Showa Denko Starts Full-Scale Marketing of “ST60-HSM™” Aluminum Alloy Board with High Heat Conductivity and High Strength for Use as On-Board Bus Bar

April 27, 2021

Showa Denko K.K.

Showa Denko K.K. (SDK) (Tokyo: 4004) has started full-scale marketing of “ST60-HSM™”*1 aluminum alloy board, which has high heat conductivity and high strength, for use as on-bard bus bar*2. In 2021, SDK started to provide several automotive parts manufacturers with samples of ST60-HSMTM aluminum-alloy boards to be used as on-board bus bars.

ST60-HSM™ developed by SDK is an aluminum alloy board which has high heat conductivity equivalent to that of pure aluminum and high strength equivalent to that of 6061 aluminum alloy*3, and is used as chassis of backlit LCDs for PCs.

Due the background of global movement to strengthen efforts toward realization of carbon neutrality, the car industry has been accelerating shift to electric cars including hybrid cars, plug-in hybrid cars and EVs. In addition, the car industry is now required to promote weight reduction of cars in order to improve fuel efficiency and increase travelable distance. Therefore, the industry is aggressively promoting shift from copper-based equipment to lighter-weight aluminum-alloy-based equipment in various components including wiring harnesses and bus bars to connect on-board motors with converters and inverters with generators.

SDK’s ST60-HSM™ is an aluminum alloy board that has high heat conductivity, high strength and high electric conductivity, and also has high fatigue strength and high heat-resisting property that are required for on-board bus bar. Aluminum bus bar made of ST60-HSM™ is 43% lighter than conventional copper bus bar*4, and also contributes to cost reduction because the new aluminum bus bar is priced lower than conventional copper bus bar.

On the basis of technologies to design and process aluminum alloys cultivated through operation of many years, SDK will aim to maximize the value of customers’ experience by providing solutions for them, thereby expanding the Showa Denko Group’s aluminum rolled products business.


  • *1 ST60-HSM™: ST60 is an aluminum alloy board developed by SDK in 2001, and has as much heat conductivity as pure aluminum and as much strength as 5052 aluminum alloy, which is a typical structural material. ST60-HSM has relatively high strength and plasticity among ST60 series aluminum alloy, has as much tensile strength as 6061 aluminum alloy, and is used for internal chassis of smartphones and tablets and metal base of their cases. HSM is ab abbreviation of High Strength Metal.
  • *2 Bus bar: Bus bar is used to conduct electricity, and many bus bars are made of copper. A bus bar can conduct more electric current than electric wire. Thus bus bar is used to conduct large current.
  • *3 6061 aluminum alloy: 6000 aluminum alloy series consists of aluminum as base material, and magnesium and silicon as additives. It has high strength, corrosion resistance and is easy to be cut. Therefore it is used as structural material. 6061 aluminum alloy includes copper and other additives to have more strength. Furthermore, 6061 aluminum alloy acquires more strength through solution treatment, hardening process and aging process.
  • *4 This amount of weight reduction is calculated on the basis that specific gravity of aluminum is 2.7 and that of copper is 8.9, while electric conductivity of aluminum is 54 and that of copper is 102.

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Brand Communication Department