Failure Analysis of Oriented Strand Board Press In-Feed Drum

This presentation involves an analysis of a press used to manufacture oriented strand board (OSB) materials. After the press had been in service for three years, a crack was observed on the in-feed drum at a partial penetration weld between the drum cylinder and end plate. The crack was ground-out and weld repaired, but after being placed back into service, the drum experienced additional cracking in a different location on the same weld. A more extensive weld repair was conducted and the press placed back into service. The failure investigation involved a review of the drum design drawings as well as a stress analysis to identify the expected fatigue life of the drum to end plate weld. Given the drum had been repaired and was in service at the time of the investigation, no metallurgical lab work was conducted. However, given the results of the drawing review and fatigue analysis, a number of candidate causes for the cracking were identified, including a design defect and manufacturing defect. A review of the operating data ruled out improper operation or operation outside of the manufacturer's design specifications. An evaluation of the long-term viability of the weld repair was also conducted.