Reduction of Lead in aluminium alloys and new innovative alternative solutions

There are several European directives and regulations, implemented also in many other countries, that are about to be modified with important restrictions about Lead content in aluminium alloys. This represents a big challenge for the global precision machining industry, hurried to find new alternative free-machining lead free alloys that shall grant at least the same results in terms of productivity and efficiency.

European Chemical Agency (ECHA) with regards to REACH requirements put Lead in the Candidate List of substances of very high concern, SVHC, where there are metals with Lead in concentration above 0.1% w/w. Until now companies are only obliged to inform customers of the presence of Lead in such metals, but there is a process of moving Lead from Candidate List to Authorisation List, this is an ongoing discussion which will be completed in the next 12 to 24 months, in order to have Lead in the Authorization list by the year 2024.  After that, companies will need a special Authorization from ECHA in order to use Lead above a certain quantity (most probably 0.1% w/w). It will be extremely difficult get such Authorization, which can be given only once and for a maximum extended time of two years, so anyway after 2026 it will be the end whatsoever. The Lead limit that ECHA is evaluating in the discussion is anything between 0.1% and 0.3% w/w, but new scientific studies commissioned by ECHA with regards to Occupational Exposure Limits are finalizing that 0.1% is the maximum quantity tolerable for an healthy working environment.

RoHS directive 2011/64/EU has been updated by the European Union with the new directive 2018/740/EU which limits the use of Lead to 0.1% w/w max starting from May 18, 2021. While RoHS applies only to electric, electronic and medical applications, nevertheless it is the first Directive promulgated by the European Union, where in its final document defines a maximum limit of 0.1% w/w.

ELV directive 2000/53/EC has been updated by the European Union with the new directive 2017/2096/EU  which limits the use of Lead to 0.4% w/w in the exemption 2(c)(i), but in the next months it will be reviewed. As REACH and RoHS are at 0,1% w/w, automotive shall probably align, it’s just a question of agreeing on a timeframe for the Lead phase-out.

There is no doubt that there is a major concern about Lead in metals, and besides all the discussions and the true or false expectations that any company may have, there are few basic fixed points: European Chemical Agency declared Lead as toxic, its level of toxicity has been equalized to Mercury or Hexavalent Chromium. European Union defined a limit of 0,1% w/w in this case only to RoHS, but the indication is clear.

Lead is a problem, not just for aluminum materials, but also for other metals like brass, stainless and steel. In fact, this chemical element is typically added to free-machining alloys to improve machinability causing a small chip forming. During the last 25 years, many lead free free-machining aluminum alloys have been developed, using tin (Sn) as chip breaker element. Unfortunately, as it is well known, tin causes weakness and cracking of machined parts when submitted to stress, low or high temperatures (< 55°F or > 320°F); due to its brittle nature, it has the dangerous tendency to suddenly break without significant previous deformation (strain).

Eural Gnutti, based in the north of Italy, is the largest extruder of aluminium alloys in Europe specialized in the segment of cold finish drawn bars. Eural has developed new free-machining aluminum alloys with lead free and tin free, becoming a world leader in the production of lead free alloys. This is shown by the excellent results obtained during the last three years with absolutely innovative initiatives in terms of materials, first of all with alloy 6026 Lead Free medium strength alloy suitable for high-speed machining, that can replace 6xxx alloys with poor machinability (6061, 6082), containing lead (6262, 6064A, 6042) or tin (6020, 6040, 6262A, 6028). The next step refers to 2033 Lead Free, an alloy with medium-high mechanical properties and a very high level of chip forming performance, created to replace alloy 2011 that in 2021 will not be RoHS compliant. Eural last creation is the brand new 2077 Lead Free, just registered past February 19, 2020. This is the only aluminum alloy which combines superior mechanical strength, with high machinability and excellent chip forming performance. 2077 Lead Free has excellent opportunities to replace many hard and very hard alloys of the previous generation, such as 2024, 2014, 2014A, 7020, and eventually also 7075 alloy in certain cases, with the ambition to establish itself as an alternative to brass and steel bars, generating unpredictable market developments. 2077 Lead Free has higher mechanical properties than 2024, and its chip forming is as good as 2011. With these peculiarities, it turns to be what aluminum market was definitely looking for.

Andrea Narra is Sales Manager of Eural Usa Inc. (PMPA Member), Eural Gnutti’s company based in Chicago opened to better serve and support metal service centers, machine shops and OEMs in US.

Contact: usa@eural.com or 312-888-0578.