Low-carbon Cu precipitation-strengthened steel (original) (raw)
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Copper Precipitation Hardened, High Strength, Weldable Steel
Materials for the New …
Steel containing 0.03% carbon, 1.35% copper and 0.84% nickel had yield strength in the 540-625 MPa (78-90 Ksi) range depending on thickness, ultimate tensile strength in the 625-690 MPa (90-100 Ksi) range, and 25-30% elongation when air cooled after hot rolling. No brittle heat-affected zone was formed during manual or automatic submerged arc welding without pre-heating or postheating. The fracture toughnesses in the plate and in the heat-affected zone were excellent.
Nano Convergence
Low carbon ferritic steel alloyed with Ti, Mo and Cu was hot rolled and interrupt cooled to produce nano-sized precipitates of copper and (Ti,Mo)C carbides. The steel had a tensile strength of 840 MPa, an increase in yield strength of 380 MPa over that of the plain carbon steel and reasonable ductility. Transmission electron microscopy and small angle neutron scattering were used to characterize size and volume fraction of the precipitates in the steels designed to form only copper precipitates and only (Ti,Mo)C carbides. The individual and combined precipitation strengthening contributions was calculated using the size and volume fraction of precipitates and compared with the measured values.
High-Strength Low-Carbon Ferritic Steel Containing Cu-Fe-Ni-Al-Mn Precipitates
Metallurgical and Materials Transactions A, 2008
An investigation of a low-carbon, Fe-Cu-based steel, for Naval ship hull applications, with a yield strength of 965 MPa, Charpy V-notch absorbed impact-energy values as high as 74 J at -40°C, and an elongation-to-failure greater than 15 pct, is presented. The increase in strength is derived from a large number density (approximately 10 23 to 10 24 m -3 ) of copper-iron-nickelaluminum-manganese precipitates. The effect on the mechanical properties of varying the thermal treatment was studied. The nanostructure of the precipitates found within the steel was characterized by atom-probe tomography. Additionally, initial welding studies show that a brittle heat-affected zone is not formed adjacent to the welds.
Influence of Cu Addition on Microstructure and Strength of Low Carbon Steel
2016
This study aim is to determine the influence of Cu addition on microstructure and strength of low carbon steel. 0.1% C steel, which contained Cu were used as specimens. The temperatures for heat treatment were determined using a software. The type of specimens was heat treated at specific temperatures in order to obtain 20% and 80% of martensite. Specimens were austenised at 1000 °C for 30 second and followed by water quenching to obtain martensitic structure. The base steel used as the base metal as specimen. The hardness increases with increasing temperature for both of steels. It is found that the hardness, yield strength and ultimate tensile strength of Cu was higher than Base steel. Changes of hardness of annealed samples almost the same in both steels. On the other hand, it is found that addition of Cu can improve tensile strength, total elongation and strength-ductility balance of the steel although no significant effect on yield stress and uniform elongation. Total elongation for Cu steel is 19%, and base steel the elongation values are 15% respectively. Although the martensite content is the same. Total hardness for Cu steel is 390 Hv and 281.8 Hv. However, the Cu steel has the highest hardness than base steel. Therefore, the addition of Cu will increase the hardness, strength and elongation of steel.
International Journal of Fatigue, 2020
Cu precipitates in steels can lead to significant changes of mechanical behavior. However, most investigations focus on the influence of these precipitates on hardness, whereas the effects on quasi-static deformation behavior and cyclic properties remain unclear. Therefore, in the present work the deformation behavior of Cu alloyed steels with two different carbon contents, 0.005 and 0.2 wt%, was analyzed in tensile as well as fatigue tests. To characterize the influence of different precipitation states, various heat treatments were performed. The heat treatment parameters were chosen based on results obtained with the short-time procedure PhyBaL CHT , which is based on cyclic indentation tests and enables the determination of microhardness and cyclic hardening potential. The results reveal that a higher C content increases hardness, decreases cyclic hardening potential and leads to generally higher tensile strength. However, only at a shorter aging time does a higher C content increase fatigue strength, whereas at a longer aging time both steel variants show comparable fatigue lifetimes, despite the significantly higher hardness and tensile strength of the steel with higher carbon content. This can be explained with the higher cyclic hardening potential of the lower carbon steel, leading to an improved fatigue lifetime. Additionally, it could be shown for both steels that an increase of cyclic hardening potential, caused by longer aging times and different precipitation states of Cu, can be associated with increased fatigue strength. However, for an overall assessment of a material's mechanical properties, both, hardness and cyclic hardening potential have to be considered.
DEVELOPMENT OF A NOVEL HIGH Cu, LOW Mn ENVIRONMENTALLY-FRIENDLY WEATHERING STEEL
ABSTRACT A novel concept of steels in which Cu replaces Mn in trapping the S is proposed. The new steel combines the technological, environmental and economics advantages resulting of the Cu addition, with the possibility of controlling the problem of the “hot shortness”. As result, it has great potential use for welded unpainted weathering structures. The improving of mechanical and impact properties by age hardening of Cu containing steels is well know, and also its effect in preventing corrosion. However, the problem of “hot shortness” increases the cost of production of the steel because of the cracking during its hot processing by scrapping the plate or the addition of Ni in preventing it. Recent results points that Cu segregates surrounding MnS inclusions in steels. Then, the “hot shortness” can be prevented in a less expensive way, by reducing the inclusions in the steel so the S is trapped by fine CuS precipitation. This paper suggests a novel alternative solution for the pr...
Development of carbon—Low alloy steel grades for low temperature applications
Materials Science and Engineering: A, 2011
Low alloy steels are processed to fulfill the requirements of low temperature applications. Besides the chemical composition, the steel should receive a suitable heat treatment to ensure the targeted mechanical properties at low temperature. In other words, the steels are designed to delay the ductile to brittle transition temperature to resist dynamic loading at subzero temperatures. Steel alloys processed for liquefied gas pipeline fittings are examples for applications that need deep subzero impact transition temperature (ITT).
Corrosion-resistant carbide-reinforced martensitic steel by Cu modification
npj Materials Degradation, 2019
Carbide-reinforced martensitic steels, known as high-speed steels (HSSs), have been used as tool materials in various industries because of their high hardness and wear resistance. Nonetheless, such steels show severe degradation when used in a corrosive environment because typical Cr 2 O 3 films, which generally realise passivity in these alloys, do not often work effectively. Here, we demonstrate that the corrosion resistance of a high-carbon-containing Fe-Cr-W-based alloy in a sulfuric acid solution can be significantly improved by the addition of trace Cu. The enrichment of Cu at the surface of the alloy as corrosion proceeds is key to inhibiting further corrosion. A theoretical model for a micro corrosion cell, which should be applicable to any material employed under the same corrosion conditions in fields such as the chemical and energy industries, was developed to interpret the experimental observations.
The effect of strain rate on the flow stress of a low carbon high strength ferritic steel that contains nanometer size Cu-Ni-Al precipitates is found to be much less than that of HSLA 65 that does not have such precipitates. This result is in agreement with the theory that such precipitates locally lower the Peierls stress for screw dislocations in body-centered cubic iron. The fracture mode in the steel is ductile over the wide ranges of strain rate and temperature investigated.