Steel Products for Shipbuilding

Transcription

1 JFE No.2 (23 11 ) p.3744 Steel Products for Shipbuilding SUZUKI Shinichi JFE MURAOKA Ryuji JFE OBINATA Tadashi JFE ENDO Shigeru JFE HORITA Tomoo JFE OMATA Kazuo JFE TMCP thermo-mechanical control process LP longitudinally profiled steel plate, NAC5 JFE-MARINE-COP TMCP 6 Abstract: Product designs and properties of 6 steel products for shipbuilding are described. They are new TMCP (thermo-mechanical control process) steel plates, weldable with high heat input, for container ships and LP (longitudinal profi le) plates, both contribute to the increase in productivity at shipyards through the large reduction of welding time, anti-corrosion steel plates for crude oil tankers NAC5 which contribute to high performance of ships from the viewpoint of corrosion, cladded steel plates for chemical tankers, anti-corrosion pipes, JFE-MARINE-COP, used in crude oil tankers for loading and unloading crude oil, and shapes for shipbuilding which are produced using TMCP to realize weldability as good as steel plates. 1. JFE-MARINE-COP TMCP 6 TMCP thermomechanical control process LP longitudinally profi led steel plate, NAC EWEL 8 TEU 39 N/mm 2 65 mm EGW 1 4 kj/cm HAZ 37

2 Table 1 Charpy impact energy of KL37 plate Thickness (mm) Welding method Heat input (kj/cm) Charpy impact energy at 55ºC (J) Grade FL HAZ l mm HAZ 3 mm Min. Ave. Min. Ave. Min. Ave. KL37 17 FAB (1) Low Cep alloy design (2) Control of grain size in HAZ (3) Control of microstructure in HAZ Fig. 1 High cooling rate by super-olac Pinning by optimum sized TiN ACR control Microallying techonology Concept of developing high strength steel plates, EWEL, for high heat input welding Absorbed energy at 4ºC (J) Thickness : 8 mm, Ave Each Heat input : 64 kj/cm Spec. ( 41 J) Ceq Fig. 1 EWEL 1) (1) Super-OLAC on line accelerated cooling 355 N/mm 2 Ceq 39 N/mm 2 (2) HAZ TiN HAZ (3) HAZ ACR atomic concentration ratio Fig. 2 8 mm YP39 N/mm 2 1 EWEL 4 F 1 FAB FCB Table 1 FAB 92 kj/cm EWEL Super-OLAC Fig. 2 FL HAZlmm HAZ3mm HAZ5mm Notch position Charpy impact energy of welded joint of EH4 plate HAZ LPG N/mm 2 2) 2.2 NAC5 Fig. 3 vapor space.1 mm/y 2 Vapor space VAPO S AC Ex.8%O2. Ex.8% O 14%CO2 2 14% CO 2.3%SOx.3% SOx Bal.N2 b al. N 2 H 2S H 2 S Inert gas IN R S Crude oil Fig. 3 Illustration of corrosion under upper deck plate in crude oil tanker 38

3 7 Conventional steel NAC5 Base metal NAC5 Weld metal Probability (%) Plate thickness : 2 mm y Conventional steel NAC5 Shop primer Ratio of corrosion rate Fig. 6 Ship age (y) Estimation of life of deck plate Fig. 4 Corrosion test results of NAC5 and conventional steel (Gas : CO2-SO2-H2S-O2-N2, 72 h) Conventional steel Fig. 5 NAC Ratio of exfoliation rate Corrosion test results of cross cut specimens coated by shop primer 5 NAC5 new anti-corrosion No N/mm 2 A, D NAC5 Fig. 4 NAC5 1 Fig. 5 NAC5 4 NAC5 2 NAC5 TMCP 3) NAC5 Fig. 6 1 NAC5 5 NAC5 2.3 LP 4 6) LP Fig. 7 LP LP1, LP2 LP LP2 LP7, LP8 2 LP LP Fig. 8 t 1 t 2 L 1 (a) LP1 t 1 t 2 L 1 L 2 L 3 t 1 t t 3 2 t 1 t 2 t 3 L 1 L 2 L 3 L 1 L 2 L 3 L 4 L 5 (c) LP7 Fig. 7 (b) LP2 (d) LP8 Various thickness profi les of LP plates 39

