hidep welding process for fabrication of low-weight t

HiDep Welding Process for Fabrication of Low-Weight T-Stiffeners with Near-Zero

Weld Distortion for Shipbuilding

Improving the Quality and

Reducing the Cost of Navy Ships

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NSRP Project: TIA No. 2017-426

NSRP “HiDep Process for Fabrication of Low-

Weight T-Stiffeners with Near-Zero Weld

Distortion for Shipbuilding”

• Bollinger Shipyards

• General Dynamics Bath Iron Works

• Vigor Shipyards

• EnergynTech, Inc.

• Gatekey Engineering, Inc.

• Hepinstall Consulting Group, Inc.

• Miller Electric Manufacturing

• Hobart Brothers Company

1/8

1/2

3/8

1/4

5/8

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String

Deck

Out of fair is the indicated distance

Stiffeners

Automated Thermal Forming – Application

Fairness Measurement:

Cost of Weld Distortion In Navy Ships

•Can exceed ½ million dollars per hull in labor costs

•Delays schedules

•Requires additional straightening (e.g., foundations)

•Damages coatings – may necessitate re-coating

•Can compromise Structural Integrity

•Fuel gas and oxygen costs

•Workman Compensation costs

Flame Straightening to Remove Distortion

1993 Laser Thermal Forming


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Aircraft Carrier Plate Forming

Steel plate and CAD model provided by Newport News Shipyard

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“Expected DD(X) Implementation benefits include 100% increase in throughput, 80% reduction in rework, 50% reduction in direct labor costs, and 75% reduction in support labor costs. The technology can also be extended to current and future U.S. Naval surface ship fabrication (e.g., LHD, LPD, and CVN-21) which will result in additional cost avoidance for the U.S. Navy.”

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Automated Thermal Forming – Control

Robot System:

2004 Induction Thermal Forming

March 1999 – Induction Thermal Forming


Robot System:

2004 Induction Thermal Forming


Robot Design:

Automated Thermal Forming – Application

July 2005

Automated Thermal Forming

At the end of the day:

• Less worker fatigue

• Improved Profitability

July 2005


PAS-Bulkhead / Hull

May 2007 21


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Industrial Engineering Test Analysis:

Manual: 17 sections = 40 hours

Robot: 44 sections = 42 hours

2.5X Productivity (5X – Fire Watch)

Flame Straightening can exceed ½ million dollars per hull in labor costs


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Thermal Forming solves a problemAfter it occurs.

Eliminating Weld Distortion prevents the problem

1) Cold column of steel (dashed line) in the discontinuous member provides strength –

the weld deposit then pulls the continuous member (blue arrows) causing distortion

2) Heated discontinuous member cools with the weld and shrinks with the weld, does

not pull the continuous member – No Distortion.

1) Conventional Arc Weld 2) HIAW (HiDep) Weld

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• Added 2nd Torch—Same Energy Level

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Melting as 1st Torch PassesMelting as 2nd Torch Passes

T- Stiffener Fabrication

Depth of melting1st Weld

Penetration

Larger Weld =Greater Shrinkage

Stiffener is notStraight

Category B Data – Government Purpose RightsDistribution authorized to project participants and NSRP ASE Program representatives. Further distribution is prohibited. 29

2nd Torch—Same Energy Level

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Melting as 1st Torch PassesMelting as 2nd Torch Passes

Depth of melting1st Weld

Penetration

Larger Weld =Greater Shrinkage

Stiffener is notStraight

Category B Data – Government Purpose RightsDistribution authorized to project participants and NSRP ASE Program representatives. Further distribution is prohibited. 30

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Welding A Ship Structure

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Welding A Ship Deck

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Welding A Ship DeckWelding A Ship Deck

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Welding A Ship Deck

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Welding A Ship Deck

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Weld Testing

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Weld Testing

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Weld Testing

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Weld Testing

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Weld Testing

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Welding A Ship Deck

Fabrication of T-StiffenersMoving Part – Stationary

Welder

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Fabrication of T-Stiffeners

40 foot Stiffeners with 24 inch Web

Moving Welder – Stationary

Part

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Moving Welder – Stationary Part

Front side Back side


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Model Validation – Comparison of Measured and Predicted

HEAT FLOW MODEL

Temperature/Phase Results

HEAT FLOW MODEL

Results—Results—Reoriented to Show Both Torches

HEAT FLOW MODEL

Weld Modeling using Neural Networks

MODELING FOR WELD ACCEPTANCE

Conclusions• Two-sided T-Fillet Hybrid Induction – Arc

Welding is ready for welding U. S. Navy ships.

• Hybrid Induction – Arc Welding will reduce or eliminate weld distortion

• Hybrid Induction – Arc Welding will provide a cost avoidance of several million dollars annually for the Navy

• Hybrid Induction – Arc Welding can reduce schedules by increasing welding productivity

Fabrication of T-Stiffener ½ inch plate with 24 inch web using Two Sided T-Fillet Hybrid Induction – Arc Welding

14” weld, 20 seconds = 42 inches per minute

hidep welding process for fabrication of low-weight t

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