CASE STUDY

Ship’s exhaust duct uses Electron Beam Welding for bolt flange

A shipbuilder needed to fuse a bolt flange to the ship’s exhaust terminal duct. The flange needed to align with the bolt pattern on the rim of a lower exhaust pipe so that the ductwork could be bolted together on the ship’s deck. The builder was looking for a solution that minimized any distortion in either flange so they aligned correctly.

Solution: Electron Beam Welding has many benefits that fit this particular application. First, the welded parts were large, but close alignment with the mating part was imperative. EB welding is executed digitally with a CNC slab, so the entire weld can be accomplished in precise detail all controlled by the computer program. You eliminate human error whereas other forms of traditional welding will not. You can repeat EB welding without the variability you get from hand-held welding processes or the inconsistency of one welder to the other. The complicated geometry of the large parts is also overcome with the computer-controlled, multi-axis settings. EB welding is a perfect application for large, complex parts.

Another benefit of using EB welding for this job was the placement of the weld. Traditional welding techniques would have simply used a corner joint to connect the two parts. There were two concerns about locating the weld in the corner. First, this weld would be too close to the bolt pattern and cause undue stress on the joint. EB welding allowed a butt weld to be positioned higher on the upright portion of the flange. The second concern was heat distortion. The heat from traditional welding can warp parts adjacent to the weld. If the flange had distorted, each bolt would have to be custom fit. EB Welding has a very low heat input. This greatly reduces any chance of ancillary disfiguring of the parts. This was a key advantage over traditional welding for this project.

CF Roark improved the quality of the exhaust duct by placing the weld in a place that made the integrity of the part better and solved an alignment problem for the customer.

If you have questions about EB welding on your parts, contact C.F. Roark at 317-852-3163. ext. 901 or [email protected].