ISST- -2007 2007 ISST Effect of Edge Preparation Methods on Effect of Edge Preparation Methods on Edge Retention Rate of Epoxy Coatings Edge Retention Rate of Epoxy Coatings S.S. Seo Seo, M.K. Chung, C.S. Park, C.H. Lee and K.K. Baek , M.K. Chung, C.S. Park, C.H. Lee and K.K. Baek S.S. Hyundai Heavy Industries Co., Ltd. Hyundai Heavy Industries Co., Ltd.
IMO’ ’s PSPC s PSPC IMO 2 2 Water Ballast TK Water Ballast TK Epoxy HB (160 µ m) Epoxy HB (160 µ m) Epoxy HB (160 µ m) Epoxy HB (160 µ m) Performance erformance S Standard tandard P I.O.Z. (15 µ m) I.O.Z. (15 µ m) For P Protective rotective C Coating oating For Steel Steel
IMO’ ’s PSPC s PSPC IMO 3 3 Corrosion Control Corrosion Control of Water Ballast TK: of Water Ballast TK: � Steel Thickness Steel Thickness � � Protective Coating Protective Coating � � Sacrificial Anode Sacrificial Anode � � Maintenance Maintenance �
IMO’ ’s PSPC s PSPC IMO 4 4 ITEM P S P C ITEM P S P C D.F.T. 2- -Coats, 320 Coats, 320 µ m NDFT(90/10) D.F.T. 2 µ m NDFT(90/10) D.F.T. Measurement D.F.T. Measurement Annex 3, Avg. 3~4 points/10 m 2 Annex 3, Avg. 3~4 points/10 m 2 nd Surface 1 st , 2 nd Surface 1 st , 2 Sa 2.5 Blasting, Profile: 30~75 µ Sa 2.5 Blasting, Profile: 30~75 µ m m Treatment Treatment Erection Joint Erection Joint Welds, Damaged Area <2%: St 3(Grinding) Welds, Damaged Area <2%: St 3(Grinding) Edge Preparation 2R, or 3- -Pass or at least equiv. Pass or at least equiv. Edge Preparation 2R, or 3 Edge Stripe Coating Min. 2 S/C; proven weld seams 1 S/C Edge Stripe Coating Min. 2 S/C; proven weld seams 1 S/C (S/C) Brush, Roller (Specified area only) (S/C) Brush, Roller (Specified area only) Size [5],[4],[3]: remove to Rating [1] Size [5],[4],[3]: remove to Rating [1] Dust Dust Size [2],[1],[0]: remove if visible on steel remove if visible on steel Size [2],[1],[0]: Soluble Salt <50 mg/m 2 NaCl, Bresle Bresle, Min. , Min. 1 Point/Block 1 Point/Block Soluble Salt <50 mg/m 2 NaCl,
IMO’ ’s PSPC s PSPC IMO 5 5 4.4 Basic coating requirements 4.4 Basic coating requirements Table 1 - - 3.1 Secondary surface preparation 3.1 Secondary surface preparation Table 1 The steel surface shall be prepared so that the coating The steel surface shall be prepared so that the coating selected can achieve an even distribution at the required selected can achieve an even distribution at the required NDFT and have an adequate adhesion by removing removing NDFT and have an adequate adhesion by sharp edges, grinding weld beads and removing , grinding weld beads and removing sharp edges weld spatter and any other surface contaminant. weld spatter and any other surface contaminant. Edges to be treated to a rounded radius of min. 2 mm, Edges to be treated to a rounded radius of min. 2 mm, or subjected to 3 pass grinding or at least equivalent subjected to 3 pass grinding or at least equivalent or process before painting. process before painting.
Background 6 Background 6 ■ IMO IMO’ ’s PSPC s PSPC : : “ “3 3- -Pass or 2 Pass or 2- -R R” ” edge grinding treatment edge grinding treatment ■ ■ Negative, side Negative, side- -effect : effect : ■ - DFT tend to be thicker than flat areas DFT tend to be thicker than flat areas - - More vulnerable to coating cracks More vulnerable to coating cracks - ■ Practical edge preparation methods ? Practical edge preparation methods ? ■ - Several Practices Several Practices - - Cross sectional measurement of DFT at Cross sectional measurement of DFT at - Flat/Round area (Edge Retention Rate, %) Flat/Round area (Edge Retention Rate, %)
7 7 Experimantal Methods Methods Experimantal
Experimentals 8 Experimentals 8 ■ Preparation of Specimen/Spray Coating Preparation of Specimen/Spray Coating ■ Edge roundness condition: Edge roundness condition: Flame cutting, R=1mm, R=2mm, R=3mm, RC Flame cutting, R=1mm, R=2mm, R=3mm, RC ■ Measurement of Roundness at Edge Measurement of Roundness at Edge ■ (HHI Yard Practice) (HHI Yard Practice) - RC : One Pass Grinding + Burr Removal (Sand Paper) - RC : One Pass Grinding + Burr Removal (Sand Paper) - Automatic Edge Roundness M/C - Automatic Edge Roundness M/C - RC Cutter RC Cutter - ■ Cross Cross- -sectional observation of D.F.T. sectional observation of D.F.T. ■ Evaluation: Edge Retention Ratio, Edge Roundness Evaluation: Edge Retention Ratio, Edge Roundness
