In steel squeeze casting process, the working condition of a punch was very rigorous. The abnormal failure models of an H13 punch, such as plastic rubbed damnification, could not be avoided easily. Based on the analys...In steel squeeze casting process, the working condition of a punch was very rigorous. The abnormal failure models of an H13 punch, such as plastic rubbed damnification, could not be avoided easily. Based on the analysis of the flow stress and the friction-shearing stress of an H13 punch in steel squeeze casting process, the following results were obtained： if the flow stress of an H13 punch was smaller than its friction-shearing stress, these abnormal failures could not be avoided; and if there were some protection measures that enable the flow stress to have a greater value than its friction-shearing one, the abnormal failures would not occur. In the production of 45^# steel valves and catenary system components, the flow stress of a lateral H13 punch without any protection measure was about 29 MPa and its friction-shearing stress was about 51 MPa, then, the abnormal failures occurred; however, when the protection measures of the punch enabled its working temperature to have a value below 682 ℃ its flow stress was greater than its friction-shearing stress, and the abnormal failures were avoided.展开更多
The occurrence of time-dependent cavitation and tensile stress in an oscillatory oil squeeze film were investigated experimentally. The test apparatus was a simple thrust bearing consisting of two parallel circular pl...The occurrence of time-dependent cavitation and tensile stress in an oscillatory oil squeeze film were investigated experimentally. The test apparatus was a simple thrust bearing consisting of two parallel circular plates separated by a thin viscous oil film. During the test, one plate was at rest while tne other (transparent) oscillated in a direction normal to its surface. This test configuration was chosen to avoid the rotational motion and complicated geometry of a squeeze film Journal bearing. The frequency of oscillation was in the range of 5 to 50 Hz and was controlled by an electro-magnetic exciter. The process of cavity formation and its subsequent development was recorded by a high-speed video camera. Concomitant pressure in the oil film was measured both within and without the cavitation region. It was found that both tensile stress and cavities existed in a squeeze film under certain working conditions.展开更多
Squeeze casting is a technology with short route,high efficiency and precise forming,possessing features of casting and plastic processing.It is widely used to produce high performance metallic structural parts.As ene...Squeeze casting is a technology with short route,high efficiency and precise forming,possessing features of casting and plastic processing.It is widely used to produce high performance metallic structural parts.As energy conservation and environmental protection concerns have risen,lightweight and high performance metal parts are urgently needed,which accelerated the development of squeeze casting technology over the past two decades in China.In this paper,research progress on squeeze casting alloys,typical parts manufacturing and development of squeeze casting equipment in China are introduced.The future trend and development priorities of squeeze casting are discussed.展开更多
The mold-filling ability of alloy mclt in squceze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built ...The mold-filling ability of alloy mclt in squceze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built based on the flowing theory of the incompressible viscous fluid. It was proved by experiments and calculations that the mold-tilling pressure and velocity are prominent influencing factors on the mold-filling ability of alloy melt. The mold-filling ability increases with the increase of the mold-filling pressure and the decrease of the proper mold-filling velocity. Moreover, the pouring temperature relatively has less effect on the mold-filling ability under the experimental conditions. The maximum deviation of theoretical calculating values with experimental results is less than 15%. The model can quantitatively estimate the effect of every factor on the mold-filling ability.展开更多
In order to improve mechanical properties of 6082 aluminum alloy,the SiC_(p)/Al 6082 composites were prepared by the addition of the micron-sized SiC_(p)articles combined with the squeeze casting.The effects of the Si...In order to improve mechanical properties of 6082 aluminum alloy,the SiC_(p)/Al 6082 composites were prepared by the addition of the micron-sized SiC_(p)articles combined with the squeeze casting.The effects of the SiC_(p)content and squeeze casting on the microstructure and mechanical properties of the 6082 aluminum alloy were investigated by SEM,EDS,TEM,tensile testing and hardness testing analysis methods.Research results exhibited that the SiC_(p)content and squeeze casting had a significant impact on the microstructure and mechanical properties of the 6082 aluminum alloy.The addition of the SiC_(p)refined the grain size of the 6082 aluminum alloy while caused the increase of the porosity with increasing the SiC_(p)content,especially in the permanent mold casting condition.Compared to the permanent mold casting,the squeeze casting obviously reduced pore defects,refined grain size and made the SiC_(p)distribute evenly as well as bond tightly with the Al matrix.The tensile strength,yield strength,elongation,elastic modulus and hardness of the 6082 aluminum alloy obtained with the SiC_(p)and squeeze casting were remarkably improved,and the optimal mechanical properties were obtained with a 2 wt.