BS 970 Steel

BS 970 is a British standard for specifying steel materials used in various applications. It covers a wide range of steel grades, each designed for specific purposes and properties. The standard has been divided into several parts, each focusing on different aspects of steel classification and specifications.

Key points about BS 970 steel include:

1. Scope: BS 970 specifies requirements for the chemical composition, mechanical properties, and other characteristics of carbon, alloy, and stainless steels used in the manufacture of various components, machinery, and structures.
2. Classification: The standard classifies steels into various categories, including carbon steel, alloy steel, and stainless steel. Each category is further divided into numerous steel grades based on their composition and properties.
3. Carbon Steel: BS 970 includes several carbon steel grades, such as BS 970 080M40 (EN8), BS 970 070M20 (EN3), and BS 970 080A42 (EN8D). These grades are commonly used in general engineering, automotive, and construction applications.
4. Alloy Steel: Alloy steel grades under BS 970 encompass a wide range of compositions and properties. Examples include BS 970 817M40 (EN24), a high-strength alloy used in applications like gears and shafts, and BS 970 826M40 (EN26), known for its excellent high-temperature strength.
5. Stainless Steel: BS 970 also covers various stainless steel grades, such as BS 970 420S37 (EN56C), a martensitic stainless steel, and BS 970 303S31 (EN58M), a free-machining stainless steel.
6. Heat Treatment: The standard provides guidance on heat treatment processes for improving the mechanical properties of steel grades, including processes like quenching and tempering.
7. Surface Finish: BS 970 includes information on surface finish requirements, such as machining allowances and tolerances.
8. Applications: Steel grades specified in BS 970 find use in a wide range of industries, including manufacturing, construction, automotive, and aerospace. They are utilized for manufacturing components like bolts, shafts, gears, and structural elements.
9. International Equivalents: Some BS 970 steel grades have equivalent designations in other international standards, such as the EN (European Norm) and AISI/SAE (American Iron and Steel Institute/Society of Automotive Engineers) standards.

It’s important to note that while BS 970 was widely used in the UK and other Commonwealth countries, it has largely been replaced by European and international standards like EN and ISO. However, historical references to BS 970 grades and specifications can still be found in many industries, and the knowledge of these steel grades remains valuable in engineering and manufacturing contexts.