Effect of austempering parameters on microstructure and mechanical properties of horizontal continuous casting ductile iron dense bars

In the present research, the orthogonal experiment was carried out to investigate the influence of different austempering process parameters(i.e. austenitizing temperature and time, and austempering temperature and time) on microstructure and mechanical properties of LZQT500-7 ductile iron dense bars with 172 mm in diameter which were produced by horizontal continuous casting(HCC). The results show that the major factors influencing the hardness of austempered ductile iron(ADI) are austenitizing temperature and austempering temperature. The fraction of retained austenite increases as the austenitizing and austempering temperatures increase. When austenitizing temperature is low, acicular ferrite and retained austenite can be effi ciently obtained by appropriately extending the austenitizing time. The proper austmepering time could ensure enough stability of retained austenite and prevent high carbon austenite decomposition. The optimal mechanical properties of ADI can be achieved with the following process parameters: austenitizing temperature and time are 866 °C and 135 min, and austempering temperature and time are 279 °C and 135 min, respectively. The microstructure of ADI under the optimal austempering process consists of fi ne acicular ferrite and a small amount of retained austenite, and the hardness, tensile strength, yield strength, elongation and impact toughness of the bars are HBW 476, 1670 MPa, 1428 MPa, 2.93% and 25.7 J, respectively.

Hot compressive deformation of eutectic Al-17at%Cu alloy on the interface of the Cu-Al composite plate produced by horizontal continuous casting

On the interface of the Cu-Al composite plate from horizontal continuous casting,the eutectic microstructure layer thickness ac-counts for more than 90%of the total interface thickness,and the deformation in rolling forming plays an important role in the quality of the composite plate.The eutectic microstructure material on the interface of the Cu-Al composite plate was prepared by changing the cooling rate of ingot solidification and the deformation in hot compression was investigated.The results show that when the deformation temperature is over 300℃,the softening effect of dynamic recrystallization ofα-Al is greater than the hardening effect,and uniform plastic deformation of eutectic microstructure is caused.The constitutive equation of flow stress in the eutectic microstructure layer was established by Arrhenius hy-perbolic-sine mathematics model,providing a reliable theoretical basis for the deformation of the Cu-Al composite plate.

Thermal Stress Model of Solidified Shell for Horizontal Continuous Casting Billet

ＴｈｅｒｍａｌＳｔｒｅｓｓＭｏｄｅｌｏｆＳｏｌｉｄｉｆｉｅｄＳｈｅｌｌｆｏｒＨｏｒｉｚｏｎｔａｌＣｏｎｔｉｎｕｏｕｓＣａｓｔｉｎｇＢｉｌｌｅｔＳＨＡＯＬｕ；ＣＡＩＫａｉＫｅ；ＬＩＵＸｉｎＨｕａａｎｄＬＩＳｈｕａｎＬｕＴｈｅｒｍａｌＳｔｒｅｓｓＭｏｄｅ...

Nu m erical Sim ulation of Tem perature Field of Copper and Copper Alloy in Horizontal Continuous Casting

To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models have been developed to describe the thermal process. Then Finite Element Method (FEM) has been applied to simulate the solidification process. Parameters including casting speed, casting temperature and cooling conditions have been analyzed. It is shown that different parameters have different influence on the thermal process and must be carefully controlled in continuous casting process. Finally, the simulated results are compared with the experimental ones.

Analysis of inhomogeneity of solidified microstructure of continuous casting copper tubular billet based on factor analysis

The horizontal continuous casting process,the initial step in TP2 copper tubular processing,directly determines the microstructure and properties of copper tubular.However,the process parameters of the continuous casting characterize time variation,multiple disturbances and strong coupling.As a consequence,their influence on a casting billet is difficult to be determined.Due to the above issues,the common factor and special factor analysis of the factor analysis model were used in this study,and the casting experiment and billet metallographic experiment were carried out to diagnose and analyze the reason of the microstructure inhomogeneity.The multiple process parameters were studied and classified using common factor analysis,2 the cast billets with abnormal microstructures were identified by GT^(2) statistics,and the most important factors affecting the microstructural homogeneity were found by special factor analysis.The calculated and experimental results show that the principal parameters influencing the inhomogeneity of solidified microstructure are the primary inlet water pressure and the primary outlet water temperature.According to the consequence of the above investigation,the inhomogeneity of the copper billet microstructure can be effectively improved when the process parameters are controlled and adjusted.

