Welding and depositing are the most common ways to restore worn-out and damaged parts during machine repairs. They are widely used both to eliminate damage (cracks, breakages and tears), and to build-up worn-out surfaces.

Restoration of parts from structural and alloy steels

NTV Scientific & Technical Firm restores and repairs parts made of structural and alloy steels and alloys taking into account their process properties and requirements to mechanical properties of the deposited metal.

The greatest economic effect is achieved when restoring large parts such as crane rollers, shafts, etc.

When restoring and repairing parts by electric welding, in order to obtain a good-quality weld joint or deposited layer of specified quality, the correct choice of electrode (wire) and welding technology are of paramount importance. The choice of electrode depends on the nature of the defect to be repaired, the steel grade of the part, and the requirements for the deposited layer.

The weldability of steel can be divided into four groups:

  • good weldability — steels with low carbon content (carbon and low alloy)

  • satisfactory weldability — carbon and low alloy steels with carbon content of 0.3–0.4%;

  • limited weldability — carbon and low alloy steels with carbon content of 0.45–0.50%;

  • poor weldability — with carbon content of more than 0.55%.


Therefore, when welding and depositing medium, high carbon and alloy steels, preheating of parts is required.

When welding such steels, subsequent tempering at a temperature of 600–650°C or at 400°C for 2 hours also gives good results.

Restoration of parts made of gray, ductile and high-strength cast irons

NTV Scientific & Technical Firm has developed a technology for welding of cracks and restoring worn-out surfaces of parts (ICE blocks and manifolds, reducing gearbox housings, electric motors, etc.) made of gray, ductile and high-strength cast iron using nickel-containing wire and cold and semi-hot semi-automatic welding. Deposited metal has a hardness of 150-200 HB and can be easily processed by the cutting tool.

To eliminate defects, gas and electric arc welding is used. With the right choice of welding methods and their careful implementation, the quality of restored parts, as a rule, meets operational requirements.

You can find more detailed examples of executed works in the gallery of works

Restoration and repair of the filter unit