Basics of Industrial Heat TreatmentBasics of Industrial Heat Treatment

What is Heat Treatment?• Heat Treatment is the

controlled heating and cooling of metals to alter their physical and mechanical properties, without changing the product shape

• Heat Treatment is often associated with increasing the strength of material

• In order to change the hardness of a metal, the internal atomic structure is actually changed during the heating and cooling

ApplicationsApplications

Common ProceduresCommon Procedures

• Preheat and Interpass Control– Prevent H cracking (Drive off moisture, reduce cooling

rate, increase H diffusion)– Redistribute solidification stresses– Minimize brittleness (cooling)

• Hydrogen Bake-Out– Remove Hydrogen, H2O– Prevent cracking and facilitate diffusion

• Post Weld Heat Treatment (PWHT)

– Relax residual stress– Hydrogen removal– Avoid Cracking– Dimensional Stability– Improved Ductility & Corrosion Resistance– Toughness

New Materials of Construction

Safety, Security, Quality, Performance and Cost

Implementation, Flexibility and Consistency

Diminishing EXPERIENCED Labor Resources

2121stst Century Challenges Century Challenges

Welding related activities

Traditional Heat TreatmentTraditional Heat Treatment OutdatedOutdated & & ObsoleteObsolete

• Labor intensive• Site Invasive• Limited Quality Control &

Oversight• Shortcuts commonplace• T&M Cost Overruns• Limited Controlability• Limited Expertise• Safety Risks• Accountability• Limited Flexibility

New MaterialsNew Materials

Mechanical Properties Mechanical Properties Not JUST Stress Relieving!Not JUST Stress Relieving!

Material HardnessTransformation Table

Preheat & PWHT are not Optional!

• 90% of Weld and Material anomalies with new alloys, attributable to improper Heat Treatment

Bill Newell, PE, IWE Newell & Associates

Weld Quality & Heat Treatment…Weld Quality & Heat Treatment…

• Plan on it• Evaluate the Job

• No Shortcuts

Data Can Be Misleading…Source of Material Defects

Before, During and After The Weld

Quality Control and Oversight

Quality Workmanship

Who specifies procedures?Who specifies procedures?

Conformance to Codes and Specifications

AWS Section D10.10 1999AWS Section D10.10 1999

Recommended Practices:

•Methods of applying controlled heat

(when furnace or oven are not practical)

•Written with more forgiving materials in mind

•In conjunction with

• Piping Fabrication Codes

• B31.1 Power Piping

• B31.3 Process Piping

• ASME Boiler and Pressure Vessels

• Repair Codes

• NBIC and API

• Standards regarding Service Environment

• NACE and ANSI

Principal ConceptsPrincipal Concepts

• Heat Affected Zone– Area immediately adjacent to the weld

• Soak Band– Localized region surrounding the weld

• Heated Band– Surface area covered by heat source

• Gradient Control Band Width– SB + HB + insulated area

• Control Zone– Grouping of one or more heat sources

controlled by a single temp measuring device

8.4 8.4 ThermocouplesThermocouples– Control

No. T/C’s required by pipe sizeNo. T/C’s required by pipe size– Placement

Positioning on the pipePositioning on the pipe– Monitoring

““recommended” points of observationrecommended” points of observation

Common ShortcomingsCommon Shortcomings– Temperature Control– Nice Charts vs. Accuracy– T/C Placement

• Recommendation• Actual Practice

– Heater selection omitted completely

(AWS Recommends 5 T/C’s but nobody conforms)

Introducing, Tomorrow’s heat treating technology … Today!

Internet Based Quality Management ModelInternet Based Quality Management Model

New innovations improve results…

Customer Driven Business ModelCustomer Driven Business Model……    “Utilizing latest advancements in Communication, Wireless and Software

Technology, to revolutionize Equipment and Process Solutions…”

• Increased Safety and Security– Fewer People, Minimize Risk while Maximizing Productivity– Non-Invasive Process Execution

• Labor Optimization– Unlimited FLEXIBILITY with limited labor resources– Multi-tasking facilitated through Process Simplification

• Superior Quality Control– Enhanced Process Control & Oversight– Weld Quality Assurance– Process Quality Management (PQM)

• Reduced Cost– Pricing Simplification, All-Inclusive Flat Rate Rental Rate– Daily Cost Analytics