COMPUTER CONTROL SYSTEM FOR DRAWING MACHINE IN HORIZONTAL CONTINUOUS CAST SET

A computer control system for drawing machine in horizontal continuous cast set was introduced.The operation features of the drawing machine were analyzed»the hardware configuration and principles of interface circuit for stroke measurements were given out.An effective method was provided,which made the process parameters progressively optimize under the software environment using friendly interface of person-and-computer communication.This method was also adaptable to optimize parameters of other production process which are hard to model.

Microstructure and properties of LZQT600-3 HCCDIBs for plunger pump cylinder

It is important to improve the comprehensive performance of the ductile iron bars(DIBs)for the cylinder block of the extra high pressure hydraulic plunger pump and accelerate the industrial application.In this work,the LZQT600-3 DIBs with the diameter of 145 mm were prepared by the horizontal continuous casting(HCC)process,that is,LZQT600-3 HCCDIBs.The microstructure and room temperature tensile properties of different sections[left-edge(surface layer),left-1/2R(left half of the radius),and the center of the HCCDIBs]were studied.The results show that the spheroidization of LZQT600-3 HCCDIBs matrix from the left-edge,left-1/2R to the center is at nodulizing grade II and above.As the cooling rate gradually decreases from surface to the center of the HCCIBs,the number of spheroidized graphite is gradually reduced,the size is gradually increased,the shape factor is decreased,and the pearlite content and lamellate spacing are increased.Along the horizontal direction of the section,the hardness of the material is distributed symmetrically around the center of the HCCDIBs.In the vertical direction,the hardness distribution in the center of the HCCDIBs is asymmetrical due to the gravity during the solidification process.Therefore,the microstructure in the lower part of the section solidifies relatively quickly.The left-edge has the best tensile mechanical properties,and the ultimate tensile strength,yield tensile strength and elongation are 597.3 MPa,418.5 MPa and 9.6%,respectively.The tensile fracture belongs to the ductile-brittle hybrid fracture.The comprehensive performances of LZQT600-3 HCCDIBs meet the actual application requirements of ultra-high pressure hydraulic plunger pump cylinder.

Preparation of 3003/4045 Cladding Hollow Billets by Horizontal Electromagnetic Continuous Casting

The 3003/4045 aluminum alloys cladding hollow billets with the diameter of 60 mm and external thickness of 3 mm are fabricated by horizontal electromagnetic continuous casting.The surface features of ingots and microstructures of the bonding interface are observed.The results show that cladding hollow billets combine the external and internal layers by metallurgical bonding without mixing when the pouring temperature of the external liquid metal is 903 K.The diffusion region with the thickness of 25 μm can be seen clearly,where mutual diffusion of Si and Mn atoms takes place. In addition,the intermetallic compound Al_(12)(FeMn)_3Si_2 is formed in the interface.

The Effect of the Combination of Electromagnetic Field on the Surface Quality and Inner Structure of HDC Casting Al 3004 Ingot

The combination of electromagnetic field is applied in the Horizontal Direct Chill(HDC)casting process to produce 3004 aluminum alloy ingot.The effect of combination of electromagnetic field on the ingot surface quality and inner structure was investigated by macro and micro-structure observation.The results show that the combination of electromagnetic field can improve the ingot surface quality and inner structure effectively.The thickness of segregation layer decreased with the application of combination of electromagnetic field.In addition,the combination of electromagnetic field can effectively improve the as-casting structure.Under the function of combination of electromagnetic field,coarse columnar grains transfer to fine equiaxed grains.