Showing papers on "Carbon steel published in 1999"

Feasibility of friction stir welding steel

Abstract: The feasibility of friction stir welding (FSW) of steel is demonstrated. Tensile and bend testing have confirmed that the mechanical properties of friction stir welded 12% chromium alloy and low carbon steel joints compare favourably with the properties of the parent metal. Some initial feasibility studies of FSW of both 12% chromium alloy and low carbon steel are described. Although more development work is needed, particularly to improve tool materials, the prognosis for continued developments in FSW of steel is shown to be good.

Corrosion Behavior of Carbon Steel in the CO2 Absorption Process Using Aqueous Amine Solutions

Abstract: The present study provides comprehensive information on the effects of process parameter variations on the corrosion behavior of carbon steel in CO2 absorption systems using aqueous amine solutions. The process parameters of interest are amine type, concentration of the amine solutions, solution temperature, CO2 loading, and oxygen content. An electrochemical testing technique was used for determining the system corrosiveness in terms of polarization behavior and corrosion rate. The experimental results suggest that the corrosion behavior is considerably sensitive to the variations in the process parameters. Increases in amine concentration, solution temperature, CO2 loading, and oxygen content accelerate the corrosion rate in the systems. In addition, different amine types yield different degrees of the system corrosiveness. Comparisons of the corrosiveness among single amine systems as well as between mixed amine systems and their precursors are also presented.

Inhibition of Carbon Dioxide Corrosion of Mild Steel by Imidazolines and Their Precursors

Abstract: Corrosion inhibition of mild steel by imidazolines and their precursors in a carbon dioxide (CO2)-containing environment was studied using rotating cylinder electrode (RCE) and linear pola...

Laser-shock processing effects on surface microstructure and mechanical properties of low carbon steel

Abstract: The effects of laser-shock processing (LSP) on the microstructure, microhardness, and residual stress of low carbon steel were studied. Laser-shock processing was performed using a Nd:glass phosphate laser with≈600 ps pulse width and up to 120 J pulse energy at power densities above 10 12 W cm −2 . The effects of shot peening were also studied for comparison. Laser-shock induced plastic deformation caused the surface to be recessed by≈1.5 μm and resulted in extensive formation of dislocations. Surface hardness increased by up to 80% after the LSP. The microstructure and mechanical properties were altered up to≈100 μm in depth. The LSP strengthening effect on low carbon steel was attributed to the presence of a high dislocation density. Shot peening resulted in a relatively higher compressive residual stress throughout the specimen than did LSP.

Experimental investigation of the cutting temperature when turning with coated indexable inserts

Abstract: This paper deals with an experimental investigation into the different factors which influence the temperature which occur at the coating/substrate–chip interface when machining a medium carbon steel and an austenitic stainless steel Both flat-faced and grooved inserts coated with TiC, TiC/TiN and TiC/Al 2 O 3 /TiN were used A standard K-type thermocouple embedded in the workpiece was used to convert measured efms to the interfacial temperature Some optimal coating structures for high speed machining of these steels corresponding to the minimum interface temperature were selected In particular, it was observed that by the proper selection of the thermal properties of the coating and the workpiece materials, which result in a substantial increase in the interface temperature, the effect of a thermal barrier in the top layer of the coating can occur

Properties of high-strength steel fiber-reinforced concrete beams in bending

Abstract: This paper presents research results of ten high-strength reinforced concrete beams and steel fiber-reinforced high strength concrete beams, with steel fiber content of 1% by volume. The enlarged ends of mild carbon steel fibers with three different dimensions were selected. This research shows that the flexural rigidity before yield stage and the displacement at 80% ultimate load in the descending curve are improved, and crack number and length at comparable loads is reduced after the addition of steel fibers. The descending part of the load-displacement curve of the concrete beams without steel fibers is much steeper than that with steel fibers, which shows that the addition of steel fibers makes the high strength concrete beams more ductile.

Molecular modeling of the inhibition of mild steel carbon dioxide corrosion by imidazolines

Abstract: Imidazolines have been used to inhibit corrosion in carbon dioxide (CO2) solutions. Molecular modeling techniques were used to study adsorption andfilm formation of imidazolines onto iron ...

