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Mathematical Model of Dynamic Operation and Optimum Control of Billet Reheating Furnace

LIU Rixin NING Baolin ** Dept.of Metallurgy , Kunming Institute of Technology , Kunming , 650093 , China*** Dept.of Thermal Energy , Northeast University of Technology , Shenyang , 110006 , China+ To whom correspondence should be addressed

材料科学技术（英文）

This paper provides a mathematical model for the billet reheating process in furnace.A new optimum method is brought up that the objective function is the integral value of enthalpy increasing process of a billet.Different delays are simulated and calculated,some proper delay strategies are ob- tained.The on-line computer control model is de- veloped.The real production conditions simulated, the temperature deviation of drop out billet from the target temperature is kept within±15℃.

关键词: reheating furnace , null , null , null , null

OXIDATION OF Ti IN MOLTEN Cu UNDER WATERY ATMOSPHERE

XUE Xiangxin DU Hegui Northeast University of Technology , Shenyang , China XUE Xiangxin Lecturer , Dept.of Ferrous Metallurgy , Northeast University of Technology , Shenyang , 110006 , China

金属学报(英文版)

An experimental study has been made of oxidation kinetics of Ti in molten Cu-Ti alloy under watery atmosphere at 1500℃.The results may be expressed as follows: [Ti]_(Cu)=0.92-0.69t O≤t≤1.0(h) [Ti]_(Cu)=0.02t~2-0.14t+0.35 1.0≤t≤6.0(h) where t is time in hour.The apparent rate and order of reaction are: (-d[Ti]_(Cu))/dt=0.69,pseudo-zeroth order,k=0.69 (-d[Ti]_(Cu))/dt=0.14-0.04t,pseudo-0.85 order,k=0.39 The apparent mass tranfer coefficient is k'=0.16 cm/h,and the relation of W~2 vs time is: W~2=1.04·10~(-4)t

关键词: Cu-Ti alloy , null , null

DIFFUSION BONDING OF SUPERPLASTIC AI ALLOY LC4

HUANG Yan , MA Longxiang Northeast Universtity of Technology , Shenyang , China lecturer , Department of Metalforming , Northeast University of Technology , Shenyang 110006 , China

金属学报(英文版)

Diffusion bonding of supcrplastic Al alloy LC4,with prior surface treatment of organic solution protecting coating after electroplishing and stainless steel wool brushing,was performed by Gleeble test machine under conditions ranged 490—530 ℃,1.0—3.0 MPa. 30—180 min and vacuum of 1.0×10~(-3) Pa.The joints were examined to have similar strength and microstructure to the base metal Discussion was made on the effect of superplastic treatment on bonding.The micromechanism for diffusion bonding of super- plastic metal was suggested as the migration of original bond interfaces caused by atomic diffusion and grain growth. Experimental results for the alloy as quench-aged state were presented to compare with the superplastic one.

关键词: superplasticity , null , null , null

IMPROVEMENT IN TENSILE PROPERTIES OF α+β TYPE Ti ALLOYS BY HYDROGEN TREATMENT

GONG Bo LAI Zuhan Northeast University of Technology , Shenyang , ChinaNIINOMI Mitsuo , KOBA YASHI Toshiro Toyohashi University of Technology , Toyohashi Japan Department of Physics , Northeast University of Technology , Shenyang 110006 , China

金属学报(英文版)

A new process to refine the microstructure of α+βtvpe Ti alloys was developed by using hydrogen as a temporary alloying element.It involves hydrogenating the alloys below the hydrogenated β transus temperature about 0-40 K,air cooling to room temperature and then dehydrogenating at 948 K.Ti-6AI-4V and Ti-5AI-2.5Fe alloys treated hy this new process show much refined microstructures,and the yield strength,ultimate strength as well as the elongation increase 8—15,5—13 and 7—14% respectively

关键词: Ti-6Al-4V , null , null , null , null

ACTIVITIES OF COMPONENTS IN MgO-B_2O_3 MELT

ZHANG Chengtao JI Chunlin Northeast University of Technology , Shenyang , China ZHANG Chengtao , Division of Physical Chemistry of Metallurgy , Northeast University of Technology , Shenyang , China

金属学报(英文版)

The activity of MgO in MgO-B2O_3 melt was experimentally determined at 1773 and 1823 K by means of slag-liquid Sn equilibrium.The activity of B_2O_3 was calculated by integrating Gibbs-Duhem equation.The standard Gibbs energies of formation of binary compounds 2MgOB_2O_3 and 3MgO·B_2O_3 were estimated with the activity data of components in B_2O_3-MgO melt.

