Technology of plasma-powder surfacing of parts of oil and gas shut-off valves

Purpose. To obtain already in the first layer of deposited metal high quality and high resistance in a corrosive environment containing hydrogen sulfide.

Specifications. When implementing the technology of plasma-powder single-layer surfacing of parts of oil and gas shut-off valves, the share of base metal in the deposited material is ≤ 5%; the ability to use a wide range of additive powders according to their chemical composition and properties.

Application area. Enterprises of the oil and gas complex, energy, and other industries.

Advantages. Compared to existing technologies, the productivity of the deposited metal has increased significantly (about 30-35%), the use of single-layer surfacing instead of multi-layer can reduce the emission of harmful substances.

Technical and economic effect. Replacing multilayer anti-corrosion arc surfacing with single-layer plasma-powder surfacing can significantly reduce the cost of expensive anti-corrosion surfacing materials and at least double labor productivity. The use of 80Х17Н35С3Р3 alloy powder based on Ni and Fe, instead of powders based on Ni and Co, when surfacing fittings operated in a corrosive environment containing hydrogen sulfide, provides savings of 25…35 dollars per 1 kg of deposited metal. In addition, during plasma-powder surfacing, compared to arc surfacing, fewer harmful substances are released, that is, the developed technology is more environmentally friendly.

Description. The conducted studies showed that in laboratory tests, the preferred indicators of wear resistance, corrosion resistance and heat resistance are the alloy 80Х17Н35С3Р3 based on Ni and Fe. The corrosion resistance in a hydrogen sulfide environment of the proposed alloy and the developed technology for its surfacing is 2.3…2.6 times higher than that of known alloys. The best tribological characteristics were also found in the metal deposited with the powder of this alloy. The friction coefficients of this alloy are stable and low (0.15), and its wear resistance is twice as high as that of other alloys. Based on these studies, an industrial technology for single-layer plasma-powder surfacing of corrosion-resistant alloys on shut-off valve parts, which are operated in corrosive environments containing hydrogen sulfide, has been developed. Using the developed technology, plasma cladding of oil and gas valve parts was carried out. The welded parts were transferred to PJSC Konotop Reinforcement Plant for industrial testing.

More details…