New Application of Stainless Steel

Several rigid substrates such as stainless steel, titanium alloy, aluminum alloy, nickel foil, silicon, and sodium lime glass have been employed for manufacturing high quality TiO2 films by metal organic chemical vapor deposition （MOCVD）. The as-deposited TiO2 films have been characterized with SEM/EDX and XRD. The photocatalytic properties were investigated by decomposition of aqueous orange Ⅱ. UV VIS photospectrometer was employed to check the absorption characteristics and photocatalytic degradation activity. The results show that films synthesized on metal substrates display higher photoactivities than that on absolute substrates such as silicon and glass. It is found that solar light is an alternative to UV-light used for illumination during photodegradation of orange Ⅱ. TiO2 film on stainless steel substrate was regarded as the best one for photocatalysis.     

Structure of a Carbon Steel–Stainless Steel Bimetal

Bimetallic samples may be produced by casting St3 structural steel between sheets of Kh18N9T stainless steel in a mold, with subsequent hot rolling of the three-layer sheet. Such samples have a structure in which Kh18N9T stainless steel appears at the outer edge on both sides, while the core consists of St3 structural steel. Analysis of the boundary between the steels confirms the absence of defects: it is continuous and of high quality. The microstructure of the junction is investigated by optical, scanning-probe, and electron microscopy. Three structural components are observed from the pearlitic to the austenitic steel: a weakened section of the ferritic layer; a strengthened section of the ferritic layer; and a dark-etching layer at the austenitic steel. The following results are obtained by scanning-probe microscopy—in particular, the constantforce contact method—and optical metallography: on approaching the boundary from the St3 steel, a carbon- free layer with purely ferritic structure is observed, rather than the usual structure for low-carbon steel, which consists of a ferrite matrix with pearlite colonies. On approaching the boundary from the Kh18N9T steel, a carburized layer is observed. In addition, the boundary includes an intermediate carbide layer (depth up to 50 μm). The change in microhardness in the region where the St3 structural steel meets the external layer of Kh18N9T stainless steel indicates considerable increase in strength of the materials. Elemental microanalysis of the St3 steel–Kh18N9T steel boundary reveals the change in concentration of the alloying elements on approaching the boundary. The presence of chromium in St3 steel and the increase in carbon concentration in Kh18N9T stainless steel confirm that two opposing diffusional fluxes are formed: the diffusion of carbon from the St3 steel; and the diffusion of alloying elements from Kh18N9T steel. The resulting carbides explain the increased hardness of both steels close to the boundary.     

Antibacterial Properties of Cerium-Bearing Stainless Steel Bearing Cerium

Antibacterial Properties of Cerium-Bearing Stainless Steel Bearing Cerium     

Fundamental Research of Making Stainless Steel by Smelting Reduction of Chromite

ＦｕｎｄａｍｅｎｔａｌＲｅｓｅａｒｃｈｏｆＭａｋｉｎｇＳｔａｉｎｌｅｓｓＳｔｅｅｌｂｙＳｍｅｌｔｉｎｇＲｅｄｕｃｔｉｏｎｏｆＣｈｒｏｍｉｔｅＤｕＴｉｎｇ；ＹｏｕＸｉａｏｍｉｎ；ＷｕＹｉｅｍｉｎｇＡｂｓｔｒａｃｔ：Ｔｗｏｐｒｏｃｅｓｓｅｓｏｆｍａｋｉｎ...     

Influence of Water Pollution on MIC of Stainless Steel 304L

Ｔｈｅｍｉｃｒｏｂｉｏｌｏｇｉｃａｌｌｙｉｎｆｌｕｅｎｃｅｄｃｏｒｒｏｓｉｏｎ(ＭＩＣ)ｏｆｓｔａｉｎｌｅｓｓｓｔｅｅｌｈａｓｒｅｃｅｉｖｅｄｐｒｅｆｅｒｅｎｔｉａｌａｔ ｔｅｎｔｉｏｎｉｎｔｈｅｌｉｔｅｒａｔｕｒｅａｎｄｅｎｇｉｎｅｅｒｉｎｇｄｅｓｉｇｎａｓｔｈｉｓｋｉｎｄｏｆｃｏｒｒｏｓｉｏｎｉｓｗｉｄｅｌｙｐｒｅｓｅｎｔｉｎｉｎｄｕｓｔｒｙａｎｄｃａｕｓｅｓｍｉｃｒｏｂｉａｌａｔｔａｃｋ[1] .ＣｏｓｔｌｙｐｉｔｔｉｎｇｆａｉｌｕｒｅｓｏｆｓｔａｉｎｌｅｓｓｓｔｅｅｌｃｏｍｐｏｎｅｎｔｓｂｙＭＩ…     

