Low carbon steel

Weld cladding is a process for producing surfaces with good corrosion resistant properties by means of depositing/laying of stainless steels on low-carbon steel components with an objective of achieving maximum economy and enhanced life. The aim of the work presented here was to investigate the effect of auxiliary preheating of the solid filler wire in mechanized gas metal arc welding (GMAW) process (by using a specially designed torch to preheat the filler wire independently, before its emergence from the torch) on the quality of the as-welded single layer stainless steel overlays. External preheating of the filler wire resulted in greater contribution of arc energy by resistive heating due to which significant drop in the main welding current values and hence low dilution levels were observed. Metallurgical aspects of the as welded overlays such as chemistry, ferrite content, and modes of solidification were studied to evaluate their suitability for service and it was found that claddings obtained through the preheating arrangement, besides higher ferrite content, possessed higher content of chromium, nickel, and molybdenum and lower content of carbon as compared to conventional GMAW claddings, thereby giving overlays with superior mechanical and corrosion resistance properties. The findings of this study not only establish the technical superiority of the new process, but also, owing to its productivity-enhanced features, justify its use for low-cost surfacing applications.

Since machine tools are used extensively throughout their functional life and consequently consuming valuable natural resources and emitting harmful pollutants during this time, this study reviews strategies for characterizing and reducing the energy consumption of milling machine tools during their use. The power demanded by a micromachining center while cutting low carbon steel under varied material removal rates was measured to model the specific energy of the machine tool. Thereafter the power demanded was studied for cutting aluminum and polycarbonate work pieces for the purpose of comparing the difference in cutting power demand relative to that of steel.

This work describes the effect of Nb supersaturation in austenite, as it applies to the strain-induced precipitation potential of Nb(CN), on the suppression of the static recrystallization of austenite during an isothermal holding period following deformation. Four low carbon steels, microalloyed with Nb, were used in this investigation. Three of the steels had variations in Nb levels at constant C and N concentrations. Two steels had different N levels at constant C and Nb concentrations. The results from the isothermal deformation experiments and the subsequent measurement of the solution behavior of Nb in austenite show that the recrystallization-stop temperature (T RXN) increases with increasing Nb supersaturation in austenite. Quantitative transmission electron microscopy analysis revealed that the volume fraction of Nb(CN) at austenite grain boundaries or subgrain boundaries was 1.5 to 2 times larger than Nb(CN) volume fractions found within the grain interiors. This high, localized volume fraction of Nb(CN) subsequently led to high values for the precipitate pinning force (F PIN). These values forF PIN were much higher than what would have been predicted from equilibrium thermodynamics describing the solution behavior of Nb in austenite.

The size and morphology of intermetallic compounds of Sn–Ag solder alloys can have a significant influence on the mechanical strength of solder joints. The aim of the present study is to characterize the as-cast microstructure of a Sn–2 wt.% Ag solder alloy, and to correlate the resulting scale of the dendritic matrix and the morphology of the Ag3Sn intermetallic compound (IMC) with the corresponding solidification cooling rate. Pre-heated low-carbon steel molds and a water-cooled solidification apparatus were used permitting a significant range of solidification cooling rates to be experimentally examined. It is shown that under very slow cooling conditions (0.02 °C/s) the microstructure of the sample is formed by a coarse dendritic matrix and a mixture of fiber and plate-like Ag3Sn IMC in the interdendritic region with the fibers located along the board line separating the matrix. For cooling rates from 0.15 to 1.15 °C/s a mixture of spheroid and fiber-like IMC and secondary dendrite arm spacings between 15 and 40 μm, with the spheroids located in the center of the interdendritic region. At higher cooling rates, of about 8 °C/s only Ag3Sn spheroids (of about 0.5 μm in diameter) prevail in the eutectic mixture.► 3D characterization of the morphology of Ag3Sn by an over-etching technique. ► Ag3Sn spheroids are associated with fine dendrite spacings, λ2, of Sn-rich phase. ► A mixture of Ag3Sn (spheroids + fiber-like) is associated with λ2 from 10 to 45 μm. ► A mixture of Ag3Sn (fibers + plate-like) is associated with λ2 of about 100 ± 15 μm. ► Pb-free solder manufacturers can control the microstructure by the cooling rate.

Three types of material whose fracture toughness tests were previously performed by using circumferentially notched bars, namely (1) a dual-phase steel with three different morphologies; (2) an Al-Zn-Mg-Cu wrought alloy; and (3) Al-Si-cast alloys with three different Si contents, were investigated in terms of accuracy and reliability of the testing method. Also, the advantages of using circumferentially notched bars
for fracture toughness determination of metallic materials were discussed. With the help of stress concentration
factors, which are associated with the bluntness of the notch, correction factors for the fracture toughness calculations are derived. The corrected fracture toughness values are found to be close to the uncorrected ones, implying that the testing procedure is reliable.

