Central Iron and Steel Institute

Beijing, China

Central Iron and Steel Institute

Beijing, China
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Ao L.,Kunming University of Science and Technology | Ao L.,Central Iron and Steel Institute | Ma D.,Central Iron and Steel Institute | Chi H.,Central Iron and Steel Institute | And 2 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2012

The effect of heat treatment process on microstructure and properties of CPR and D2 cold work steels was investigated. The results show that the distribution of eutectic carbides in CPR steel is more uniform than that in D2 steel. After heating at 1050°C, then quenching in oil, the hardness of CPR and D2 steel is 64.7 and 65 HRC, respectively. Both CPR and D2 steel have obvious secondary hardening effect during tempering. Temper resistance of CPR steel is much better than D2 steel, and the temperature ranges for heat treatment of CPR steel is more broad.

Chen X.-M.,Harbin Institute of Technology | Song S.-H.,Harbin Institute of Technology | Weng L.-Q.,Harbin Institute of Technology | Liu S.-J.,Harbin Institute of Technology | Wang K.,Central Iron and Steel Institute
Materials Science and Engineering A | Year: 2011

Equilibrium grain boundary segregation of phosphorus in a Ti-stabilized interstitial free (IF) steel is measured using Auger electron spectroscopy (AES) after the specimens are aged for adequate time at different temperatures between 600 and 850 °C. Based on the experimental data of equilibrium grain boundary segregation along with the McLean equilibrium segregation theory, the free energy of segregation of phosphorus is evaluated to be ∼44.8. kJ/mol, being independent of temperature. With the AES results being combined with the ductile-to-brittle transition temperatures (DBTTs) determined by impact tests, a relationship between DBTT and phosphorus boundary concentration is established. Predictions with the relationship indicate that cold work embrittlement may be severe if the steel is annealed at relatively low temperatures after cold rolling. © 2011 Elsevier B.V.

Chen X.-M.,Harbin Institute of Technology | Song S.-H.,Harbin Institute of Technology | Weng L.-Q.,Harbin Institute of Technology | Wang K.,Central Iron and Steel Institute
Materials Letters | Year: 2012

The ductile-to-brittle transition temperature (DBTT) and hardness of an interstitial free steel solid-solution-strengthened by phosphorus are experimentally evaluated under different conditions. The results demonstrate a linear relationship between DBTT and hardness under constant phosphorus grain boundary concentration and grain size. The DBTT increases with increasing hardness, showing a hardening embrittlement effect. With reference to a previous study concerning the effect of phosphorus boundary segregation on the ductile-to-brittle transition for the same steel, which shows a non-hardening embrittlement effect, it is seen that the two embrittlement effects are independent of each other and that the combined embrittlement effect under an average grain size of ∼ 70 μm can be expressed as DBTT (°C) = 0.24HV + 1.60CP - 34.8, where HV is the Vickers hardness value and CP is the phosphorus boundary concentration in at.%. © 2011 Elsevier B.V. All rights reserved.

Han M.,Central Iron and Steel Institute | Hu J.-Y.,Central Iron and Steel Institute | Chen Y.-H.,Central Iron and Steel Institute | Wang H.-Z.,Central Iron and Steel Institute
Yejin Fenxi/Metallurgical Analysis | Year: 2010

Laser-ablation conditions and plasma conditions have been optimized for the analysis of nickel-base superalloy sample. Spectral interferences of laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) were investigated. Titanium was chosen as the internal standard. Several manners have been attempted and evaluated to fix up superalloy chips. The aggregated chips on a plate glass by double-sided adhesive could be a good substitute of bulk reference materials. As a result, the correction limitation caused by the lack of matrix-matched bulk reference materials was gotten over. The method was applied to analyze eighteen trace elements (B, P, Sc, Cu, Zn, Ga, Ge, As, Se, Ag, In, Sn, Sb, Te, Hf, Tl, Pb and Bi) in CRM of superalloy, and the determination limits of most elements were lower than 1 μg/g except B, Mg, P and Se lower than 10 μg/g. For most of trace elements in CRMs, RSDs were smaller than 15%. Furthermore, ten trace elements in four samples were quantitatively analyzed by the method, and the quantitative results agreed well with the certified values.

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