scholarly journals Development of a Hot-rolled Low Carbon Steel with High Yield Strength

2006 ◽  
Vol 46 (5) ◽  
pp. 754-758 ◽  
Author(s):  
Hai-Long Yi ◽  
Lin-Xiu Du ◽  
Guo-Dong Wang ◽  
Xiang-Hua Liu
1993 ◽  
Vol 90 (7-8) ◽  
pp. 917-922
Author(s):  
Y. Matsuda ◽  
M. Nishino ◽  
J. Ikeda

Alloy Digest ◽  
1972 ◽  
Vol 21 (8) ◽  

Abstract AISI 1015 is a low-carbon steel used in the annealed, cold-worked, hot-rolled or normalized condition for general purpose construction and engineering. It is also used for case-hardened components. It combines good machinability, good workability and good weldability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-48. Producer or source: Carbon steel mills.


Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 995
Author(s):  
Haitao Xiao ◽  
Shaobo Zheng ◽  
Yan Xin ◽  
Jiali Xu ◽  
Ke Han ◽  
...  

Surface hardening improves the strength of low-carbon steel without interfering with the toughness of its core. In this study, we focused on the microstructure in the surface layer (0–200 μm) of our low-carbon steel, where we discovered an unexpectedly high level of hardness. We confirmed the presence of not only upper bainite and acicular ferrite but also lath martensite in the hard surface layer. In area of 0–50 μm, a mixed microstructure of lath martensite and B1 upper bainite was formed as a result of high cooling rate (about 50–100 K/s). In area of 50–200 μm, a mixed microstructure of acicular ferrite and B2 upper bainite was formed. The average nanohardness of the martensite was as high as 9.87 ± 0.51 GPa, which was equivalent to the level reported for steel with twenty times the carbon content. The ultrafine laths with an average width of 128 nm was considered to be a key cause of high nanohardness. The average nanohardness of the ferrites was much lower than for martensite: 4.18 ± 0.39 GPa for upper bainite and 2.93 ± 0.30 GPa for acicular ferrite. Yield strength, likewise, was much higher for martensite (2378 ± 123 MPa) than for upper bainite (1007 ± 94 MPa) or acicular ferrite (706 ± 72 MPa). The high yield strength value of martensite gave the surface layer an exceptional resistance to abrasion to a degree that would be unachievable without additional heat treatment in other steels with similar carbon content.


2010 ◽  
Vol 654-656 ◽  
pp. 11-16 ◽  
Author(s):  
Setsuo Takaki

Yielding of polycrystalline low carbon steel is characterized by a clear yield point followed by unstable Lüders deformation and such a yielding behavior is taken over to fine grained steel with the grain size of 1μm or less. Yield strength of ferritic steel is increased with grain refinement standing on the Hall-Petch relation. The following equation is realized up to 0.2μm grain size in the relation between yield strength y and grain size d: y [MPa]= 100+600×d[μm]-1/2. In low carbon steel, it might be concluded that the Hall-Petch coefficient (ky) is around 600MPa•μm1/2. However, the ky value of interstitial free steels is substantially small as 130-180MPa•μm1/2 and it can be greatly increased by a small amount of solute carbon less than 20ppm. It was also cleared that the disappearance of yield point by purifying is due to the decrease in the ky value. On the other hand, the ky value is changeable depending on heat treatment conditions such as cooling condition from an elevated temperature and aging treatment at 90°C. These results suggest the contribution of carbon segregation at grain boundary in terms of the change in the ky value. On the contrary, substitutional elements such as Cr and Si do not give large influence to the ky value in comparison with the effect by carbon.


2011 ◽  
Vol 462-463 ◽  
pp. 407-412 ◽  
Author(s):  
Komsan Ngamkham ◽  
Satian Niltawach ◽  
Somrerk Chandra-ambhorn

The objective of this work was to carry out tensile tests to investigate the effect of finishing temperature on mechanical adhesion of thermal oxide scale on hot-rolled low carbon steel strips. Two hot-rolled low carbon steel strips were produced in an industrial hot rolling line by fixing a coiling temperature at 620 °C and varying finishing temperatures at 820 and 910 °C. Two testing methods were conducted. First, each of a number of samples was subjected to a given imposed strain with ex-situ imaging of scale surface after straining. Second, only one sample was strained in a test with ex-situ imaging of scale surface at every 2 mm elongation of the sample. A spallation ratio, an area where scale was spalled out and normalised by the total area observed by microscope, was plotted as a function of the imposed strain. These two methods gave the same tendency of results as follows. At a given strain, the spallation ratio of scale on steel produced using higher finishing temperature was larger. The gradient of spallation ratio with respect to the imposed strain of that scale was also steeper. This reflects the higher susceptibility of scale to spall out with increasing imposed strain. This behaviour might be related to the larger thickness of scale on steel produced using higher finishing temperature. For the second testing method, lowering the magnification of microscope to observe scale spallation from 50x to 20x increased R2 of the curve of spallation ratio versus the imposed strain, as well as improved the reproducibility of the test.


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