This paper describes the development of an inorganic alternative to coal or coal replacement for bentonite bonded molds (greensand molding) and the realization in an operating foundry. Through a time period of 1.5 yea...This paper describes the development of an inorganic alternative to coal or coal replacement for bentonite bonded molds (greensand molding) and the realization in an operating foundry. Through a time period of 1.5 years, Componenta Foundry changed in many steps from a classical green sand system to a coal free system, based on ENVIBOND developed in the GO-APIC project and further development as an S&B project. At Componenta Foundry, the percentage of casting defects or scrap did not increase. There was a tendency of an increase in stress (scabbing) defects and of a decrease in penetration defects. Benzene emission is reduced by 40%, odor emission has lower values (not statistically proven). Visible is less smoke in the foundry, especially at the cooling line. The benefits for health and emissions are clearly seen.展开更多
Coal has often been regarded as a problem additive to solve and improve the surface finish of iron castings,but at the same time causes other issues such as increased loss on ignition,total fines and moisture in syste...Coal has often been regarded as a problem additive to solve and improve the surface finish of iron castings,but at the same time causes other issues such as increased loss on ignition,total fines and moisture in system sands.Although many altermatives have been tried,there is no real substitute for thw all round properties of this wonderful natural resource.With the correct choice of coal,the combination of low ash,high volatile and swell index properties coupled with the key element of grading size,ensures castings are produced free from metal penetration and surface related problems.By careful selection,safe handling and processing coal continues to offer a good simple cost effective solution.Coal is subject to regulations in storage,processing and transportation and then further subjected to safe handling and use by the foundry.Despite these handicaps,it is still economical to the end user and modern processing and grading methods ensure it is used in the optimum condition to help produce quality castings.展开更多
The need for control of raw materials is critical to the success of iron casting production from greensand systems. The base silica sand is often overlooked with the main focus on bentonite additions. Carbonaceous add...The need for control of raw materials is critical to the success of iron casting production from greensand systems. The base silica sand is often overlooked with the main focus on bentonite additions. Carbonaceous additives can be considered a "necessary evil" to ensure a good surface finish and reduction in sand related surface defects. Other additives are used when systems get out of balance and these in turn add further to the complex nature of greensand systems. For castings requiring cores this becomes a bigger issue as many differing resin systems are employed for core production and these must be taken into consideration when controlling both the carbonaceous levels and the overall grading of the sand system. The twin effects on additional carbon and loss-on-ignition and overall sand grading need careful understanding and control. Various control methods are examined including traditional methods such as volatiles and loss-on-ignition along with bentonite determination methods and grading methods. Newer control methods such as total carbon are reviewed along with the overall package of testing and control methods.Various predictive methods are looked at as a control feature as well. The quality of additives and their role and more importantly their interaction is highlighted,as this is an area often neglected as foundrymen battle for success in consistent quality castings. Suggested in-coming control tests are discussed allied to additions at the mixer. Also reviewed is the interpretation of results and the action required to ensure control and more importantly consistent quality castings from greensand systems with the emphasis on the understanding and control of carbonaceous additive on casting performance.展开更多
文摘This paper describes the development of an inorganic alternative to coal or coal replacement for bentonite bonded molds (greensand molding) and the realization in an operating foundry. Through a time period of 1.5 years, Componenta Foundry changed in many steps from a classical green sand system to a coal free system, based on ENVIBOND developed in the GO-APIC project and further development as an S&B project. At Componenta Foundry, the percentage of casting defects or scrap did not increase. There was a tendency of an increase in stress (scabbing) defects and of a decrease in penetration defects. Benzene emission is reduced by 40%, odor emission has lower values (not statistically proven). Visible is less smoke in the foundry, especially at the cooling line. The benefits for health and emissions are clearly seen.
文摘Coal has often been regarded as a problem additive to solve and improve the surface finish of iron castings,but at the same time causes other issues such as increased loss on ignition,total fines and moisture in system sands.Although many altermatives have been tried,there is no real substitute for thw all round properties of this wonderful natural resource.With the correct choice of coal,the combination of low ash,high volatile and swell index properties coupled with the key element of grading size,ensures castings are produced free from metal penetration and surface related problems.By careful selection,safe handling and processing coal continues to offer a good simple cost effective solution.Coal is subject to regulations in storage,processing and transportation and then further subjected to safe handling and use by the foundry.Despite these handicaps,it is still economical to the end user and modern processing and grading methods ensure it is used in the optimum condition to help produce quality castings.
文摘The need for control of raw materials is critical to the success of iron casting production from greensand systems. The base silica sand is often overlooked with the main focus on bentonite additions. Carbonaceous additives can be considered a "necessary evil" to ensure a good surface finish and reduction in sand related surface defects. Other additives are used when systems get out of balance and these in turn add further to the complex nature of greensand systems. For castings requiring cores this becomes a bigger issue as many differing resin systems are employed for core production and these must be taken into consideration when controlling both the carbonaceous levels and the overall grading of the sand system. The twin effects on additional carbon and loss-on-ignition and overall sand grading need careful understanding and control. Various control methods are examined including traditional methods such as volatiles and loss-on-ignition along with bentonite determination methods and grading methods. Newer control methods such as total carbon are reviewed along with the overall package of testing and control methods.Various predictive methods are looked at as a control feature as well. The quality of additives and their role and more importantly their interaction is highlighted,as this is an area often neglected as foundrymen battle for success in consistent quality castings. Suggested in-coming control tests are discussed allied to additions at the mixer. Also reviewed is the interpretation of results and the action required to ensure control and more importantly consistent quality castings from greensand systems with the emphasis on the understanding and control of carbonaceous additive on casting performance.
