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Matching cases

Improved friction and wear properties without using lead
Developed a new lead-free bronze alloy that follows environmental regulation standards.

Akashi Gohdoh Inc.

Searched for a new lead-free sliding material, while following the regulations

Used the Supporting Industry Program (SIP) to improve their own skills and to raise the standard of the domestic industry.

Cylinder blocks and valve plates are used as parts in oil hydraulic pumps for construction machinery. These parts require high resistance and excellent sliding properties. Akashi Gohdoh holds a large share of the market in bimetal-type hydraulic parts which combine lead bronze with steel-based materials. Lead bronze is metal alloy that consists of 80% copper, 10% tin and 10% lead. Lead has necessary properties for sliding parts, such as lubricity and wear resistance, and improves processability. Moreover, it is reasonably priced, so it is the main additional element in current copper alloy sliding parts.
Lead is strictly regulated and there are tough standards for elution into drinking water, since it is a hazardous material which affects human health. Changing to lead-free copper alloys for metal water supply parts is already well underway. Research is being conducted at many companies in many countries as regulation is expected to be applied to more and more sliding parts for industrial equipment and construction machinery. However, none of this research has yet developed a lead-free copper alloy which has performance equivalent to or better than that of lead alloys.
Akashi Gohdoh, a manufacturer of hydraulic parts for industrial equipment and construction machinery, decided to take up the development challenge through the SIP, in order to help the technology revive. "Truth be told, I hadn't fixed on a goal at that time," says the president of the company, Iwao Akashi. Occupying a leading position in the casting industry in Japan as a chairman of the Japan Non-Ferrous Alloy Casting Association, Mr. Akashi saw to it that the development was carried out not as a project for a single company but as one for the whole association. He embarked on the project because he wanted his company to grow along with its competitors, in order to raise the standard of the domestic industry. In addition, he asked one of his company's customers, Komatsu Ltd. to take a role as an observer, the better to create a product for which there would be a demand.
Discovery of a next-generation bronze alloy with a pearlite structure

Looking back on those days, Takafumi Akashi, the managing director who led the research, says, "We looked at the substance next to lead in the periodic table, bismuth (Bi). Research proceeded based on the hypothesis that Bi was similar to lead, so that lead might be replaceable with Bi. However, it wasn't easy." A rare metal, Bi is expensive. Wondering if there might be another method besides simple replacement, they redid the whole experiment, but no answer was found after making over 400 types of samples. As time went by, everyone spoke less and less the bi-monthly meetings. Just as it looked like the research would crash into the rocks, good news came from the laboratory at the industrial testing station. They had succeeded in making a layered structure inside the metallic structure, by compositing with an alloying element.
"It was a totally new idea, and a breakthrough. It was also lucky that the professor himself knew about the pearlite structure, which is similar to the structure of iron," says Mr. Takafumi. Even without lead, bronze alloy with a layered eutectoid structure showed high wear resistance and seize resistance equivalent to that of lead. The conclusion was that the new sliding material, "pearlite bronze", would be extremely effective as an eco-friendly alternative material.
Ready to go for the international market! Various use in other fields are also expected

After the SIP project ended, an exclusive Technical Development Division was opened at Akashi Gohdoh in order to continuously improve development through testing in actual machines. Trial hydraulic cylinder blocks which mixed pearlite bronze with iron based materials were sold to six domestic and overseas companies. "We received a good reaction at trade fairs and exhibitions in each country. We have deployed sales people in Switzerland and the United States, and are conducting sales activities mainly in Europe and the United States," says the managing director. As it became more likely that the new regulations would come into force, many downstream companies also showed interest in the product. With patents already acquired in Europe, the United States and South Korea and applications in India and China pending, their response to regulation has been progressing steadily, especially with regard to demand in Europe, where environmental regulations are especially strict.
Of relevance to the above is the fact that bronze which contains lead is also used for turbocharger parts in the automobile field. The lead-free bronze can be expected to make a very large contribution if regulation is expanded. This trend should spread widely to machine parts in other fields, too.

Key points of successful commercialization and matching

● "Selecting a theme" which will be accepted by users is important
They undertook the challenge because regulation was approaching. Developing something that no-one else has is a key to surviving in times when the number casting manufacturers is dwindling. It is vital to keep a steady watch at all times on the way the world is turning.
● A vision for commercialization is necessary
What really counts for the company is what happens after R&D. The key point is whether or not the company is able to make commercialization the goal and build a vision that will lead to achieving it. What is needed is the ability to read the market on a global scale and understand where there is demand.

Advice for making the most of the SIP

Takafumi Akashi, Managing Director.
Although the period of the SIP project was three years, by the time our application was approval we had only four months left of the first year. Those four months were almost entirely taken up by ordering equipment. So, we effectively had only two years, but you know what they say, "You're at your wisest when things are tough". I think we were greedy for results because we were short on time.
It was challenging to have to calculate the budget each year instead of just a total for all three years. Every time something unexpected happened when we actually tried something we had to conduct more research and experiments, and the things we needed changed. Of course, some things went over budget. If we had been able look into the future, they might have been easier to factor in... What is more, it is not the case that the research ends with the SIP project. You must have both the resolve and the funds necessary to take your results all the way to commercialization.
I think the way we conducted our research, that is, in collaboration with universities and downstream companies and with everything managed by the association, was the ideal way to have done it. However, when working on group research, delays can occur due to differences of opinion between members. Therefore, in the interests of flexibility I recommend a small research group rather than a big one.

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