Hitachi, Ltd.

The Japane Steel Works, Ltd.

Masao Shiga

Shigeyoshi Nakamura

Yutaka Fukui

Takeshi Onoda

Kishio Hidaka

Toshio Fujita

Ryo Hiraga

Mitsuo Kuriyama

Nobuo Shimizu

Norio Yamada

Seishin Kirihara

Takatoshi Yoshioka

Hajime Toriya

Katsukuni Hisano

Masahiko Arai

Ryoichi Kaneko

Katsumi Iijima

Yasuo Watanabe

Ryoichi Sasaki

Yasuhiko Tanaka

Toshimi Tan

Kei Kobayashi

Masahiro Kobayashi

Masao Kawakami

Masayuki Sukekawa

Keiichi Tsuchiya

Kiyoshi Hiyama

Norio Morisada

Yasuhiro Harada

Kazuhiko Ueda

Gas turbine for power generation

A steam turbine blade made of a martensite steel having high strength and high toughness, and a low pressure steam turbine and a steam turbine power generating plant using the steam turbine blades. The steam turbine blade is made of a martensite steel containing C of 0.13-0.40%; Si less than 0.5%; Mn less than 1.5%; Ni of 2-3.5%; Cr of 8-13%; Mo of 1.5-4%; at least one kind of Nb and Ta of 0.02-0.3% in total; V of 0.05-0.35; and N of 0.04-0.15%.

Steam turbine blade, and steam turbine and steam turbine power plant using the same

Gas turbine for power generation, and combined power generation system

A compact steam turbine power-generation plant has a compact steam turbine that operates at a high temperature in a range of 600 to 660&deg; C. Ferrite based heat resisting steels provide for thermal efficiency. The main steam temperature and the reheated steam temperature can be set in a range of 600 to 660&deg; C. by making the main parts exposed to the high temperature atmosphere, such as the rotor shaft, from ferrite based forged steels and cast steels and by making a final stage blade of a low pressure turbine from a martensite steel. The final stage blade is made from a ferrite based forged steel having a tensile strength of 120 kgf/mm or more; the rotor shaft is made from a ferrite based forged steel having a 10 h creep rupture strength of 11 kgf/mm or more; and the inner casing is made from a ferrite based cast steel having a 10 h creep rupture strength of 10 kgf/mm or more.

Steam turbine power-generation plant and steam turbine

A compact steam turbine power-generation plant has a compact steam turbine that operates at a high temperature in a range of 600 to 660&deg; C. Ferrite based heat resisting steels provide for thermal efficiency. The main steam temperature and the reheated steam temperature can be set in a range of 600 to 660&deg; C. by making the main parts exposed to the high temperature atmosphere, such as the rotor shaft, from ferrite based forged steels and cast steels and by making a final stage blade of a low pressure turbine from a martensite steel. The final stage blade is made from a ferrite based forged steel having a tensile strength of 120 kgf/mm,or more; the rotor shaft is made from a ferrite based forged steel having a 10,h creep rupture strength of 11 kgf/mm,or more; and the inner casing is made from a ferrite based cast steel having a 10,h creep rupture strength of 10 kgf/mm,or more.

Method of making a turbine blade

A steam turbine in which principal components to be exposed to high temperatures are all made of ferritic steel, whereby the temperatures of main steam and reheat steam can be increased to 610-660 (&deg; C.). The rotor shaft (,in FIG.,) of the steam turbine is made of ferritic forged steel whose 100,000-hour creep rupture strength is at least 15 (kg/mm,) at the service temperature of the rotor shaft. Likewise, the casing (,) is made of ferritic cast steel whose 100,000-hour creep rupture strength is at least 10 (kg/mm,). The steam turbine of high thermal efficiency can be applied to a steam-turbine power plant.

Steam-turbine power plant and steam turbine

A steam turbine includes a rotor shaft, movable blades assembled on the rotor shaft, fixed blades for guiding inflow of steam to the moving blades, and an inner casing for holding the fixed blades. The rotor shaft and at least a first stage of the movable blades are made of high-strength martensitic steel comprising 0.05-0.20(%) of C, at most 0.15(%) of Si, 0.3-0.7(%) of Mn, 9.5-13(%) of Cr, 0.3-0.7(%) of Ni, 0.05-0.35(%) of V, 0.02-0.15(%) of Nb, 0.01-0.06(%) of N, 0.05-0.5(%) of Mo, 1.0-3.5(%) of W, 2-10(%) of Co and 0.0005-0.03(%) of B and at least 78(%) of Fe (the percentages being given in terms of weight). The inner casings is made of martensitic cast steel comprising 0.06-0.16(%) of C, at most 0.5(%) of Si, at most 1(%) of Mn, 0.2-1.0(%) of Ni, 8-12(%) of Cr, 0.05-0.35(%) of V, 0.01-0.15(%) of Nb, 0.01-0.1(%) of N, at most 1.5% of Mo, 1-4(%) of W and 0.0005-0.03(%) of B and at least 85(%) of Fe (the percentages being given in terms of weight). The rotor shaft has a length of at least 5 (m) and has a minimum diameter of at least 600 (mm) at a portion where the fixed blades are assembled. The first stage of said moving blades has a length of at least 35 (mm) at a blade portion thereof.

