mechanical properties tables, they were split into two separate tables. Q195; Q215(A 、 B) Q235(A 、 B 、 C) Q255(A 、 B) Q275; b. Next：The reason analysis of round steel surface crack and the solution measure.Properties and classification of alloy steels (also known as ordinary low alloy steel, HSLA) 1. Their carbon content, microstructure and properties compare as follows: The mechanical properties of structural steel are fundamental to its classification and application. Carbon structural steel. Low Carbon Steels: 17-4 Stainless Steel. II. last two numbers approximate amount of carbon (expresses in 0.01%) Though based on the carbon content, but classified according to the level of main mechanical properties of practical importance. Carbon steel can be classified into three categories according to its carbon content: low-carbon steel (or mild-carbon steel), medium-carbon steel and high-carbon steel . This is the most commonly used commercial classification: i. Metal Classification - Deciphering the Codes Introduction. As per the World Steel Association, steel is an alloy comprising predominantly iron and carbon (2%), manganese (1%) with traces of oxygen, sulphur, phosphorus and silicon.Steel possesses properties that include durability, versatility and strength making it an ideal material for use in building and construction activities. To assist the user in keeping track of which comparison criteria were used for a given steel, each table within a chapter was sequentially numbered and appended with either the letter A or B. a. Mechanical Properties of Structural Steel - S235, S275, S355. Low alloy structural steel. AISI - SAE CLASSIFICATION SYSTEM AISI XXXX American Iron and Steel Institute (AISI) classifies alloys by chemistry 4 digit number 1st number is the major alloying element 2nd number designates the subgroup alloying element OR the relative percent of primary alloying element. Types of carbon steel and their properties. c. General structural steel for a specific purpose. The properties of structural steel result from both its chemical composition and its method of manufacture, including processing during fabrication. It is mainly used to manufacture Bridges, ships, vehicles, boilers, high pressure vessels, oil and gas pipelines, large steel structures, etc. Comprehensive classification (1) Ordinary steel. Product standards define the limits for composition, quality and performance and these limits are used or presumed by structural designers. Commercial steels have carbon, normally, up to 1.5% maximum as the higher carbon content makes the steel extremely brittle. Such as steel for bridge, ship, boiler, pressure vessel, agricultural machinery, etc. Table numbers ending in the Use. ... and also because there are a wide range of heat treatments to choose from to reach a specified hardness or other properties.