Pastimes.

Selected items from the pages of the monthly magazine of ASM International: Metal Progress (1930-86) and its successor, Advanced Materials & Processes (1985-present).

60 YEARS AGO ...

August 1948:

Golfers for years were annoyed by spikes that tipped, and dug into the feet instead of the fairway. The Old Colony Shoe Company did something about this. It developed a golf shoe with an inner steel plate to which the spikes are anchored. To prevent rust, the steel was cadmium plated. Golfers went for the shoe. They still do, but what they do not realize is that now the plate in their shoes is made not of steel but of Revere nickel silver, spring grade, which is inherently rust-proof and needs no plating whatever.

--From an advertisement of Revere Copper and Brass, Inc.

During World War II, problems arose as a result of the expanded use of welding, particularly when applied to rigid, massive structures, when steels were used having greater tensile strength and harden-ability than mild steel, and when the welded structures had to be used at low temperature. The results of several recent investigations indicate that, under many service conditions, the performance of a welded joint, even when made in accordance with the best accepted practices, is far from satisfactory and can be improved considerably if and when proper research points the way. Two major examples of such investigations were discussed.

The first example was the investigation, under Navy sponsorship, of the structural failures of Liberty ships. One phase of this investigation dealt with tests of specimens reproducing full-scale ship sections-for example, the corners of hatches. These tests indicated that a random change in the welding procedure (preheating the steel at 4000 F.) was of greater benefit than a carefully planned change in the chemical composition of the steel.

The second example was the investigation of portions of simple butt-welded steel plates by subjecting them to high-velocity impact, normal to the plane of the plate-- This impact was produced by a detonating wave traveling through a column of explosive .... Because of the high rate of strain during this test, the conditions were probably equivalent to triaxial tension at low temperature.

--From "Abstracts of Important Articles," G.S. Mikhalapov, "Structural Strength of the Welded Joint," Journal of the American Welding Society, V. 27, No. 3, 1948, p. 193-206.

40 YEARS AGO ...

August 1968:

Fabricators of deep-drawn sheets often have problems in determining acceptability for forming. A leading manufacturer of bread pans was faced with this problem: the material, tin plate, had exhibited suitable tensile strengths and appeared to have satisfactory ductility, but the rejection rate was disturbingly high. He brought the problem to our attention.

We used samples taken from bread pans that had been formed successfully and those that had broken during the drawing operation. A series of tests indicated that tensile strengths of all specimens were much the same. ...

In the next step, we employed the Ductomatic, a self-contained testing unit that duplicates a wide range of drawing stresses. Circular discs about 3 in. in diameter were made from bottoms of acceptable and rejected pans; they were lubricated with Vaseline.

The Ductomatic clamped specimens at a constant, preset pressure, and pressed the forming tool up into them at a predetermined speed, stopping when a full cup formed or the material failed.

... Material from well-formed pans could be successfully formed in discs up to 74 mm in diameter, but material from broken pans could not be drawn in discs greater than 70 mm in diameter. ...

As a result, the manufacturer could set up definite parameters of quality control testing. A quick check made with discs 74 mm in diameter rapidly determines the suitability of incoming material. If discs of this size can be formed into full cups, the material is acceptable. If not, the lots are immediately rejected.

--From Forum: MTS, "How to Test All the Wires in a Stand," by William Henry, Tinius Olsen Testing Machine Co.

[ILLUSTRATION OMITTED]

20 YEARS AGO ...

August 1988:

Although crystalline thermoplastics hold the biggest share of the high-volume connector market, other materials also are specified. Thermosets such as diallyl phthalate (DAP) and phenolics are used for their high-heat capabilities and chemical resistance. Unfortunately, these materials are expensive, difficult to mold in complex configurations, and they can be moisture sensitive. Amorphous thermoplastics like polyetherimide (PEI), polyethersulfone (PES), and polycarbonate (PC) are also used, but while an amorphous structure makes a polymer less prone to warpage, it also increases susceptibility of the connector to chemical attack by many of the degreasers and cleaning agents used in the electronics industry.

A connector's insulating plastic housing typically is molded of a glass-reinforced, flame-retardant crystalline polymer, most commonly polybutylene terephthalate (PBT), nylon, polyethylene terephthalate (PET), or polyphenylene sulfide (PPS). Crystalline materials provide longer spiral flow lengths for improved filling of long or complicated mold shapes, especially for thin-walled connectors, with a minimum of gates. These materials are also characterized by excellent, broad-based chemical resistance. New materials such as polycyclohexane dimethylene terephthalate (PCT), and liquid-crystal polymers (LCPs) are boosting the thermal and mechanical capabilities of crystalline thermoplastics into the high-performance area.

--From "Thermoplastic Polyester Connector Materials," by Ronald Walczak and Philip Richards, GE Plastics