UNDERSTANDING THE STRENGTH OF STEELS
There are several recognized tests to determine the actual strength and wear resistance of steel. All use identical shape and sized samples to eliminate other variables.
- YIELD STRENGTH - When you pull on a test sample to the point it no longer returns to it's origninal size and shape.
- TENSILE STRENGTH - When you pull on a test sample to the point it fails/breaks.
Abrasion Resistance – the ASTM G65 test is the standardized test to measure the material weight loss from the sample, measured in grams. A hard rubber wheel is forced against the test sample at a given pressure, for a specific number of revolutions of the wheel. Special test sand is metered between the surface of the wheel and the test sample.
High Hardness
High hardness is a key to combating abrasion. You can inexpensively make any steel hard by adding plenty of Carbon. However, if that is all you add; the resulting steel will be brittle and unable to tolerate impact.
Impact Strength
Impact Strength – the Tensile and Yield tests pull the steel sample. For this test a hammer smashes into our steel sample after it has been chilled to a lower temperature. The Charpy test determines the level of resistance prior to the sample failing at the cold temperature. The lower the temperature, the less any steel can withstand impact.
You can make steel resist impact by adding Nickel, Chromium and Molybdenum alloying elements.
Making a steel hard AND impact resistant, as a former co-worker once said; “Separates the Men from the Boys.”
Jominy Test
A Jominy Test determines how readily any steel will harden. Inthe video above, the sample is heated orange hot then quenched, by cooling only one end of the sample.
This slow cooling reveals how readily the steel the heat treatment.
The hardness is then tested at 1/16” points starting from the cooled end. If your steel is actually through-hardened, the hardness readings will be the same over the entire length of the sample.
If the hardness readings drop off, the steel IS NOT through hardened, despite the manufacturer’s claims.
The best outcome is to have a through hardened wear resistant steel, that also withstands impact in your most challenging applications.
Welcome to QT PLUS.
What Are The QT-PLUS ® Test Results?
The Tensile Strength of QT-PLUS is 225,000 psi. For comparison, mild steel (A36) is 36,000 psi. This is why most fabricators cannot bend QT-PLUS as it requires 4 times the force used to form mild steel. If your local fabricator can form 1.5” thick mild steel, they are only able to form 3/8” thick QT-PLUS.
The Yield Strength is 165,000 psi. Since QT-PLUS is not intended for structural applications, we do not recommend it for this purpose. Structural steel needs to have a much wider separation between Yield Strength and Tensile Strength. We include this data for your reference.
The Charpy Impact Test registers impact resistance. The American Welding Society (AWS) considers a weldment successful when the sample weld withstands 20 ft/lbs. with the sample cooled to -40°F. JADCO’s QT PLUS withstands 25 ft/lbs. with the material cooled to -40°F.
Hardness target range is 500 BHN, with the average hardness for less than 1” thickness plate at 461 to 537 BHN. Steel thickness greater than 1” averages 444 to 514 BHN.
JADCO’s QT PLUS…THIS HARDNESS IS MAINTAINED THROUGHOUT THE THICKNESS OF THE STEEL. IT IS “THROUGH HARD.”
JADCO’s QT PLUS delivers greater performance IN YOUR WEAR APPLICATIONS than the various AR400 steel plates you have used previously.
Being able to create wear resistant steel having the same hardness through the entire thickness of the steel, demands you accurately control the alloying chemistry with precise heat treating.
Doesn’t Every Steel Company Make Their Wear Plate Last As Long As JADCO QT PLUS?
The quick answer is No; although the attention to detail required at the steel mill in Pennsylvania is available to anyone. Yet most wear plate distributors choose to reduce the proper quantities and percentages of these essential alloying elements, to get a lower selling price. When you have to cut back on these critical alloys, wear life always suffers.
For over the last 42+ years JADCO has focused exclusively on delivering consistent, longer equipment life for our customers.
Now you understand why we are able to deliver better results to our customers. We think differently by strictly focusing to improve your current results.
Allow us to help you today by calling (724) 452-5252, or email info@jadcomfg.com.
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.
When your standard wear plate gives out, be certain to give JADCO a shout! (724) 452-5252.
