Corrosion-resistant austenitic-ferritic steel 0Kh20N6MD2T

Conclusion The commercially used corrosion-resistant steel 0Kh20N6MD2T can be hardened by aging, without distortion, to a yield point of at least 60kg/mm² and ultimate strength of at least 80 kg/mm² with reduction in section of at least 50%, specific elongation no less than 20%, and impact strength at least 6 kgm/cm² in bar material. In cast material the elongation is at least 15% with the same strength characteristics.The steel has good welding and forming characteristics; it is used for manufacturing welded apparatus of complex shape made by deep drawing.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 71–74, June, 1967.     

Weldability evaluation of high tensile plates using GMAW process

High tensile plates, SAILMA-450 high impact (HI) (yield strength, 45 kg/mm² minimum; ultimate tensile strength, 57 kg/mm² minimum; elongation, 19% minimum; Charpy impact energy 2.0 kg.m at −20 °C minimum) were successfully developed at the Steel Authority of India Ltd., up to 32 mm plate thickness. Since then the steel has been extensively used for the fabrication of impellers, bridges, excavators, and mining machineries, where welding is an important processing step. The present study deals with the weldability properties of SAILMA-450 HI plates employing the gas metal arc welding process and carbon dioxide gas. Implant and elastic restraint cracking tests were conducted to assess the cold cracking resistance of the weld joint under different welding conditions. The static fatigue limit values were found to be in excess of minimum specified yield strength at higher heat input levels (9.4 and 13.0 kJ/cm), indicating adequate cold cracking resistance. The critical restraint intensities, K _cr, were found to vary between 720 and 1280 kg/mm², indicating that the process can be utilized for fabrication of structures involving moderate to low restraint intensities (200 to 1000 kg/mm²). Lamellar tear tests conducted using full thickness plates at heat input levels ranging from 10 to 27 kJ/cm showed no incidence of lamellar tear upon visual, ultrasonic, and four-section macroexamination. These tests were repeated using machined plates, such that the midthickness of the plates (segregated zone) corresponded to the heat affected zone of the weld. No cracks were observed, indicating good lamellar tear resistance of the weld joint. Optimized welding conditions were formulated based on these tests. The weld joint was subjected to extensive tests to assess the physical properties and soundness of the weld joint. The weld joint exhibited good strength (64.7 kg/mm²) and impact toughness (5.7 and 3.5 kg.m at −20 °C for weld metal and heat affected zone properties. Crack tip opening displacement (CTOD) tests carried out for parent metal, heat-affected zone, and weld metal resulted in δm values of 0.41, 0.40, and 0.34 mm, respectively, which indicates adequate resistance to cleavage fracture. It was concluded that the weld joint conforms to the requirements of SAILMA-450 HI specification and ensures a high integrity of the fabricated products.     

Effect of temperature on failure of gas cylinders

A number of ammonia cylinders burst during open storage in a field in the month of June. The cause of failure was studied. No flaws in the cylinder material were detected. Under normal conditions, the tangential stress (5.4 kg/mm ² )in the cylinder is well below the yield strength (49 kg/mm ² ). The tangential stress increases with the rise of temperature of the ammonia. As long as some vapor exists inside the cylinder, the liquid remains in equilibrium with the vapor, the cylinder pressure is equal to the vapor pressure of ammonia at that temperature, and the rise in tangential stress is insignificant (0.14 kg/mm ² /°C). However, as the temperature increases, the specific volume of the liquid ammonia inside the cylinder also increases. The cylinder is completely filled with liquid under certain conditions in accordance with the bulk thermal expansion of the liquid; under these conditions, the cylinder pressure rises sharply with increased temperature, causing a large rise in tangential stress (4.76 kg/mm ² /°C). Thus, an approximate 10 °C temperature rise in a cylinder filled with liquid ammonia can lead to failure.     

Strain hardening of steel 20 in hydrostatic extrusion

Conclusions As the result of hydrostatic extrusion, the ultimate strength of steel 20 increases from 40 kg/mm² in the original condition to 74 kg/mm² with 70% deformation. The reduction of the ductility is explained by cold working of the ferrite matrix and the oriented arrangement of pearlite colonies in the structure.Donets Physicotechnical Institute. Kommunar Mining-Metallurgical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 71–72, May, 1975.     

