At the present, the European transport sector has to meet several challenges, such as competition of emerging countries, as well as more restrictive legislation regarding CO2 emissions. HardALU project aims at reduction of weight by substituting iron by light and high performance aluminium castings, in particular engine blocks. This will be achieved by making High Pressure Die Castings (HPDC) heat treatable using Fluidized Bed (FB) Technology, which allows reducing significantly the heat treatment time and thus avoiding blistering.
Advanced manufacturing technologies are needed in order to facilitate the production of high performance aluminium components. HPDC is a highly productive process but the conventional heat treatment technology cannot be applied due to the formation of blisters. Whereas, all the other manufacturing technologies for engine blocks, allow the application of conventional T6 heat treatment. At present FB is not industrially applied to any aluminium casting in Europe. However, FB heat treatment offers a much higher rate of heat transfer than conventional furnaces.
On the other hand, aluminium casting manufactured by other technologies: sand, low pressure, etc. that are nowadays heat treated (T6/T7) in conventional air furnaces, could also benefit from the shortened heat treatment in FB furnaces by a reduction of 80% in time and a reduction of 30% of energy consumption.
The main innovations of the application of FB heat treatments in the manufacturing process of HPDC are:
-To enable heat treatment of “HPDC” parts, thus increasing their mechanical properties and making it possible to reduce their weight or replace heavier iron castings
-To reduce by 2% CO2 emission by replacing iron (a reduction of 28kg is expected from replacing a iron engine block of average 55kg)
-Additional 30% of reduction of CO2 emission associated to the reduction of gas consumption when the alternative FB T6/T7 heat treatment is applied.
-To generate a new niche market for heat treatment lines for HPDC parts
Industrial problem:
-The most typical HPDC parts in cars are engine block, gear box and a vast number of brackets and accessories. At present, these HPDC parts cannot be fully heat treated (T6 or T7) due to the problem of blistering.
-Other important automotive parts such as cylinder heads, suspension parts, wheels and brake components are usually not casted in HPDC and require a conventional T6 or T7 heat treatment. The T6/T7 heat treatments account for 12-25% of the value added of these castings.
-Conventional T6/T7 treatments include a quench in water from 490–540ºC to 60–80°C. However, water quenching also causes severe internal residual stress, as well as distortion in the case of castings with a complex geometry and with high differences in thickness. Air quench or oil quench can avoid these problems, but the tensile properties are notably lower or a subsequent post-treatment (cleaning) is needed.
This innovative business will boost the company internationally in the heat treatment market as there is no competitor for this technology in Europe. Moreover, its HPDC foundry clients will be able to produce components with enhanced performance at levels above actual standards; a new niche market is expected. Within the strategy of HORMESA the transfer to other markets such as railway and aircraft castings, is considered in the following years with the companies own resources.
