A carefully drilled 1mm hole in the rear mid-frame of a 12 year-old Duple 425 coach has provided evidence of the zero-corrosion performance of 3CR12 stainless steel. When engineers at Blackpool Design Engineering drained the vehicle’s tubing during refurbishment, they found that water trapped inside sections of the 3CR12 stainless steel tube frame was perfectly clear, while the mild steel body panel fastening screws were corroded. Engineering Director John Mollart said: “We were amazed to discover clear water pouring out of the tubing when we tilted the coach during a routine inspection. The water had obviously built up over the years after the body panel fastening screws had corroded and sheered off. Had the frame being made of mild steel, not only would the water have been discoloured, but the frame would probably have disintegrated as well. It is further evidence of the benefits of using this remarkable material.” Manufactured from Cromweld 3CR12, the body structure of the 1989 Ellison Coaches owned Duple 425 showed no signs of corrosion despite almost one million miles of service. Cromweld 3CR12, with its high-strength and low-weight properties and good weldability, is suitable for chassis construction, bus, coach and rail car body frames and vehicle sections. It is made by Cromweld Steels.
