Hitachi, Ltd.

Takeshi Onoda

Shigeyoshi Nakamura

Yutaka Fukui

Mitsuo Kuriyama

Masao Shiga

Masao Siga

Yasuo Watanabe

Masateru Suwa

Ryo Hiraga

Ryoichi Kaneko

Toshimi Tan

Shintaro Takahashi

Hidefumi Kajiwara

Yoshimi Maeno

Toshio Fujita

Kishio Hidaka

Nobuo Shimizu

Norio Yamada

Shinya Imano

Hiroyuki Doi

Masahiko Arai

Kiyoshi Namura

Masakazu Takasumi

Yoshiaki Yamazaki

Eiji Saito

Shigemichi Inoue

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

The moving blades of a rotor included in a steam turbine are formed so that the width of a gap between opposite end surfaces of first connecting members of adjacent blades along the direction of rotation of the rotor and the width of a gap between opposite end surfaces of second connecting members of the adjacent blades along the direction of rotation of the rotor are determined so as to make the second connecting members start coming into contact with each other at a rotating speed of the rotor higher than a rotating speed at which the first connecting members of the adjacent blades start to come into contact with each other.

Steam turbine

A steam turbine blade made of Ti-base alloy comprising an &agr;&plus;&bgr; type phase in which a difference of a tensile strength is small between a blade portion and a dovetail portion, a tensile strength at a room temperature of the dovetail portion is equal to or more than 100 kg/mm and a suitable toughness is commonly provided together with a strength, as a steam turbine blade having a length of 43 inch or more, a method of manufacturing the same, a steam turbine power generating plant and a low pressure steam turbine. In the steam turbine blade having a blade portion and a plurality of fork type dovetails, wherein the blade is made of Ti-base alloy structured such that a length of the blade portion is equal to or more than 52 inches with respect to a rotational speed 3000 rpm of the blade or equal to or more than 43 inches with respect to the rotational speed 3600 rpm, and a tensile strength at a room temperature of the dovetail is equal to or more than 100 kg/mm , preferably equal to or more than 110 kg/mm and equal to or more than 96 % of the tensile strength at the room temperature of the blade portion.

Method of making steam turbine blade

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 steam turbine for use in a thermal or nuclear power plant includes moving blades of a rotor which vibrate as the rotor rotates, inducing an excessive stress in joints of connecting members for connecting the adjacent moving blades and blade portions of the moving blades and damaging the joints. The moving blades are formed so that a width of a gap between opposite end surfaces of first connecting members of adjacent blades along the direction of rotation of the rotor and a width of a gap between opposite end surfaces of second connecting members of the adjacent blades along a direction of rotation of the rotor are determined so as to make the second connecting members start coming into contact with each other at a rotating speed of the rotor higher than a rotating speed at which the first connecting members of the adjacent blades start come into contact with each other.

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 comprising a rotor shaft integrating high and low pressure portions provided with blades at the final stage thereof having a length not less than 30 inches, wherein a steam temperature at first stage blades is 530&deg; C., a ratio (L/D) of a length (L) defined between bearings of the rotor shaft to a diameter (D) measured between the terminal ends of final stage blades is 1.4 to 2.3. This rotor shaft is composed of heat resisting steel containing by weight 0.15 to 0.4% C, not more than 0.1% Si, 0.05 to 0.25% Mn, 1.5 to 2.5% Ni, 0.8 to 2.5% Cr, 0.8 to 2.5% Mo and 0.15 to 0.35% V and, further, the heat resisting steel may contain at least one of Nb, Ta, W, Ti, Al, Zr, B, Ca, and rare earth elements.

Steam turbine, rotor shaft thereof, and heat resisting steel

There is provided a steam turbine blade made of Ti-base alloy comprising an &agr;&plus;&bgr; type phase in which a difference of a tensile strength is small between a blade portion and a dovetail portion, a tensile strength at a room temperature of the dovetail portion is equal to or more than 100 kg/mm,and a suitable toughness is commonly provided together with a strength, as a steam turbine blade having a length of 43 inch or more, a method of manufacturing the same, a steam turbine power generating plant and a low pressure steam turbine. In the steam turbine blade having a blade portion and a plurality of fork type dovetails, wherein the blade is made of Ti-base alloy structured such that a length of the blade portion is equal to or more than 52 inches with respect to a rotational speed 3000 rpm of the blade or equal to or more than 43 inches with respect to the rotational speed 3600 rpm, and a tensile strength at a room temperature of the dovetail is equal to or more than 100 kg/mm,, preferably equal to or more than 110 kg/mm,and equal to or more than 96% of the tensile strength at the room temperature of the blade portion.

Steam turbine blade, method of manufacturing the same, steam turbine power generating plant and low pressure steam turbine

A combined cycle power generation system in which a generator is driven by a steam turbine and a gas turbine includes a steam turbine rotor having a mono-block rotor shaft with blades mounted thereon in multi-stages from a high pressure side to a low pressure side and a casing covering the rotor. An inlet temperature of steam to first stage blades is not less than 530&deg; C. and the rotor shaft is made of a Ni&mdash;Cr&mdash;Mo&mdash;V low alloy steel of bainitic structure having a higher creep rupture strength at the high pressure side than at the low pressure side and a 538&deg; C. and 10,h creep rupture strength not less than 12 kg/mm,at a central portion, and having mounted thereon at the central portion, first stage blades at the high pressure side or FATT of not more than 20&deg; C. Final stage blades are mounted at the low pressure side having a room temperature V-notch impact value of not less than 4 kg/m, and blades of at least a final stage have a value of blade length in inches times revolution in rpm of not less than 125,000 and are made of martensite stainless steel including 8-13 wt. % Cr.

High and low pressure sides-integrating system turbine, long blades thereof and combined cycle power generation system

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 high and low pressure sides integrating steam turbine having high and low pressure sides integrating steam turbine blades, each made of a martensite steel including 8-13 wt % Cr, and having a blade length of 33 inches or more for 60 Hz power generation and 40 inches for 50 Hz power generation.

High and low pressure sides-integrating steam turbine, long blades

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.

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Hitachi, Japan

Takeshi Onoda