Report of the tests of metals and other materials made at the United States Testing Laboratory at Watertown Arsenal, Massachusetts, during the fiscal year ended

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ... 3414. 50 X. Stock B middle of bar. Note large excess of free ferrite and its tendency to occur in streaks. Micrograph 3415. 500 X. Stock B middle of bar. Sorbite and ferrite. Micrograph 3416. 500 X. Stock B outside of bar. Sorbite and ferrite. with micrograph 3415. To be compared Micrograph 3417. 50 X. Stock B outside of bar. Less excess of ferrite than occurred in center of bar. To be compared with micrograph 3414, Micrograph 3419. 50 X. Stock B center of bar after heat treatment at this arsenal as follows: Oil quench 815, followed by drawing at 650. Little excess ferrite. Bands of ferrite almost removed. Compare with structure before treatment, micrograph 3414. Micrograph 3420. 500 X. Stock B center of bar after heat treatment outlined above, pare with micrograph 3415 of the same stock before treatment. ComReported to have Micrograph 3412. 50 X. Stock A center of bar. Note very large brains. been annealed at 760 C. Micrograph 3413. 500 X. Stock A center of bar. Pearlite and fa«ile. I b fl ti at dc re that a specimen annular in form is more likely to take permanent set than-a solid specimen. Chemical analysis. The chemical analysis of both bars showed them to be of desirable composition, stock A being about 0.10 per cent higher in carbon than stock B. MICROSCOPICAL. The heat treatment as reported on stock B was an oil quench from 1,425 F., or 774 C., and annealed at 1,175 F., or 635 C. The heat treatment as reported on stock A was annealing at 1,400 F., or 760 C. Micrographs Nos. 3414 and 3415, at 50 and 500 diameters, respectively, show the structure of stock B in the middle of the bar. The structure is decidedly bad, being not only streaked, but showing also the triangular arrangement of ferrite. Micrographs Nos. 3417 and 3416, at 50 and 500 diamet...