Glossary (and Abbreviations)

Glossary and Abbreviations


  • API (organization): American Petroleum Institute
  • ASME (organization): American Society of Mechanical Engineers
  • AWS (organization): American Welding Society
  • FCP: Flexible Ceramic Pad. This is the heater used in electrical resistance HT.
  • GCB: Gradient Control Band. This is the widest band and covers all area under insulation.
  • HAZ: Heat Affected Zone. It refers to the parts of the base metal that is around a weld and has been affected by the heat from welding activities.
  • HB: Heated Band. This band receives most of its heat from the SB, and its size is in-between that of GCB and SB.
  • HT: Heat treatment. This is the engineering process used to prepare materials for welding, transformation, etc.
  • Hydrogen Bakeout: This HT process is used to remove harmful substances from the workpiece, such as hydrogen, moisture, etc. In other words, it removes more than just hydrogen.


  • LNG: Liquid natural gas. Examples are: methane, ethane, etc. This industry uses a lot of HT, welding, etc.
  • Lower Critical Temperature: This refers to the temperature HT must avoid reaching or exceeding because it may change a material’s attributes and molecular structure. Different materials can have different lower critical temperatures.
  • NBIC (organization): National Boiler Inspection Code
  • OD: Outer Diameter. This term is usually used to describe a pipe’s size, and it refers to a pipe’s diameter that includes the thickness of the pipe wall.
  • Post-Heating: This HT process may not be present in all HT projects and is often used to transition the HT process in-between shifts.
  • PPE: Personal protective equipment. Example are gloves, face-shield, etc.
  • Pre-Heat: This HT process begins before the welding starts and continues through the welding process.
  • PWHT: Post-Weld Heat Treatment. This HT process takes place after the welding is done.


  • SB: Soak Band. This band is the narrowest, hottest band situated at the heart of the GCB and SB.
  • T/C: Thermocouple. This is the temperature monitor and control device attached to the workpiece.
  • Welding Tacks: It refers to the small welds (also called spot welds) that hold things in place before the welding begins.
  • WRC (organization): Welding Research Council

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Organizations for Quality Codes

OrganizationCode ExamplesWebsite
(To download or buy code documents)
American Petroleum Institute
API 510
API 650
American Society of Mechanical Engineers
ASME B31.1
ASME B31.3
American Welding Society
AWS D10.22
AWS D10.10
National Boiler Inspection Code
NBIC Part 3
Welding Research Council
WRC bulletin 452

Quality means doing it right–when no one is looking.

Henry Ford

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