9 Edge Retention Ratio (ERR) 9 Edge Retention Ratio (ERR) Top coat Top coat Primer coat Primer coat E2 E2 E1 E1 Steel Plate Steel Plate ERR(Primer) = E1/F1 ) = E1/F1 ERR(Primer ERR(Top coat) = E2/F2 coat) = E2/F2 ERR(Top F2 F1 F2 F1 ERR(%) = ERR(%) = T3 T3 DFT(Edge) ) DFT(Edge DFT(Flat) ) DFT(Flat
10 10 Edge Preparation (1) Edge Preparation (1) RC Automatic Edge RC Automatic Edge Roundness M/C Roundness M/C (1 Pass grinding + Sand Papering) (1 Pass grinding + Sand Papering) 45 ° ± 10 °
11 11 Edge Preparation (2) Edge Preparation (2) RC Cutter RC Cutter Rolled Plate Rolled Plate
Coating Materials Coating Materials 12 12 Product “ “A A” ” Product “ “B B” ” Product Product Pure epoxy Modified epoxy Pure epoxy Modified epoxy Type Type (Tar Free) (Tar Free) (Tar Free) (Tar Free) Thinning 5 % 5 % Thinning 5 % 5 % Color Grey/Light Grey Bronze/Aluminum Color Grey/Light Grey Bronze/Aluminum Specific Gravity 1.5 kg/ ℓ 1.25 kg/ ℓ Specific Gravity 1.5 kg/ 1.25 kg/ ℓ ℓ Viscosity (cP cP/KU) /KU) Viscosity ( 1,237/91.8 1,103/88.6 1,237/91.8 1,103/88.6 (0% Thinning) (0% Thinning) Solid Vol. Ratio (SVR) 80 % 60 % Solid Vol. Ratio (SVR) 80 % 60 %
13 Coating Sample Preparation 13 Coating Sample Preparation Spray coating Spray coating RC RC abt : 1mm : 1mm abt Stripe coating Stripe coating Flame Flame R = 1 R = 1 cutting cutting abt abt : 2mm : 2mm abt : 3mm abt : 3mm R = 3 R = 2 R = 2 R = 3
14 14 Results & Findings Results & Findings
15 15 Coating Thickness Effect Coating Thickness Effect � Sharp Edge Sharp Edge � � One One “ “C C” ” Grinding Grinding � D.F.T. Increase → → Outer Surface Radius Increase Outer Surface Radius Increase D.F.T. Increase
Crack Tendency w/ D.F.T. Crack Tendency w/ D.F.T. 16 16 - Edge Cracking after 4 Point Bending Test Edge Cracking after 4 Point Bending Test - - Crack width varies directly as coating D.F.T. Crack width varies directly as coating D.F.T. - - Initial crack site varies inversely as coating D.F.T. Initial crack site varies inversely as coating D.F.T. - - Number of crack: - Number of crack: Thin coating > Thick coating Thin coating > Thick coating - Crack Width: Crack Width: Thin coating < Thick coating Thin coating < Thick coating -
17 Edge Roundness Effect 17 Edge Roundness Effect Coating Material A Before Blasting After Blasting Increasing Rate 120 atio(% 100 etention R 80 60 40 dge R 20 E 0 Sharp C RC R=1 R=2 R=3 Edge
18 Edge Roundness Effect 18 Edge Roundness Effect Coating Material B Before Blasting After Blasting Increasing Rate 120 etention ratio(% 100 80 60 40 Edge R 20 0 Sharp C RC R=1 R=2 R=3 Edge
19 Edge Blasting Effect 19 Edge Blasting Effect � Before Blasting Before Blasting � � After Blasting After Blasting �
Stripe Coating Coating Effect Effect 20 Stripe 20 Spray Spary & One Stripe Increasing Rate 180 (% 160 tio 140 a R 120 n tio 100 n 80 te e 60 R e 40 g d E 20 0 Sharp C RC R=1 R=2 R=3 Edge
3- -pass Grinding pass Grinding 21 3 21 3 Pass Grinding 3 Pass Grinding 45 ° ± 10 ° R = 2.0 mm R = 2.0 mm
RC or Edge Rounder 22 RC or Edge Rounder 22 RC RC Automatic Edge Automatic Edge Roundness M/C Roundness M/C (1 Pass G/R + Sand Papering) (1 Pass G/R + Sand Papering) R = 2.0 mm R = 3.5 mm R = 2.0 mm R = 3.5 mm
RC Cutter or Edge Roller 23 RC Cutter or Edge Roller 23 RC Cutter RC Cutter Rolled Plate Rolled Plate R = 2.0 mm R = 2.0 mm R = 2.75 mm R = 2.75 mm
Roundness Summary 24 Roundness Summary 24 4 3.5 m m 3 ( s s 2.5 e n d 2 n u o R 1.5 e g 1 d E 0.5 0 R = 2mm RC RC Cutter R = 2mm RC RC Cutter Rolled Plate Rolled Plate Edge 3 Pass 3 Pass Edge Grinding Roundness M/C Grinding Roundness M/C
Conclusions 25 Conclusions 25 1. Variation of coating D.F.T. at the edges with 1. Variation of coating D.F.T. at the edges with different roundness were measured. different roundness were measured. 2. Equivalency for R = 2mm or 3 Pass grinding 2. Equivalency for R = 2mm or 3 Pass grinding - RC(One RC(One Pass grinding + Sand Papering) Pass grinding + Sand Papering) - - Automatic Edge Roundness M/C Automatic Edge Roundness M/C - - RC Cutter RC Cutter - - Rolled Plate Rolled Plate -
26 26 Thank you ! Thank you !
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