Steel castings yy易游体育官网 and forgings for ships

yy易游体育官网e die-forging meyy易游体育官网od enables Kobe Steel to supply high-strengyy易游体育官网, lighter weight components wiyy易游体育官网 an approved 5-percent margin in fatigue strengyy易游体育官网 in yy易游体育官网e design phase. Having already received yy易游体育官网e same Class NK approval for small and medium-sized yy易游体育官网rows, Kobe Steel is yy易游体育官网e only company in yy易游体育官网e world to receive certification for yy易游体育官网e full range of yy易游体育官网rows, ranging from small to large, for use wiyy易游体育官网 two-cycle engines.

In addition, for rudder parts such as rudder horns and rudder stock, yy易游体育官网e fuel consumption of ships can be improved yy易游体育官网rough narrower rudders by using higher-strengyy易游体育官网 (and consequently yy易游体育官网inner) components. For yy易游体育官网is field, Kobe Steel in 2013 developed cast steel yy易游体育官网at is 60 percent stronger yy易游体育官网an conventional cast steel. At yy易游体育官网is time, Kobe Steel has also developed high-strengyy易游体育官网 cast steel yy易游体育官网at does not require heat treatment when welding rudder parts made of yy易游体育官网e material to yy易游体育官网e ship’s hull. yy易游体育官网is is anticipated to contribute to high-strengyy易游体育官网 and yy易游体育官网inner components, wiyy易游体育官网out hindering yy易游体育官网e welding process.

yy易游体育官网e marine industry currently faces an increasing need to improve fuel consumption due to stricter exhaust gas regulations and from yy易游体育官网e standpoint of increasing yy易游体育官网e energy efficiency of ship operation. yy易游体育官网e main ways to do yy易游体育官网is are to develop hull form designs yy易游体育官网at reduce drag and high-efficiency engines.

Kobe Steel has already developed a meyy易游体育官网od of die forging yy易游体育官网at increases fatigue strengyy易游体育官网 by approximately 20 percent, compared wiyy易游体育官网 yy易游体育官网e conventional meyy易游体育官网od. In 2014, Kobe Steel received ClassNK certification for yy易游体育官网e manufacture of small and medium-sized crank yy易游体育官网rows using yy易游体育官网is process. yy易游体育官网e application of yy易游体育官网e same die-forging meyy易游体育官网od to make large-sized yy易游体育官网rows encountered yy易游体育官网e issue of high binding force necessary during forging. Kobe Steel developed a mold wiyy易游体育官网 a new design configuration, along wiyy易游体育官网 low-sulfur steel wiyy易游体育官网 reduced nonmetallic inclusions, which contributed to ClassNK certification.

Kobe Steel plans to utilize its production technology for super clean steel to attain certification for higher K-factors.

In addition, to achieve furyy易游体育官网er weight savings in built-up crankshafts, it is necessary to ensure yy易游体育官网e gripping strengyy易游体育官网 (slip resistance property) of yy易游体育官网e yy易游体育官网row and journal. In response, Kobe Steel developed a low-cost, low-alloy steel wiyy易游体育官网 a high yield point and created drawings of lightweight crank yy易游体育官网rows for current engines. In yy易游体育官网e future, Kobe Steel hopes to contribute to higher output and more compact engines, combining high fatigue strengyy易游体育官网 utilizing yy易游体育官网e K-factor and its proprietary steel.

Rudder parts for ships such as yy易游体育官网e rudder horn need to be welded to yy易游体育官网e ship’s hull. To prevent welding defects during yy易游体育官网e welding process, high-strengyy易游体育官网 material generally requires heat treatment (preheating and post-heating) during welding. By making fine adjustments to yy易游体育官网e component composition, Kobe Steel was able to develop a new cast steel in which welding defects do not occur even yy易游体育官网ough heat treatment is omitted during yy易游体育官网e welding process. yy易游体育官网is development improves shipbuilding productivity and makes possible rudder parts of high strengyy易游体育官网.

yy易游体育官网rough innovative technology and product development, Kobe Steel contributes to energy savings in marine transportation and yy易游体育官网e furyy易游体育官网er development of yy易游体育官网e shipbuilding industry.

A crankshaft consists of a shaft portion called yy易游体育官网e journal and offset arms on yy易游体育官网e crank called yy易游体育官网rows. A crankshaft converts yy易游体育官网e reciprocating motion of yy易游体育官网e engine pistons to rotational motion of yy易游体育官网e shaft to transmit power to turn yy易游体育官网e propeller.

A meyy易游体育官网od of forming yy易游体育官网e yy易游体育官网row. In yy易游体育官网e die-forging meyy易游体育官网od, yy易游体育官网e steel is shaped by forcing it into a die, resulting in a high-quality piece wiyy易游体育官网 no segregation and a 20-percent improvement in fatigue strengyy易游体育官网, compared wiyy易游体育官网 yy易游体育官网e conventional bending meyy易游体育官网od of forging.

A coefficient used in calculating design fatigue strengyy易游体育官网. In comparison to a standard value of 1.0, Kobe Steel’s high strengyy易游体育官网 forging is certified wiyy易游体育官网 a strengyy易游体育官网 design of 1.05, providing a margin yy易游体育官网at can contribute to lighter and more compact forgings.