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Die Casting Offer Rapid Tooling

GC Die Casting Offer Rapid Tooling

Cleveland, OH – Advancements in rapid machining and prototyping are being developed at Case Western Reserve University (CWRU) that will considerably shorten the lead time for die casting tooling. Rapid tooling is important when a relatively small number of parts are required. This is important to DLA when tooling is no longer available to produce spare parts for aging weapon systems. Tooling lead time can play critical role to the overall procurement lead time, significantly affecting weapon system readiness. Rapid tooling methods that shorten lead times and reduce costs will expand the DLA casting supply base for high quality, dimensionally accurate parts.

Over the past year, CWRU has been working with NADCA and GC Die Casting company to develop a higher quality heat sink for military-tracked vehicles utilizing rapid tooling methods. Rubberized tank tracks are subjected to demanding operating conditions. In addition to normal wear and tear, they are exposed to temperature extremes that can affect performance and result in separation between the rubber and the track. To prevent separation, an aluminum heat sink that absorbs excessive heat from the rubber is embedded between the track and the rubber. Die casting is the most cost effective fabrication method for this heat sink because of the large production volumes involved.

GC Die Casting company, the die caster for these parts, had to frequently replace the HI3 steel dies because of excessive thermal fatigue cracking. The project team recommended replacing the HI3 steel dies with two alternate grades of steel. The new dies were completed in record time utilizing rapid tooling methods. Compared to HI3, a die set fabricated from one of the alternate steel grades produced twice as many castings before any welding repair was deemed necessary. The die set fabricated from the other alternate steel grade made three to four times as many castings. NADCA and AFS are supporting the technology transfer to their membership and CWRU is applying the lessons learned on Rapid Tooling to recent USCAR and DOE projects. In the the coming year, CWRU will collect, process, and report performance data from the rapid tooling production guidelines for fabrication of rapid tooling. The close collaboration and synergy fostered by the AMC program between the R&D teams, the CAST-IT application engineers, and the metalcasting associations and their members is very unique, making significant contributions to DLA and the metalcasting industry.

Mechanical Properties of Malleable Iron

The different grades of malleable iron are essentially the result of different heat treatments. Just as a medium carbon steel can be heat treated to a wide range in properties so can malleable iron, but malleable is even more versatile. The combined carbon content, on which heat treatment depends, can be adjusted from none, as when the microstructure is entirely ferritic, to that of a fully pearlitic structure. Read more

Mechanical Properties of Cast Carbon and Low Alloy Steels

For the purpose of this article, carbon steels are considered to be those steels in which carbon is the principal alloying element. Other elements that are present and that, in general, are required to be reported are manganese, silicon, phosphorous and sulfur. In a sense, all of these elements are residuals from the raw materials used in the manufacture of the steel, although the addition of manganese is often made during the steel making process to counter the deleterious effect of sulfur and silicon is added to aid in deoxidation. Read more

Cast Copper Alloys

A Primer on Selecting Cast Copper Alloys

Traditionally, cast copper alloys were classified by a variety of systems including the ASTM letter-number designation based on nominal composition, by trade names, and by descriptive terms such as “ounce metal,” “Navy M” and so forth. However, with technological developments, new alloys were produced and existing alloys modified, making the old designation systems inadequate and misleading.

A new system was developed based on a precise description of the composition range for each alloy, which is now the accepted alloy designation system used in North America for cast copper and copper alloy products. Originally developed as a three digit system by the copper and brass industry, the designations have now been expanded to five digits that follow a prefix letter “C,” and have been made part of the Unified Numbering System (UNS) for Metals and Alloys. The UNS is managed jointly by the American Society for Testing and Materials, and the Society of Automotive Engineers. Read more

Mechanical Properties of Cast Iron

Ductile iron is characterized by having all of its graphite occur in microscopic spheroids. Although this graphite constitutes about 10% by volume of ductile iron, its compact spherical shape minimizes the effect on mechanical properties. The graphite in commercially produced ductile iron is not always in perfect spheres. It can occur in a somewhat irregular form, but if it is still chunky as Type II in ASTM Standard A247, the properties of the iron will be similar to cast iron with spheroidal graphite. Of course, further degradation can influence mechanical properties. The shape of the graphite is established when the metal solidifies, and it cannot be changed in any way except by remelting the metal.  Read more

Aluminum Casting

The term “cast iron” designates an entire family of metals with a wide variety of properties. It is a generic term like steel which also designates a family of metals. Steels and cast irons are both primarily iron with carbon as the main alloying element. Steels contain less than 2% and usually less than 1% carbon, while all cast irons contain more than 2% carbon. About 2% is the maximum carbon content at which iron can solidify as a single phase alloy with all of the carbon in solution in austenite. Thus, the cast irons by definition solidify as heterogeneous alloys and always have more than one constituent in their microstructure. Read more