Effects of type of binder and its composition on the welding and properties of electrodes with basic coatings

Pokhodnya, I. K.; Ponomarev, V. E.; Milichenko, S S; Skorina, N.V.; Макаренко, В. Д.; Marchenko, A.E.; Gorpenyuk, V N

doi:10.1080/09507118709452094

Cited by 5 publications

(7 citation statements)

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“…This problem is solved by the use of surface hardening technologies (surface plastic deformation, chemical-thermal treatment (CTT), surface hardening) for low-or medium-carbon steels treated with the structure of tempering sorbets. The result is steels with a strong surface and a viscous plastic core [11,12]. CONCLUSIONS 1.…”

Section: Research Results and Their Discussionmentioning

confidence: 93%

Investigation of mechanical properties and crack resistance parameters of steel reinforcements of reinforced concrete structures of long-term special term

Kulikov¹,

Makarenko²,

Khoruzhiy³

et al. 2021

UWT

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It is known that the fatigue process begins with the plastic deformation of the surface layers of the metal fittings. Moreover, the displacement of dislocations under conditions of re-alternating loads is observed at loads below the elastic limit of the metal. The rate of local plastic deformation during cyclic deformation is several orders of magnitude higher than the rate of deformation under static loading. Dislocation slip begins in grains with a favorable orientation near stress concentrators. As the number of cycles in the surface layers increases, the density of dislocations and the number of vacancies increases. When the base number of NR cycles is reached, a surface reinforced layer of metal with a large number of germinal cracks is formed, the size of which does not reach a critical value. Increasing the number of cycles cannot cause further development of fracture in such a layer. Only when the stresses exceed the endurance limit of the crack reach a critical length, after which the process of their discharge into the main crack begins with the spread of the latter. The results of experimental studies indicate a strong effect of diffusion hydrogen on static and cyclic parameters of crack resistance. It was found that with increasing flooding, especially when the hydrogen content exceeds 5 cm3/100g, both static strength and long-term strength (fatigue) decrease sharply. Moreover, for these areas of hydrogen solution in reinforcing steel is characterized by a viscous nature of fracture, while for heavily flooded reinforcement (from 5 to 12 cm3/100g is characterized by brittle fracture by the mechanism of microfission in the hardened (martensite or troostite structure). allowed to determine the optimal hydrogen content in reinforcing steel (3…5 cm3 /100g), the excess of which will reduce the crack resistance of reinforcement during long-term operation, especially in corrosive environments. The results of the research confirm the above data. bainite structure y sharply reduces the crack resistance of reinforcing steel, which makes it impossible to use in the manufacture of reinforcement involved in reinforced concrete structures designed for long-term operation (more than 50…60 years). Thus, the obtained diagram can be recommended to designers of reinforced concrete structures for hydraulic purposes, as it greatly facilitates the reasonable choice of reinforcement in the development of reinforced concrete structures for responsible and long-term use.

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Section: Research Results and Their Discussionmentioning

confidence: 93%

Investigation of mechanical properties and crack resistance parameters of steel reinforcements of reinforced concrete structures of long-term special term

Kulikov¹,

Makarenko²,

Khoruzhiy³

et al. 2021

UWT

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“…According to the developed diffusion model of hydrogen segregation, the critical value of hydrogen depends on the grade of steels, stress state, operating conditions. In our case (underground sewer system) the critical level of hydrogen in the fittings is approximately 5…6 cm 3 /100g [11]. This volume is sufficient to dramatically accelerate the process of nucleation and development of cracks (submicrocracks).…”

mentioning

confidence: 79%

“…The effect of hydrogen on the endurance limit and static strength limit was investigated on samples of steel grade 20ГС which before experiments were flooded to the required level in special chambers with hydrogen medium. The hydrogen content in steel samples cut from reinforcing bars was determined by vacuum melting on a chromatographic unit VH-6 company Gereus (Germany) [10,11]. The duration of flooding of the samples was about 72…78 hours, depending on the required volume of flooding.…”

Section: Methods Of Experimental Research Materials Criteria and Equipmentmentioning

confidence: 99%

Investigation of the relationship between the strength limit and the long time fatigue of steel reinforcements of reinforced concrete structures

