Welding Metallurgy
What welding heat does to metal, followed through an apprentice's metallurgy block at a fabrication shop in Pasadena, on the Houston Ship Channel: crystals, grains and phases, iron and carbon and the steel family, mechanical properties and the tensile, hardness, Charpy and bend tests, heat input, heat flow and the t8/5 cooling time, weld metal, dilution and the zones of the heat-affected zone, hardenability, carbon equivalent and hydrogen cracking, preheat and interpass temperature to AWS D1.1 practice, stainless steels, aluminum, cast iron and other metals, distortion and residual stress, weld defects and their causes, and a capstone repair of a cracked loader boom planned from the chemistry up.
WLD-130 12 lessons · 3 h 34 min ▶ Video lessons coming soon
Offered by HSM University · Welding
This is the American version of this course. See the Canadian version.
What you'll learn
- Explain why metallurgy matters to welders, identify the zones of a weld, and calculate heat input with a process efficiency factor
- Describe metallic bonding, the BCC, FCC and HCP crystal structures, grains, grain size, solid solutions and phases, and relate them to weld properties
- Read the steel end of the iron-carbon diagram, apply the lever rule, and describe ferrite, pearlite, bainite, martensite, common heat treatments and the steel families
- Explain yield and tensile strength, elongation, hardness, Charpy toughness, the ductile-to-brittle transition, bend tests and fatigue, and evaluate test results
- Explain heat flow from a moving arc, thermal cycles and the t8/5 cooling time, and estimate how heat input, thickness and preheat change cooling
- Describe weld metal solidification, dilution, and the coarse-grained, fine-grained, intercritical and subcritical zones of a steel HAZ
- Calculate carbon equivalent and Pcm, explain hardenability, and describe the causes and prevention of hydrogen-induced cracking
- Determine, apply, measure and record preheat and interpass temperatures, and distinguish post-heat from post-weld heat treatment
- Describe the welding metallurgy of stainless steels, stainless to carbon steel joints, aluminum, cast iron and other metals met in fabrication and repair
- Explain the causes of distortion and residual stress, estimate shrinkage, and apply design, fit-up and sequence methods to prevent and correct distortion
- Identify weld discontinuities and defects, explain their causes, and describe how defects are removed and repaired
- Plan and carry out a repair of a cracked hardenable steel part, choosing preheat, heat input and sequence and controlling distortion and inspection
Course content
12 lessons · 3 h 34 min total · final exam
- 1 Why welders need metallurgy 18 min · quiz
- 2 Structure of metals: crystals, grains and phases 19 min · quiz
- 3 Iron, carbon and the steel family 18 min · quiz
- 4 Mechanical properties and how they are tested 17 min · quiz
- 5 Heat flow and cooling rate in welding 16 min · quiz
- 6 The weld zone and the heat-affected zone 16 min · quiz
- 7 Hardenability, carbon equivalent and hydrogen cracking 17 min · quiz
- 8 Preheat and interpass temperature 18 min · quiz
- 9 Stainless steels, aluminum and other metals 19 min · quiz
- 10 Distortion and residual stress 16 min · quiz
- 11 Weld defects and their causes 19 min · quiz
- 12 Capstone: choosing preheat and controlling distortion on a repair 21 min · quiz
- E Final exam 20 questions
Requirements
Recommended background. You can start any course at any time.
Description
What welding heat does to metal, followed through an apprentice's metallurgy block at a fabrication shop in Pasadena, on the Houston Ship Channel: crystals, grains and phases, iron and carbon and the steel family, mechanical properties and the tensile, hardness, Charpy and bend tests, heat input, heat flow and the t8/5 cooling time, weld metal, dilution and the zones of the heat-affected zone, hardenability, carbon equivalent and hydrogen cracking, preheat and interpass temperature to AWS D1.1 practice, stainless steels, aluminum, cast iron and other metals, distortion and residual stress, weld defects and their causes, and a capstone repair of a cracked loader boom planned from the chemistry up.