关键词: MgO-B_2O_3 , null , null

SPALLING MECHANISM OF NITRIDED LAYER OF AUSTENITIC STEEL 4Cr14Ni14W2Mo

SUN Xudong LI Jian Northeast University of Technology , Shenyang , China Lecturer , Dept.of Materials Science and Engineering , Northeast University of Technology , Shenyang , China

金属学报(英文版)

The tendency of spalling of the nitrided layer of the hot rolled austenitic steel 4Cr14Ni14W2Mo exhibits close relation to the nitrided surface orientation relative to the rol- led steel rod.It is found that the dislocations in the imperfectly recrystalized steel align as parallel dislocation walls in macroscopic extent,and the thickness of the“white sublayer”in the nitrided layer is much larger at the surface which is parallel to the dislocation walls.On such surface the spalling of the nitrided layer happens often.

关键词: nitriding , null , null

PHASE DIAGRAM OF SYSTEM NdCl_3-LiCl-KCl

ZHANG Yifeng Northeast University of Technology , Shenyang , ChinaZHENG Chaogui YE Yupu Peking University , Beijing , China Department of Chemistry , Northeast University of Technology , Shenyang.China

金属学报(英文版)

The phase diagram of system NdCl_3-LiCl-KCl has been investigated by DTA.Six surfaces corresponding to the prhnary crystallization of NdCl_3,LiCl,KCl,γ-KCl·NdCl_3, β-3KCl·NdCl_3 and 2KCl·NdCl_3 respectively,eleven univariant lines related to the sec- ondary crystallization,two ternary eutectics E_1(70.5wt-% NdCl_3+8.0wt-% KCl,360℃) and E,(5.0wt-% NdCl_3+ 53.0wt-% KCl,355℃)and one ternary peritectic P (67.0wt-% NdCl_3+10.0wt-% KCl,375℃)were found.It is also chtrified that this study on the system NdCl_3- KCl differs from previous work in the two transition temperatures: e_1(77.0 wt-% NdCl_3,484℃),e_2(40.0wt-% NdCl_3,620℃),p (70.0wt-%NdCl_3,610℃),3KCl·NdCl_3(690℃)and two reactions: α-3KGl·NdCl_3β-3KGl·NdCl_3 (355℃) β-SKGl·NdCl_3γ-3KCl·NdCl_3 (450℃) The eutectic point e_5(31.0wt-%LiCl,460C)is determined for the pseudobinary system 3KCl·NdCl_3—LiCl.

关键词: ternary system NdCl_3—LiCl—KCl , null

INTERNAL FRICTION OF GRAIN BOUNDARIES IN Fe-P AND Fe-P-La ALLOYS CONTAINING TRACE Cu

JI Jingwen WEI Quanjin GENG Dianqi WU Yuqin Northeast University of Technology , Shenyang , China Professor , Dept.of Physics , Northeast University of Technology , Shenyang 110006 , China

金属学报(英文版)

The grain boundary internal friction(GBIF)in Fe-P and Fe-P-La alloys containing trace Cu has been studied.It is found that an addition of 0.584—0.722 wt-% La obviously reduces the IF,shifts grain boundary peaks towards higher temperatures,and produces a small addi- tional peak at even higher temperature.The mechanism of GBIF is explained as the movement of defects of atomic size,namely point defects,at gram boundaries and/or their clusters un- der stress.

关键词: internal friction , null , null , null , null

PHASE DIAGRAMS OF SYSTEMS SmCl_3-CaCl_2 AND SmCl_3-LiCl

ZHANG Yifeng MENG Bo GU Yunyan Northeast University of Technology , Shenyang , China Professor , Department of Chemistry , Northeast University of Technology , Shenyang 110006 , China

金属学报(英文版)

The phase diagrams of binary systems SmCl_3-CaCl_2 and SmCl_3-LiCl were determined by DTA and X-ray diffraction analysis.The system SmCl_3-CaCl_2 is of a simple eutectic type with eutectic point of 55.8mol-% SmCl_3 at 545℃.The system SmCl_3-LiCl is of the type with incongruent melting phase 2SmCl_3·LiCl at peritectic point 434℃ and with eutectic point of 31.5 mol-% SmCl_3 at 395℃.

关键词: SmCl_3-CaCl_2 , null , null