ABSTRACTS OF LITERATURE
The articles listed below are from recent technical journals and may be of interest to members. Copies are available from Margaret O’Malley at IST Headquarters.
DeFord, R., "All Things Springs - Loading on the Legs of Torsion Springs?", Wire Forming Technology International, Summer 2015, p. 20
Both compression and extension springs have straightforward calculations. In both cases, the springs are either being pushed or pulled and typically respond with forces that are predictable. Not a whole lot of surprises under conventional deflection practices.
But torsion springs provide forces based on torque. That means the calculations are producing inch-lbs or foot-lbs, not just pounds.
Wright, Dr. R. N., "The Strength of Steel - Surface Issues - Part 1 Outline of Surface Issues in Wire Processing", Wire Forming Technology International, Summer 2015, p. 22
I am starting a new series at this point, entitled “Surface Issues”. The emphasis will be on such areas as friction, lubrication, surface quality, and near-surface metallurgical character. Most of the metallurgical emphasis will continue to be on steel. This series will focus on deformation processing, and will not, generally, extend to surface engineering technologies, such as plating, polishing, pickling, grinding and machining, although we may wander into such areas to illustrate basic points.
Wright, Dr. R. N., "Tips From WireDrawing 101® - Wire Drawing Temperature — Part 10", Wire Forming Technology International, September/October 2015, p.46
This is the last of a series of columns addressing the effects of temperature on lubrication, recovery and recrystallization, residual stress, dynamic strain aging and martensite formation. This column addresses dynamic strain aging and martensite formation.
Sebastian D., "What You Need to Know About Stress Relieving", Springs, Fall 2015, Vol. 54, No. 4, pp. 19-20
Stress relieving is a simple, basic process that in most cases allows a spring to function as designed. It is critical to the process. So like any properly designed manufacturing process, it should be monitored with statistical process to assure product integrity. There are a number of methods that can be used, from temperature measurements, belt speeds, change in diameter, amount of set a spring takes, and others.
It is both temperature and time dependent, so it is important to monitor and control both.
Kirk, Dr. D., "Verification of Peening Intensity", The Shot Peener, Fall 2015, Volume 29, Issue 4, pp. 28-36
Periodic verification of shot stream peening intensity is a necessity. Variability of this intensity can never be completely removed, even with the use of every available control device.
Specified procedures for verification are not always completely clear and may require interpretation.
Verification when using a single holder can be specified in a relatively straightforward manner. The use of just a single strip is specified in SAE J443 and may be carried out at either the peening intensity point (H, T) on the saturation curve or at a nearby peening time that has a corresponding “Target Height” - which differs from H. The arc height obtained for the peened strip must lie within ±0.038 mm (0.0015 in) of the corresponding target height.
Verification when using multiple holders is specified in SAE J443 and requires one strip for each holder. To simplify verification, these strips can be peened using a single, common, verification peening time. This selected time can lie anywhere between the shortest and the longest peening intensity point times obtained for the set of holders. The arc heights obtained for the peened strips must lie within ± 0.0015" of a corresponding target height. This target arc height is the intersection of the common peening time with the saturation curve for that holder.