%SiC_(p),and they increased 10.73%,72.7%,193.9%,23.5%and 25.2%,respectively,compared to those of the6082 aluminum alloy obtained without SiC_(p)and squeeze casting.The fracture surface of the SiC_(p)/Al 6082 composites obtained with the squeeze casting was dense and exhibited a ductile fracture mode.展开更多
The effect of squeeze casting on microstructure and mechanical properties of hypereutectic Al-xS i alloys（x = 15, 17.5, 22 wt%） was investigated in this study. Results show that microstructure of the hypereutectic A...The effect of squeeze casting on microstructure and mechanical properties of hypereutectic Al-xS i alloys（x = 15, 17.5, 22 wt%） was investigated in this study. Results show that microstructure of the hypereutectic Al-x Si alloys was obviously improved by squeeze casting. The amount of coarse primary Si phase decreased, while that of fine primary α-Al dendrites increased with the increase of squeeze casting pressure. Due to the decrease of coarse primary Si particles, cracking of the matrix was reduced, whilst the fine microstructure, and mechanical properties of the squeeze casting alloys were improved. Compared with gravity casting alloys, mechanical properties of the hypereutectic Al-xS i alloys solidified at 600 MPa were improved significantly. Hardness of the squeeze casting hypereutectic Al-（15, 17.5, 22 wt%） Si alloys was improved by 15.91%, 12.23%, 17.48%, ultimate tensile strength was improved by 37.85%, 32.27%, 22.74%,and elongation was improved by 55.83%, 167.86%, 126.76%, respectively. Due to the uniform distribution of Si phases in squeeze casting Al-x Si alloys, their wear resistance was markedly enhanced.展开更多
An orthogonal test was conducted to investigate the influence of technical parameters of squeeze casting on the strength and ductility of AISigCu3 alloys. The experimental results showed that when the forming pressure...An orthogonal test was conducted to investigate the influence of technical parameters of squeeze casting on the strength and ductility of AISigCu3 alloys. The experimental results showed that when the forming pressure was higher than 65 MPa, the strength （ab） of A1Si9Cu3 alloys decreased with the forming pressure and pouring temperature increasing, whereas ab increased with the increase of filling velocity and mould preheating temperature. The ductility （6） by alloy was improved by increasing the forming pressure and filling velocity, but decreased with pouring temperature increasing. When the mould preheating temperature increased, the ductility increased first, and then decreased. Under the optimized parameters of pouring temperature 730 ℃, forming pressure 75 MPa, filling velocity 0.50 m/s, and mould preheating temperature 220 ℃, the tensile strength, elongation, and hardness of A1Si9Cu3 alloys obtained in squeeze casting were improved by 16.7%, 9.1%, and 10.1%, respectively, as compared with those of sand castings.展开更多
Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properti...Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.展开更多
Semi-solid AZ91D magnesium alloy billets were prepared by near-liquidus heat holding.Semi-solid squeeze casting was conducted at 575,585 and 595℃,respectively,with 1 mm·s^-1 squeeze speed.The semisolid squeeze c...Semi-solid AZ91D magnesium alloy billets were prepared by near-liquidus heat holding.Semi-solid squeeze casting was conducted at 575,585 and 595℃,respectively,with 1 mm·s^-1 squeeze speed.The semisolid squeeze casting AZ91D samples were heat treated by T4(solution at 415℃for 24 h)and T6(solution at 415℃for 24 h+220℃for 8 h)processes,respectively.The microstructure and mechanical properties of the alloy in different states were investigated by means of OM,SEM and tensile testing machine.The results show that compared to as-cast alloy,the grain size of the semi-solid squeezed AZ91D decreased significantly,and with the increase of semi-solid squeeze temperature,the grain size of AZ91D increased.The grains of the alloy were refined by T4 treatment,and further refined by T6 treatment.T6 treatment greatly improved the tensile strength,elongation,and hardness,but did not significantly improve yield strength.After 575℃squeeze casting and T6 treatment,the ultimate tensile strength(UTS)reached 285 MPa,the elongation reached 13.36%,and the hardness also reached the maximum(106.8 HV),but the yield strength(YS)was only 180 MPa.During the process of semi-solid squeeze casting and heat treatment,the matrix grain was refined and a large number of precipitated and secondary precipitated phases of Mg17Al12 appeared.Both the average size of matrix grain and secondary precipitated phase decreased,while the volume fraction of secondary precipitated phase increased.All these resulted in high tensile strength,elongation and hardness.展开更多
