Mitsubishi Materials Corporation


May 20, 2021

April 21, 2021

Mitsubishi Materials Corporation

Start of Full-Scale Production of Copper Alloy "MSP5" for Automotive Small Terminals
- Accelerating CASE with Our Unique Copper Processing Technology

Mitsubishi Materials Corporation has started full-scale production of its Cu-Mg solid-solution strengthened*1 copper alloy "MSP5".

With the development of autonomous driving cars and increase in electrical components driven by Connected, Autonomous, Shared & Service, and Electric (CASE) mobility trends, the need for small automotive terminals have been increasing. In Japan, the push to simplify manufacturing processes and to reduce environmental burden has also led to increase in demand for solderless press-fit terminals.
The material for these small terminals used in automotive electrical components must have high strength, high electrical conductivity, and high stress relaxation resistance (resistance against decrease in stress due to heat). Excellent formability is also required to prevent cracks from forming during bending process, especially for box-shaped terminals.

Our sales, development, and research department have been working closely to commercialize products that best meets the needs of our customers. With our unique copper processing technology that we have honed over the years, in 2015 we developed MSP5. MSP5 has excellent formability as well as excellent strength, high electrical conductivity, and high stress relaxation resistance, making it ideal for small automotive terminals and press-fit terminals. Samples provided to our customers have led to positive feedback regarding its high performance and reliability. Now, we are proud to announce the start of its full-scale production.

Features of MSP5

1. Excellent material properties
Boasts the highest level of strength-conductivity balance among copper alloys, with 0.2% proof stress of more than 700MPa at SH temper (forming direction of small terminal springs) and electrical conductivity of 43%IACS. In addition, excellent stress relaxation resistance with residual stress rate (rate of initially applied stress that remains after prolonged heating) of 80% or more at 150℃ for 1,000 hours).

2. Ease of handling
Bending property of R/t = 0 (R: bend radius, t: plate thickness), making it suitable for box-bend terminals and for small terminals. Also unique to solid-solution strengthened alloy is its excellent press workability (good dimensional accuracy and burr resistance during punching), making it an ideal substitute for phosphor bronze. Furthermore, a low Young's modulus of 115GPa results in a wider elastic deformation area and suppression of plastic deformation, ideal for press-fit terminals where after insertion, a sustained contact force is required for electrical connection reliability.

3. Reduced environmental impact by ecofriendly manufacturing process
As a solid-solution strengthened copper alloy, MSP5 can be manufactured in principle by a simpler process than that of precipitation strengthened copper alloys*2 which require complicated heat treatment, keeping CO2 emissions low during manufacturing.

In 1986, we started the manufacture and sale of MSP1, a high-performance Cu-Mg solid-solution strengthened copper alloy used for automotive terminals, busbars, and relays that has been well received for many years. Recently, we have expanded the lineup of MSP series by adding the MSP5 as well as MSP8, a copper alloy ideal for high-voltage and large-current busbars and terminals for electric vehicles. The MSP series has been adopted by our many customers as the copper alloys for automotive electronic and electrical equipment.

Based on the corporate philosophy of "For People, Society, and the Earth," Mitsubishi Materials Group has established a vision: "We will become the leading business group committed to creating a sustainable world through materials innovation, with use of our unique and distinctive technologies, for People, Society, and the Earth." We will continue helping to create an affluent society by developing and providing technologies and products that further promote the use of electrical components for automobiles.

*1: Solid-solution strengthening

A method of strengthening a material by dissolving other atoms (solute atoms) into the matrix of parent atoms (solvent atoms).

*2: Precipitation strengthening

A method of strengthening a material by precipitating other atoms (solute atoms) in the matrix of parent atoms (solvent atoms).

Contact details for inquiries
Public Relations Dept., Corporate Communication Dept.

Contact details for products
Group I, Rolled Product Sales Dept., Rolled Product Div., Copper & Copper Alloy
Business Unit, Advanced Products Company