Control of the growth of zinc–iron phases in the hot-dip galvanizing process

Abstract: Zinc–iron phases may develop at the steel substrate/zinc coating interface during the hot-dip galvanizing process. These phases are hard and brittle, and make the material unsuitable for the forming process. Growth of the zinc–iron phases could be controlled adding 0.18 to 0.30% of aluminium to the galvanizing bath, which reacts with iron to produce a thin layer of intermetallic Fe 2 Al 5 . The latter hinders alloying between the steel sheet and molten zinc, and is therefore referred to as the inhibition layer since it inhibits or retards the formation of Fe–Zn phases. Nevertheless, this layer is unstable and local growth of Fe–Zn phases (‘out-burst’) is found at longer immersion times. This ‘out-burst’ phenomenon depends on many factors, such as the chemical compositions of both the bath and the steel, and the immersion time. The aim of the work was to investigate the influence of both immersion time and a small addition of titanium to the galvanizing bath on coating characteristics. Thus, plain carbon steel sheets were galvanized with alloys A and B, which had different chemical compositions. The immersion time was varied between 1 and 120 s. Cross-sections of samples were observed by scanning electron microscopy. The analysis showed that, even for very short immersion times, samples galvanized with alloy A develop ‘out-bursts’ whereas those with alloy B do not, even for longer immersion times. The Fe 2 Al 5 intermetallic structure was also investigated. It was observed that samples galvanized with alloy B showed, for the same immersion time, bigger grains than the ones galvanized with alloy A. However, for both alloys, the intermetallic development was greater for longer immersion time. Such observations suggest that a small amount of titanium could serve as a catalyst for the iron–aluminium reaction, allowing a greater development of the inhibition layer and delaying growth of the Fe–Zn intermetallic.

Surface Roughness of Solidified Mold Flux in Continuous Casting Process

Abstract: Heat transfer in continuous casting mold is important to decide the surface quality of the cast slab of middle carbon steel. Many researchers have recently studied the mechanism of reducing the heat transfer between the mold and the solidified shell, and some of them have pointed out that the interfacial thermal resistance between the mold and surface of solidified mold flux has caused decreasing heat transfer. In the present study, the surface roughness of solidified mold fluxes used for low carbon and middle carbon steel casting, Na2O-CaO-SiO2 and Li2O-CaO-SiO2 slag systems, was measured by a confocal scanning laser microscope combined with an infrared image furnace. It was found that the surface roughness was in the range of approximately 10-30 μm when the crystalline phase precipitated. Furthermore, the faster the cooling rate, the smoother the surface roughness of the solidified mold flux became. In the contrast, the surface roughness of the slag, of which critical cooling rate is faster, increased. The surface roughness of the mold flux for middle carbon steel casting became rougher than that for low carbon steel casting. As a result, the surface roughness was related to normalized cooling rate, which is the ratio of actual experimental cooling rate to critical cooling rate. The experimental data of surface roughness were fairly in agreement with calculated values on the assumption of one dimensional heat transfer in the continuous casting mold.

Temperature Measurement of CBN Tool in Turning of High Hardness Steel

Abstract: The temperature at the tool flank, which has an effect on the tool life and on the machined surface integrity, is measured using a two-color pyrometer with a fused fiber coupler. This pyrometer makes it possible to measure the temperature of a very small object without emissivity affecting the results. A CBN tool is used as the cutting tool. A high carbon chromium bearing steel, a chromium molybdenum steel and a quenched carbon steel are used as work materials. The temperature of the tool is highly affected by the cutting speed, but the influence of the depth of cut and the feed rate is not so great. In the cutting of the high carbon chromium bearing steel, the temperature is 800 °C at a cutting speed of 100 m/min and increases with the increase of cutting speed, reaching 950 °C at 300 m/min. There is a close relation between the tool temperature and the hardness of the work material. The influence of cutting speed on tool wear is considerable.

The kinetics and mechanism of multi-component diffusion on AISI 1045 steel

Abstract: A multi-component diffusion study of boron, chromium, aluminum and silicon on an AISI 1045 steel substrate has been carried out by pack cementation A commercial boriding powder (Ekabor-3) and an Fe–Cr alloy powder plus NH 4 Cl activator make up 30 wt% of the pack, and 70 wt% of Al 2 O 3 serves as an inert diluent and supply source of aluminum atoms The structure and constituent changes of the coated layers and their thickness and hardness, as influenced by different pack compositions, have been investigated at 1000°C The kinetics of the reaction, K = K 0 exp(− Q / RT ), have also been determined in this work by varying the NH 4 Cl additions The results show that Q and K 0 decrease with increasing amount of NH 4 Cl addition at temperatures between 900°C and 1000°C

