The various attributes of rolled threads are often admired, the materials that can be rolled are seldom outlined in broad terms. Here we outline materials that can be rolled.
Steels are nearly all roll-able. Included in the steel family are Structural, Case Hardening, Nitriding, Free Cutting, Heat Treatable, Tempered, Tool Steel, High Speed, Stainless, Cast Steel, Malleable Iron and Cast Iron with an elongation factor greater than 8%.
Rollability is also practical in Copper, Copper Alloys, Zinc Alloys, Aluminum Alloys and Titanium Alloys. In addition, Nickel, Monel, Hastelloy, Inconel, Waspaloy and Titanium are also good candidates for rolling.
The principle deciding factor in the ability of any material to roll is an elongation factor of 8 percent or greater. As can be seen by the listing, many of these same materials are difficult to machine and tough on tooling. Roll life varies throughout the variety of material applications but cost per thread is always an advantage rolling has over cut threads.
The tensile strength of a rolled thread increases from about 40% to as much as 300% in some materials. The tensile strength improvement makes rolling highly desirable in military, aviation and automotive applications. Marine applications using Nitronix 50 and 60 are especially suited to rolling. This is a material with notorious work hardening ability.
We can predict with relative accuracy if your material is a good candidate for thread rolling. If it conforms to the materials we’ve outlined and the hardness is less than 45 on the Rockwell C scale, then it’s time to roll threads if you’re currently cutting threads. By cutting your threads, you’re adding cost and lowering the quality of your finished product.