WORK PROGRAMME. Proposal for a new output to amend the IGC and IGF Codes to include high manganese austenitic steel for cryogenic service

Transcription

1 E MARITIME SAFETY COMMITTEE 96th session Agenda item 23 7 February 2016 Original: ENGLISH WORK PROGRAMME Proposal for a new output to amend the IGC and IGF Codes to include high manganese austenitic steel for cryogenic service Submitted by the Republic of Korea SUMMARY Executive summary: This document proposes a new output on amendments to the IGC and IGF Codes to include high manganese austenitic steel for cryogenic service, to be included in the biennial agenda of the Sub-Committee on Carriage of Cargoes and Containers, and aims to increase safety in terms of design and materials when planning for and establishing systems and equipment such as cargo tanks, fuel tanks and piping of LNG carriers and LNG-fuelled ships Strategic direction: 5.2 High-level action: Output: No related provisions Action to be taken: Paragraph 29 Related documents: Resolution MSC.370(93); resolution MSC.391(95) and CCC 2/INF.18 Introduction 1 This document proposes a new output to amend both the IGC and IGF Codes with the aim of increasing safety in terms of system design and cryogenic materials for cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships. 2 This proposal is submitted in accordance with paragraph 4.8 of the Guidelines on the Organization and method of work of the Maritime Safety Committee and the Marine Environment Protection Committee and their subsidiary bodies (MSC-MEPC.1/Circ.4/Rev.4), taking into account the Guidance on drafting amendments to the 1974 SOLAS Convention and related mandatory instruments (MSC.1/Circ.1500).

2 Page 2 IMO's objectives 3 As stated in the Strategic Plan for the Organization (for the six-year period ) (resolution A.1097(29)), one of the broad categories for enabling IMO to achieve its mission objectives in the years ahead includes "enhancing technical, operational and safety management standards". 4 The proposal falls under the scope of Strategic Direction 5.2 "Enhancing technical, operational and safety management standards" and contributes to the implementation of High-level Action item "Keep under review the technical and operational safety aspects of all types of ships, including fishing vessels". Background 5 Due to the increasing global demand for Liquefied Natural Gas (LNG), which is an environment-friendly energy source, the number of shipbuilding orders for large-sized LNG carriers for transportation purposes has been on the rise. At the same time, utilization of LNG for marine fuel has been emerging as one of the most feasible methods of complying with the regulations in MARPOL Annex VI regarding air pollutants in ships' exhaust gas. As a result, the construction of LNG-fuelled ships has been increasing, while relevant vessels and offshore structures, including LNG bunkering ships, small- and medium-sized LNG carriers and LNG bunkering terminals are being continuously developed. 6 In this regard, it is timely to develop ways to raise the level of safety, in terms of system design and cryogenic materials, while improving the economic feasibility for cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships. Compelling need 7 There have been no discussions with regard to metallic materials for cryogenic applications since the adoption of the IGC and IGF Codes. This could be one factor preventing shipowners and LNG industries from using a newly developed metallic material for cryogenic service. 8 The newly developed, high manganese austenitic steel (high Mn steel) possesses mechanical properties comparable to those of materials for cryogenic service listed in both the IGC and IGF Codes, and can be used for cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships. The key properties of high Mn steel are described in document CCC 2/INF.18 (Republic of Korea). More detailed information regarding the base metal and welding consumables is provided in annex 2. 9 The toughness level of high Mn steel easily meets the requirements of the IGC and IGF Codes, being similar to that of 9% nickel steel. High Mn steel also showed superiority over existing materials in terms of ultimate tensile strength and elongation. In addition, the relatively small thermal expansion coefficient of high Mn steel leads to the advantage that the displacement caused by temperature change can be considered to a minimum when designing cryogenic equipment and devices. 10 Consequently, high Mn steel can strengthen the structure of cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships. Moreover, the high level of ultimate tensile strength and elongation will deter potential catastrophic failures that may occur on equipment or devices during emergencies, such as shipwreck, collision, fire and explosion. Thus, the level of ship safety will be increased.