A study of Ni3Al coating on carbon steel surface via the SHS casting route

Abstract: A nickel aluminide (Ni3Al) coating on a carbon steel surface was fabricated by the self-propagating high-temperature synthesis (SHS) casting route. Coating phases were determined by using X-ray diffraction (XRD). The microstructure of the coating and bonding interface between the substrate and the coating, and the distribution of elements adjacent to the interface, were analyzed by using electron probe microanalysis (EPMA). The microhardness of the coating was measured. The tribological properties of the coating at different elevated temperatures were investigated and the worn surfaces at different temperatures were analyzed by EPMA. The elemental chemical state of the worn surface was determined by using X-ray photoelectron spectroscopy (XPS). The results show that the coating was composed of Ni3Al phase, and that its microstructure was dense and pure. Elements had diffused mutually at both sides of the interface and a metallurgical bonding interface was formed. The heat of the reaction coarsened the grain size of the substrate near the interface. The hardness of the coating is higher than that of the substrate. Wear loss and friction coefficient of the coating vary with the testing temperature. The coating had a good resistance to oxidation at elevated temperature. Oxidation of the coating occurred as a result of friction at the temperature of 873 K. The mechanisms of combustion synthesis of Ni3Al coatings on carbon steel substrates are discussed in detail. It is pointed out that the combustion temperature and the wettability between the product of the reaction and the substrate are significant to obtain the coating.

Effect of coarse initial grain size on microstructure and mechanical properties of weld metal and HAZ of a low carbon steel

Abstract: In this study, the effects of coarse initial grain size with varying heat inputs on microstructure and mechanical properties of weld metal and heat-affected zone (HAZ) were investigated. In the welding experiments, SAE 1020 steel specimens in hot-rolled and in grain-coarsened conditions were used. The specimens taken from the hot-rolled steel (original) plate were heat treated at 1100°C for 45 min and then cooled in a furnace in order to obtain a coarse initial grain size. The original and grain-coarsened specimens were welded using a submerged arc welding machine with heat inputs of 0.5, 1 and 2 kJ/mm. Following the welding, microstructure, hardness and toughness of weld metals and HAZs were investigated. From the results, we tried to establish a relationship between initial grain size, microstructure, hardness and toughness of weld metals and HAZs. From the results of the toughness tests, it was seen that the weld metals of coarse initial grain sized specimens and original specimens exhibited nearly the same toughness values with the same heat input, whereas different HAZ toughness values were obtained with the same heat input. Maximum toughness of HAZ of the coarse initial grain sized specimen was achieved with a high input, while maximum toughness of original specimen was obtained with a medium heat input. As a result, considering the heat input, it was observed that the coarse initial grain size had a great influence on the microstructure, hardness and toughness of HAZ of a low carbon steel. Thus, taking into consideration the plate thickness, a higher heat input should be used with respect to the maximum toughness of the HAZ in the welding of grain-coarsened low carbon steels.

Evaluating Zn, Al & Al-Zn Coatings on Carbon Steel in a Special Atmosphere

Abstract: Abstract This paper presents a comparative evaluation of Al, Zn and Al–Zn coatings on carbon steel, exposed to a coastal-marine atmosphere. It is a very aggressive atmosphere with high wind velocities (corrosion–erosion rate ≈ 1.4 mm/year (55.12 mpy) for ASTM 1029 steel). Two flame spraying zinc coatings with pore sealers were also evaluated. ISO and ASTM standards were used for the evaluation. After a 2-year exposure the best performance was achieved by the flame spraying Zn/15Al alloy (85% Zn–15%Al) with some damage of the coatings. But the one with a wash primer pore sealer did not show signs of damage.

Microstructure of X52 and X65 pipeline steels

Abstract: The microstructure of two commercial pipeline steels X52 and X65 was examined to provide a foundation for the understanding of the IGSCC mechanism of pipeline steels Observation of the microstructure was carried out using scanning electron microscopy (SEM) and an analytical electron microscope The microstructure of X52 and X65 pipeline steels shows banding of pearlite rich and ferrite rich areas The ferrite grains were about 10 μm in size with curved grain boundaries There was carbide at the ferrite grain boundaries for X52 steel, and there was circumstantial evidence to suggest carbon segregation at the boundaries The pearlite colonies were consistent with nucleation by a number of different mechanisms

Investigation of the Inhibitive Effect of N-Phosphono-Methyl-Glycine on the Corrosion of Carbon Steel in Neutral Solutions by Electrochemical Techniques

Abstract: Steady-state current-voltage curves for various disk rotation rates were combined with electrochemical impedance measurements to investigate the corrosion inhibition of carbon steel by N-p...