe a product, but should not be relied upon for precise engineering calculations or material selection.
In summary, guaranteed values provide the highest level of certainty, typical values provide a guide to the expected properties, and nominal values provide a general description of the product. When selecting a material, it's important to consider the level of precision required for the application and to use the appropriate value accordingly.