Wrought magnesium alloy AZ80 with a thick section of 20 mm was prepared by squeeze casting (SC) and permanent steel mold casting (PSMC). The porosity measurements of the SC and PSMC depicted that SC AZ80 had a pore co...Wrought magnesium alloy AZ80 with a thick section of 20 mm was prepared by squeeze casting (SC) and permanent steel mold casting (PSMC). The porosity measurements of the SC and PSMC depicted that SC AZ80 had a pore content of 0.52%, which was 77% lower than 2.21% of PSMC AZ80 counterpart. The YS, UTS, e<sub>f</sub>, E and strengthening rate of cast AZ80 were determined by mechanical pulling. The engineering stress versus strain bended lines showed that SC AZ80 had a YS of 84.7 MPa, a UTS of 168.2 MPa, 5.1% in e<sub>f</sub>, and 25.1 GPa in modulus. But, the YS, UTS and e<sub>f</sub> of the PSMC AZ80 specimen were only 71.6 MPa, 109.0 MPa, 1.9% and 21.9 GPa. The findings of the mechanical pulling evidently depicted that the YS, UTS, e<sub>f</sub> and E of SC AZ80 were 18%, 54%, 174% and 15% higher than PSMC counterpart. The computed resilience and toughness suggested that the SC AZ80 exhibited greater resistance to tensile loads during elastic deformation and possessed higher capacity to absorb energy during plastic deformation compared to the PSMC AZ80. At the beginning of permanent change, the strengthening rate of SC AZ80 was 10,341 MPa, which was 9% greater than 9489 MPa of PSMC AZ80. The high mechanical characteristics of SC AZ80 should be primarily attributed to its low porosity level. .展开更多
Inorganic scale deposits are a major water-related problem encountered in producing oil and gas wells. The harshness of scale deposits is dependent on the field operating conditions. Scale deposits can vary from mild ...Inorganic scale deposits are a major water-related problem encountered in producing oil and gas wells. The harshness of scale deposits is dependent on the field operating conditions. Scale deposits can vary from mild scaling tendencies to extreme. In general, the scale deposit will cause a reduction in formation pores, declining productivity and eventually blockage of the wellbore and hence unexpected downtime if it is allowed to persevere. To overcome this, the productivity of an oil and gas well is ensured by handling scale deposits via removal or prevention methods. Scale prevention is the best and cost-e ective method for handling scale deposits that ensures production continuity. Inhibition through 'threshold' scale inhibitor treatment is the most common method that is proven to prevent or reduce likely deposits. This paper examines the art of synthetic scale inhibitors, in particular, threshold scale inhibitors in oil and gas production. It discusses the chemistry of those inhibitors, inhibition mechanisms, treatment methods and key properties for their applications. It also highlights the chemistry of the synthetic routes often used to produce them in the laboratory and/or industry. Finally, it highlights the environmental concerns for the applicability of threshold scale inhibitors.展开更多
文摘In steel squeeze casting process, the working condition of a punch was very rigorous. The abnormal failure models of an H13 punch, such as plastic rubbed damnification, could not be avoided easily. Based on the analysis of the flow stress and the friction-shearing stress of an H13 punch in steel squeeze casting process, the following results were obtained： if the flow stress of an H13 punch was smaller than its friction-shearing stress, these abnormal failures could not be avoided; and if there were some protection measures that enable the flow stress to have a greater value than its friction-shearing one, the abnormal failures would not occur. In the production of 45^# steel valves and catenary system components, the flow stress of a lateral H13 punch without any protection measure was about 29 MPa and its friction-shearing stress was about 51 MPa, then, the abnormal failures occurred; however, when the protection measures of the punch enabled its working temperature to have a value below 682 ℃ its flow stress was greater than its friction-shearing stress, and the abnormal failures were avoided.
文摘The occurrence of time-dependent cavitation and tensile stress in an oscillatory oil squeeze film were investigated experimentally. The test apparatus was a simple thrust bearing consisting of two parallel circular plates separated by a thin viscous oil film. During the test, one plate was at rest while tne other (transparent) oscillated in a direction normal to its surface. This test configuration was chosen to avoid the rotational motion and complicated geometry of a squeeze film Journal bearing. The frequency of oscillation was in the range of 5 to 50 Hz and was controlled by an electro-magnetic exciter. The process of cavity formation and its subsequent development was recorded by a high-speed video camera. Concomitant pressure in the oil film was measured both within and without the cavitation region. It was found that both tensile stress and cavities existed in a squeeze film under certain working conditions.