Thermal Response of Mould in High Speed Casting of Stainless Steel Billet

Ｉｎｖｉｅｗｏｆｈｅａｔｔｒａｎｓｆｅｒ ,ｔｈｅｒｏｌｅｏｆｍｏｕｌｄｉｎｃｏｎｔｉｎｕｏｕｓｃａｓｔｉｎｇｃａｎｎｅｖｅｒｂｅｏｖｅｒｓｔａｔｅｄａｓｉｔｃｏｎ ｔｒｏｌｓｂｏｔｈｔｈｅｂｉｌｌｅｔｑｕａｌｉｔｙａｎｄ ｐｒｏｄｕｃｔｉｖｉｔｙｏｆａｃａｓｔｅｒｔｏａｇｒｅａｔｅｘｔｅｎｔ .Ｉｎｔｈｉｓｓｔｕｄｙ ,ＡｔｌａｓＳｔｅｅｌｗａｓｃｈｏｓｅｎａｓｔｈｅｌｏｃａｔｉｏｎｆｏｒａｐｌａｎｔｔｒｉａｌｂｅｃａｕｓｅｖｅｒｙｌｉｔｔｌｅｄａｔａａｒｅａｖａｉｌａｂｌｅｏｎｈｅａｔｔｒａｎｓｆｅ…     

Production Conditions and Properties of Layered Materials Type of Composite Based on a Stainless Steel ― Steel

Fabrication conditions and some properties of wear-resistant and corrosion-resistant layered materials type of composite based on a stainless steel steel were investigated. The materials were produced by joint pressing and sintering of the layers. The working layer was based on stainless steel Kh18N15 with additions of Cr₃C₂ and MoS₂, and the substrates were unalloyed iron, low-alloy chromium steel, and stainless steel. The quality of layer bonding was evaluated by metallographic investigation and electron-probe microanalysis of the interface between layers, and also determination of the strength properties. It was established that the most favorable conditions for structure and property formation in the layered composites are obtained by using a stainless steel substrate and a working layer with an intermediate sublayer.     

Metallurgical Studies of Austenitic Stainless Steel 304 under Warm Deep Drawing

Austenitic stainless steel 304 was deep drawn with different blank diameters under warm conditions using 20 t hydraulic press. A number of deep drawing experiments both at room temperature and at 150 ℃ were conducted to study the metallography. Also, tensile test experiments were conducted on a universal testing machine up to 700 ℃ and the broken specimens were used to study the fractography of the material using scanning electron microscopy in various regions. The microstructure changes were observed at limiting draw ratio （LDR） when the cup is drawn at different temperatures. In austenitic stainless steel, martensite formation takes place that is not only affected by temperature, hut also influenced by the rate at which the material is deformed. In austenitic stainless steel 304, dynamic strain regime appears above 300 ℃ and it decreases the formability of material due to brittle fracture as studied in its fractography. From the metallographic studies, the maximum LDR of the material is observed at 150 ℃ before dynamic strain regime. It is also observed that at 150 ℃, grains are coarse in the drawn cups at LDR.     

Crack Properties of Lean Duplex Stainless Steel 2101 in Hot-formming Processes

The crack behavior of LDX 2101 by hot compression tests in the temperature range of 950 to 1150 ℃ and strain rate range of 0.01 to 30 s-1 was studied.The hot workability map of LDX 2101 was constructed and the alloy exhibited a better crack resistance at higher temperature and lower strain rate.Microvoids initiated and coalesced into crack at subsurface on the equatorial plane of bulge surface under secondary tensile condition.The cracks were orientated at an angle of approximately 45° with respect to the c...     

Effects of Hydrogen Ion Implantation on TiCC Coating of Stainless Steel

Titanium carbide coatings are widely used as various wearresistant material. The hydrogen erosion resistance of TiCC films and the effect of hydrogen participation on TiCC films were studied. Seventyfive percent TiCC films are prepared on stainless steel surface by using ion mixing, where TiCC films are deposited by rf magnetron sputtering followed by argon ion bombardment. The samples are then submitted to hydrogen ion implantation at 12×10-3 Pa. Characterization for the 75% TiCC films was done with SIMS, XRD, AES, and XPS. Secondary ion mass spectroscopy (SIMS) was used to analyze hydrogen concentration variation with depth, XRay diffraction (XRD) was used to identify the phases, and Auger electron spectra (AES) as well as Xray photoelectron spectra (XPS) were used to check the effects of hydrogen on shifts of chemical bonding states of C and Ti in the TiCC films. It is found that TiCC films on stainless steel surface can prevent hydrogen from entering stainless steel.     