High-strength structural steels with a structure of low-carbon bainite subjected to thermomechanical treatment

Conclusions The development of TMT for low-pearlite and pearlite-free steels has led to the development of steels containing 0.06% C, 1.8% Mn, 0.3% Mo, and 0.05–0.09% Nb. Depending on the type of TMT, the most important parameters of which are the final rolling temperature and the total deformation at temperatures below 900°, the transformation occurs partially or completely in the intermediate region. The high dislocation density of the bainite has a substantial effect on the increase of the yield strength.Large rolling reductions at temperatures below 870° favor the formation of ferrite nuclei. The polygonal ferrite formed in this case has a characteristic grain size of grade 13–14.Rolling under laboratory conditions showed that by selecting the conditions of TMT one can control the mechanical properties of the steel. A guaranteed yield strength of 70 kgf/mm² and transition temperature T₅₀=–25° can be obtained on plates 13 mm thick, while after rolling under other conditions the ductile-brittle transition temperature is –125° and the yield strength 45 kgf/mm². Numerous production tests indicate that a yield strength of at least 50 kgf/mm² in the hot rolled condition can be obtained for plates 20 mm thick. In rolling mills permitting substantial reduction at low temperatures these values can be improved. For example, a yield strength of 56 kgf/mm² and transition temperature of –60° can be obtained for plates 30 mm thick. The steel has substantial reserves of strength due to precipitation hardening, which amount to 8–12 kgf/mm² after tempering at 600–625°. The weldability of the steel is good due to its low carbon content.Stahl und Eisen,93, No. 22, 1041 (1973).Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 11–18, December, 1975.     

Effect of warm extrusion on structure and properties of steel 20Kh

Conclusion Warm extrusion of steel 20Kh at 600–800° makes it possible to obtain a structure with high strength and ductile characteristics: _0.2=40–50 kg/mm², _b=50–60 kg/mm², =60–75%.Voroshilovgrad Machine Construction Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 56–57, March, 1976.     

Maraging steels with high strength and plasticity

Conclusions Steel 1, with _b = 260–280 kg/mm², retains high local plasticity even in notched samples, but has a high crack sensitivity.Steel 2, with _b = 235–245 kg/mm², has a relatively low crack sensitivity under static load. Additional studies of the structural strength are needed to determine the practical applications of steels 2 and 3.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 70–74, August, 1970.     

Mechanical properties of alloy KhN40MDTYu at low temperatures

Conclusion The optimal strength, ductility, and toughness of alloy KhN40MDTYu at cryogenic temperatures result from quenching + aging or from deformation with no heat treatment: _b = 180kg/mm², _0.2 = 100–120 kg/mm², =20%, =15%,a _n=5–7 kg-m/cm² at –253°C.Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 64–65, July, 1972.     

Field-activated pressure-assisted combustion synthesis tungsten carbide–cobalt composites

FAPACS process was utilized to produce WC–10wt%Co composites from reactants’ mixtures of tungsten, cobalt and different kinds of carbon sources (activated carbon and carbon black). The Vickers microhardness of end products were 1804 kg/mm² for the former and 1899 kg/mm² for the latter.     

行波磁场耦合顺序凝固改善ZL205A大型薄壁件缺陷及性能

利用行波磁场耦合顺序凝固连续地处理大型薄壁ZL205A合金铸件,消除收缩缺陷,提高力学性能.实验结合模拟,针对行波磁场参数优化对补缩行为、显微组织和性能的影响进行系统的研究.结果表明,本研究条件下,当励磁电流为20 A、频率为200 Hz时,磁场力达到最大值;磁场力随着到磁场发生器距离越近而越大,更有利于对薄壁铸件进行...     

Development of friction stir welding of high strength steel sheet

Abstract

For friction stir welding (FSW) of advanced high strength steel (AHSS) sheets with tensile strength grades between 590 and 1180?N?mm^?2, the appropriate welding condition range and the influence of welding conditions on microstructures and mechanical properties of the welds were investigated. The appropriate welding conditions to avoid defects such as the incomplete consolidation at the bottom of the weld were obtained for the steel sheets up to 1180?N?mm^?2 grade. The higher tool rotation speed evidently resulted in the larger volume fraction of martensite and higher hardness in the stir zone (SZ), attributed to an increase in the peak temperature of its thermal cycle. The tensile strength of the weld joint was as high as that of the base metal for the steels up to 980?N?mm^?2 grade, but slightly lower than that of the base metal for the steel of 1180?N?mm^?2 grade due to the heat affected zone (HAZ) softening.     

High-temperature thermoplastic strengthening of steels St3sp and 09G2S

Conclusions We worked out a regime of high-temperature thermoplastic treatment of steels St3sp and 09G2S consisting in austenization at 1020°C, strain (=200%, =5.7%) at 940°C with subsequent cooling at a rate >100°C/sec.As a result of such treatment the tensile strength of steel St3sp is increased to 1230 N/mm², of steel 09G2S to 960 N/mm², and the conventional yield strength to 1100 and 840 N/mm², respectively.N. É. Bauman Moscow State Technical University. All-Union Research Institute of Metallurgical Machinery Construction. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 18–19, July, 1991.     