基金supported by Guangdong-Natural Science Foundation of China(GD-NSFC,grant No.U1034001)Natural Science Foundation of China(grant No.51374110)Specialized Research Fund for Doctoral Program of Higher Education(grant No.20120172110045)
文摘Squeeze casting is a technology with short route,high efficiency and precise forming,possessing features of casting and plastic processing.It is widely used to produce high performance metallic structural parts.As energy conservation and environmental protection concerns have risen,lightweight and high performance metal parts are urgently needed,which accelerated the development of squeeze casting technology over the past two decades in China.In this paper,research progress on squeeze casting alloys,typical parts manufacturing and development of squeeze casting equipment in China are introduced.The future trend and development priorities of squeeze casting are discussed.
文摘The mold-filling ability of alloy mclt in squceze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built based on the flowing theory of the incompressible viscous fluid. It was proved by experiments and calculations that the mold-tilling pressure and velocity are prominent influencing factors on the mold-filling ability of alloy melt. The mold-filling ability increases with the increase of the mold-filling pressure and the decrease of the proper mold-filling velocity. Moreover, the pouring temperature relatively has less effect on the mold-filling ability under the experimental conditions. The maximum deviation of theoretical calculating values with experimental results is less than 15%. The model can quantitatively estimate the effect of every factor on the mold-filling ability.
基金financially supported by the National Key Research and Development Program of China(Nos.2020YFB2008300 and 2020YFB2008304)the State Key Laboratory of High Performance Complex Manufacturing in CSU(No.Kfkt2019-01)the Analytical and Testing Center,HUST。
文摘In order to improve mechanical properties of 6082 aluminum alloy,the SiC_(p)/Al 6082 composites were prepared by the addition of the micron-sized SiC_(p)articles combined with the squeeze casting.The effects of the SiC_(p)content and squeeze casting on the microstructure and mechanical properties of the 6082 aluminum alloy were investigated by SEM,EDS,TEM,tensile testing and hardness testing analysis methods.Research results exhibited that the SiC_(p)content and squeeze casting had a significant impact on the microstructure and mechanical properties of the 6082 aluminum alloy.The addition of the SiC_(p)refined the grain size of the 6082 aluminum alloy while caused the increase of the porosity with increasing the SiC_(p)content,especially in the permanent mold casting condition.Compared to the permanent mold casting,the squeeze casting obviously reduced pore defects,refined grain size and made the SiC_(p)distribute evenly as well as bond tightly with the Al matrix.The tensile strength,yield strength,elongation,elastic modulus and hardness of the 6082 aluminum alloy obtained with the SiC_(p)and squeeze casting were remarkably improved,and the optimal mechanical properties were obtained with a 2 wt.%SiC_(p),and they increased 10.73%,72.7%,193.9%,23.5%and 25.2%,respectively,compared to those of the6082 aluminum alloy obtained without SiC_(p)and squeeze casting.The fracture surface of the SiC_(p)/Al 6082 composites obtained with the squeeze casting was dense and exhibited a ductile fracture mode.
基金support from the National Natural Science Foundation of China(Grant No.51674168)Shenyang Application Basic Research Fund(Grant No.F14-231-1-23)
文摘The effect of squeeze casting on microstructure and mechanical properties of hypereutectic Al-xS i alloys（x = 15, 17.5, 22 wt%） was investigated in this study. Results show that microstructure of the hypereutectic Al-x Si alloys was obviously improved by squeeze casting. The amount of coarse primary Si phase decreased, while that of fine primary α-Al dendrites increased with the increase of squeeze casting pressure. Due to the decrease of coarse primary Si particles, cracking of the matrix was reduced, whilst the fine microstructure, and mechanical properties of the squeeze casting alloys were improved. Compared with gravity casting alloys, mechanical properties of the hypereutectic Al-xS i alloys solidified at 600 MPa were improved significantly. Hardness of the squeeze casting hypereutectic Al-（15, 17.5, 22 wt%） Si alloys was improved by 15.91%, 12.23%, 17.48%, ultimate tensile strength was improved by 37.85%, 32.27%, 22.74%,and elongation was improved by 55.83%, 167.86%, 126.76%, respectively. Due to the uniform distribution of Si phases in squeeze casting Al-x Si alloys, their wear resistance was markedly enhanced.
基金Project(11C26211304055) supported by Small to Medium Enterprise Innovation Fund
文摘An orthogonal test was conducted to investigate the influence of technical parameters of squeeze casting on the strength and ductility of AISigCu3 alloys. The experimental results showed that when the forming pressure was higher than 65 MPa, the strength （ab） of A1Si9Cu3 alloys decreased with the forming pressure and pouring temperature increasing, whereas ab increased with the increase of filling velocity and mould preheating temperature. The ductility （6） by alloy was improved by increasing the forming pressure and filling velocity, but decreased with pouring temperature increasing. When the mould preheating temperature increased, the ductility increased first, and then decreased. Under the optimized parameters of pouring temperature 730 ℃, forming pressure 75 MPa, filling velocity 0.50 m/s, and mould preheating temperature 220 ℃, the tensile strength, elongation, and hardness of A1Si9Cu3 alloys obtained in squeeze casting were improved by 16.7%, 9.1%, and 10.1%, respectively, as compared with those of sand castings.