Corrosion Behaviour of Chrome–Manganese Austenitic Stainless Steels and AISI 304 Stainless Steel in Chloride Environment

Electrochemical behaviour of chrome–manganese austenitic stainless steels (Cr–Mn ASS) and AISI 304 stainless steel (SS) is evaluated in various chloride (Cl^?) concentrations (Cl^? free to 20,000 ppm) to simulate rural, industrial and marine environment. Potentiodynamic polarization and electrochemical impedance spectroscopy has clearly shown that with increase in Cl^? concentration, the corrosion rate of both Cr–Mn ASS and AISI 304 SS increases and polarization resistance decreases. Comparatively, Cr–Mn ASS is more affected by Cl^? concentration than AISI 304 SS. This is attributed to relatively low Cr content and lack of Ni. The findings have been explained with the help of point defect model. However, in less aggressive environment of up to 100 ppm Cl^? concentration, Cr–Mn ASS may be a candidate material as a cheaper substitute of AISI 304 SS. Ways of improving corrosion resistance of Cr–Mn ASS by alloying with various elements have also been discussed. It is argued that a dedicated effort is needed to improve corrosion resistance of Ni-free or low-Ni Cr–Mn ASS.     

Precipitation Kinetics of Cr2N in High Nitrogen Austenitic Stainless Steel

 The precipitation behavior of Cr2N during isothermal aging in the temperature range from 700 ℃ to 950 ℃ in Fe 18Cr 12Mn 048N (in mass percent) high nitrogen austenitic stainless steel, including morphology and content of precipitate, was investigated using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The isothermal precipitation kinetics curve of Cr2N and the corresponding precipitation activation energy were obtained. The results show that Cr2N phase precipitates in a cellular way and its morphology is transformed from initial granular precipitates to lamellar ones in the cell with increasing aging time. The nose temperature of Cr2N precipitation is about 800 ℃, with a corresponding incubation period of 30 min, and the ceiling temperature of Cr2N precipitation is 950 ℃. The diffusion activation energy of Cr2N precipitation is 296 kJ/mol.     

Hot Compression Behavior of AsCast Precipitation Hardening Stainless Steel

 High temperature deformation characteristics of a semiaustenitic grade of precipitation hardening stainless steels were investigated by conducting hot compression tests at temperatures of 900-1 100 ℃ and strain rates of 0001-1 s-1. Flow behavior of this alloy was investigated and it was realized that dynamic recrystallization (DRX) was responsible for flow softening. The correlation between critical strain for initiation of DRX and deformation parameters including temperature and strain rate, and therefore, Zener Hollomon parameter (Z) was studied. Metallographic observation was performed to determine the as deformed microstructure. Microstructural observation shows that recrystallized grain size increases with increasing the temperature and decreasing the strain rate. The activation energy required for DRX of the investigated steel was determined using correlations of flow stress versus temperature and strain rate. The calculated value of activation energy, 460 kJ/mol, is in accordance with other studies on stainless steels. The relationship between peak strain and Z parameter is proposed.     

Studies on Welding and Sensitization of Chrome–Manganese Austenitic Stainless Steel

The standard composition of austenitic stainless steel (ASS) includes Cr and Ni. However, due to rising cost of Ni, search for suitable alternative is always on. Manganese, on account of being an austenite stabilizer, can be considered as a replacement of Ni. Chrome–manganese steel (part of 200 series of ASS) contains chromium (≤15%) and low nickel. However, there is not enough confidence about their service life. Present work is an attempt to study the effect of welding and sensitization characteristics of this steel. The heat affected zone (HAZ) is identified microstructurally as per ASTM standard A262 Practice A test. Time temperature sensitization (TTS) diagram is established and critical cooling rate (CCR) is estimated. double loop electrochemical potentiokinetic reactivation (DLEPR) technique is used to quantify degree of sensitization (DOS) for heat treated and welded samples. The DOS for thermally aged sample at 750°C for 180 min is found to be 32.56% whereas for welded sample it is 31.30%. The results are discussed and mechanism of micro-structural changes due to welding of such steel is suggested.     

