A range of topics were tackled at the recent foundry seminar organised by the Chesterfield and Sheffield branch. 60 branch members and guests from around the country were treated to three technical presentations during the afternoon meeting, as well as the chance to catch up with friends from the industry in a relaxed setting.
Steve Illingworth Prof MICME and Joe Howden FICME of AMCOL spoke about the production of chromite sand for use in foundries which originates mainly from South Africa. Chromite sand, is a by-product of the production of Fe-Cr for use in stainless steel production. Only 3% of chromite extraction is used as foundry grade moulding sand & often processed & sold by trading companies who have little knowledge of the foundry industry.
This situation often leads to short supply quality & price variations as the demand for Fe-Cr is the main driver for the mining companies.
Joe explained that many of the large South African mining companies have been investing heavily in pelletizing plants in order to process more of their waste fines currently used for foundry sand instead for maximum production of Fe-Cr.
In order to have long term influence over Supply Quality & Price Amcol has purchased an open cast mine facility near Johannesburg which is dedicated to the production of high quality foundry chromite using modern & sophisticated processing techniques to improve quality marketed as Hevi-sand with the ability to offer long term price commitments important to foundry customers
Specifications & testing procedures for chromite sand are outdated & often meaningless. For example the Jackson Turbidity Test uses a ‘standard candle’ as a light source leading to variable & inconsistent results – research by Amcol into modern day alternatives are ongoing
Steve spoke about the importance of proper grading of the sand to obtain not just an AFS value but also the sieve distribution to ensure that the sand properties and performance in the foundry can be optimised. He invited foundries to contact the company to discuss their requirements so that Amcol and foundries can work together to deliver what modern foundries require through R&D and technical support to develop relevant and improved specifications.
Ian Nicholls spoke about the history of the development of the first cast nodes for use offshore both in the North Sea oil platforms and more latterly in the Gulf of Mexico (cast nodes were developed as an alternative to fabricated nodes with the aim of removing welded joints from the stress critical regions of the nodes). This work required the development of new low carbon manganese steels that were weldable (for joining with other parts of the offshore structure) as well as extensive development work and testing by the company to reduce the variability of the castings.
More recently SFEL has built up extensive design expertise so that it can offer prototype castings for new projects for defence, forging and offshore oil and gas applications and can design for casting (with suitable tapers and directional solidification). Ian spoke about the high customer expectations and the company’s reliance on its highly skilled staff, including moulders, coremakers and patternmakers, to enable it to offer ultra large castings - 600 tonnes of poured steel to produce castings of up to 350t in weight. Showing examples of the range of castings that the company produces, Ian also described how volatile the market is today; while production continues to grow, the companies markets around the world vary significantly from year to year, demonstrating how a strategic and flexible approach is required in order to remain at the technological forefront and globally competitive.
Prof John Campbell OBE FrEng FICME then spoke to delegates about the production of steel castings with optimum quality, using counter gravity filling to control the fill rate and maintain a quiescent liquid metal surface during filling. He graphically demonstrated how the use of conical pouring basins and sprues that are not full during casting filling can lead to significant air entrainment leading to mould damage and damage to metal quality. He discussed the use of offset step pouring basins and filters as well as running system design to optimise casting quality, as foundries should be aiming to ‘manage the oxide film’ to produce castings with excellent surface finishes and improved ductility.
Mike Leaney, branch secretary, was delighted by the range, as well as the number of people at the event which attracted members from around the region as well as from as far afield as Scotland and Somerset.
National president Steve Bell MBE FICME, who was attending along with a number of colleagues from Union Electric Steel, was also able to present certificates to Ian Nicholls and Joe Howden, both of whom have recently been made Fellows of ICME for their services to the institute and wider industry.