- Corrosion Experts
- Technical Groups
ACA Auckland Division held a live meeting on Thursday 14th September at the Surrey Hotel in Grey Lynn. The meeting was joint with SCANZ and it was sponsored by Metal Spray Supplies Ltd (MSS).
The first speaker (of three) was Stewart Hobbs, structural engineer and Principal of Proconsult Ltd. Stewart’s presentation was a review of the steps that have been taken over a decade to extend the life of the aircraft maintenance hangar No.2, built in 1964, operated by Air NZ at the Auckland International Airport. In 2009 a condition assessment of Hangar 2 showed that many structural elements of the large building were corroded and suffering structural damage. The hangar is situated in a severe marine environment next to the Manukau Harbour. In 2010 the remaining life of Hangar 2 was estimated to be about 10 years. In 2020 Proconsult was requested to develop a program of repairs for the damaged hangar elements to allow the building to remain in service until a new Hangar No.4 was completed. Stewart explained how the life extension repairs on roof trusses, roofing, cladding, and rolling doors, have now been carried out. Hangar 2 is still in service for a finite period while a new hangar is built.
The second speaker was Peter Walters a specialist coatings consultant who is a Life Member of SCANZ. Peter has been involved with the NZ paint industry since 1971 and his subject was the evolution of paint coating systems on iron and steel bridges. His first case study described the coatings on “The Iron Bridge” in Coalbrookdale over the River Severn in England. This ancient bridge was built in 1779. It has been painted many times over the years and Peter outlined the evolution of the coatings on the iron structure to stop corrosion. He then described the bridge construction from 1883 and the paint coating methodologies for Scotland’s 2.5 km long-span suspension Forth Bridge. He outlined the evolution of the paint systems and application methods employed on the steel members. This was followed by two short videos illustrating the way that paint was applied onto the Forth Bridge in the 1930s, compared to 2011 when it was finally coated with red colour glass flake epoxy paint.
The third speaker was Les Boulton, corrosion consultant (retired) and a Life Member of ACA. His subject was the development in engineering materials over the years. The talk commenced with a brief review of the evolution of carbon steel, tool steels, galvanised steel, zincalume and their corrosion weaknesses illustrated with real life examples showing how they may fail due to corrosion and fatigue. The next group of alloys discussed were aluminium and its many alloys. Copper and the copper alloys were then described as being used for thousands of years’ service and still important today. Electroplating of copper alloys was also briefly described.
The many types of stainless steel were then discussed; particularly the improvement in welding of stainless alloys over decades, Titanium and the development of titanium alloys was outlined. Other high alloy materials such as nickel-containing alloys are important in many industries. Advances have been made in engineering plastics and high-strength durable plastics that can replace metals. Les then described the recent use of composite materials, such as stainless steel rebar in concrete and carbon fibre. He finally noted that global research into new engineering materials was always ongoing.
After a Q&A session the speakers were thanked for their contributions by Chair Matt Vercoe. Matt also thanked SCANZ for participating, which concluded the interesting and thought-provoking meeting.