Carbon steel, GOST, grades, properties, types, qualities

Carbon steel — is a tool steel containing 0.04-2% carbon and always present impurities, not containing alloying elements. Carbon steel Depending on the percentage of carbon content, it is divided into three main types:

• low-carbon;
• medium-carbon;
• high-carbon.

This material requires heat treatment to become hard and strong enough to withstand the loads required for critical components. SAW is used in tool manufacturing.

Carbon steel classified as:

• high quality, contains up to 0.035% phosphorus and sulfur;
• high quality, contains up to 0.025% phosphorus and sulfur.

Carbon steel grade

Carbon steel grade which have a wide variety. According to GOST 1435-99, the metallurgical industry produces the following grades of carbon tool steel:

• U7;
• U7A;
• U8;
• U8A;
• U9A;
• U10;
• U11;
• UNA;
• U12;
• U12A;
• U13;
• U13A.

The letter U indicates that the steel is carbon. The letter A at the end of the grade designates a high-quality steel group with a higher sulfur and phosphorus content. The numbers in the designation indicate the percentage of carbon in the alloy, multiplied by 10 for convenience. The absence of the letter A indicates high-quality steel. The number indicates the carbon content, which is medium, while G indicates a high manganese content.

Carbon steel grade They are inexpensive and extremely hard, which distinguishes them from other tool steels. These grades have low wear resistance and heat resistance. Carbon steel grade U7 and U7A grades are successfully used for woodworking tools—axes, chisels, and gouges—as well as metalworking tools—chisels, forging dies, metalworking tools, hammers, sledgehammers, screwdrivers, nippers, etc. U8, U8A, U8G, and U8GA grades are used to manufacture tools that are highly resistant to heat during operation and withstand rotational loads—wood routers, countersinks, rip saws, circular saws, knurling rollers, etc.

Carbon steel grade U10 and U10A are used to make needle wire and tools that don't heat up the cutting edge. U13 and U13A are used for tools requiring increased wear resistance, including razor blades, surgical instruments, and tools for engraving metal and stone.

Carbon steel GOST This standard was introduced to ensure that buyers could purchase steel with specific properties and composition. If a consumer sees material that complies with GOST, they can be confident in its quality. GOST stands for a specific standard that manufacturers' products must meet.

Carbon steel grade Steel has various characteristics. The division of this material into grades is necessary for its classification. For example, a factory produces construction tools. This requires the use of steel with high strength properties. This is where a steel marking system comes in. The manufacturer already knows that a certain steel grade has the required characteristics and can purchase it immediately from the supplier, without wasting time examining each new batch of steel.

Alloys differ from each other by the method of creation. For example, ordinary quality carbon steel It is smelted in open-hearth furnaces. The material is then cast into large ingots. Ordinary carbon steel Contains many non-metallic inclusions. Striping can be seen along the cross-section of this material when rolled.

They are smelted in open-hearth furnaces high-quality carbon steels, while the production process is subject to very strict requirements. Adherence to all standards results in a material with a low content of non-metallic inclusions. The highest quality metals are produced in electric furnaces, which are distinguished by excellent mechanical properties.

Carbon steel of ordinary quality grade There are many grades. Among them are St1kp, St2kp, St3kp, St4ps, and so on up to St6sp. The first letters "St" are an abbreviation for "Steel." The following number denotes the grade number assigned to the material depending on its chemical composition. The higher the number, the higher the carbon content in the alloy. Some designations include the letter "G." This indicates that manganese has been added to the alloy, and its content in the mass fraction of steel is 0.8% or more. At the end of the marking are two letters indicating the oxidation state of the material. "Sp" means calm, "kp" means boiling, and "ps" stands for semi-calm.

Ordinary carbon steel GOST assigned 380-2005. It is excellent for the production of hot-rolled products.

Carbon steel qualities Depend on their manganese content. There are alloys with normal manganese content (up to 0.8 TP3T) and with higher manganese content (up to 1.2 TP3T). Manganese increases the hardenability and strength properties of steel. However, manganese also makes the material less ductile and malleable.

The difference between alloy and carbon steels

Carbon alloy steels They are so called because certain metals are added to them during production. This is done to give the material the desired mechanical or chemical properties.

Carbon and alloy steels They have one important difference. Carbon steel is created using the same materials as the original raw material, including iron, carbon, and harmful impurities such as phosphorus and sulfur. If other metals, such as chromium or copper, are added to the material, the alloy is called an alloy.

Features of structural steel

Carbon structural steels They are used in the production of various mechanisms and machine bodies. They are also used to create structural elements. Alloys containing molybdenum and nickel are used in the production of mechanical engineering equipment. These elements increase the toughness of the alloys.

Structural steels used in construction contain low levels of alloying elements. Their distinguishing feature is their excellent weldability.

Methods of welding carbon steels

Welding of carbon steels This can be accomplished using several methods. If submerged arc welding is chosen, welding wire is required. AN-348-A and OSC-45 are used as fluxes. Welding should be performed at low currents.

Argon arc welding with a non-consumable electrode is often used. The main problem with this method is the formation of pores. This is due to the insufficient deoxidation of the base metal. To eliminate this problem, it is necessary to reduce the amount of base metal in the deposit. The welder must select the correct welding mode. The work is performed with direct current (DC) and straight polarity.

Qualities of carbon steel

Properties of carbon steel are significantly improved when it is heat treated.

After this process, the alloy acquires high hardness, strength, the ability to respond to heavy loads, and withstand high temperatures when the cutting edge is in operation. Qualities of carbon steel This makes it one of the most sought-after types of steel. The material's characteristics and properties are regulated during smelting, ensuring the required percentage content of the alloying elements is maintained. Qualities of carbon steel allow it to be successfully welded and processed by cutting, alloying elements introduced into it change its properties, mechanical properties increase, and cold brittleness decreases.

Types of carbon steel

Types of carbon steel are divided into:

• A - supplied according to its mechanical properties, which can be changed;
• B - according to its chemical properties, while the mechanical properties change, and the level is determined by the chemical composition;
• B- are supplied according to chemical content and their mechanical properties for parts.

Types of carbon steel According to the type of processing, the following are distinguished:

• hot rolled;
• forged;
• calibrated;
• round with a special surface finish.

According to the degree of deoxidation:

• semi-calm;
• calm;
• boiling.