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Products Spotlight Vol.12 No - 神戸製鋼所

1 KOBELCO WELDING Spotlight Increased efficiency in coal-fired power generationhas reduced that industry s consumption of fuels,thereby decreasing carbon dioxide emissions asso-ciated with global warming. In a related trend, highperformance steels have been developed to resistthe increased temperatures and pressures of steamin the boilers. W-enhanced 9-12Cr steels (such asASME P92 and P122) are now regarded as state-of-the-art high-Cr ferritic steels that are superior to9Cr-1Mo-V-Nb steel (typically ASME P91) increep rupture strength. To accommodate this grade of steel, Kobe Steelhas developed CR-12S for shielded metal arcwelding and TG-S12 CRS for gas tungsten arcwelding.

1 Products Spotlight KOBELCO WELDING TODAYVol.12 No.1 Increased efficiency in coal-fired power generation has reduced that industry’s consumption of fuels, thereby decreasing carbon dioxide emissions asso-

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Transcription of Products Spotlight Vol.12 No - 神戸製鋼所

1 1 KOBELCO WELDING Spotlight Increased efficiency in coal-fired power generationhas reduced that industry s consumption of fuels,thereby decreasing carbon dioxide emissions asso-ciated with global warming. In a related trend, highperformance steels have been developed to resistthe increased temperatures and pressures of steamin the boilers. W-enhanced 9-12Cr steels (such asASME P92 and P122) are now regarded as state-of-the-art high-Cr ferritic steels that are superior to9Cr-1Mo-V-Nb steel (typically ASME P91) increep rupture strength. To accommodate this grade of steel, Kobe Steelhas developed CR-12S for shielded metal arcwelding and TG-S12 CRS for gas tungsten arcwelding.

2 Tables 1 and 2 show the unique chemicalcompositions and excellent mechanical propertiesof these filler chemical compositions of CR-12S and TG-12 CRS are designed with the proper chromiumequivalent (Creq) so as to minimize the precipita-tion of delta ferrite in the martensitic matrix,thereby assuring sufficient impact toughness andcreep rupture strength. Typical applications for these filler metals includeheaders and main steam pipes in supercritical pres-sure boilers and ultra-supercritical pressure boilerswhich operate at higher temperatures and pressuresas compared with conventional 1: Main steam pipes (left) and a header (right) in posi-tion connected with a bundle of tubes.

3 (Source: MitsubishiHeavy Industries, Ltd. and National Institute of Materials Sci-ence, Japan)Table 1: Chemical compositions of CR-12S deposited metaland TG-S12 CRS wireTrade SamplingDeposited metalWirePolarityAC*11. Welding current: 160A; Welding position: *22. Welding current: 140A; Welding position: *33. Creq = Cr+6Si+4Mo+ +11V+5Nb+ +8Ti 40C 2Mn 4Ni 2Co 30N Cu (mass%) 6&5 67* 6 &567* 6 &56 &5 66 KLQLQJ LQ WKH :HOGLQJ RI6 XSHU DQG 8 OWUD 6 XSHU&ULWLFDO 3 UHVVXUH %RLOHUVT able 2: Mechanical properties of CR-12S deposited metaland TG-S12 CRS weld metal at room temperature*1 Trade PolarityAC*2 DCEP* (MPa)*4648652686TS (MPa)*4768771790El (%)*4262523RA (%)*46468682vE (J) at 0 C*5406044 PWHT740 C 8h FC1.

4 Welding conditions in GTAW: Base metal: (F) SUS410J3 per the Thermal Power Technical Standard of Japan; Shielding gas: Ar. 2. Welding current: 160A; Heat input: 12kJ/cm; Preheat & interpass temperature: 200-250 C; Welding position: Welding current: 140A; Heat input: 18kJ/cm; Preheat & interpass temperature: 200-250 C; Welding position: Test specimen (JIS Z 3111, Type A2): , : Average for three specimens (JIS Z 3111 Type 4)2 KOBELCO WELDING Expecting a fruitful business recoveryafter overcoming the worldwide financial crisis Since Lehman Brothers, a US investment bank, went bankrupt in September lastyear, triggering a once-in-a-hundred-years global economic recession, the serious-ness of the slump has only continued to grow.

