The present work deals with the comprehensive study of the effect of combination of high-temperature thermo-mechanical (HTTM) treatment and multistep austempering on wear, corrosion and low-cycle fatigue (LCF) behavior of the new deformable austempered ductile irons (DADI). The research was conducted in laboratory conditions followed by field tests carried out in Caspian oil well environment. Two compositions of DADI were cast for the experiments: (1) high-silicon (2.2 - 2.5% Si) and low-alloyed (Mo, Cu), and (2) low-silicon (0.5 - 0.85% Si) and aluminum-containing (1.5 - 2% Al). The efficient production technology for fabrication of critical parts of oil well pumps from the new DADI, currently produced from steels, has been developed. Field tests conducted in the oil fields with the two deep-well pumps (DWP), “standard” (with the conventional, steel parts) and “tentative” (with the DADI parts), were performed for comparative assessment of performance parameters of the developed material. After tests, the rates of depletion of barrel-plunger pairs were measured. The obtained data show that the developed, new, cast irons may be an efficient substitute for critical steel parts of deep-well pumps, since the pumps fabricated from the offered DADI have better performance parameters than the pumps made from conventional steel.