Kabushiki Kaisha Kobe Seiko Sho

Kabushiki Kaisha Kobe Seiko Sho (kobe Steel, Ltd.)

Nobuaki Hinago

Chikara Saeki

Kiyonori Ozeki

Mamoru Ishikawa

Hideki Iwamoto

Disclosed is a producing method which allows low-cost and highly productive production of a seamless tube with a grooved inner surface having a smooth outer surface and an inner surface formed with plural types of grooves such that a protrusion is not formed at the produced seamless tube with a grooved inner surface. The tube is reduced in diameter by using a die and a plug. Then, the outer surface of the tube is pressed against a grooved plug by means of a pair of rolls such that a groove is formed in a portion of the inner surface of the tube. The process flattens the cross-sectional configuration of the tube in the direction in which the tube is pressed with the rolls. Subsequently, a sizing process using a die is performed with respect to the tube such that the tube has a generally circular configuration. Then, the outer surface of the tube is pressed against a grooved plug by means of another pair of rolls disposed such that the rotation axes thereof are orthogonal to the rotation axes of the rolls, whereby a groove is formed in a portion of the inner surface of the tube. Thereafter, the tube is subjected to a diameter reducing process using a die.

Method for producing seamless tube with grooved inner surface

A tube having a grooved inner surface capable of achieving high condensing performance and high evaporating performance even in a region of a small flow rate of a refrigerant and preferable as a heat exchanger tube for a condenser as well as an evaporator and its fabrication method, wherein spiral groove fabricating zones formed with spiral grooves are arranged at an inner surface of a metal or an alloy tube and intersecting groove fabricating zones formed with intersecting groove groups intersected with pluralities of grooves are arranged at the inner surface of the metal or the alloy tube at regions different from each other, singles or pluralities of the spiral groove fabricating zones and the intersecting groove fabricating zones are alternately arranged in a tube circumferential direction of the metal or the alloy tube, when a fabrication width of the spiral groove fabricating zone in the tube circumferential direction is designated by W and a fabrication width of the intersecting groove fabricating zone is designated by W , a ratio W /W of W to W falls in a range of 1.1 through 3.0 and the ratio W /W can also be made to fall in a range of 0.3 through 0.9.

Tube having grooved inner surface and its production method

Disclosed is a heat transfer tube with grooves in an inner surface thereof, which is excellent in both evaporation performance and condensation performance. In the heat transfer tube with grooves in an inner surface thereof according to the present invention, groove processing regions 1 having a width W1 and groove processing regions 2 having a width W2 are alternately arranged in the inner surface thereof, and a linear groove region 3 having a width W3 extending in a longitudinal direction of the tube is arranged between the groove processing region 1 and the groove processing region 2. The width W1 is larger than the width W2. A group of grooves within the groove processing region 1 are helically formed at a torsional angle .theta.1 with respect to a longitudinal direction of the tube, and a group of grooves within the groove processing region 2 are at a torsional angle .theta.2 different from .theta.1 with respect to the longitudinal direction of the tube and helically formed so that a torsional direction thereof is reversed to a torsional direction of the groove processing region 1.

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Hatano, Japan

Nobuaki Hinago