Papers by Keyword: C Content

Abstract: Two kinds of C-Si-Mn-Cr-Mo-Nb tested steels with different C content were disigned, and controlled rolling and controlled cooling experiment of tested steels have been carried out in lab to analyze the effect of C on microstructure and mechanical property of high strength hot rolled dual phase steel. It is shown that two kinds of tested steels obtained ferrite and martensite microstructure under controlled rolling and step cooling process. With the increase of C content from 0.032wt% to 0.064wt%, ferrite grain size refines from 9.8μm to 5.0μm, width of martensite colony reduces from 10μm to 5.8μm, and martensite volume fraction increases from 11% to 25%. Yielding strength of high C tested steel is higher than that of low C steel by 55MPa, and amplification of tensile strength is about 155MPa. Elongation ratio decreases about 6.4%. Increasing of yielding strength is determined by strengthening of ferrite grain refining. The amplification of tensile strength is effect by volume fraction and refining of strengthening phase.

Abstract: In order to find the reasons of that the hardness of 1Cr17Ni2 stainless steel partial components after being quenched is weakened, based on the sampling analysis on the partial components to produces the components to carry on the sampling analysis, and to compare the contrast that the maximum of the hardness of quenched material is lower than (the average value of the hardness – the standard deviation) to that the minimum is higher than (the average value of the hardness + the standard deviation), we draw an exciting conclusion. The Cr content in steel is on the high side and the Ni content is on the low side. Especially the components present low hardness after being quenched whose C content is low, and the components present high hardness after being quenched whose C content is high. The reason why components have low hardness is that the contents of the element C and Ni to making Austenite in the 1Cr17Ni2 stainless steel is low, the contents of the element Cr to making Ferrite is high, and the martensite hardness is low and the Ferritecontents is high after being quenched.

Abstract: Steel-bonded cemented carbide GT35 was fabricated from natural ilmenite by in-situ carbothermic reduction and vacuum pressureless sintering. The effects of C content on the mechanical properties and microstructures of GT35 composites were investigated. As an excellent reducer, carbon provides an impetus for a series of reductive process. C content determines the melting point of the steel matrix, and directly affects the mechanism of dissolving and segregating of TiC particles, forming a netlike microstructure. Besides, the liquid steel whose viscosplasticity is determined by C content was coated on the surface of the composite and refrained the release of CO. The results showed that the good mechanical properties of steel-bonded cemented carbide GT35 composite were obtained with 0.9wt.% C at the same sintering conditions and the density reached 6.12g/cm3, the average bending strength was over 1229MPa after heat treatment, the mean hardness HRC was 69.4. It also showed that in-situ reduction of natural limonite was a feasible way to fabricate good performance GT35 composite with a relatively low cost.