The sheer number of ferrous and non-ferrous metals and their alloys makes it difficult to structure metal specifications in a single, uniform way. In practice, metal specifications are often defined by standards, each of which may describe metal products, delivery conditions, and material properties in its own particular manner.
Materials from around the world are commonly grouped by chemical composition or mechanical properties, and sometimes by delivery condition, such as flat products, bars, or pipes. It is important to remember that most metal specifications are complex documents that cannot be reduced to a single line of text. The sections below outline the major standard systems in use today.
Table 1. Typical Information Contained in a Metal Specification
Specification Element
Purpose
Example
Material designation
Identifies the material or alloy
ASTM A240, EN 10088
Chemical composition
Defines allowable alloying elements and composition limits
Chromium, nickel, carbon content
Mechanical properties
Specifies minimum performance requirements
Tensile strength, yield strength, hardness
Product form
Identifies the supplied product
Plate, sheet, bar, pipe, wire
Delivery condition
Defines the required condition of supply
Annealed, normalized, quenched & tempered, cold worked
Processing requirements
Specifies manufacturing or heat-treatment requirements where applicable
Heat treatment, forging, rolling, welding requirements, etc.
Inspection & testing
Defines verification and acceptance methods
Tensile testing, chemical analysis, hardness testing
In the United States, the most widely used metal specifications are those published by ASTM. These specifications represent a consensus drawn from the producers, fabricators, and users of metal products.
Many ASTM specifications have been adopted by the American Society of Mechanical Engineers (ASME) with little or no modification. ASME adds the prefix "S" to the ASTM designation, so ASME SA 249 and ASTM A 249 are, for example, the same specification. Similarly, SAE often relies on ASTM specifications to define the properties of bars, wires, and other products.
Euronorm (abbreviated EN) is a harmonized standardization system shared across European countries. Although EN is accepted and effectively used throughout Europe, metal specifications based on older national systems still appear in many documents. These "obsolete" systems include the German DIN, British BS, French AFNOR, and Italian UNI, all of which remain relevant in practice.
Japanese JIS standard specifications are developed by the Japanese Industrial Standards Committee (JISC) in Tokyo. This is a well-developed system that has frequently served as the basis for other national metal specification systems across Asia and the Pacific region, including the Korean, Chinese, and Taiwanese systems.
Other widely used metal specifications include those issued by the International Organization for Standardization (ISO), as well as the Russian GOST. GOST is, in practice, the de facto standard throughout the Commonwealth of Independent States.
A specification only tells part of the story, since it draws on everything from a material's chemistry to the way its performance is measured and governed. The rest of our Metal series covers that wider context. Metal Composition explains the chemical makeup that specifications set limits on, while Metal Properties looks at the mechanical and physical behaviour those documents are written to guarantee. Metal Grades shows how the resulting materials are organised into families, and Metal Standards steps back to explain the broader frameworks that specifications operate within, which is a useful distinction to keep clear. When you need to match a specified material to its counterpart elsewhere, Metal Equivalents and Cross-Referencing walks through how that comparison is made.
Metal specifications define the products, delivery conditions, and properties of metals and their alloys. They provide a consistent basis for grouping materials by chemical composition, mechanical properties, or delivery form, and act as a reference shared by producers, fabricators, and users.
Many ASME specifications are ASTM specifications adopted with little or no modification. ASME simply adds the prefix "S" to the ASTM designation, so ASME SA 249 and ASTM A 249 refer to the same specification.
No. Although Euronorm (EN) is the harmonized European system and is used throughout Europe, older national standards such as the German DIN, British BS, French AFNOR, and Italian UNI still appear in many existing documents and remain relevant.
The JIS system, developed by the Japanese Industrial Standards Committee, is well elaborated and has often been used as the basis for other national systems across Asia and the Pacific, including the Korean, Chinese, and Taiwanese standards.
The most widely used international specifications are those issued by the International Organization for Standardization (ISO). The Russian GOST system is also significant and functions as the de facto standard throughout the Commonwealth of Independent States.