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Рассмотрено влияние вида деформирования на эффект Баушингера при циклическом нагружении на примере стали 40 после закалки и высокого отпуска. В таком состоянии сталь обладает достаточной пластичностью, чтобы изучать ее поведение в большом диапазоне степеней деформации. Циклическое нагружение проведено по схемам: растяжение-сжатие, изгиб-выпрямление, кручение реверсивное и одностороннее. Изучены эффект Баушингера и упрочняемость в зависимости от накопленной степени деформации и промежуточной термической обработки в виде низкотемпературного отжига (300 °С-возврат). В результате исследования установлено, что эффект Баушингера проявляется только при деформации растяжением и изгибом. Упрочняемость стали в основном зависит от накопленной степени деформации и практически не зависит от реверсивности. Термическая обработка даже после первого цикла устраняет эффект Баушингера при изгибе, между циклами нагружения и способствует значительному эффекту упрочнения, особенно при сдвиговой деформации. Предел текучести становится равным пределу прочности. Ключевые слова: эффект Баушингера, циклическое нагружение, растяжение, кручение, изгиб This article examines the influence of the type of deformation on the Bauschinger effect under cyclic loading, using the example of steel in grade 40 after quenching and hightemperature tempering. In this state, steel has sufficient plasticity to study the behavior of the material in a large range of degrees of deformation. The cyclic deformation was performed as tension-compression, bending-rectification, reversible torsion and one-sided torsion. The Bauschinger effect and hardening depending on the accumulated degree of deformation and intermediate heat treatment in the form of low-temperature annealing (300 °С-return) was studied. As a result, it was established that the Bauschinger effect manifested itself only when the steel was deformed by stretching and bending. Hardenability of steel depends mainly on the accumulated degree of deformation and virtually does not depend on reversibility. Heat treatment even after the first cycle eliminates the Bauschinger effect when bending, between the cycles, and contributes to a significant strengthening effect, especially with shear deformation. The yield point becomes equal to the strength limit.

It is known that the temperature of the beginning of recrystallization of niobium alloys is increased by introducing refractory metals with atomic sizes close to that of niobium. The addition of nitrogen can also increase the recrystallization temperature of niobium alloys. The temperature threshold of niobium recrystallization depends on the production process, namely, the degree of deformation in cold treatment, the deformation temperature, the initial grain size, the regime of the subsequent heat treatment, etc. However, only a few works have been devoted to the joint effect of deformation, nitriding, and heat treatment on the recrystallization of industrial niobium alloys. The present paper concerns determination of the temperature threshold of recrystallization of industrial niobium alloy 5VMTs after chemical heat treatment and estimation of the relaxation strength of arch springs fabricated from this alloy.The effect of alloying on the temperature of the beginning of recrystallization of niobium alloys is considered in [ 1,2], and the production process is described in [3].

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