ADI Treatments Ltd has recently installed the world’s largest sealed quench Austempering furnace. The new facility, costing more than £1M, provides controlled atmosphere heat treatment services for cast iron and steel component manufacturers. The principal application will be in the production of Austempered Ductile Iron castings with dimensions up to 1.8m; steel fabrications can also be processed.
The furnace is an extended version of the plant operated at the company’s West Bromwich factory since 1997. US market leaders AFC Holcroft, who built the original plant, were asked to customise the new furnace for larger components and loads up to 2.5 tonnes. The patented design incorporates a controlled atmosphere batch furnace with recirculating roof fans, radiant tubes, intermediate purge transfer chamber, enclosed vestibule and integral Austempering quench tank. AFC were able to modify their proven design and enhance capability. Particular attention was given to the circulation in the enlarged salt quenching facility, to ensure homogeneity of the process and final properties. A state of the art HMI was also added to enhance process and quality control. The final manufacture was outsourced to AFC’s Mexican partners. This proved to be the most efficient and economical route for supply with delivery time reduced to little more than 6 months from final confirmation of the specification. Another benefit of the manufacturing co-operation was the lower tariff applicable to imports from Mexico.
Paul Mayes, ADI Treatment’s Chief Engineer, explained some of the challenges presented by the scale of the plant, ”Following tests in Mexico, the unit was dismantled into three parts for ocean freight to the UK. However after docking at Southampton the consignment could not be offloaded because of handling limitations. The furnace sailed on to Antwerp before transhipment back to Felixstowe. A three-truck convoy with a police escort completed the final 200 miles to our factory. Because of production commitments we had to be ready to begin the installation immediately. Some months earlier we excavated the large pit needed to house the sealed quench bath, including 30 tonnes of special salt, beneath the furnace. We reassembled the system in quick time with the help of several expert teams of local contractors. Although we designed the original factory to take further capacity we did not foresee the need to “shoehorn” an outsize machine into the only suitable position. Fortunately our calculations proved correct; we finished the installation without any reengineering and a few centimetres clear of the lowest roof members. Even more critical was the pit to furnace interfacing which also had to accommodate 14mm thermal expansion. On assembly we found we were happily clear by 1mm. Now we are completing commissioning trials. Our furnace engineers and operators are receiving training and the system will be integrated in the company’s ISO 9001:2000 protocol”.
ADI Treatments Managing Director Simon Day summarised his optimism for the new facility, “Austempered Ductile Iron has only a 30 year commercial history, making it one of the younger engineering materials currently deployed. Recent theoretical and applied research has added greatly to our understanding of its properties and behaviour. This has helped us to work with designers and manufacturers to find competitive solutions. For example we were able to win a major contract to produce ADI components for Wind Turbines, which justified this major investment. More widely, we now have a unique facility that can provide strategic opportunities for our European foundry partners and their customers. We look forward to inviting them to our Open Day in the next few months ”.