Teräslaji

Teräslaji is a Finnish term used in the metalworking and steel industries to refer to a steel grade or type. It denotes a class of steel defined by its chemical composition and the corresponding mechanical properties, and it is applied in design, manufacturing, and procurement to specify expected performance. The term encompasses carbon steels, alloy steels, and stainless steels, each with characteristic behavior under use and processing.

Etymology and usage: the word teräslaji combines teräs (steel) and laji (kind or type). In Finnish technical literature and industry practice, teräslaji functions as a broad label for a steel category, often accompanied by a more precise standard designation or grade code that identifies exact chemical composition and treatment history.

Classification: carbon steels form a broad group with varying carbon content that influences hardness and strength; alloy steels introduce alloying elements such as chromium, nickel, vanadium, or molybdenum to enhance properties like strength, toughness, or wear resistance; stainless steels are defined by high chromium content and often additional alloying elements to improve corrosion resistance. Tool steels, spring steels, and other specialized subtypes are also described under the umbrella of teräslaji when appropriate for a given application.

Properties and standards: teräslaji classifications guide expected properties such as yield and tensile strength, hardness, toughness, machinability, and weldability. Properties are confirmed through testing and heat treatment procedures, and grade designations often align with international and national standards (for example EN or KS standards) to ensure interoperability in procurement and production.

See also: steel, metallurgy, ferrous alloys, steel grade designation.