WHY DO WELDS CRACK ON WEAR PLATE?JADCO • Rich F.
Everyone has experienced a time when “chemistry” between two people interacting is not compatible. Unfortunately, the same is often true when welding wear resistant steel.
Lets look closely at where and how these cracks occur; and how to tell what caused the crack.
- When a crack runs down the center of the weld, it is a sign of dissimilar steels.
- This crack tells you the chemistry of the weld isn’t compatible with the base steel.
Many common welding products do NOT work well with wear resistant steel. Deciding what caused your weld to crack on wear resistant steel can often be easily determined when you know what the cracks are telling you.
These cranks are most often caused by welding dissimilar steels, or due to a difference in chemistry between the wear plate and the welding material.
Wear Plate Chemistry Determines What Welding Alloy To Use
If you are welding plate, bar, angle, tube or casting, the first place to look is the chemistry of the base metal Not The Material Shape. You need to select the correct welding alloy to closely match the material. They need to be compatible.
Wear plates can have a wide variety of alloying elements to enhance the wear performance of the steel. The most common elements are Nickel, Chromium and Molybdenum, usually called Moly.
The percentages often vary wildly between manufacturers as discussed in our “CAN YOU IDENTIFY IF YOU HAVE A WEAR PLATE PROBLEM?” blog article from September 4, 2019.
Common stick electrodes or welding wire must have these alloying elements to successfully weld quality wear plate such as JADCO QT-PLUS ®.
It is a welding best-practice to check the Material Safety Data Sheets (MSDS) on file for the welding alloys you are currently using, to determine the chemistry of your current welding products.
To be safe, having a welding alloy with 1% Nickel will properly weld nearly all wear resistant steels.
Take the mystery out of what welding product to use with JADCO FUSION™ ULTRA BOND.
This welding wire was developed to successfully weld QT Plus or AR500 type steels, and remove any worry about weld bead center line cracking.
If your crack is at the edge or toes of the weld, that is a different issue.
Weld Bead Profile: The final weld passes must be uniform in shape and contour.
The edges or toes of the weld beads should taper smoothly into the base plate, undercutting should not be allowed (see image (left) below). Any and all visible weld imperfections should be removed and repaired before successive weld passes are made.
Next, in the above image, the arrow is pointing to an area of extreme undercut on the toes of this weld. Undercutting is probably the most common of all welding defects.
Undercutting is usually caused by welding with too much amperage, and excessive the weave motion. The combination melts the base metal without allowing adequate weld deposit to form. This will quickly form a crack in equipment with heavy loading and stresses.
The amount of heat introduced into the weld can have dramatic effects reducing the joint strength and wear plate hardness.
Use Stringer Passes When Welding Any Wear Resistant Steel:
Welds on thick plates should be made on alternating sides, to help control distortion.
WEAVE BEADS SHOULD BE AVOIDED.
Keep it simple; use straight stringer beads when welding wear plate or any high strength steel.
If welding out of position makes it necessary to use weave beads, the deposit width should be limited to five (5) times the diameter of the welding wire. For FCAW wire, the formula is wire diameter x 5: .045” wire x 5 = .225”, or a maximum width weave of ¼” is allowable. Solid MIG or GMAW wires are not recommended as they do not contain the alloying elements required.
If you are using SMAW or stick electrodes, do not weave more than 2 time the diameter of the wire. 1/8” rod x 2 = ¼” maximum weave.
Always Use Proper Welding Practices – Clean And Dry
- Always weld on clean shiny metal. When you take 1/16” off the surface with a grinder, you have solid clean metal.
- All cracked areas must be removed before you preheat and weld.
- Do not weld over rust, paint, dirt, oil or grease. If you cannot take the time to prepare the weld area correctly; you will have to do it over in the future.
- Do not weld over worn areas where there are small cracks or spalled areas. This surface will have no structural integrity due to the micro cracks. This area needs to be removed with a grinder.
- Do not weld hardfacing over existing hardfacing without a cushion pass that is compatible with both materials.
Following these suggestions will remove 95% of your cracked weld issues.
Please Remember…Always Weld Safely:
- Use personal protective equipment including: protective welding clothing; welding gloves, eye protection, steel toe shoes, welding helmet with correct darkness shade and skull cap. Other equipment may be required by specific locations or projects.
- Equipment – Verify all electrical components are secure with tight connections and no exposed electrical wires. Have the correct shielding gas for the wire.
- Ventilation – have adequate air movement so you minimize inhalation hazards.
- Verify any flammable items are removed from the area. If they cannot be removed shield with welding blankets or barriers. Have adequate fire extinguishers readily available and know how to use them.
Now that you know how to prevent welding crack issues before they happen, get the most life for your equipment when you have to replace your wear plate. JADCO’s QT-PLUS delivers greater wear performance in your applications than the AR400 type steel you are currently using.
Having the ability to create wear resistant steel having the same hardness through the thickness of the steel, requires precise chemistry control and careful heat treating
Does Everyone Make Their Wear Resistant Steel Last As Long As JADCO QT-PLUS?
Our attention to critical levels of alloying chemistry and detailed heat treat procedures from the steel mill in Pennsylvania is available to EVERYONE. Yet most steel wear plate distributors choose to reduce costs in both areas to lower their prices. They don’t care how long their wear steel lasts in your equipment. They are happy to sell you more underperforming wear plate again in a few months.
For the last 40 years JADCO has focused exclusively on delivering longer, consistent wear plate life for our customers. Allow us to help you today by calling 724. 452.5252, or email firstname.lastname@example.org.
We will schedule a meeting with one of our local wear plate specialists at a time that best fits your schedule.
Remember, the only thing you have to lose by not working with JADCO, are your profits.