Effect of original structure on the strengthening process and the properties of bands of alloy 36NKhTYu

Conclusions

• 1. Deformation and refining of austenite grains, the grain boundary length increasing, results from cold plastic deformation of alloy 36NKhTYu. With relatively small deformation (10–30%) the process is accompanied by slip in certain systems of planes, and with 40% deformation or more by formation of strain twins.

• 2. Cold plastic deformation induces a substantial increase in the strength characteristics due to the increase of the dislocation density (to 10¹¹ cm⁻²). After quenching from 1100° and 70% cold plastic deformation the mechanical properties of bands 0.15 mm thick are as follows: σ_b = 110 kgf/mm², σ_0.2 = 108 kgf/mm², δ=3%.

• 3. The change in the structure of the cold worked bands in the process of plastic deformation has a large effect on the decomposition of the solid solution and the formation of strengthening γ′ phase during aging. The same level of properties (σ_b = 155 kgf/mm², σ_0.2 kgf/mm²) after quenching from 950 and 1100° is attained if the alloy is deformed 50 and 70% respectively before aging.

• 4. Cold working by rolling during production of thin bands makes it possible to obtain high strength of the material after aging, improve the quality of parts due to the higher rigidity of the bands, and reduce the possibility of nicks, dents, and other surface defects.