3 Page 3 11 In conclusion, high Mn steel could replace existing materials for cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships. Analysis of the issue 12 Tables 6.3 and 6.4 in the IGC Code (resolution MSC.370(93)) and tables 7.3 and 7.4 in the IGF Code (resolution MSC.391(95)) state that materials for cryogenic application must have an appropriate level of toughness at the cryogenic temperature of minus 165 C. 13 The increasing demand for LNG carriers and LNG-fuelled ships gives rise to the need to raise the level of safety in terms of design and materials. 14 The IGC and IGF Codes contain provisions for materials including 9% nickel steel, austenitic steel, aluminium alloy and austenitic Fe-Ni alloy, but not for newly developed materials. Analysis of implications 15 This proposal does not incur any additional cost to the maritime industry. It is intended only to highlight the necessity to ensure safety in terms of design and materials while improving economic feasibility for cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships. 16 A completed checklist of administrative requirements and burdens, in line with MSC-MEPC.1/Circ.4/Rev.4, is provided in annex 3 to this document. Benefits 17 The benefits that would be gained from this proposal are:.1 enhancing safety when planning and installing cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships; and.2 in terms of economic feasibility, a continuous rise in the demand for LNG-fuelled ships and relevant equipment and devices may lead to a shortage of nickel, which is used in a wide range of industries, including medicine, kitchenware, aerospace, electric and electronics. High Mn steel, being manganese-based steel not containing nickel elements, holds the potential to ease the issue of nickel scarcity. Industry standards 18 The IGC Code provides a technical standard for LNG carriers, specifying 9% nickel steel, austenitic steel, aluminium alloy and austenitic Fe-Ni alloy as materials suitable for a minimum design temperature of minus 165 C. 19 The IGF Code provides a technical standard for LNG-fuelled ships and lists the same metallic materials as the IGC Code for a minimum design temperature of minus 165 C. 20 The base metal of high Mn steel is registered as KS-D-3031 in Korean Industrial Standards. Consumables for shielded metal arc welding flux cored arc welding, and submerged arc welding are registered as KS-D-7142, KS-D-7143 and KS-D-7144 in Korean Industrial Standards, respectively.

4 Page 4 21 The base metal of high Mn steel and its welding consumables are approved by IACS members such as KR, ABS, BV, DNV-GL and LR. Output 22 As an approach to reaping the benefits and addressing the issues described in paragraphs 7 to 17 above, it is proposed to include high Mn steel as a material suitable for cryogenic applications in the IGC and IGF Codes, as shown in annex. Human element 23 This proposal intends to give the designer more options in selecting materials for cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships. 24 The completed checklist for considering human element issues by IMO bodies (MSC-MEPC.7/Circ.1) is provided in annex 4 to this document. Priority/urgency 25 Environmental regulations in MARPOL Annex VI regarding air pollutants in ships' exhaust gas, such as NOx and SOx, in conjunction with the Paris Convention, are expected to lead to an increase in the number ships and offshore structures connected to the use of LNG, such as LNG carriers, LNG-fuelled ships, LNG bunkering ships and LNG bunkering terminals. This can increase greatly the possibility of catastrophic failures that may occur under emergencies such as shipwreck, collision, fire and explosion. 26 High Mn steel shows superiority in terms of ultimate tensile strength and elongation over existing cryogenic materials in IGC and IGF Codes. Furthermore, it indicates a much smaller level of thermal expansion coefficient compared to cryogenic materials listed in IGC and IGF Codes. 27 Consequently, high Mn steel can strengthen the structure of cargo tanks, fuel tanks and piping systems of LNG carriers and LNG-fuelled ships such that it will contribute to improving the structural safeties and preventing the possible destructive damages of those LNG-related ships. 28 It is recommended that the proposed new output on "Amendments to the IGC and IGF Codes to include high manganese austenitic steel for cryogenic service" is added to the biennial agenda of the Sub-Committee on Carriage of Cargoes and Containers, and that the output is added to the agenda of CCC 3. The completed check/monitoring sheet (parts I and II) given in annex 2 to MSC.1/Circ.1500 is set out in annex 5. Action requested of the Committee 29 The Committee is invited to consider the above proposal and justification; include in the biennial agenda of the CCC Sub-Committee the new item on "Amendments to the IGC and IGF Codes to include high manganese austenitic steel for cryogenic service"; and include the output in the agenda for CCC 3. ***

