Toyota Jidosha Kabushiki Kaisha

Chuo Hatsujo Kabushiki Kaisha

Aichi Steel Works, Ltd.

Chikatoshi Maeda

Hideki Iba

Minoru Kawasaki

Akio Sato

Yasuyuki Suzuki

Toshio Ozone

Osamu Nakano

Tadashi Takeuchi

Atsushi Sugimoto

Makoto Kawagoe

Shigeru Yasuda

A process of cladding by welding includes the steps of: (1) preparing a workpiece having a cladding-scheduled portion including an exposed normal region, the exposed normal region having a normal surface including a possibility that a foreign substance portion exists, and the foreign substance portion to form a defect of cladding; (2) irradiating the exposed region of the cladding-scheduled portion of the workpiece with an high-density energy beam, the high-density energy beam capable of eliminating or decreasing the foreign substance portion, substantially without melting the exposed normal region of the cladding-scheduled portion; and (3) covering the exposed normal region of the cladding-scheduled portion of the workpiece with a clad layer.

Process of cladding by welding

A magnesium alloy includes 0.1 to 6.0% by weight of Al, 0.25 to 6.0% by weight of Zn, 0.1 to 4.0% by weight of rare earth element (hereinafter referred to as 'R.E.'), and balance of Mg and inevitable impurities. Preferably, it includes 1.0 to 3.0% by weight of Al ('a'), 0.25 to 3.0% by weight of Zn ('b') and 0.5 to 4.0% by weight of R.E.: wherein when 'b' is in a range, 0.25.ltoreq.'b'.ltoreq.1.0, 'a' and 'c' satisfy a relationship, 'c'.ltoreq.'a'+1.0; and when 'b' is in a range, 1.0.ltoreq.'b'.ltoreq.3.0, 'a,' 'b' and 'c' satisfy a relationship, 'c'.ltoreq.'a'+'b'.ltoreq.(1/2)'c'+4.0; in order to further improve creep properties at elevated temperatures while maintaining enhanced tensile strength at room temperature and up to 100.degree. C. at least.

Heat resistant magnesium alloy

A magnesium alloy includes 0.1 to 6.0% by weight of Al, 1.0 to 6.0% by weight of Zn, 0.1 to 3.0% by weight of rare earth element (hereinafter referred to as 'R.E.'), and balance of Mg and inevitable impurities. By thusly adding Al and Zn, the castability, especially the die-castability, is improved. At the same time, the room temperature strength can be improved because the Mg-Al-Zn crystals having a reduced brittleness are dispersed uniformly in the crystal grains. Further, by adding R.E. as aforementioned, the high temperature strength is improved because the Mg-Al-Zn-R.E. crystals having a higher melting point and being less likely to melt are present in the crystal grain boundaries between the Mg-Al-Zn crystals. This magnesium alloy is excellent in castability, can be die-cast, has a higher tensile strength at room temperature, and is satisfactory in high temperature properties and creep properties. Moreover, when the magnesium alloy includes R.E. in a reduced amount of 0.1 to 2.0% by weight, and further includes 0.1 to 2.0% by weight of Zr and 0.1 to 3.0% by weight of Si, it becomes a magnesium alloy, which is further excellent in the castability, which has a higher tensile strength at room temperature, which is further superb in the high temperature properties and the creep properties, and at the same time whose corrosion resistance is upgraded.

A spring steel having a good durability and a good sag-resistance consisting essentially of by weight 0.35-0.55% carbon, 1.80-3.00% silicon, 0.50-1.50% manganese, 0.50-3.00% nickel, 0.10-1.50% chromium, 0.01-0.05% aluminum and 0.010-0.025% nitrogen, the remainder being iron and inevitable impurities. The spring steel has been completed for the purpose of obtaining a spring steel having a high toughness in a high hardness of not less than HRC 55 and having a good sag-resistance, in particular examining the contents of nickel, chromium and nitrogen in addition to the carbon content.

Spring steel having good durability and sag-resistance

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Chikatoshi Maeda