{"id":382,"date":"2019-01-07T15:15:38","date_gmt":"2019-01-07T13:15:38","guid":{"rendered":"https:\/\/fractory.co\/?p=382"},"modified":"2024-01-26T17:18:42","modified_gmt":"2024-01-26T15:18:42","slug":"structural-steels-s235-s275-s355-s420-and-their-properties","status":"publish","type":"post","link":"https:\/\/fractory.com\/structural-steels-s235-s275-s355-s420-and-their-properties\/","title":{"rendered":"Structural Steels S235, S275, S355, S420 and Their Properties"},"content":{"rendered":"

Structural steels are ferrous metals<\/a>\u00a0that belong to the group of mild steels<\/a>. In this post, we’ll cover the uses, mechanical properties and chemical composition of the most used grades – S235, S275, S355 and S420.<\/p>\n

Structural Steel Applications<\/h2>\n

Structural steels are the most widely used steels because of their sufficient qualities and comparatively low price. This combination makes them useful in different sectors. Every year, about 25% of structural steels are used in the construction of buildings<\/a>.<\/p>\n

Mechanical engineers favour it when building machinery that does not have many special needs like high durability or resistance to heavy loads.<\/p>\n

Sometimes resistance to\u00a0material\u00a0wear<\/a> is important, while maintaining a low weight itself. This is the case with forestry and mining equipment, for example. It is then advisable to turn to wear-resistant and high-strength steels, like Hardox and Strenx.<\/p>\n

Corrosion Protection<\/h2>\n

Structural steels require an extra layer of protection against the weather. They tend to corrode easily, so powder coating<\/a> is commonly used, irrespective of a machine’s surroundings – inside or outside. For a lasting coating, the metal surface should be pretreated (chemical etching or phosphating<\/a>) and cleaned (blasting, washing or wiping) beforehand.<\/p>\n

\"Corroded
Corrosion<\/a> finds its way despite the paint<\/figcaption><\/figure>\n

Another more durable way to protect structural steel against corrosion is galvanisation<\/a>. The quality and applicability of a zinc coating depends on the steel’s chemical composition – the percentage of phosphorus (P) and silicium (Si) are decisive:<\/p>\n