5 Annex 1, page 1 ANNEX 1 PROPOSED AMENDMENTS TO THE IGC AND IGF CODES Tables 6.3 and 6.4 of the IGC Code and tables 7.3 and 7.4 of the IGF Code list "Austenitic steels, such as types 304, 304L, 316, 316L, 321 and 347. Solution treated" in one of the cells in the column for "chemical composition and heat treatment". In the context of the aforementioned tables and in order to include high manganese austenitic steel as a material for cryogenic applications, three options are proposed as follows. Option 1 is to delete the words "such as types 304, 304L, 316, 316L, 321 and 347 solution treated" from the original text. This means that the amended text "Austenitic steels" encompasses all austenitic steels, including the high manganese austenitic steel. Option 2 is to add the words "high manganese austenitic steel" in the original sentence to read as "Austenitic steels, such as types 304, 304L, 316, 316L, 321, 347 solution treated and high manganese austenitic steel (see note 10) ". A note called Note (10), explaining that high manganese austenitic steel means the austenitic steel containing more than 22% manganese, is added to table (Note (9) in the case of table 6.4 of the IGC Code and table 7.4 of the IGF Code). Option 3 is to insert a row for high manganese austenitic steel in tables 6.3 and 6.4 of IGC Code and tables 7.3 and 7.4 of IGF Code as follows: " % nickel steel. Double normalized and tempered or quenched and tempered Austenitic steels, such as types 304, 304L, 316, 316L, 321 and 347. Solution treated Aluminium alloys; such as type 5083 annealed Not required -165 Austenitic Fe-Ni alloy (36% nickel) Heat treatment as agreed Not required -165 High Manganese Austenitic Steel (> 22% manganese) -196 " ***

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7 Annex 2, page 1 ANNEX 2 * HIGH MANGANESE AUSTENITIC STEEL FOR CRYOGENIC APPLICATIONS Contents 1 Introduction 2 Welding properties 2.1 Applicable welding consumables 2.2 Various properties of weld joint including requisite fracture toughness 2.3 Stress Corrosion Crack (SCC) susceptibility of base metal and weld joint 2.4 Weldability such as weld crack susceptibility (especially, hot crack), preheating, short bead, etc. 3 Workability 3.1 Bending Test 3.2 Formability 4 Actual application records for cryogenic service 4.1 Prismatic pressure tank for LNG storage 4.2 Cylindrical pressure tank for LNG storage 4.3 New construction of a bulk carrier with LNG fuel tanks made of high manganese steel 5 Conclusion * This annex is reproduced in English only

8 Annex 2, page 2 1 Introduction 1.1 High manganese austenitic steel (high Mn steel) for cryogenic applications was introduced at CCC 2 by the submission, on 10 July 2015, of document CCC 2/INF.18 on "Introduction to High Manganese Steel for Cryogenic Applications" (Republic of Korea). Basic information on the base metal can be referred to in document CCC 2/INF In the aforementioned information document, it appears that high Mn steel is more stable than materials listed in the IGC and IGF Codes at cryogenic temperature and its mechanical properties at the liquefaction temperature of LNG are satisfactory. 1.3 After the introduction of high Mn steel CCC 2, several agencies reviewed the information document and requested additional technical information on the following issues..1 applicable welding consumables;.2 various properties of weld joint including requisite fracture toughness;.3 Stress Corrosion Crack (SCC) susceptibility of base metal and weld joint;.4 weldability such as weld crack susceptibility (especially, hot crack), preheating, short bead, etc.;.5 workability such as line heating, forming, bending, etc.; and.6 actual application records of high manganese austenitic steel for cryogenic service, if available. 1.4 In the case where high Mn steel is considered to be candidate material intended for cargo tanks, fuel tanks and piping of LNG carriers and LNG-fuelled ships, the detail information on above items should be provided at least for further consideration. This document presents detail explanation for all comments. 2 Welding properties 2.1 Applicable welding consumables Welding consumables for Flux Core-Arc Welding (FCAW), Submerged-Arc Welding (SAW) and Gas Tungsten-Arc Welding (GTAW) are developed with the chemical composition and mechanical properties listed in tables 1 and 2. FCAW consumable is approved by the Korean Register as shown in figure 1. Table 1 Chemical composition of welding consumables for FCAW, SAW and GTAW Welding Process Chemical composition (wt.%) C Mn Ni (eq.) Cr (eq.) Fe FCA Type 1 0.1~ ~ Bal. Type 2 0.1~0.5 15~25 18~ Bal. SA 0.2~0.6 15~25 18~ Bal. GTA ~25 18~ Bal.

9 Annex 2, page 3 Table 2 Mechanical properties of welding consumables for FCAW, SAW and GTAW Requirement of Mechanical properties (All weld metal) Welding Process YS(MPa) TS(MPa) El. (%) -196 (J) FCA Type Type SA GTA Figure 1 Type approval certificate for welding consumables of FCAW

