Everyone likes to have a “Rule of Thumb” to use as a quick and easy guide. To make the best use of these maxims, it helps to understand where they came from, and what the limitations are in their use. When it comes to taking the right steps to ensure a robust stamping process, a surface strain analysis using a forming limit diagram is recommended. The forming limit curve should [...]
The correct way to use the Mylar strip is to measure from the center-width locations of the boundary line around the circumference of the now-deformed ellipse. Measuring from inside-to-inside or outside-to-outside is wrong! With a fuzzy ellipse boundary line (old stencil, poor gridding technique, etc.), it is not hard to make measurement errors more severe than just measuring the outside-to-outside dimensions of a crisp circle/ellipse. The width of the line [...]
To determine if a grade of steel is prone to secondary cold work embrittlement, the ductile-to-brittle transition temperature (DBTT) is determined. The DBTT is the highest temperature at which a brittle crack is formed. More information about the cause for secondary cold work embrittlement and how to test for it can be found in THIS FREE DOWNLOAD. Let Engineering Quality Solutions determine if your grade is at risk for secondary [...]
Think about pulling a bar in tension. Load divided by cross-sectional area is force, or stress. But what cross section are you considering? Before starting that pull, the bar had a known cross-section of, let's say, 0.5" wide x metal thickness. It's easy to measure these, since it is your starting material. At any load, the engineering stress is the load divided by this initial cross-sectional area. While you are [...]
NONE!!! Steel is, by minimal definition, an alloy of iron and up to 2 percent carbon (if it is more than 2 percent, the alloy is cast iron). Carbon is small enough to fit into the interstices (gaps) of a primarily iron matrix, making it an "interstitial element" in steel. If the steel alloy has an ultralow carbon level (typically less than 50 parts per million), most of these [...]