Effect of pulsed current on structure of Al-Mg-Si aluminum-based alloy during cold deformation

The effect of the current density on the formation of the structure of the AD33 Al-Mg-Si alloy during deformation by rolling is studied. It is shown that, at a current density of 30 A/mm², the electroplastic deformation by rolling (EPDR) of the AD33 alloy increases its ultimate strength. A decrease in the deformability of the material with increasing current density to 100 A/mm² and higher is related to the melting of fusible eutectic, which leads to the appearance of microcracks at the grain and subgrain boundaries.     

Structural changes in 12Kh1MF pipe during creep tests

Conclusions Steel 12Kh1MF can be used at 585°C and a stress of 10 kg/mm² with up to 1.5% residual deformation.F. E. Dzerzhinskii Heat Engineering Scientific-Research Institute, Ural Branch. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No 7, pp. 6–9, July, 1976     

Effects of Hydrostatic Pressure on the Corrosion of Copper in Sea Water

Abstract

A study has been made of the effect of hydrostatic pressure, ranging from 1 to 300 atm. (0·102 to 30·6 N.mm^?2) on the corrosion of copper in sea water at pH 7·8 and at a temperature of 10°c. The experimental technique ensured that the content of dissolved oxygen in the sea water was virtually constant over the pressure range, at a value of 7·0 ppm. The same test series was also carried out in a 3·5% NaCl solution.

The weight loss of the copper was found to increase with increase in pressure, both in sea water and in NaCl, and reached a maximum at a pressure of 150 atm. (～15 N.mm^?2) in both solutions. The increased pressure has no influence on the anodic dissolution process for copper, but accelerates the cathodic process. Protective films adhering to the corroded surfaces are identical for the two solutions at ambient pressure. However, at higher pressures adherent corrosion products form only in NaCl solutions. These products were found to be the same as those formed at ambient pressure.     

Ein nichtrostender Vergütungsstahl mit hohen Festigkeits- und Zähigkeitswerten für den Maschinen- und Apparatebau

A martensitic stainless steel with high strength and impact properties for chemical and mechanical engineering purposes Within the last few years the low carbon martensitic stainless steel X4CrNiMo 165, WNr. 1.4418, is increasingly used due to it's excellent technological properties. The steel can he offered with tensile strength up to 850 N/mm² and yield strength up to 1000 N/mm² together with superior impact properties at room temperature and sub-zero-temperature. So this steel has special significance concerning chemical engineering, where corrosion resistance as well as high tensile and impact values are demanded. There is no selective corrosion attack in boiling sulfuric acid (Strauß-Test), if the material is quenched and tempered correctly. Welding operations may be done without preheating the material.     

Deformable alloys based on the Al - Mg - Se system

Aluminum alloys with magnesium that are deformable and not strengthened by heat treatment are widely used as a structural meterial due to their good weldability, high corrosion resistance, and high ductility. However, even the strongest alloys of this system, containing 5–6% Mg, have low strength characteristics. For example, annealed sheets of alloy AMg6 have _b = 340 N/mm² and _0.2 = 180 N/mm². The present work concerns the possibility of strengthening AI - Mg alloys by an additional alloying with scandium.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 33 – 36, June, 1996.     

Iridium coating prepared on rhenium substrate by electrodeposition in molten salt in the air atmosphere

Compact and smooth iridium coating was obtained on the surface of the rhenium substrate by electrodeposition from molten salts of chlorides at the temperature of 600 °C in the air. The deposition rate is about 25 μm/h at cathodic current density of 25 mA/cm². The iridium coating has a columnar structure with preferential growth orientation of <111>. The coating/substrate interface exhibits excellent adherence with no evidence of delamination, cracks, or other defects. No obvious diffusion layer is found within the as-deposited coating. The microhardness of the coating is 442 kg/mm² and the bond strength between the coating and substrate is higher than 16 MPa.     

Low-alloy steel with elevated strength for apparatuses for complex preparation and processing of natural gas containing hydrogen sulfide

Apparatuses for complex preparation and processing of hydrogen sulfide-containing natural gas are commonly produced from carbon steels of the 20Yuch type. However, the strength level of these steels is low (σ_0.2≥240 N/mm²). Low-alloy weldable steel 09G2S has a higher strength, namely, σ_0.2≥300 N/mm² for rolled stock up to 32 mm thick and σ_0.2≥275 N/mm² for rolled stock up to 80 mm thick. At the same time, steel 09G2S has a low cold strength (the semibrittleness temperatureT ₅₀≥−30°C) and a low resistance to hydrogen sulfide cracking (the threshold stress σ_th=0.6σ_0.2). The present paper is devoted to the effect of the composition and structure on the set of properties of new low-alloy plate steel 09GSNBTs, which possesses elevated strength and is resistant to hydrogen sulfide cracking. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 2–5, February, 1997.