Low-carbon steel and its main characteristics

Low carbon steel – This alloy contains no alloying elements, contains impurities, and has a low carbon content of up to 0.25%. This alloy does contain manganese and silicon, but due to their low percentages (manganese – no more than 1%, silicon – no more than 0.8%), they do not have a noticeable alloying effect on the material. Low-carbon steel It is distinguished by its softness and low manganese content.

This alloy's softness precludes precise surface finishing. However, its softness, toughness, and ductility make it possible to create case-hardened blanks and parts for subsequent welding/carburizing. The alloy's machinability is very poor, and the surface of the workpiece is highly rough. Precision machining is quite difficult.

Properties of low-carbon steel

Properties of low-carbon steel They do not have high strength properties. On the contrary, their ductility and toughness are high. Low-carbon steel grades are sometimes used for case-hardened products, which require additional case-hardening to achieve the required hardness and impart wear resistance through further processing. Products made from this steel are weldable and forged quite well.

Properties of low-alloy steel These properties do not allow for full-scale work with this metal. However, normalizing and cold drawing processes can significantly improve surface finish. Due to their good ductility (δ = 33…23%), low-carbon steels can be successfully cold-formed without losing their mechanical properties, as local stress is evenly distributed and cracks do not form. This steel is easily hardened and weldable.

Properties of low-carbon steel have a number of disadvantages:

• low strength Te = 330…460 MPa, Sto.2 = 200…280 MPa;
• low impact strength;
• It is very sensitive to mechanical aging, as it experiences stress concentration under repeated loads, so it is not used to make products that are subject to repeated loads.

Low-carbon steel grades and their main applications

Low-carbon steel grade Depending on its composition, it has specific industrial uses. This type of alloy includes 05 kp, 08, 10, 10 ps, which are actively used for the production of washers, gaskets, and other low-load structural and machine components. Depending on which brand low-carbon steelThe alloy finds application in various industries. For example, high resistance to static hydrogen fatigue is demonstrated by:

• 20;
• VMStZsp;
• C75;
• APS 10M4;
• 18X1PMF.

Next brands low-carbon steel are used as cemented:

• 10;
• 15;
• 20.

In the production of gears with subsequent cementation, the following are used:

• St20;
• St20G.

Alloys:

• EP620;
• EP355;
• 03 are used as charge blanks and produced in the form of rods of various sizes. This charge additive is used in the smelting process of special alloys for the production of individual parts and special rolled products.

To create welded structures, the following are used: low-carbon steel grades:

• St0;
• St1sp;
• St1ps;
• St1kp;
• St2sp;
• St2ps;
• Grade 2;
• St3sp;
• ST3 class (GOST 380);
• steel 10;
• steel 15;
• steel 20 (GOST 1050);
• S235-S295;
• P235-P295 (EN 10025, EN 10027-1, EN 10028-2).

For alloys produced in the CIS countries, as well as in accordance with established GOST regulations, steel marking is carried out as follows:

• the letter preceding the brand name indicates the group to which the alloy belongs (there are three groups in total, A, B, C; group “A” is not indicated on the marking);
• "St" or "steel" indicates that the alloy is common;
• the first digit in the mark indicates the GOST number, a number from 0 to 6;
• the degree of deoxidation is indicated by the following abbreviations: “sp”, “ps”, “kp” (in the case of steels of group “A”, the designation “sp” is not indicated and is taken as such by default);
• the next digit is the steel category number, according to GOST from 0 to 6. The first category is not indicated in the designation;
• If the marking contains a dash between the first and second digits, this means that no requirements were imposed on the steel regarding the degree of deoxidation.