5 Japanese industry has not avoided eco-nomic hardship, with those enterprises dependent on exports being hit doubly hardfrom a decrease in sales as well as appreciation of the Japanese yen. Leading automo-bile and electronics manufacturers have announced that large losses are to be expectedas they settle their accounts at the end of the financial year. Even though the majorindustrialized countries agreed on measures to boost economies and stabilize finances,conditions worldwide have only worsened, with financial turmoil accelerating andstock prices falling everywhere. In an environment such as this, Kobe Steel must also be prepared for a severe fiscalyear in 2009 and aim at securing the highest sales possible while also strengtheningKobelco s overseas foothold by fortifying the company's financial and business posi-tion.

6 However, as necessity is the mother of invention, innovation may now be moreforthcoming during this period of adversity than in times of economic boom. We areaware that, in 2009, all employees must be crisis-conscious, work out new plans withoriginality and ingenuity and push innovation forward to build a basis for the com-pany's future prosperity and stronger business structure. In newly emerging countries, many brand new enterprises have achieved No. 1 sta-tus within their particular arenas. These global challengers tend to have a characteris-tic business strategy that emphasizes at least one or two of the following points. 1) Achieving competitive cost performance2) Investing in human resources3) Penetrating deeply into target markets4) Adopting a pinpoint marketing strategy5) Being ambitious and swift when entering foreign markets6) Innovating with originality and ingenuity (Investing amply in research and devel-opment in order to supply innovative Products )7) Accepting market pluralism (Responding flexibly to differences in customers'needs and distribution structures)

7 The Kobelco Welding Company Group is also a global industry with nine footholdsoverseas, and we intend to formulate strategies that are tailored to fit the needs of themain industries in such fields as automobile manufacturing, shipbuilding or energydevelopment. The article in these pages on the welding of equipment related to powerboilers demonstrates our awareness that in China, India and Brazil there is steadydemand for improvement of infrastructure. The article promotes our only one in theworld product and provides technical support to our customers. It is our sincere hope that we will overcome the present business difficulties andprosper together with our customers.

8 We hope that you will extend your support andhelp us to further popularize the Kobelco brand throughout the 6&5 6&5 67* 6 &567* 6 &56P1 Shining in the welding of super and ultra super criti-cal pressure boilersP3-7 Heat-resistant high-Cr ferritic steel welding consumables for boilersP9-10 Celebratingthe anniversaries ofTKW (40), KMWT (20)and KWS (30)%106'065&UHHS &UHHS5 XSWXUHP8 Creep rupture strength is essential for heat-resisting steels and filler metalsToshiyuki OkuzumiGeneral ManagerInternational Operations CompanyKobe Steel, WELDING Highlight Thermal electric power generated from fossil fuelssuch as coal and oil satisfies around 50% of theworld s total demand for electric energy.

9 The chal-lenge for the thermal electric power industry hasbeen to improve power generation efficiency inorder to reduce costs as well as carbon dioxideemissions. Power generation efficiency can beimproved by increasing the steam temperature andpressure in the power generating turbines. Figure 1shows how steam temperature and pressure hasbeen increasing in recent years in thermal electricpower boilers in Japan. Research into ultra-supercritical pressure power plants that operatewith steam heated to a temperature of 650 C andpressurized to 34 MPa has also been 1: Increases in steam temperature and pressure forthermal electric power boilers in structural materials used in high-temperaturehigh-pressure steam boilers must be able to with-stand severe conditions for long periods of opera-tion.

10 Creep rupture strength that is adequate atelevated temperatures over long service periods isessential, and thermal fatigue resistance is impor-tant to accommodate the variations in operatingconditions caused by system shutdown and startupas well as variable loads in day and night opera-tions. To meet such stringent requirements, heat-resistant high-Cr (9-12Cr) ferritic steels (P91, P92and P122) have been developed. For example,Modified 9Cr-1Mo (9Cr-1Mo-V-Nb) steel (P91)has been used in many thermal electric power boil-ers around the world for two decades. This articleintroduces a line of 9-12Cr ferritic steel filler met-als for thermal electric power of 9-12Cr ferritic steelsResearch into heat-resistant ferritic as well asaustenitic steels has been on-going for many ferritic steel is characterized by alower thermal expansion coefficient as comparedwith heat-resistant austenitic steel, giving it moreresistance to temperature fluctuations caused byvariable operation conditions and shutdowns, andis thus more suitable for the structural materials inthermal power boilers.