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.

Q:We need to need to filter molten metal for a large casting, to eliminate inclusions and reduce clean room costs, but the currently available filter technologies are insufficient – mainly because the filter material “plugs off” too quickly during the pouring sequence. What products are available to address this?

A:For this issue there are a few different technical solutions for you to consider. The first would to be rig up your gating system to filter through multiple filters, to handle the increased capacity required for pouring large-scale castings. Another possible solution might be be to filter through an assembly piece with multiple filters, or a filter with increased surface area, such as a tube. A third option would be to find a filter that can handle the same thermal shock properties as a conventional filter, and has an engineered design to allow for the increased capacity — and still would supply the filtration capabilities required to eliminate the inclusions you describe. Among these three options, the easiest to implement and most cost-effective would be the third option. Next, with all the metal-filtering technologies out there you would need to find such a filter. And now, and the most viable place to find such an ideal product would be in the emerging venue of additive manufacturing. In other words, a “3D-printed filter.” Recently, ASK Chemicals introduced its EXACTPORE 3D line, which would check all the boxes required to solve your issue. These filters offer iron and steel foundries (as well as investment casters) new and more efficient filtration options for the highest casting quality. Thanks to their particularly sophisticated and well thought-through design, EXACTPORE 3D filters provide the highest structural integrity and thus safety and efficiency in use. Metal purity is one of the most important requirements for foundries: “Best practice” molten-metal filtration includes sintered ceramic foam filters, but the structure of the filter foams in particular means that this form of filtration also has its limits. During the ceramic coating and sintering process, tiny particles may form inside the filter structure, which are only slightly sintered with the base material. Flow through the filter can cause these particles to detach, which impairs the purity of the melt and can lead to inclusions in the casting. The high structural integrity of EXACTPORE 3D filters ensures the absence of loose particles and thus prevents contamination of the melt by so-called filter bits and time-consuming reworking. A further advantage of the new filter generation is its higher flow capacity. Due to the uniformity of the pore design and the structurally consistent geometry, the flow capacity of the EXACTPORE 3D filters is significantly higher than sintered ceramic foam filters with the same filter and pore size, and thus offers foundries an opportunity to further increase manufacturing productivity. The uniformity of the pore design and the structural integrity of the new filters also significantly reduces turbulence compared to conventional solutions and greatly protects against reoxidation caused by entrained air. In fact, hardly any impurities get into the mold, which leads to less reworking, improved surface quality and lower rejection rates and ultimately increases profitability. “Finally, our new filters are manufactured in such a way that the design possibilities are virtually limitless,” according to Bob Gage, market manager-Filters, referring to the flexibility and variability that is possible thanks to additive manufacturing of the new EXACTPORE 3D filters. “With our new filters there are almost no limitations as to what we can offer our customers in terms of pore design,” he emphasized. “We can produce almost any pore size – even unconventional ones – in order to guarantee the best possible filter quality with constant flow properties.

A: Tonnage poured, a primary indicator of productivity in the metalcasting industry – specifically sand casting – has been in decline for several decades due to several factors (e.g., lightweight automotive designs, including for electric vehicles.)

Furthermore, the industry has a diminished appeal today, impacting labor supply due to environmental concerns (e.g., VOCs), dangerous working conditions, and poor wages. Understandably, in the past few decades many OEMs have repositioned their operations to lower-cost emerging markets (e.g., China, Mexico, Turkey, etc.) Those manufacturers who are unable, or unwilling, to follow suit have borne these burdens, aided in-part by value-added services offered by their suppliers/partners.

Labor shortages should be re-emphasized as a serious impediment to the metalcasting industry and its overall vitality. Relatively recently, manufacturers in well-established regions (e.g., U.S., Germany) have been forced to operate ‘lean’ in order to remain competitive with operators in emerging markets.

Likewise, major foundry consumable providers have been forced to scale-back their service offerings, such as dedicated bulk tank applications with fully equipped telemetry equipment for volume tracking of supplies. Even technical expertise is harder to come by as experienced technicians and metallurgists retire from the industry, with fewer experts ready to take up their work and responsibilities.

Amidst these latter challenges stands the on-going global pandemic. In 2020, particularly, we noticed the increased need for technical support, as foundry doors remained closed to suppliers to prevent the spread of COVID-19. Virtual field services, a widely unknown term until then, was primarily operating within ad hoc Apple Facetime calls that proved beneficial in the right circumstances (e.g., quality cellular connection / Wi-Fi). Unfortunately, however, many of our customers either suffered from poor connectivity, or needed greater instruction and documentation than a mere visual aid. With this in mind, ASK Chemicals has developed a new virtual service concept, as a supplement to the well-known on-site technical service.

ASKNow – virtual field services – makes it possible to create “cases” that contain documents, pictures, and video content. Customer and ASK Chemicals teams are using annotation and pointing tools to better collaborate on their cases. What sets the service offering apart are unique features believed to be beneficial to the foundry industry, in particular:

•  Low-bandwidth video/audio options for remote site locations;
•  Quick and easy annotation (pictures/videos);
•  Ability to record video and connect to third-party live-streaming headsets;
•  Cloud-based collaboration of annotated files, for seamless transfer of information; and,

ASKNow virtual field services is a service option to our customer-base as a fast and efficient alternative service experience, where traditional face-to-face consultations may not be required. With the launch of ASK Now, we have been able to support our customers in the shortest possible time. Long waiting times and, in the worst case, production downtimes are definitely a distant reality with ASKNow.