Basics Industrial Heat Treatment
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Transcript of Basics Industrial Heat Treatment
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