References To Past Product Liability Cases Fail To Convince District Court To Exclude A Metallurgy Expert

    Metallurgy Expert

    Court: United States District Court for the Southern District of Ohio, Western Division
    Jurisdiction: Federal
    Case Name: Magna Mach. Co. v. Hodge Foundry Inc.,
    Citation: 2015 U.S. Dist. LEXIS 178616

    In this products liability case involving a fractured iron casting, a plaintiff manufacturer sought to exclude the testimony of the defendant’s expert metallurgist on the basis that the expert failed to declare the specific force that caused the product in question to fracture. In an attempt to support its motion to exclude, the plaintiff referenced unpublished decisions from similar product liability cases. However, the court ultimately decided that found that these references were inappropriate, and the plaintiff’s motion to exclude the metallurgist’s testimony was denied.


    Plaintiff Magna Machine Company, Inc., a large-part manufacturer, used an iron casting designed by the defendant manufacturer, Hodge Foundry, Inc.. During the machining process, the iron casting fractured causing significant damages. Over the next nine months, Magna incurred nearly $500,000 in property damages, extra expenses, lost production, and business interruption while their equipment was under repair. The plaintiff sued the defendant for negligence in design and manufacturing.

    The Metallurgy Expert Witness

    The defendant designated a metallurgical engineer as a rebuttal expert on the issue of damages. The expert had more than 40 years of industry experience and was published in  topics ranging from alloyed metals to thermal effects. In order to compose his report, the metallurgical expert examined the iron casting in question, performed chemical and strength tests on samples, and reviewed the defendant’s manufacturing design. The expert also investigated how the defendant handled heat treatment during the casting process. 

    After his thorough investigation, the metallurgist opined that the chemical composition of the iron casting was consistent with industry specifications. He further opined that residual stress did not contribute to the fracture, rather, that the casting failed due to external force. 

    Plaintiff’s Pushback

    Although the plaintiff didn’t challenge the expert’s principles or methodology, Magna moved to exclude the expert testimony arguing that the metallurgist’s conclusions were speculative. The plaintiff argued that the expert based his opinions on the assumption that the iron casting was properly heat-treated. The plaintiff also argued that the expert failed to identify the force that caused the casting to fracture, and that as such, the expert’s conclusions were inadmissible for lack of specificity.

    In order to support its assertion that the metallurgy expert’s testimony was inadmissible, the plaintiff consulted unpublished decisions from Davison v. Cole Sewell Corp., 231 F. App’x 444 (6th Cir. 2007); One Beacon Ins. Co. v. Broadcast Dev. Grp., Inc., 147 F. App’x 535 (6th Cir. 2005) (per curiam). In both cases, the courts discussed the experts’ alleged inability to identify a specific cause for the accidents primarily in relation to the merits of the plaintiff’s’ negligence claims.

    Court’s Discussions

    The court found that the expert’s testimony regarding the chemical composition of the iron casting and the strength tests conducted were based on sufficient career experience as a metallurgical engineer. The report supported that his methodology was sound within his industry, and described testing of the heat-treatment process, including specific temperature readings. As for the plaintiff’s concern that the expert failed to identify a specific causal force, the court pointed out that Rule 702 inquiry focuses “solely on principles and methodology, not on the conclusions that they generate.”

    In regard to the plaintiff’s references to Davison v. Cole Sewell Corp., and One Beacon Ins. Co. v. Broadcast Dev. Grp., Inc., the court found that these references were inappropriate and outside the scope of the case at hand. In both cases, the ultimate causation was a necessary element of the plaintiff’s’ negligence claims. Furthermore, the appellate courts’ comments on the ability of the experts to opine on the cause of the accidents were made in the context of the legal sufficiency of the claims. Additionally, the evidentiary rulings in Davison and One Beacon were not based on the number of potential causes each expert identified.


    The motion to exclude the metallurgist’s testimony was denied. The court held that the expert metallurgist was qualified to opine on the subject matter of the case, that his testimony was relevant to the issues in question, and that his methodology and conclusions were reliable and generally accepted by other metallurgic engineers. Thus, it was concluded that the metallurgy expert’s scientific knowledge would assist the trier of fact to understand the facts of the case.