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 ...

May 1948:

If the allowable unit stress of a material is 10,000 pounds per square inch, and the calculated load is 40,000 pounds ... what should the sectional area be?

In theory ... 4 square inches. But in practice, this isn't always the right answer ... as many perplexing failures of parts in service will attest. For in complex parts and assemblies, the stresses stubbornly refuse to fall into a uniform pattern.

There's a new way--now--to find the right answer, through the Baldwin SR-4 Strain Gage. It's one of the most effective of the modern design tools, eliminates "guesstimates," provides data that never previously has been obtainable.

Baldwin SR-4's located at dozens, hundreds or even thousands of points, can "map" actual stresses, give precise stress pattern, permit design on a completely sound and practical basis.

--From "Here's a Little Something That Fills the Gap," an advertisement of Baldwin Locomotive Works, Philadelphia, Pa.

No evidence was obtained which would lead to the belief that the product of the subzero treatment was better or different in any way from that obtained by double quenching. Due to the expense, subzero treatment does not seem to offer any advantage in the processing of carburized and ground products, such as roller bearing parts. However, if minimum distortion is of paramount importance in production, deep freezing does seem to offer some hope of producing single quenched parts from medium-alloy steels, having surface hardnesses and microstructures substantially equivalent to those obtained by double treatment, and without the added distortion inherent in the double quench.

--A conclusion of the experimental work described in "Subzero Treatments for Carburized Medium-Alloy Parts," by J. C. Selby and E. S. Rowland, Metallurgical Dept., Steel & Tube Div., Timken Roller Bearing Co., Canton, Ohio

The Harshaw Spectroscopic Metal Analyzer is now being used for all types of ferrous and nonferrous metal sorting and identification. It is also used for quantitative analyses. For example, the quantitative analysis of magnesium in aluminum alloys can be carried out in one minute with an accuracy of 5% of the amount present.

The unit consists of a fixed deviation glass prism spectrometer mounted on a portable cabinet.... An automatic arc striker is included.

[ILLUSTRATION OMITTED]

--From an advertisement of Harshaw Scientific, Div. Harshaw Chemical Co., Cleveland, Ohio

40 YEARS AGO ...

May 1968:

Greater safety, reduced solvent losses, minimum air pollution, and increased worker comfort are some advantages claimed for inhibited 1-1-1 trichloroethane, a new cleaning solvent.

Dow Chemical Co. has just announced its national availability under the tradename Chlorothene VG. The solvent has been marketed in the Los Angeles area for the last two years in compliance with air pollution control standards....

Dow engineers expect Chlorothene VG to replace trichloroethylene and perchloroethylene even in many applications where pollution is not a problem.... Metal Progress will carry an in-depth report on the solvent in the June issue.

--From "Improved Solvent for Vapor Degreasing or Cold-Cleaning Operations Available," a story in Technical News in Brief

"Quick Facts about Alloy Steels" appeared for the first time in 1956, as a collection of Bethlehem alloy steel advertisements.

The first booklet was well received, and we kept adding more of these informative advertisements as we reprinted it. Today it has grown to 52-page size, and is in its Ninth Edition.

More than 320,000 booklets have been requested by engineers, designers, professors, and others.

--From "The Little Booklet on Alloy Steels That Grew Into a Textbook," an advertisement of Bethlehem Steel Corp., Bethlehem, Pa.

20 YEARS AGO ...

May 1988:

Ceramic-fiber reinforced metal-matrix composites (MMCs) are potential materials for applications requiring good strength at high temperatures, good structural rigidity and dimensional stability, light weight, and good fabricability.... Cost, however, remains a barrier to adopting these composites for noncritical applications. Most MMC components are made by powder metallurgy processing, requiring hot pressing of the forging preform. The near-net-shape process called squeeze casting, however, offers a technique to manufacture ceramic-fiber reinforced MMC components at affordable costs....

The solidification of liquid metal under pressure--squeeze casting--helps achieve defect-free castings with improved metallurgical properties.... The process yields the highest mechanical properties attainable in a cast product. In fact, the tensile properties of ferrous and nonferrous squeeze castings are comparable to those of forgings....

Adaptation of the squeeze casting process to the making of composites incorporates a porous ceramic [fiber] preform ..., which is held in the die cavity by a fixture. The fibrous preform is quickly and totally infiltrated by the molten metal under pressure, resulting in a sound, fully dense fiber-reinforced part.

--From "'Squeezing' Production Costs From Metal-Ceramic Composites," by Suresh K. Verma and John L. Dorcic, IIT Research Institute, Chicago, Ill.