Chernyshеv¹,

Makarenko²,

Khomutetska³

et al. 2021

TIT

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The results of experimental studies have shown a strong effect of diffusion hydrogen on the static and cyclic parameters of crack resistance of reinforcing steel. It was found that with increasing flooding, especially when the hydrogen content exceeds 5 cm3/100g, both static strength and long-term strength (fatigue) decrease sharply. Moreover, these areas of hydrogen solution in reinforcing steel are characterized by a viscous nature of fracture, while for heavily flooded reinforcement (from 5 to 12 cm3/100g) is characterized by brittle fracture by the mechanism of microcracking in the hardened (martensite or troostite structure). The analysis of the obtained experimental results allowed to determine the optimal hydrogen content in the reinforcing steel (3…5 cm3/100g), the excess of which can cause a decrease in the crack resistance of the reinforcement during long-term operation, especially in corrosive environments. The mechanism of hydrogen influence on crack resistance of metal at static and alternating loading which consists in diffusion and dislocation movement of hydrogen in structure of a reinforcing core that as a result that causes strong flooding of steel and its embrittlement is offered. It is established that carbon and low-alloy sieves, which are characterized by ferritic-pearlitic and sorbitol structure provide high resistance, especially to long-term fatigue, and the transition to steels with a structure of martensite or tempered (transient structure of bainite) structure of bainite sharply reduces reinforcing steel, which makes it impossible to use in the manufacture of reinforcement involved in reinforced concrete structures designed for long-term operation (more than 50…60 years). Thus, the obtained diagram can be recommended to designers of reinforced concrete structures for hydraulic purposes, as it greatly facilitates the reasonable choice of reinforcement in the development of reinforced concrete structures for responsible and long-term use.

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“…However, it should be noted that the absolute values of σtssc should not yet be used in the design of reinforced concrete structures for critical purposes, for example for hydraulic underground structures due to lack of reliable methods for determining and predicting their fatigue (long-term) strength, as they can change and carbon gas and their partial pressures, pH, ambient temperature, process stops, condition of structures, etc.) [4,9,12]. Therefore, in calculations of long-term strength and load-bearing capacity of reinforcing steels of reinforced concrete structures, determining the diameter of reinforcement, the initial parameter may be the minimum allowable value of the yield strength of steel σmin 0.2, and the suitability of structural materials is evaluated by ultimate stresses [10]: ktssc = σtssc/σmin 0.2 (Fig.…”

Section: Skrn Researchmentioning

confidence: 99%

“…In domestic and foreign studies by a number of authors it is noted that the reasons for the decrease in resistance to SCRN and VIR of some carbon and low-alloy steels may be the presence of silicates, as well as microleaching of individual alloying elements or impurities, or violation of thermomechanical modes of reinforcement rods [12,13].…”

Section: Study Of Corrosion Fatigue (Long-term Strength)mentioning

confidence: 99%

Research of corrosion and mechanical resistance of reinforce-ment steels designated for operation in hydraulic structures

Sukach¹,

Киндрачук²,

Макаренко³

2021

UWT

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Analytical inspection showed that with a long service life of reinforced concrete structures of hydraulic structures, their individual elements such as reinforcing bars are destroyed due to insufficient fatigue and corrosion strength of the reinforcement metal. They occur mainly under the action of the main variable loads − bending, vibrations of reinforced concrete slabs, mechanical and erosion of the environment. The main causes of failure of the valve are its rupture and wear due to repeated action of force factors. The surface zone of the reinforcement in connection with concrete is especially intensively destroyed due to weak adhesion strength. The use of low-strength reinforcing steels can also be one of the reasons for the failure of reinforcement joints with concrete. Improving the corrosion and mechanical reliability of reinforced concrete structures of hydraulic structures is possible through the use of: for the manufacture of reinforcing bars which are the main power structure of reinforced concrete economically modified alloy steels, which undergo complex heat treatment and are characterized by high corrosion and fatigue properties. alternating) loads; The resistance against SCRN, VIR and corrosion-mechanical fatigue of reinforcing steels intended for the construction industry has been studied. It was found that the experimental steels, economically modified REE, copper-nickel, especially chromium niobium and vanadium meet the requirements of the International Standard NACE MR 0175-96 on chemical composition and mechanical properties, and steels of grades10HSNDA and 20F do not have a sufficiently high resistance SCRN <limits σ0.2min) and corrosion-fatigue failure, and steels of grades 20F and 06G2B showed low resistance to VIR (CLR> 6% and CTR> 3%). Therefore, it is necessary to carry out a full (100%) input control of corrosion and mechanical resistance of all materials involved in the manufacture of reinforced concrete structures for hydraulic purposes for operation in hydrogen sulfide-containing environment.

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Effects of type of binder and its composition on the welding and properties of electrodes with basic coatings

Cited by 5 publications

References 0 publications

Investigation of mechanical properties and crack resistance parameters of steel reinforcements of reinforced concrete structures of long-term special term

Investigation of mechanical properties and crack resistance parameters of steel reinforcements of reinforced concrete structures of long-term special term

Investigation of the relationship between the strength limit and the long time fatigue of steel reinforcements of reinforced concrete structures

Research of corrosion and mechanical resistance of reinforce-ment steels designated for operation in hydraulic structures

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