Evrim Berk 030060161 5th Week

1-) Double Aging

Previous One

Employment of two aging treatments to control the type of precipitate formed from a supersaturated matrix in order to obtain the desired properties. The first aging treatment, sometimes referred to as intermediate or stabilizing, is usually carried out at higher temperature than the second
(Principles of the Heat Treatment of plain carbon and low alloy steels, Brooks C.R., Page #472)

New One

Double aging is an effective method for achieving high alloy strength in a reasonable total aging time and yields a dense distribution of fine precipitate particles. In all cases the peak level of strength achieved by the alloy is increased and the kinetics of the aging are accelerated if the alloy is aged directly from as-forged condition, without intermediate annealing. This behaviour presumably reflects the contribution of matrix defects left over from the forging process.

(Abrams H. Clark E. Hood J. Brij S, Optimization of Processing, Properties and Service Performance Through, Page #87)

2-) Material Indices / Index

Previous One

A material index is a combination of material properties which characterizes the performance of a material in a given appliacation.

Michael. F. Ashby, Materials Selection In Mechanical Design.P. 70

New One

Each Combination of function, objective and constraint leads to a performance metric containing a group of material properties or material index. The index is characteristic of combination. The point of interest here is that materials with extreme values of certain indices are well suited to meet certain sets of design requirements. Indices allow comparisons, if the spoke is at present made from a reference material Mo and has a mass Mo, a competing material Mı with mass Mı, will be lighter than Mo, for the same load capacity, by the factor giving a direct measure ıf the gain in performance achieved from switching from Mo to Mı.

(Ashby M. Johnson K., Materials and Design: The art and science of Material Selection in Product Design, Chapter 7)

3-) Hydraulic Interlock

Previous One

Hydraulic interlock devices should prevent the mold from closing when the door is open. These devices often consist of a hydraulic switch and an actuating arm.

(Terry L. Richardson,Erik Lokensgard, Industrial plastics: theory and applications, p.158)

New One

A hydraulic interlock system is an alternative to electrical interlock systems. The normally closed valve opens when the irrigation water pump is operrating and closes when the pump is cut off and water pressure drops, preventing the fumigant from entering the injection system. Hydraulic interlocks also prevent fumigant from entering the irrigation line if the irrigation system loses pressure.

(Cohen S. Martin T., Field Fumigation, p.54 - 56)

4-) Side Cutting Angle

Previous One

It is defined as the angle formed between the cutting edge and the workpiece The direction of radial cutting forces is determined by the lead angle of the cutting tool. As the lead angle increases, the forces become more radial. Cutting forces tend to project off the cutting edge at right angles to the lead angle. In turning operations, at a low lead angle (0°) the forces are projected into the axis of the workpiece, while at a high lead angle (45°) the forces are projected across the radius of the workpiece. Lead angles do not impact total cutting forces, only the direction of the cutting force.
Lead angles control the chip thickness. As the lead angle increases the chip tends to become thinner and longer. As the lead angle decreases the chip tends to become thicker and shorter. Neither the volume of the chip nor the power consumed change with changes in lead angle.
It is important to note, that the amount of resultant (measured) cutting forces changes very little with changes in lead angle.

(Hwaiyu Geng; Manufacturing Engineering Handbook 4th Edition; pg. 27.12)

New One

The side cutting edge angle of the tool has practically no effect on thevalue of the cutting force or power consumed for a given depth of cutand feed. Large side cutting edge angles are lightly to cause the tool to chatter.

The following are the advantages of increasing this angle:

•It increases tool life as, for the same depth of cut; the cutting force isdistributed on a wider surface.

•It diminishes the chip thickness for the same amount of feed andpermits greater cutting speed.

•It dissipates heat quickly for having wider cutting edge.

(Ghose J., Therory of Metal Cutting & Machine Tools; pg. 50)