Research and development studies associated with the introduction of this innovation indicated that a major change in the basic steel type, as supplied by AIS, would be necessary and, with their collaboration, a move away from the then current semi-killed steel to a rimmed and then finally to a capped steel grade was made. This change, incidentally, has held for over twenty years and until the recent introduction of continuous slab casting at AIS required a further change to a fully killed steel containing small controlled amounts of aluminium.

A major advantage of the galvanizing line adopted by Lysaght was that it could easily produce a high strength coated product. The cold reduced strip is given only a recovery type heat treatment before coating, so that the steel retains its cold reduced strength after galvanizing. Most roofing and much wall cladding product made in Australia is hard cycle, where the high strength allows long spans to be used economically, a process advantage exploited in Australia well before it saw extensive adoption overseas.

On modern high-speed continuous galvanizing lines, control of the coating mass of zinc and its uniform distribution across the sheet and from side to side, changed from the older coating roll method to gas knife stripping, that is, blowing a jet of gas on each side of the emerging strip. Although Lysaght initially used a steam stripping process under licence, it was found to have numerous problems and they developed an improved technology using air knife stripping. This proved to be very satisfactory, resulting in cost savings and reduced noise levels. Further research concerning the fluid flow conditions of stripping led to an optimum jet design and finally to an elegant feed-back feed-forward computer control system of coating mass control which was probably the first such system operating world-wide. Edge build up of the zinc on the strip, another world-wide problem, was successfully overcome by a patented vane system which has since been adopted by others overseas.

Major developments at the Port Kembla plant include the manufacture of electrical steels by cold reduction in 1966 when a decarburizing strand anneal line was installed. In 1967 a new chromate passivation treatment for galvanized steel was developed and electrogalvanizing was begun in 1968. In 1970 an important invention led to the development of a new Lysaght lead-zinc Wet Flux Galvanizing Process and over the next fifteen years, half a dozen lines using the process have been licensed overseas.

The Lysaght tandem cold reduction mill at Port Kembla, installed in 1955, was extended to five stands in 1969 but was old and due for replacement ten years later. Instead it was decided to up-grade the mill so that, today, it is fully automated with an in-house developed control system based on extensive simulation models, the result of some years research effort. The up-graded mill became one of the most advanced in the world and the basic models were sold in America and Germany.

Australian Academy of Technological Sciences and Engineering