Welding of low-carbon steel, modes, types and methods of welding

High quality welding of joints The welding of low-carbon steel parts is usually carried out in an industrial environment, since a whole range of measures and conditions must be strictly observed to ensure reliability and proper welding of metals.

Low-carbon steels Alloys with a low carbon content, reaching a maximum of 0.25%, are called low-alloy steels. Steels containing up to 4% of alloying elements (carbon content is not taken into account) are called low-alloy steels.

Low carbon and low-alloy Structural steels are distinguished by their good weldability. This makes them the most widely used and widespread metals in the construction of structures and mechanisms.

Welding of low-carbon steel It is successfully used in most welded structures in the form of sheets and rolled sections. This alloy is extremely weldable, and a number of requirements are required to achieve a strong bond between the two metals, ensuring a clean, defect-free joint along the entire weld perimeter. It is crucial that the mechanical properties of the weld, the weld zone, and the weld joint meet the minimum mechanical properties of the base metal and do not fall below established standards.

Depending on the degree of deoxidation, ordinary quality steels are divided into:

• boiling - kp;
• semi-calm - ps;
• calm - sp.

As with other welding processes, there should be no lack of fusion, cracks, pores, or undercuts. The weld joint must be sufficiently strong to avoid brittleness. Sometimes  welding low-carbon steel Requirements for the corrosion resistance of welded joints are also required. If the product will be subject to vibration, impact loads, temperature changes, etc., welding is also used.

Low-alloy wire grade Sv-10G2 is used in electroslag welding. This choice ensures uniform strength of the metal and weld. Heat treatment increases impact toughness but does not improve the strength or ductility of the weld metal.

Boiling steel

Steels in this group contain approximately 0.07% of silicon (Si). They are produced by incomplete deoxidation of the steel with manganese. When exposed to low temperatures, this steel becomes brittle. After welding, it may age in the heat-affected zone.

They became calm

Killed steels contain at least 0.12% silicon (Si). They are produced by deoxidizing steel with silicon, manganese, and aluminum. They have a uniform distribution of sulfur and phosphorus. Killed steels are less responsive to heating and less prone to aging.

Semi-quiet steel

This type of steel has intermediate properties between calm and boiling steel. Carbon steels are produced in three grades of ordinary quality.

Group A steels are not used for welding; they are specified based on their mechanical properties. The letter "A" is not included in the steel designation, for example, "St2."

Steels of groups B and V are classified according to their chemical and mechanical properties, respectively. The steel group designation is preceded by the letter BSt2, BSt3.

Semi-killed steel grades 3 and 5 can be supplied with increased manganese content. These steels are designated with the letter G after the grade designation (e.g., BSt3Gps).

For the manufacture of critical structures, ordinary steels of group B should be used. The manufacture of welded structures from low-carbon steels of ordinary quality does not require the use of heat treatment.

What is the weldability of low-carbon steels?

What is the weldability of low-carbon steels? It can be welded fairly well, using all welding methods. The key is high-quality welds across the entire length of the joint. Various arc welding methods can be used, but this increases the metal content and weight of the part. Therefore, its strength properties need to be improved; alloying elements are added to the steel to strengthen the melt and enhance chemical bonding.

What is the weldability of low-carbon steels? When a weld cools rapidly, its strength increases, but its ductility decreases. Cooling rate is especially important in arc welding. The quality of the weld depends on both the properties of the weld metal and the properties of the metal in the weld zone.