Profitability

Our US experts recommend:

Of course using a high-efficiency release agent can prolong the period of time between necessary cleaning for core or mold tooling, but a quick and easy way to extend machine uptime is to use a fast and efficient metal cleaner to remove residual binder and sand build-up on a pattern or mold and/or tool faces. These are newly formulated metal cleaners that not only will ensure that the tooling is clean, to provide the ideal surface to produce a core or mold, they also help keep vents clear and open. Tooling and vents that are free of debris will decrease system downtime, thereby increasing the productivity of the operation.  Keep in mind that metal cleaners are solvents formulated to dissolve binders:  Always check the compatibility of the metal cleaner with the tooling material and any seals or plastic that may be in contact with it. There are “environmentally friendly” or “green” metal cleaners offered by various developers, and used by some foundries, but these products typically do not work as completely and efficiently as the more ad-vanced formulations. If handled properly, ASK’s metal cleaners are the most efficient and economical to use.  

Cleaners break down cold-box resins in less than 15 minutes, as compared to older formulations that may soften the resin but never truly break it down.

Spraying or brushing the metal cleaner directly on the built up areas and then allowing it to soak for at least 15 minutes is the most effective way to clean metal pat-terns.  Then, the softened films can be removed easily. This can all be accom-plished without removing the tooling from the core machine, saving addi-tional down time.  Small parts can be immersed or soaked in the cleaner. Ideally all excess cleaner should be re-moved prior to re-com-missioning the tooling into the manufacturing process. Personal protective equipment is essential for workers handling or applying the metal cleaners as most are corrosive and can cause irritation if mishandled. Operators should wear chemical resistant gloves and goggles.  A face shield also may be recommended.  In order to know for sure, it is critical that Safety Data Sheets (SDSs) should be read carefully and understood fully before using metal cleaners.   

So, consult with your ASK Chemicals contact for the best overall recommendation.

We currently have two processes, for gray and ductile iron casting. Our smaller, high-volume castings are poured on an automatic molding line (green sand, vertically parted) with an automatic pour-ing unit (stopper rod.)  Here, we inoculate in-stream with good results, however we occasionally struggle with carbides on some ductile iron products.  
For our larger castings we use no-bake (PEP SET™) molding on a medium-sized loop line.  Once made, these molds are moved to the pouring floor for hand pouring. For these no-bake castings the microstruc-ture and mechanical properties are highly unpredict-able and result in high scrap rates. Can you suggest a more reliable inoculation practice for these floor-molded castings?

Our US experts recommend:

The improved metallurgical quality of the casting poured in your green-sand operation can be directly attributed to the late (in-stream) inoculation practice. Adding a late inoculation step to the larger, hand-poured molds could improve the metallurgical quality of these castings.  However, using in-stream inoculation might not be practical, so other methods will need to be considered.
In recent years, increasing demands for improved mechanical properties and the challenges encountered by foundries trying to inoculate electric furnace iron have established a need for potent inoculation that is introduced just before the casting cavity is filled, i.e. late inoculation.  
On your automatic molding line you have satisfied these de-manding specifications by adopting late inoculation in the form of in-stream inoculation.  In-stream inoculation is well suited to applications that involve pouring the casting in the same location each and every time.  However, due to the need for specialized equipment, employing in-stream inoculation for hand-poured castings is not so easy.
Moving the ladle from mold to mold on the pouring floor is a challenge in any case. Now consider moving equipment along with the ladle, and it is clear that this can be a very time consuming and cumbersome process. Well, perhaps you could have a mem-ber of the pouring crew add a carefully metered, precise addition of sized material to the iron stream, during mold filling. That would be a solid solution except for the drawbacks: labor costs, safety concerns, and the likelihood that the feed-rate of the inoculant will be inconsistent are a few of the disadvantages of this practice. 
So, let’s consider a more practical method for late inoculation of hand poured castings: using solid, cast ferrosilicon inserts in the mold (or pouring basin.) This technique is widely accepted as a viable method for late inoculation of hand poured castings. In fact, it is commonly used for all types of molding and pouring op-erations.  Using solid cast inserts for your late inoculation of gray and ductile iron would provide these benefits:

  •  No fade. The inoculant goes into solution as close to solidification as possible.
  •  Proper addition rates.  Solid cast inserts are produced in more than 15 different sizes, so providing the proper addition rate (0.1 – 0.2%) for your mold is not a problem.
  •  Uniform inoculation. The insert dissolves continuously during pouring, providing even, uniform inoculation.
  •  No slag generation. The inoculant goes into solution in the absence of atmosphere, resulting in very clean inoculation. 
  •  Potent inoculation effect.  These inserts are engineered to provide maximum effect for gray and ductile iron.

So, if you’re looking for a more reliable inoculation practice that will improve the metallurgical quality of castings, reduce variability, and save money by reducing scrap, consider late inoculation with solid cast inserts.  GERMALLOY™ is recommended for ductile iron castings; OPTIGRAN™ is the choice for gray iron castings. Metallurgy experts at ASK Chemicals can provide recommenda-tions for the proper sizing and application of mold inoculation for no-bake and green-sand operations.

So, consult with your ASK Chemicals contact for the best overall recommendation.