10 Annex 2, page Various properties of weld joint including requisite fracture toughness General Weldability was assessed by welding plates of 30 mm thickness with two welding processes, FCAW (Flux cored arc welding) and SAW (Submerged arc welding). FCAW with a heat input of 15 kj/cm was carried out, with single bevel groove for Charpy impact test and K groove for CTOD test. SAW of 30kJ/cm heat input was manufactured for a plate with K groove The approved welding consumables were used. In FCAW for Charpy impact test, welding was carried out with a welding wire of 1.2 mm diameter and shielding gas of 100% CO 2. Welding current of 180 A, welding voltage of 32 V, and a welding speed of 23 cpm were used. Except K groove, other welding conditions for FCAW for CTOD were the same with that for FCAW for Charpy impact test. For SAW, a welding wire of 4 mm diameter was used. Welding current, welding voltage and welding speed were 500 A, 30 V and 30cpm, respectively Tables 3, 4 and 5 shows the weld detail for FCAW and SAW, respectively. Sections for each weld are shown in figures 2, 3 and 4. Table 3 Welding conditions of FCAW for Charpy impact test Figure 2 Section for Charpy impact test(fcaw)

11 Annex 2, page 5 Table 4 Welding conditions of FCAW for CTOD test Figure 3 Section of CTOD test (FCAW) Table 5 Welding conditions of SAW for Charpy impact test Figure 4 Section of Charpy impact test (SAW)

12 Annex 2, page CVN (Charpy V-notch) test A set of 3 Charpy V-notch impact specimens with the notch located at weldment, at the fusion line and at a distance 2, 5 and minimum 20 mm from the fusion line were taken. Specimens of base metal were taken to be used for reference. The test temperature was chosen as 20 C, -50 C, -100 C, -150 C, and -196 C Figures 5 and 6 show the Charpy Impact Energy trend of FCAW and SAW and figure 7 indicates the tested specimen. Table 6 shows the detail absorbed energy In FCAW, the minimum impact energy is 77 J at fusion line +5 mm. At other locations, the absorbed energy is above the minimum value The minimum value of SAW is 54 J at weld metal. Charpy impact energy of SAW is a little lower than that of FCAW due to the higher welding heat input All cases satisfy the minimum impact energy of 27 J at -196 C required in the IGC Code. Figure 5 Charpy impact energy of FCAW

13 Annex 2, page 7 Figure 6 Charpy impact energy for SAW Figure 7 Specimens of Charpy impact energy for FCAW and SAW

14 Annex 2, page 8 Table 6 Details of Charpy impact energy for FCAW and SAW CTOD test CTOD Tests for FCAW welded joint and SAW welded joint were conducted in line with BS In FCAW welded joint, two notch location was chosen at fusion line (CGHAZ) and weld metal. Weld metal of SAW was at notch location. Three specimens were tested for each condition. Figure 8 shows the notch location at fusion line in FCAW welded joint and its specimen shape. Figure 8 Specimen positions of CTOD and shape Tables 7 and 8 show the CTOD of FCA welded joint and SA welded joint. CTOD with notch location at fusion line (CGHAZ) in FCA welded joint are 0.37 mm, 0.36 mm and 0.44 mm, which shows the good toughness of high Mn steel.

15 Annex 2, page In case that notch is located at weld metal of FCAW, CTOD of 0.51 mm, 0.52 mm and 0.51mm are measured. Similarly, CTOD of SAW welded joint are 0.56 mm, 0.41 mm and 0.54 mm. It shows that weld metal of FCAW and SAW has good toughness Figure 9 shows the P-V Curve and a fractured surface which shows that the CTOD tests are valid. Table 7 CTOD of FCA welded joint Weld joint Notch location Specimen no. Test temp. ( o C) B (Bx2B) (mm) a/w CTOD (mm) FCAW FL (CGHAZ) WM Weld joint SAW Notch location WM Table 8 CTOD of SA welded joint Specimen no. Test temp. ( o C) B (Bx2B) (mm) a/w CTOD (mm) Figure 9 P-V Curve and fractured surface

16 Annex 2, page Stress Corrosion Crack (SCC) susceptibility SCC of base metal The SCC test method is immersion corrosion testing of materials based on ASTM G31. The specimens are submerged in the solution of 3.5% NaCl at 25 C for 14 days Before SCC of base metal was tested, type 304 stainless steel is assumed to be resistant to 3.5% NaCl and omitted in SCC tests. Instead, 9% Ni steel and 0.07C-1.5% Mn steel were tested with high Mn steel for comparison of SCC resistance Figure 10 indicates the measured corrosion rate for 9% Ni steel, high Mn steel, and 0.07% C-1.5% Mn steel. The corrosion rate of high Mn steel is lower than that of 9% Ni steel, showing that high Mn steel has superiority over 9% Ni steel in resistance of stress corrosion crack. Figure 10 Immersion test results of base metal Another SCC test was carried out in line with ASTM G36, where the test specimens were prepared by ASTM G39. In this method, test specimens with a stress of yield strength applied were immersed in boiling solution of 42% MgCl 2 and the fracture time was measured For type 304 stainless steel, five tests were carried out and the fracture time was measured 0.31 hr, 0.38 hr, 0.39 hr, 0.39 hr, and 0.41 hr, respectively, with the mean value of 0.38 hr. The specimen of high Mn steel did not fracture and the test was stopped, even after 336 hours had passed. This indicates that high Mn steel has a better resistance to SCC than type 304 stainless steel.