A steam turbine has main components such as rotor shaft exposed to high temperature and intermediate pressure, which are made of a ferritic steel and the main steam temperature and the re-heat steam temperature are 610.degree. C. to 660.degree. C., and a steam turbine power plant employs the turbine. Further, the rotating blades are made of only a martensitic steel or a combination of the martensitic steel and a Ni base alloy, the turbine rotor is made of a ferritic forged steel having a creep rupture strength at the operating temperature for 100 thousands hours of above 15 kg/mm.sup.2, and the casing is made of a ferritic cast steel having a creep rupture strength at the operating temperature for 100 thousands hours of above 10 kg/mm.sup.2.

High strength heat resisting cast steel, steam turbine casing, steam

A heat resisting steel whose metal structure is entirely martensite phase produced by tempering after quenching. The steel comprises, by weight, 0.05 to 0.20% C, not more than 0.15% Si, not more than 1.5% Mn, not more than 1.0% Ni, 8.5 to 13.0% Cr, not more than 3.50% Mo, not more than 3.5% W, 0.05 to 0.30% V, 0.01 to 0.20% Nb, not more than 5.0% Co, 0.001 to 0.020% boron, 0.005 to 0.040% nitrogen, 0.0005 to 0.0050% oxygen and 0.00001 to 0.0002% hydrogen. The steel has preferably not more than 10 of the Cr equivalent. The steel has 10 kgf/mm.sup.2 or more of 100,000 hours creep rupture strength at 650.degree. C.

Heat resisting steel and steam turbine rotor shaft and method of making

A steam turbine in which principal components to be exposed to high temperatures are all made of ferritic steel, whereby the temperatures of main steam and reheat steam can be increased to 610-660 (.degree.C.). The rotor shaft (23 in FIG. 1) of the steam turbine is made of ferritic forged steel whose 100,000-hour creep rupture strength is at least 15 (kg/mm.sup.2) at the service temperature of the rotor shaft. Likewise, the casing (18) is made of ferritic cast steel whose 100,000-hour creep rupture strength is at least 10 (kg/mm.sup.2). The steam turbine of high thermal efficiency can be applied to a steam-turbine power plant.

A high-strength austenitic steel having a fully austenite structure and consisting essentially of 0.02 to 0.15 wt % of C, not greater than 1.5 wt % of Si, not greater than 2.5 wt % of Mn, 8 to 20 wt % of Ni, 13 to 25 wt % of Cr, 0.02 to 0.25 wt % of Al, not greater than 0.1 wt % of N, at least one of 0.001 to 0.01 wt % of B, 0.02 to 0.5 wt % of Nb, 0.01 to 0.2 wt % of Ti and 0.02 to 0.6 wt % of V and the balance substantialy Fe, with the weight ratio (Al/N) ranging between 1 and 4.5. This steel is suitable for use as the material of, for example, inner casing of steam turbine, valve body incorporated in the steam turbine, rotor shaft, and chemical equipment such as reaction pipe and vessel for styrene monomer producing facility.

High-strength austenitic steel

A steam turbine rotor shaft made of precipitation-hardened forged austenite steel, comprising first, second and succeeding layers of build-up welding provided on an outer surface of a bearing portion of a journal section in the rotor shaft, the first layer being provided by use of a welding rod of Ni base alloy, the second and succeeding layers being provided by use of a welding rod of low alloy steel which layers have better bearing characteristics than those of the austenite steel.

Steam turbine rotor shaft

A heat resisting steel suitable for use as material of steam turbine parts. The steel has a substantially whole tempered martensite structure and consisting essentially of, by weight, 8 to 13% of Cr, 0.5 to 2% of Mo, 0.02 to 0.5% of V, 0.02 to 0.15% of Nb, 0.025 to 0.1% of N, 0.05 to 0.25% of C, not greater than 0.6% of Si, not greater than 1.5% of Mn, not greater than 1.5% of Ni, 0.0005 to 0.02% of Al, 0.1 to 0.5% of W and the balance substantially Fe, the ratio W/Al between W content and Al content ranging between 10 and 110.

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Hitachiohta, Japan

Masao Shiga