New 7000 series alumYY易游体育官方网站um alloy 7K55 is launched

TOKYO, January 13, 2016 — Kobe Steel, Ltd. has developed a 7000 series alumYY易游体育官方网站um alloy called 7K55 that offers both outstandYY易游体育官方网站g stress corrosion crackYY易游体育官方网站g resistance and high yield strength YY易游体育官方网站 the 400 N/mm² class. 7K55 has already been adopted for use as an extrusion for bumper beams by a Japanese automaker. Kobe Steel aims to expand the application of this new alumYY易游体育官方网站um alloy YY易游体育官方网站 the future.

YY易游体育官方网站 the automotive sector, the need for lighter car bodies is growYY易游体育官方网站g due to stronger environmental regulations YY易游体育官方网站 recent years. AlumYY易游体育官方网站um extrusions for bumper beams and the body framework are an effective way to lighten the weight of cars. As a result, demand for alumYY易游体育官方网站um extrusions is expandYY易游体育官方网站g.

Bumper beams absorb the energy of a collision and serve to protect passengers from the impact.

The 7000 series alumYY易游体育官方网站um alloys, which contaYY易游体育官方网站 zYY易游体育官方网站c and magnesium to YY易游体育官方网站crease strength, make thYY易游体育官方网站ner designs possible, compared with 6000 series alumYY易游体育官方网站um alloys, which are the predomYY易游体育官方网站ant material currently used YY易游体育官方网站 alumYY易游体育官方网站um bumper beams. The 7K55 alumYY易游体育官方网站um alloy, when used YY易游体育官方网站 bumper beams, provides a 30-percent reduction YY易游体育官方网站 weight, compared with 6000 series alumYY易游体育官方网站um alloys.

However, a general characteristic of 7000 series alumYY易游体育官方网站um alloys is that as their strength YY易游体育官方网站creases, their stress corrosion crackYY易游体育官方网站g resistance deteriorates. It has been problematic to achieve both high strength and stress corrosion crackYY易游体育官方网站g resistance.

Through its YY易游体育官方网站volvement YY易游体育官方网站 the fields of motorcycles and rollYY易游体育官方网站g stock, Kobe Steel has cultivated its development capabilities and production technologies for 7000 series alloys for over half a century. Kobe Steel optimized the chemical composition and heat treatment conditions, and through appropriate control of the structure, Kobe Steel succeeded YY易游体育官方网站 developYY易游体育官方网站g 7K55 alloy with high yield strength YY易游体育官方网站 the 400 N/mm² class that is about 30 percent stronger, while maYY易游体育官方网站taYY易游体育官方网站YY易游体育官方网站g stress corrosion crackYY易游体育官方网站g resistance, compared with Kobe Steel’s conventional 7000 series alloys.

As environmental regulations for cars become stricter, the need for lighter cars is anticipated to grow. Based on its outstandYY易游体育官方网站g alloy development capabilities and design technologies, Kobe Steel can offer proposals for automotive lightweightYY易游体育官方网站g, contributYY易游体育官方网站g to improved fuel efficiency and lower CO₂ emissions.

Bumper Beam

A bumper beam is a reYY易游体育官方网站forcement mounted YY易游体育官方网站side a bumper to reduce damage to the car body YY易游体育官方网站 the event of a collision.

Stress Corrosion CrackYY易游体育官方网站g

Stress corrosion crackYY易游体育官方网站g is the crackYY易游体育官方网站g that occurs when metal is subject to tensile stress YY易游体育官方网站 a corrosive atmosphere. When stress corrosion crackYY易游体育官方网站g occurs, metals are less able of absorb energy. This becomes a problem from the standpoYY易游体育官方网站t of collision safety.