4 Weld seam Weld seam Sep Sep May 2 Jan. 21 Taper ratio 4/1 8/ (a) Normal plate (b) Lengthwise differential thickness plate (c) LP plate Plate delivered (t) Fig. 8 Example of an omission of weld seams and reduction of weight by using LP plate Upper deck Cargo hold Trans-bulk head Fig Year Taper ratio : Thickness reduction per 1 mm length Supply record of LP steel plates for shipbuilding 17 t LP 2 5 t 7 m 218 t Fig. 9 Bottom plate Examples of typical application of LP plate for shipbuilding Fig. 8 (a) Fig. 8 (b) Fig. 8 (c) LP Fig. 9 LP LP LP 4 k A, B, D 5 k A, D, E Fig LP LP LP LP mm/m LP 2 2 LP t LP LP 2.4 Fig. 11 Quantity of order (t) Fig Year Change in quantity of order of clad steel plates for chemical tankers 4

5 Table 2 Corrosion resistance of stainless clad steel Pitting corrosion JIS G578 5 C, 24 h (g/m 2 h) Intergranular corrosion JIS G h, 1t-bend SCC (U-bend) Boiling 2%NaCl 5 h, 8t-bend Table 5 Bend test results Bend test* KA 316L t (9 3)mm Direction : T Face bend r 1.5 t Good Root bend r 2. t Good Side bend r 2. t Good *JIS G 61 KA 316L Ave No crack No crack JFE-MARINE-COP Table 3 Table 4 KA 316L Corrosion rate in phosphoric and sulfuric acids Phosphoric acid 75 C (mm/y) %sulfuric acid 5 C (mm/y) Phosphoric acid : 44%P2O5 8.3%SO %Fe 3.8%Al 3 1.3%F.2%Cl KA 316L t (9 3)mm Direction : T Tensile test and V-notch Charpy impact test results YS (MPa) Tensile test* YS (MPa) El (%) Impact test** ve 2 C (J) *Full thickness, W 25 mm, GL 2 mm **3/4 size V-notch Charpy impact test of base metal Table 2 SCC Table Table 4 Table 5 4 MPa STPY4 Cr 4 MPa JFE-MARINE-COP JFE-MARINE-COP 3.2 JFE-MARINE-COP Table 6 JFE-MARINE-COP Cu, Ni, Cr Ca Super-OLAC 5 Cr 1 Cr JFE-MARINE-COP Cr 4 MPa 5 Fig BENETIA JFE-MARINE-COP Fig. 13 Cu, Ni, Ca JFE-MARINE-COP y Fig. 14 JFE-MARINE-COP SMAW Table 6 C (mass%) Chemical composition and manufacturing process of JFE-MARINE-COP Chemical composition Si (mass%) Mn (mass%) Others Process Cu, Ni, Cr Super-OLAC 41

6 Corrosion rate (mm/y) JFE-MARINE-COP 1%Cr STPY4 5ºC 3h Synthetic sea water 3.3 JFE-MARINE-COP JISSTPY4 STPY mm 1 16 mm 5 t Base metal Seam welded joint Fig. 12 Corrosion rate of JFE-MARINE-COP in synthetic sea water in comparison with those of 1 Cr, high C steel and STPY4 JFE NKBS NAB BP TMCP 4.2 Fig. 13 Cracking area ratio (%) Fig. 14 Cross sections of the MARINE-COP after 3 years of service as a cargo oil tank in the BENETIA JFE-MARINE-COP 1. Cr (High C) Testing temperature ( C) Results of weld cold cracking evaluation test or Tekken test of JFE-MARINE-COP in comparison with 1 Cr, high C steel (1) SMAW /LBK52 (2) GMAW /MGK-52 (3) TIG /TGSK JFE NKBS Table 7 NAB, BP, ABS FB AB JFE JIS NKBS DH36 JFE TMCP EH4 JFE NAB FEM 2Hi NAB Fig TMCP TMCP 42

7 Table 7 Dimensions of shapes for shipbuilding Shape NAB BP No. of size 28 4 Section dimensions (mm) Unit weight, W (kg/m) Moment of inertia, I X (cm 4 ) Brand A B t 1 t JFE JFE ABS NKBS AB NKBS JFE FB NKBS Table 8 Available TMCP shapes approved by certifying organization Standard Classification of ships Chemical composition YP (kgf/mm 2 ) Grade NK AB LR NV BV KR Cr Steel C eq (LR) 32, 36 4 A, D E A, D E Si-Mn Si-Mn Nb Nb.36 : JFE has the general approval Bloom BD mill R1 mill OLAC Flange cooling R2 mill F mill Furnace BD mill Fig. 15 Kaliber rolling process of NAB F mill R2 mill R1 mill Fig. 16 Location of water cooling equipment TMCP TMCP TMCP (1) TMCP NAB TMCP NAB (2) TMCP TMCP Fig. 16 OLAC TMCP (3) TMCP JFE TMCP Table 8 5. TMCP Only 1, No.1 43

8 1). NKK no p ). vol.34 no.4 22 p ) p.315 4) vol.3 no p ) vol.32 no.3 2 p ) p