17 Annex 2, page SCC of weld joints In accordance with ASTM G31, immersion corrosion testing of welded joints was performed. Specimens of welded joint by FCAW and SAW and base metal were tested for comparison Figure 11 shows the result. The corrosion rate of FCAW, mm/year is very close to that of SAW, mm/year. In section "SCC of base metal", the corrosion rate of the base metal of high Mn steel is found to be similar to that of 9%Ni steel. It is expected that the weldments of FCAW and SAW should have the similar corrosion rate with 9% Ni steel, too Figure 11 Corrosion rate of weldment of FCAW and SAW Corrosion Rate (mm/year) FCAW(PT-400HM) SAW(PC-400M/POS-CF1) Base Metal(High Mn) 2.4 Weldability such as weld crack susceptibility (especially, hot crack), preheating, short bead, etc Weld crack susceptibility In order to assess the weld crack susceptibility of high Mn steel, transverse Varestraint method, the representative way for assessing the susceptibility of hot crack was implemented In this method, the crack length as shown in figure 12 was measured at weld fusion zone, to compare hot crack susceptibility with 9% Ni steel. Several strain of 1%, 2%, 3% and 4% were applied and total crack length was measured Figure 13 shows the test result with PT-400HM and Inconel 625, indicating the crack length of high Mn steel and 9% Ni steel, respectively. It shows that high Mn steel has better hot crack resistance than 9% Ni steel, for all applied strain.

18 Annex 2, page 12 Figure 12 Transverse Varestraint test result of high Mn steel Figure 13 Comparison of crack length between high Mn steel and 9% Ni steel

19 Annex 2, page Preheating Preheating is usually carried out to prevent formation of cold cracks. High Mn steel is basically composed of an austenite phase with high toughness in base metal and weldment. Therefore, high Mn steel is not susceptible to cold cracking In order to apply preheat in working place, a preheating temperature between 15 C and 150 C is proposed, as in figure 14, based on ASME SFA 5.22 "Specification for stainless steel electrode for flux cored arc welding & Stainless steel flux cored rods for gas tungsten arc welding". Figure 14 Preheat temperature based on ASME SFA Short bead The short bead is related with cold crack caused by three parameters, brittle microstructure (martensite), residual stress and hydrogen. In steel with low carbon content with C eq of 0.37, a maximum hardness above 34 Hv results in the cold crack Hardness values measured for FCAW and SAW ire shown in figures 15 and 16. The maximum hardness is about 250 Hv below the critical maximum hardness of 340 Hv for low carbon steel with C eq of 0.37.

20 Annex 2, page 14 Figure 15 Hardness measurement of FCAW Figure 16 Hardness measurement of SAW As mentioned in section on preheating, base metal and weldment of high Mn steel are composed of an austenite phase resistant to cold crack, and hardness of weldment is as low. It can be guessed that there is no limit for short bead length of high Mn steel. Based on the short bead of 50 mm for stainless steel, it is proposed that 50 mm is applicable to the short bead length of high Mn steel. 3. Workability 3.1 Bending test Face bend specimens, root bend specimens and side bend specimen were prepared in line with UR W2. Also, the procedure of the bending test followed UR W Bending specimens of base metal with the direction transverse to the rolling direction were prepared. Table 9 and figure 17 show the test result. There is no crack nor any other defect greater than 3 mm in length in any direction on the surface of bent specimens. Table 9 Bending test results of base metal

21 Annex 2, page 15 Figure 17 Bending test of base metal Specimens from Butt welding of a thickness of 12 mm were prepared with double V groove as shown in figure 18. Eight sets of specimens with the face, root and side bend specimen were taken and tested As shown in table 10 and figure 19, there is no crack nor any other defect greater than 3 mm in length on the bent surface of welding specimen. Figure 18 Butt weld preparation for bending test

22 Annex 2, page 16 Table 10 Bending test results of welding specimens Figure 19 Bending test result of welding specimens 3.2 Formability The term formability is commonly used to describe the ability of steel to maintain its structural integrity while being plastically deformed into various shapes In steel sheet forming operations, the metal is plastically deformed by tensile loads, often without significant changes in sheet thickness or surface characteristics. The cold formability of steel plate is directly related to the yield strength and ductility of the material. The lower the yield strength, the smaller the load required to produce permanent deformation. High ductility allows large deformation without fracture. These forming characteristics are normally estimated from an analysis of the mechanical properties of steel, which are determined by uniaxial tensile tests Figure 20 show the tensile test result of high Mn steel. Compared to other materials, high Mn steel is guessed to need more load due to higher yield strength and tensile strength.

