BS in Materials Engineering
Materials Engineering Department
Oliver Racing Parts (ORP) has historically purchased connecting rod bolts made of high strength, high cost, nickel-cobalt alloy, MP35N, and a medium strength, low cost, proprietary tool steel called ARP 2000. ORP has recently acquired capabilities to manufacture their own bolts. To determine the quality of their product as it compares to their previous supplier, ORP produced three different types of ⅜” diameter bolts: one set of bolts made of MP35N, and two sets of H11 bolts, designated H11A and H11B for their respective processing. The H11, ARP 2000, and MP35N bolts were tensile tested using a custom designed test fixture. The ultimate tensile strength, percent elongation, and percent reduction in area were measured. The fracture mode of each bolt was also investigated. 30 bolts from each lot were tested, except the H11A, the strength of which exceeded the limitation of the test fixture. The chief purpose of this investigation was to determine if there were significant differences between the H11 and ARP 2000 bolts, and between the MP35N bolts from the different companies. The data acquired proved that both heat treatments of H11 are both significantly stronger than ARP 2000, and that there is no discernable difference in strength between the MP35N bolts produced by the two different companies.