基金Project(51335009)supported by the National Natural Science Foundation of ChinaProject(2014JQ7273)supported by the Natural Science Foundation of Shaanxi Province of ChinaProject(CXY1514(1))supported by the Xi’an Science and Technology Plan Projects,China
文摘Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.
文摘Semi-solid AZ91D magnesium alloy billets were prepared by near-liquidus heat holding.Semi-solid squeeze casting was conducted at 575,585 and 595℃,respectively,with 1 mm·s^-1 squeeze speed.The semisolid squeeze casting AZ91D samples were heat treated by T4(solution at 415℃for 24 h)and T6(solution at 415℃for 24 h+220℃for 8 h)processes,respectively.The microstructure and mechanical properties of the alloy in different states were investigated by means of OM,SEM and tensile testing machine.The results show that compared to as-cast alloy,the grain size of the semi-solid squeezed AZ91D decreased significantly,and with the increase of semi-solid squeeze temperature,the grain size of AZ91D increased.The grains of the alloy were refined by T4 treatment,and further refined by T6 treatment.T6 treatment greatly improved the tensile strength,elongation,and hardness,but did not significantly improve yield strength.After 575℃squeeze casting and T6 treatment,the ultimate tensile strength(UTS)reached 285 MPa,the elongation reached 13.36%,and the hardness also reached the maximum(106.8 HV),but the yield strength(YS)was only 180 MPa.During the process of semi-solid squeeze casting and heat treatment,the matrix grain was refined and a large number of precipitated and secondary precipitated phases of Mg17Al12 appeared.Both the average size of matrix grain and secondary precipitated phase decreased,while the volume fraction of secondary precipitated phase increased.All these resulted in high tensile strength,elongation and hardness.
文摘Wrought magnesium alloy AZ80 with a thick section of 20 mm was prepared by squeeze casting (SC) and permanent steel mold casting (PSMC). The porosity measurements of the SC and PSMC depicted that SC AZ80 had a pore content of 0.52%, which was 77% lower than 2.21% of PSMC AZ80 counterpart. The YS, UTS, e<sub>f</sub>, E and strengthening rate of cast AZ80 were determined by mechanical pulling. The engineering stress versus strain bended lines showed that SC AZ80 had a YS of 84.7 MPa, a UTS of 168.2 MPa, 5.1% in e<sub>f</sub>, and 25.1 GPa in modulus. But, the YS, UTS and e<sub>f</sub> of the PSMC AZ80 specimen were only 71.6 MPa, 109.0 MPa, 1.9% and 21.9 GPa. The findings of the mechanical pulling evidently depicted that the YS, UTS, e<sub>f</sub> and E of SC AZ80 were 18%, 54%, 174% and 15% higher than PSMC counterpart. The computed resilience and toughness suggested that the SC AZ80 exhibited greater resistance to tensile loads during elastic deformation and possessed higher capacity to absorb energy during plastic deformation compared to the PSMC AZ80. At the beginning of permanent change, the strengthening rate of SC AZ80 was 10,341 MPa, which was 9% greater than 9489 MPa of PSMC AZ80. The high mechanical characteristics of SC AZ80 should be primarily attributed to its low porosity level. .
文摘Inorganic scale deposits are a major water-related problem encountered in producing oil and gas wells. The harshness of scale deposits is dependent on the field operating conditions. Scale deposits can vary from mild scaling tendencies to extreme. In general, the scale deposit will cause a reduction in formation pores, declining productivity and eventually blockage of the wellbore and hence unexpected downtime if it is allowed to persevere. To overcome this, the productivity of an oil and gas well is ensured by handling scale deposits via removal or prevention methods. Scale prevention is the best and cost-e ective method for handling scale deposits that ensures production continuity. Inhibition through 'threshold' scale inhibitor treatment is the most common method that is proven to prevent or reduce likely deposits. This paper examines the art of synthetic scale inhibitors, in particular, threshold scale inhibitors in oil and gas production. It discusses the chemistry of those inhibitors, inhibition mechanisms, treatment methods and key properties for their applications. It also highlights the chemistry of the synthetic routes often used to produce them in the laboratory and/or industry. Finally, it highlights the environmental concerns for the applicability of threshold scale inhibitors.