... A nickel based matrix reinforced with WC/W 2 C carbides is deposited by a CO 2 laser on low carbon steel substrates. Different coatings are made with three different particle sizes of the carbides and volume fractions ranging from 0 up to 50%. ...

Laser-induced breakdown spectroscopy system (LIBS) had been designed for analysis of the industrial alloy via analysis induced plasma emission, laser spectroscopy to plasma produce one of the applications resulting from the interaction of the laser beam with material. The design consists of Nd:YAG laser passively Q-Switched with output energy (50-mJ @ 1064 nm) and (9 ns) pulse duration the laser beam was focused via converging lens with a focal length (100mm) that generates (7.07*108W/mm2) power intensity, optical analysis system was used that operated on the analysis of plasma light resulting from the interaction of lasers with the target, within spectrum range of 320-740 nm and (0.5nm) optical resolution. The analysis results obtained show a variety of metallic elements in the industrial alloy, the results obtained by using X-ray fluorescence system (XRF), and other spectral references have been compared. LIBS have shown detection of the main elements in the sample with other elements are manganese, aluminum, sulfur, phosphorus, silicon, and carbon, these elements not identified in the XRF.

In this study a simple method is introduced to produce dual phase ferrite-martensite structure in plain low carbon steel. This simple method is based on cold-rolling of ferrite-pearlite structures and interical annealing treatments before ice-water quenching. The specimens intercritical annealed at 850ºC revealed the optimum mechanical properties in term of hardness, strength and uniform elongation.

Since welding technology is currently used to assemble the frame of driver's seats, it is important to develop laser welding technology for steel and aluminium. For this reason, the purpose of the present work was to examine the structure and selected properties of aluminium-steel joints using the example of an EN AW-6060 aluminium alloy and DC04 low-alloy steel welded in laser technology. Overlapping joints were made, weld type-following the hole laser welding method-laser beam (LB) using a high power disk laser (TRUMPF TruDisk3302), in which the active medium is a yttrium-aluminium crystal (YAG). Metallographic microstructure investigations were carried out using a light microscope from Carl Zeiss-Observer Z1m, and the weld microstructures were investigated using an SEM Supra 35 microscope, also from Carl Zeiss. The chemical composition analysis in micro-areas was carried out using an X-ray energy dispersion spectrometer from EDAX, which was a part of the SEM Supra 35. The hardness of the substrate material and the welded area was measured following the Vickers method using an FM-ARS 9000 micro hardness tester from Tokyo, Japan. It was found that there is a potential for commercial use of laser welding to make a low-carbon steel-aluminium alloy joint. During the formation of the weld in its microstructure, intermetallic compounds of the FexAly type were created, which significantly reduced the mechanical and plastic properties of the joint. The hardness of the weld created wasabout seven times higher than that of DC04 carbon steel. The choice of laser welding parameters (primarily, laser power and beam speed) significantly impacted the weld structure and properties.

This paper presents a study made on 40 iron archaeological artefacts buried in soil during several centuries. Samples were taken with the adhering soil and cross-sections were made. The used characterisation techniques are optical and electronic microscopies, EDS coupled to SEM, EPMA, micro-XRD under synchrotron radiation, micro-Raman spectrometry. A specific vocabulary is proposed to describe the corrosion layout. The most identified corrosion layout is made of several ten micrometers zones of magnetite and/or maghemite embedded in a goethite matrix. A corrosion mechanism is proposed in order to explain this profile. When the soil water contains more chlorine or carbonates, some specific corrosion product appear as akaganeite, oxychlorides and siderite.

Addition of boron in low carbon (0.06% max) hot rolled steel has improved its formability. A unique combination of properties with low strain hardening exponent (n) and high total elongation has resulted into higher percentage of cold reducibility of hot rolled coils.

Use of High Magnetic Fields to Improve Material Properties for Hydraulics, Automotive and Truck Components ... Gerard M. Ludtka, Principal Investigator Gail M. Ludtka John B. Wilgen Roger A. Kisner Materials Science & Technology Division Oak Ridge National Laboratory

The samples of AISI 1018 Low carbon steel were heated to austenite zone then cooled in different mediums with different cooling rates. Mechanical tests show increase in hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio as cooling rate is increase. Ductility has inverse proportionality to cooling rate. The resulting microstructures show decreasing in grains sizes accompanying to cooling rate increase. The relations between mechanical properties and grains size are opposites of relations between mechanical properties with cooling rates. Hardness, yield strength, tensile strength, modulus of elasticity, and yield/tensile ratio increase as grains size decreases, while ductility decreases.