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May, 1925
Forging- Stamping - Heat Treating
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FIG. 18—Photo-micrograph of the intermediate section at the FIG. 19—Another photo-micrograph of the intermediate sec­
line of contact. In this instance distortion of the grain tion at the line of contact. This illustration covers the
structure occurred at or near the surface, the grains being same area as Fig. 19 and shows that the distortion occurred
flattened and elongated out of all proportion to their or­ only in the grains adjacent to the line of contact. The
iginal dimensions, as can be seen bv comparing this illus­ magnification in this instance was 35 diameters.
tration with the two views of Fig. 17, the magnification in lily seen; it is illustrated in Fig. 18. The grains
all three illustrations being the same, 100 diameters.
flattened and elongated out of all proportion to the
indicate that the compression of the section is uniform original dimensions. A fourth photo-micrograph was
throughout the total volume compressed.
taken of this same area at a magnification of 35 diam­
To substantiate this conclusion, one of the annealed eters, to give a better idea of the effect of the distor­
connecting-rods was coin-pressed across one-half the tion. It can be seen from an inspection of Fig. 19 that
area of the piston-pin boss. This gave three different the distortion occurred only in the grains adjacent to
conditions on a cross-section through the boss. One the line of contact. This showed conclusively that the
section, which was the original structure not com­ coin-pressing operation did not affect the material adpressed,
is shown at the left of Fig. 17; a second secjacent to the surface. It was a uniform compression
tion in which the structure was compressed is repro­ throughout the entire volume of the part coin-pressed.
duced at the right. The latter should show a decided From the foregoing, the conclusions reached are that:
grain-distortion. It was prepared and examined un­
(1) A coining press will squeeze parts to size
der the microscope, and no difference between the with the same degree of accuracy as is accomplished
original structure and the structure which had under­ by the removal of surplus stock through cutting
gone compression was revealed. Photo-micrographs operations.
at a magnification of 100 diameters, showing the sec­
(2) There is absolutely no difference in the
tions at the surface before and after compression, were molecular constituency of the parts after they are
made. It was apparent that the grain structures were squeezed.
identical.
(3) Under quantity-production conditions, the
To show what would happen if the distortion oc­ average number of parts prepared per hour by a
curred at or near the surface, a third photo-micrograph coining press is 900 per cent greater than is secured
was taken at the line of contact. The effect was read- with usual machining methods.
Steel Treaters Spring Sectional Meeting
Arrangements have been completed for the annual
spring sectional meeting of the American Society for
Steel Treating, which is to be held at Hotel Van
Curler, Schenectady, N. Y., May 28. 29 and 30. under
the auspices of the local chapter. Technical sessions
are to be held during the morning of Thursday, May
28, and the evening of Friday, May 29, with one session
scheduled at the Research Laboratory of the
General Electric Company at 4:30 P. M. of the same
day. Two of the papers announced are: "Results of
Examination of Metals with the X-Ray," by Col. Tracy
C. Dickson, commanding officer, Watertown Arsenal,
and "Manufacture of Guns by the Cold Working-
Process," by Dr. F S. Langenberg, director of laboratories,
Watertown Arsenal, Watertown, Mass.
Besides a visit to the plant of the Ludlum Steel
Company at Watervliet, N. Y., Thursday afternoon.
May 28, the plant of the American Locomotive Works
will be visited Friday morning, followed by a luncheon
and a trip through the works at the invitation of the
General Electric Company. For Decoration Day,
Saturday, May 30, a trip to Lake George has been
scheduled. A banquet is to be held Thursday evening
at the Hotel Van Curler, with addresses by Dr.
W. R. Whitney, director, Research Laboratory, General
Electric Company, and R. B. McColl, manager,
the American Locomotive Works.