23 Eng. Stress (MPa) Annex 2, page 17 However, it can be thought that fracture does not occur thanks to the material's high toughness. This demonstrates that high Mn steel has proper formability Figure 20 Tensile test result of high Mn steel High Mn 9% Ni Type Al Eng. Strain (%) Also, the bend test is useful for assessing the formability of steel plates. Judging from the bending test results in section 2.5.1, the formability of high Mn steel is assessed to be good In order to verify the workability of high Mn steel synthetically, several pressure tanks were manufactured. One is the cylindrical pressure tank, with a volume of 24 m 3 and design pressure of 9 bar. This tank as shown in figure 21 went through a hydrostatic test and had no problem such as leakage. The other is the prismatic pressure tank displayed in figure 22. This tank with the dimension of 11,814 mm 2,074 mm 2,510 mm has a volume of 52 m 3 and design pressure of 10 bar. After manufacturing, it was tested by hydrostatic test and cryogenic test with liquid nitrogen and the result satisfied the requirement This indicates that the high Mn steel has comparable workability to other material such as 9% Ni steel, type 304 stainless steel, and Al 5083.

24 Annex 2, page 18 Figure 21 Cylindrical pressure tank (volume of 24 m 3 and design pressure of 9 bar) Figure 22 Prismatic pressure tank (volume of 52 m 3 and design pressure of 10 bar)

25 Annex 2, page Actual application records for cryogenic service 4.1 Prismatic pressure tank for LNG storage This tank is the prismatic pressure tank mentioned in paragraph 3.2.5, which was manufactured for LNG storage After manufacturing, it went through the cryogenic test and hydrostatic test and structural integrity was assessed In the cryogenic test, LNG should have been used, but liquefied nitrogen was used instead of LNG due to the possibility of explosion. Because the temperature of LNG is minus 165 C and liquefied nitrogen has the temperature of minus 196 C, the condition of the cryogenic test was more severe. Figure 23 shows the cryogenic test of the pressure tank Hydrostatic test with the pressure of 15.1 bar, using water as a medium, was carried out Both the cryogenic and the hydrostatic tests were done in the presence of a surveyor and satisfied the requirements. The Korean Register approved the pressure tank for LNG storage and figure 24 indicates the certificate for the pressure vessel. Figure 23 Prismatic pressure tank under cryogenic test

26 Annex 2, page 20 Figure 24 Certificate for the prismatic pressure tank for LNG storage

27 Annex 2, page Cylindrical pressure tank for LNG storage This is the cylindrical pressure tank mentioned in paragraph and was manufactured for LNG storage. Figure 25 shows the completed tank The cryogenic test was omitted and the hydrostatic test was carried out to investigate the structural integrity In the hydrostatic test, the maximum pressure of 15 bar held for 50 minutes. The test was carried out in the presence of a surveyor and showed that there were no problems. Figure 26 indicates pressure test record approved by Korean Register. Figure 25 Cylindrical pressure tank for LNG storage

28 Annex 2, page 22 Figure 26 Pressure test record approved by Korean Register

29 Annex 2, page New construction of a bulk carrier with LNG fuel tanks made of high manganese steel A new shipbuilding project for an LNG-fuelled ship with a pressure tank of high Mn steel is in the planning stages. The ship is a bulk carrier of 32,000 dwt intended for transferring limestone between Donghae harbour and Gwangyang harbour as shown in figure 27. The pressure tank for LNG fuel with a volume of 500 m 3 is planned to be made of high Mn steel. The shipowner plans to order the ship in the first half of 2016 and receive it in the second half of Figure 27 Route between Donghae harbor and Gwangyang harbor 5 Conclusion 5.1 Welding consumables for FCAW, SAW and GTAW were developed. FCAW welding consumables were approved by KR, ABS, BV, DNV-GL, and LR. 5.2 Charpy Impact test and CTOD of weld joint demonstrate that the high Mn steel satisfies the minimum impact energy in the IGC and IGF Code and have good fracture toughness. 5.3 Stress Corrosion Crack (SCC) susceptibility of base metal was tested based on ASTM G31 and G39. Results show that high Mn steel has lower corrosion rate than 9% Ni steel in immersion corrosion test and it does not fracture after 336 hours have passed. In comparison, type 304 stainless steel breaks on average at 0.38 hr in a boiling solution of 42% MgCl 2. This shows that base metal of high Mn steel has superiority in SCC over 9% Ni steel, and type 304 stainless steel. Based on ASTM G31, weldments of FCAW and SAW were tested and results indicate that weldment of FCAW and SAW has similar corrosion rate as 9% Ni steel.

