Welding Notes

Weld as hot as you can stand.

Always give the process time to heat up.

Other Resources

Standards Backgrounds

  • ASME defines standards for pressure vessels
    • guidance for Technic Safety BC
  • AWS defines standards for structural welding
    • basis/used by CSA and CWB

Processes

  • Oxy-fuel welding
  • Oxy-fuel cutting

Parts of a Weld

parts-of-a-weld

Stick Welding Process

Basic Process

Rod Specifications

Note: welding rods are make from (very) high quality steel. Usually direct from ore (not remelt/recycled) to ensure content is known.

Example rod specification: 6011 ->

  • 60: tensile strength of 60,000 lb/in
  • 1: (third digit) welding position
  • 1: (fourth digit) flux

European/metric specifications are different.

The flux is a protective coating that gasifies due to the heat of the arc and acts as a shielding gas.

General Amperage Settings

Rule of thumb for US/imperial rod specifications: use the decimal equivalent of the rod size.

e.g. 1/16" rod -> 0.0625 -> start at ~62A.

Types of Rods

Naming/specification mostly based on the type of flux.

Cellulose

Harsh deep penetration.

Tolerates a small amount moisture, so convenient for home use.

Aside: fun & interesting experiment- wrap steel wire/rod in some newspaper to make your own welding stick.

One of the first types of welding rod to be developed.

Common types:

  • 6010 - for DC welding, flux includes sodium
  • 6011 - for AC & DC welding, flux includes potassium

Rutile Fill Freeze

Medium to low penetration.

Either DC or AC.

Fills fast, and cools quickly (freezes.)

Rutile is Titanium Dioxide.

Common types:

  • 6013 - for sheet metal
  • 7014 - for carbon and low alloy steels

Rutile and Iron Powder

Fast fill and medium penetration.

AC or DC.

Common Types:

  • 7024: flat & horizontal positions only (fast fill -> quick/large/hot puddle!)

DCEP

Low hyrdrogen, CaCo- lime. Medium penetration.

Used for structural welding. Rods must be kept in a rod oven (moisture sensitive.)

Common Types:

  • 7018

Using the AirCo 150A BumbleBee

This is on loan from Terry. If you’re not sure, check with him first!

For ~1/4" steel: DC, high current range, ~125A

Jan 9th, 2021 session

Material Preparation and Cleanup

Abrasives and cutting discs (zip wheels) are colour coded.

Important to note that there is NO standard for colour coding or other markings on abrasive wheels and discs between manufacturers!

Don’t mix material and abrasive wheels & discs- they act differently and using the wrong type of material for a given abbassive wheel/disc can clog the surface, cause excessive heat, and catastrophic failure. Or just do a bad job if you’re lucky.

So keep abrasives separated by the material they’re intended to be used on.

Be very careful with cutting discs; the high angular (rotational) speeds translate into very fast linear speeds. You don’t want one shattering!

Quick/rough test: tap the cutting disc or grinding wheel. It should have a sharp sound or ring. A “thud” may indicate damage. Check thoroughly before using.

Make sure discs are seated properly and that locking nuts are properly placed and tightened.

Always do a quick “blip” (briefly pull the trigger) so the disc just starts to spin up to speed. Look for any wobble or other issues before applying full power and spinning up to full speed.

Distortion Control

(Arc) Welding dumps a lot of heat into the metal, causing it to expand, and then shrink as it cools. This distortion is something that needs to be controlled to result in accurate and usable parts.

Terry drew and explained different clamping, filleting, order-of-weld, and other techniques for controlling distortion in different joint types (overlapping, ‘T’, butt, etc.)

This instructional film (from the Lincoln foundation?), fondly known as “Mr Shrink”, maybe old, but is still relevant, and covers most of what Terry presented: