Here is your most recent issue of High Current News. It's packed full of information to keep you updated with the latest MIG & TIG news, product information and updates from D/F MACHINE SPECIALTIES.

D/F MACHINE SPECIALTIES, family owned and operated since 1966, is a world leader in the design, development, and manufacture of American made MIG (GMAW) & TIG (GTAW) torches for robotic and welding automation equipment, welding products, consumables and accessories.

D/F has released a brand new color product catalog! Featuring the most popular D/F MIG & TIG welding equipment, accessories and consumables, the catalog will cater to your informational and ordering needs.

You can request your own free copy of the catalog in two ways:

1. Email D/F at sales@dfmachinespecialties.com with your name, and your company's name and address of where you would like the catalog to be sent.

2. Fill out the reservation form located here.

Click to download the catalog in digital form as a PDF.

Detection and Prevention of Weld Cracking

One of the most important aspects of crating successful welds is the prevention of weld cracking. In order to prevent cracking one must understand how cracks form.

Cracks do not always occur immediately after welding, and cannot always be seen from the outside. Cracks can occur below the weld metal, and can propagate from continued bending, twisting, flexing, heat expansion and contraction, and other stresses occurring over time.

The major cause of weld cracking is when the stresses internal to the weld overtake the strength of the base metal or weld metal. These stresses build up to a focal point and a crack is often the result. There are several signs to look for and methods to use to prevent and detect weld cracks.

Crater Cracks
The weld pool is at its greatest volume when the metal is in liquid form. As a weld cools it contracts, and if there is not enough volume to overcome this shrinking, a crater crack will often be the result. It often occurs near the end of a weld, so one method used to help prevent it from happening is to pause briefly at the end of the weld to ensure adequate volume.

Longitudinal Cracks
An overly concave weld contour can be the best candidate for a longitudinal weld. Similar to crater cracks, longitudinal cracks occur when there is not enough weld material to compensate for contraction and stress, but occur throughout the length of the weld. Concavity can occur when voltage is too high. Lowering voltage only 1-1.5v in many cases) will make a flatter weld contour. In turn, if voltage is too high it might cause you to lose control of the weld bead making travel speed faster. This could also result in concave welds.

Cracking Due To Excessive Filler Material
Creating a, overly convex weld bead contour, though not commonly associated with weld cracking, can also cause problems. Convexity occurs when an too much weld material is used and an excessively high bead profile is produced. Increasing filler material also increases the stresses associated with shrinkage and contraction, and like overly concave profiles, if the stresses overcome the strength of the base metal, the weld will crack.

Excessive filler material can also lead to Undercut and Overlap defects. Undercut occurs when the base metal and filler metal are not properly merged, and there is a small gap between them rather than a smooth transition. This reduces the overall thickness of the base metal and can make cracking a little easier. Overlap, or cold lapping, occurs when the filler metal toe does not get cold enough to fuse with the base metal and just laps over, or lays over the base metal surface. This lack of fusion can cause the weld to crack away from the base metal.

In the end it is very important to detect and prevent weld defects in order to make a clean, strong, and aesthetically pleasing weld. The most crucial of these defects is cracks. Avoiding cracks is a big step in achieving successful welds.

If you have any questions about avoiding cracks and other defects, please do not hesitate to contact the factory.

Phone: (507) 625-6200 · Email: sales@dfmachinespecialties.com

We look forward to helping you with your welding applications!

Frequently Asked Questions

D/F has now added a Frequently Asked Questions page to the website! This page will be continually updated and added to in hopes of fulfilling the needs of anyone who might have a common question about D/F's equipment or welding in general. Please visit the FAQ page here.

Do You Have Photos of Projects? Submit Them to WIN!

D/F's new Photo Gallery showcases D/F equipment in action over the years, and we are constantly adding to the gallery. We want to see how our equipment helps brings out the best of your creativity and skill, or simply how your equipment is setup and used.

Submit your photos and projects to:
Newsletter@DFMachineSpecialties.com

For project submissions, things to include:

• Photos of your project
• What did you make?
• How did you make it?
• Which D/F products did you use?

Project submissions will be put in a drawing for a chance to Win A Gift Card to your local Best Buy Consumer Electronics Store.

Check out the D/F Photo Gallery here.

Quick-Click Buttons

The following are buttons that link you directly to the D/F website. Just click on the icon below for the desired item.

Contact Tips		Casings/ Conduits
Gas Nozzles		Wire Feeder Adapters
Liners		Utility Stations
Mounting Brackets		Mounting Arms
Noz. Thread Chaser Taps		FAQ

Words from the Editor

Greetings from D/F!
Thank you for reading our High Current News e-newsletter. Please share this issue with a friend and send us your comments.
Enjoy!

Best Regards,
Dave Judd, Editor
D/F Machine Specialties, Inc.

• New D/F Product Catalog

• Preventing Weld Cracking

• Frequently Asked Questions

• Got Projects? Submit to WIN!

• New Products
• Nozzle Thread Chaser Taps