30 Annex 2, page Transverse Varestraint method, the representative way for measuring susceptibility of hot crack was tested and shows that the hot crack resistance of high Mn steel is higher than that of 9% Ni steel. 5.5 Base metal and weldment of high Mn steel have an austenite phase, resistant to cold cracking. In line with preheating for other austenite steel, preheating between 15 C and150 C is proposed. The minimum short bead length for tack welding and repair welding is proposed as 50 mm based on the guideline of stainless steel. 5.6 Through bending test, no crack nor any other defects greater than 3 mm in length in any direction on the surface of the bend specimen occurred. The tensile test result of high Mn steel shows that it has proper formability due to high toughness and tensile strength. 5.7 Several LNG storage pressure tanks were manufactured and tested by hydrostatic pressure test and cryogenic test with liquid nitrogen. Results indicate that high Mn steel has comparable workability to other material such as 9% Ni steel, type 304 stainless steel and Al The actual application of high Mn steel for cryogenic service was tried. One example is the prismatic pressure tank for LNG storage with a volume of m 3, approved by the Korean Register. Another example is the pressure tank for LNG storage with a volume of 24 m 3, which was manufactured and pressure tested using a test approved by the Korean Register. Furthermore, a new bulk carrier with a pressure tank for LNG fuel made of high Mn steel is being planned to be built. 5.9 Judging from the above, it can be guessed that high Mn steel can be a candidate material intended for cargo tanks, fuel tanks and piping of LNG carriers and LNG-fuelled ships In conclusion, it is deemed necessary to discuss and consider the inclusion of high Mn steel as a material for cryogenic applications in tables 6.3 and 6.4 of the IGC Code and in tables 7.3 and 7.4 of the IGF Code. References Korean Industrial Standards, High manganese austenitic steel plates for pressure vessels for low-temperature service, KS-D-3031, Feb CCC 2/INF.18 on "Introduction to High Manganese Steel for Cryogenic Applications", submitted by the Republic of Korea on 10 July ***

31 Annex 3, page 1 ANNEX 3 CHECKLIST FOR IDENTIFYING ADMINISTRATIVE REQUIREMENTS AND BURDENS This checklist should be used when preparing the analysis of implications, required for submissions of proposals for inclusion of unplanned outputs. For the purpose of this analysis, the terms "administrative requirements" and "burdens" are as defined in resolution A.1043(27) on Periodic review of administrative requirements in mandatory IMO instruments, i.e. administrative requirements are an obligation arising from future IMO mandatory instruments to provide or retain information or data, and administrative burdens are those administrative requirements that are or have become unnecessary, disproportionate or even obsolete. Instructions: (A) If the answer to any of the questions below is YES, the Member State proposing an unplanned output should provide supporting details on whether the burdens are likely to involve start-up and/or ongoing cost. The Member State should also give a brief description of the requirement and, if possible, provide recommendations for further work (e.g. would it be possible to combine the activity with an existing requirement?). (B) If the proposal for the unplanned output does not contain such an activity, answer NR (Not required). 1. Notification and reporting? Reporting certain events before or after the event has taken place, e.g. notification of voyage, statistical reporting for IMO Members, etc. NR x Yes Start-up Ongoing Description: (if the answer is yes) 2. Record keeping? Keeping statutory documents up to date, e.g. records of accidents, records of cargo, records of inspections, records of education, etc. NR x Yes Start-up Ongoing Description: (if the answer is yes) 3. Publication and documentation? Producing documents for third parties, e.g. warning signs, registration displays, publication of results of testing, etc. NR x Yes Start-up Ongoing Description: (if the answer is yes) 4. Permits or applications? Applying for and maintaining permission to operate, e.g. certificates, classification society costs, etc. Description: (if the answer is yes) 5. Other identified burdens? NR NR x x Yes Start-up Ongoing Yes Start-up Ongoing Description: (if the answer is yes) ***