Improving Corrosion Resistance of Stainless Steel by Yttrium Addition: An AES Analysis

Ｔｈｅａｄｄｉｔｉｏｎｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎｔｏｍａｔｅｒｉａｌｓｃｏｕｌｄｐｏｓｓｉｂｌｙｉｍｐｒｏｖｅｔｈｅｉｒｆｕｎｃ ｔｉｏｎｓｓｉｇｎｉｆｉｃａｎｔｌｙ .Ｔｈｅｒｅｆｏｒｅ ,ａｄｄｉｎｇｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｉｎｔｏｍａｔｅｒｉａｌｓｉｓｓｔｉｌｌａｈｏｔｔｏｐｉｃｉｎｍａｔｅｒｉａｌｓｓｃｉｅｎｃｅ .Ｔｈｒｅｅｋｉｎｄｓｏｆｓｔａｉｎｌｅｓｓｓｔｅｅｌｓｗｅｒｅｃｏｍｐａｒａｔｉｖｅｌｙｉｎｖｅｓｔｉｇａｔｅｄｉｎｔｈｉｓｐａｐｅｒ.Ｗｅｆｏｕｎｄｔｈａ…     

Mechanism of Brittle Cracking for High-Purity Cr18Mo2 Ferritic Stainless Steel

ＭｅｃｈａｎｉｓｍｏｆＢｒｉｔｌｅＣｒａｃｋｉｎｇｆｏｒＨｉｇｈ┐ＰｕｒｉｔｙＣｒ１８Ｍｏ２ＦｅｒｒｉｔｉｃＳｔａｉｎｌｅｓＳｔｅｅｌＬｉｕＢｉｎ，ＬｕＳｈｉｙｉｎｇ，ＷａｎｇＸｉｎｚｅｎｇ①ＡＢＳＴＲＡＣＴＡｓｔｕｄｙｈａｓｂｅｅｎｃａｒｒｉｅｄｏ...     

Uniaxial TimeDependent Ratcheting of SS304 Stainless Steel at High Temperatures

The uniaxial timedependent strain cyclic behaviors and ratcheting of SS304 stainless steel were studied at high temperatures (350 ℃ and 700 ℃). The effects of straining and stressing rates, holding time at the peak and/or valley of each cycle in addition to ambient temperature on the cyclic softening/hardening behavior and ratcheting of the material were discussed. It can be seen from experimental results that the material presents remarkable time dependence at 700 ℃, and the ratcheting strain depends greatly on the stressing rate, holding time and ambient temperature. Some significant conclusions are obtained, which are useful to build a constitutive model describing the timedependent cyclic deformation of the material.     

Erosion and Corrosion of Mild Steel and Stainless Steel in Sodium Carbonate／Bicarbonate Solution Bearing Alumina Particle

With a rotating cylinder electrode apparatus, the polarization behaviors of the mildsteel and the stainless steel 0Crl8Ni9 in NaHCO3 (0.5M) NazCO3 (0.5M) solution with andwithout erodent particles were investigated and compared. The results show that the rotationspeed of cylinder hardly affects the polarization behavior of sample in solution without particlesbut exerts a great influence on that with particles. Increasing rotation speed, the free corrosionpotential shifts to positive direction and the oxygen limiting current density increases. Both themild steel and stainless steel 0Crl8Ni9 experience a significant increase of the mass loss by in-creasing erosion, and erosive wear was dominated by severe micro-plowing. The insufficientmechanical strength of both materials leads to a low resistance to particle removal. Increasingperipheral velocities of the rotating cylinder enhances the corrosion rate of the mild steel. Thestainless steel 0Crl8Ni9, due to a high erosive wear, also suffers from similar erosion-corrosiondamage, despite that its corrosion resistance is much higher than that of the mild steel.     

Structure Evolution and Solidification Behavior of Austenitic Stainless Steel in Pulsed Magnetic Field

 To understand the solidification behavior of austenitic stainless steel in pulsed magnetic field, the solidification process is investigated by means of the self made high voltage pulse power source and the solidification tester. The results show that the solidification structure of austenitic stainless steel can be remarkably refined in pulsed magnetic field, yet the grains become coarse again when the magnetic intensity is exceedingly large, indicating that an optimal intensity range existed for structure refinement. The solidification temperature can be enhanced with an increase in the magnetic intensity. The solidification time is shortened obviously, but the shortening degree is reduced with the increase of the magnetic intensity.