Extending sleeve life in a borehole pipe by thermocyclic treatment

详细

The wear resistance of cylindrical bushes in borehole pumps may be improved by thermocyclic treatment of the cast Kh12 steel blanks, including 3–4 cycles over the range 25–950°C, with 30-min holding at the elevated temperature. In that case, a relatively hard martensite layer (HRC 65) is formed at the bush’s working surface. The martensite layer is also characterized by elevated impact strength. The wear resistance of the bush may also be increased by the formation of considerable compressive stress (500 MPa) in a (5–6)-mm layer at the bush’s working surface under the influence of martensitic transformation at the end of heat treatment.