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33 Annex 4, page 1 ANNEX 4 CHECKLIST FOR CONSIDERING HUMAN ELEMENT ISSUES BY IMO BODIES Instructions: If the answer to any of the questions below is: (A) YES, the preparing body should provide supporting details and/or recommendation for further work. (B) NO, the preparing body should make proper justification as to why human element issues were not considered. (C) NA (Not Applicable), the preparing body should make proper justification as to why human element issues were not considered applicable. Subject Being Assessed: (e.g. Resolution, Instrument, Circular being considered) Resolution MSC.370(93) and resolution MSC.391(95) Responsible Body: (e.g. Committee, Sub-Committee, Working Group, Correspondence Group, Member State) MSC, then CCC 1. Was the human element considered during development or Yes No NA amendment process related to this subject? 2. Has input from seafarers or their proxies been solicited? Yes No NA 3. Are the solutions proposed for the subject in agreement with existing instruments? (Identify instruments considered in comments section) 4. Have human element solutions been made as an alternative and/or in conjunction with technical solutions? 5. Has human element guidance on the application and/or implementation of the proposed solution been provided for the following: Administrations? Yes No NA Yes No NA Yes No NA Shipowners/managers? Yes No NA Seafarers? Yes No NA Surveyors? Yes No NA 6. At some point, before final adoption, has the solution been reviewed or considered by a relevant IMO body with relevant human element Yes No NA expertise? 7. Does the solution address safeguards to avoid single person errors? Yes No NA 8. Does the solution address safeguards to avoid organizational errors? Yes No NA 9. If the proposal is to be directed at seafarers, is the information in a form that can be presented to and is easily understood by the Yes No NA seafarer? 10. Have human element experts been consulted in development of the solution? Yes No NA 11. HUMAN ELEMENT: Has the proposal been assessed against each of the factors below? CREWING. The number of qualified personnel required and available to safely operate, maintain, support, and provide training for system. Yes No NA PERSONNEL. The necessary knowledge, skills, abilities, and experience levels that are needed to properly perform job tasks. Yes No NA TRAINING. The process and tools by which personnel acquire or improve the necessary knowledge, skills, and abilities to achieve Yes No NA desired job/task performance OCCUPATIONAL HEALTH AND SAFETY. The management Yes No NA

34 Annex 4, page 2 systems, programmes, procedures, policies, training, documentation, equipment, etc. to properly manage risks. WORKING ENVIRONMENT. Conditions that are necessary to 9%tain Yes No NA the safety, health, and comfort of those on working on board, such as noise, vibration, lighting, climate, and other factors that affect crew endurance, fatigue, alertness and morale. HUMAN SURVIVABILITY. System features that reduce the risk of Yes No NA illness, injury, or death in a catastrophic event such as fire, explosion, spill, collision, flooding, or intentional attack. The assessment should consider desired human performance in emergency situations for detection, response, evacuation, survival and rescue and the interface with emergency procedures, systems, facilities and equipment. HUMAN FACTORS ENGINEERING. Human-system interface to be Yes No NA consistent with the physical, cognitive, and sensory abilities of the user population. Comments: (1) Justification if answers are NO or Not Applicable. (2) Recommendations for additional human element assessment needed. (3) Key risk management strategies employed. (4) Other comments. (5) Supporting documentation. ***

35 Annex 5, page 1 ANNEX 5 * CHECK/MONITORING SHEET FOR THE PROCESSING OF AMENDMENTS TO THE CONVENTION AND RELATED MANDATORY INSTRUMENT (PROPOSAL/DEVELOPMENT) Part I Submitter of proposal (refer to section of MSC.1/Circ.1500) 1 Submitted by (Document Number and submitter) (Republic of Korea) 2 Meeting session: MSC 96 3 Date of submission: 7 February 2016 Part II Details of proposed amendment(s) or new mandatory instrument (refer to sections and of MSC.1/Circ.1500) 1 High-level action plan 5.2.1, Keep under review the technical and operational safety aspects of all types of ships, including fishing vessels. 2 Planned output Amendments to the IGC and IGF Codes to include high manganese austenitic steel for cryogenic service 3 Recommended type of amendments (MSC.1/Circ.1481) (delete as appropriate) Four-year cycle of entry into force 4 Instruments intended for amendment (SOLAS, LSA Code, etc.) or developed (new code, new version of a code, etc.) IGC Code (resolution MSC.370(93)) and IGF Code (resolution MSC.391(95)) 5 Intended application (scope, size, type, tonnage/length restriction, service (International/non-international), activity, etc.) All ships to which resolutions MSC.370(93) and MSC.391(95) apply 6 Application to new/existing ships All ships to which resolutions MSC.370(93) and MSC.391(95) apply 7 Proposed coordinating sub-committee Sub-Committee on Carriage of Cargoes and Containers 8 Anticipated supporting sub-committees None 9 Time scale for completion CCC 3 is expected to finalize and submit to MSC 98 (summer 2017) for approval, with a view to adoption at MSC 99 (spring 2018) 10 Expected date(s) for entry into force and implementation/application 1 January Any relevant decision taken or instruction given by the Committee: None * This annex is reproduced in English only