YONGKWANG FLEXIBLE IND. CO., LTD.

Repair Method of Half-shell Metallic Bellows(Damaged Metallic Expansion Bellows)

forHRSG

Content

1. Scope of Application

2. Code and Standard

3. Installation Procedure

4. Inspection

5. Required Utility and Tool

6. YONGKWANG Experience

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1. Scope of Application

1. The metallic expansion bellows used at pipe penetration area of HRSG casing have had continuously problems by various causes (SCC, spatter, dent, etc.) during erection and operation.

2. Leaking high temperature gas due to failures of bellows becomes the cause of hot spot around bellows or damages to the surrounding equipment.

3. Repair of metallic bellows is very special work and take long time and lots of cost. (Special welder needed)

4. This document shall be applied repair work of damaged bellows for HRSG.(Welding Spatter) (Welding strike Hole) (Big Dent) (Insufficient Insulation)

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2. Code and Standard

Code and standard shall be applied in strict accordance with the latest issue in effect (unless otherwise noted)

2.1 American Society of Mechanical Engineers (ASME)

2.1.1 ASME Section I: Power Boiler

2.1.2 ASME Section II: Material Specification

2.1.3 ASME Section IX: Welding and Brazing Qualification

2.2 American Welding Society (AWS)

2.2.1 AWS D1.1: Steel Structure

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3. Installation ProcedureThe installation work should be carried out each process in accordance with procedure by the specialist of YONGKWANG. The process steps are as follows.3.1 Scaffolding

For safety, scaffolding shall be installed prior to site inspection work considered modificationsite situation.

3.2 Material VerificationThe material should be verified to material identification prior to repair work.

3.3 Remove Damaged Metallic BellowsThe damaged metallic bellows shall be removed by gas cutting and/or grinder for replacement of new half-shell metallic bellows (as Fig 1).The exist weld area shall be removed and flatted by smooth grinder.

(Fig 1. Removal Damaged Bellows)

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3. Installation Procedure3.4 Inspect to Inner Insulation

The inner insulation on pipe should be inspected prior to install half-shell metallic bellows. The replacement of insulation shall be required, if found damage.

3.5 Fit-up to Half-shell Metallic BellowsThe half-shell metallic bellows should fit up with tack welds on pipe (as Fig 2).

(Fig 2. Fit-up Half-shell Metallic Bellows)

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3. Installation Procedure

3.6 Welds on Half-shell Metallic BellowsThe weld shall be applied by the qualified and experienced welder of YONGKWANG.(as Fig 3 & 4).The welder shall check the inner back purging prior to weld.

(Fig 3. Welds on Half-shell Metallic Bellows) (Fig 4. Welds on Half-shell Metallic Bellows)

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3. Installation Procedure

3.7 Penetrant TestThe welds shall be verified soundness by penetrant test.

(Fig 5. Penetrant Test)

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3. Installation Procedure

3.8 Bellows Upper Cover Plate WeldsThe Upper cover plate shall be welded on casing plate for fixing.

(Fig 6. Cover Plate Welding)

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3. Installation Procedure

3.9 Bellows SettingThe bellows shall be adjust and settled according to required dimension.

(Fig 7. Bellows Setting) (Fig 8. Bellows Setting)

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3. Installation Procedure

3.10 Bellows Lower Plate WeldsThe lower plate shall be welded on pipe.

(Fig 9. Lower Plate Welds on Pipe)

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4. Inspection

After repair, the welds area shall be inspected visual and penetrant test by YONGKWANG Specialist and client.

(Fig 10. Final Installation)

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5. Required Utility and Tool

For bellows welding, special welding machine will be hand carry by YONGKWANG.

The required utility and equipment to be supplied by client as below,

1) 220V Electric Power Supply

2) Small Table or Scaffolding for Access to Damaged Bellows

3) Dye Penetrant Test Material

4) 4” Grinder with Wheel

5) Gas Cutting Equipment (Full Set)

6) Argon Gas Supply

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6. YONGKWANG Experience

- End of Document -

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Customer Country Location Year

Doosan Heavy Industries Co., Ltd. Bahrain AL EZZEL 2008

Doosan Heavy Industries Co., Ltd. Thailand BANG PAKONG 2009

Doosan Heavy Industries Co., Ltd. Spain Castellon 2010

Doosan Heavy Industries Co., Ltd. USA Edwardsport 2010

Doosan Heavy Industries Co., Ltd. UAE E-Mal 2008

Doosan Heavy Industries Co., Ltd. Algeria Hadjret 2009

Doosan Heavy Industries Co., Ltd. Israel Haifa 2005

Doosan Heavy Industries Co., Ltd. Dubai Jebel Ali 2005

Doosan Heavy Industries Co., Ltd. Portugal Lares 2012

Doosan Heavy Industries Co., Ltd. France Montoir 2009

Doosan Heavy Industries Co., Ltd. Spain Sabon Aceca 2010

Doosan Heavy Industries Co., Ltd. Singapore Seraya 2010

Doosan Heavy Industries Co., Ltd. Brazil Termo PE 2005