S55
INTERNAL STRAINS IN TREATED TUBE.
Slice.	Anneal-	Strains released.		Stresses per square inch.	
	ing temperature.	Rings 1.	Rings 2.	Rings 1, compression.	Rings 2, tension.
A-B 2		° F.	Inches.	Inches.	Pounds.	Pounds.
	207	. 00465	.0011	26,700	4,170
A-B 3		302	. 00345	.00185	19,900	7,000
A-B 4		403	. 00295	.0007	17,000	2,800
A-B 6		505	.0038	.0005	21,900	1,900
A-B 7		600	.00355	.0013	20,400	4,900
A—B 8		700	.00215	. 0004	12,400	1,500
A-B 10		805	.0025	.00045	14,400	1,600
A-B 11		905	.00145	. 00025	8,300	900
A-B 12		1,000	.0008	.00015	4,600	600
A-B 14		1,100	.0003	a. 00045	1,700	«1,700
« Compressive strain and stress.
The reduction in the magnitude of the internal strains upon exposure to different annealing temperatures is illustrated in the above table. The partial or complete relief from such strains, it is seen, may be accomplished by temperatures below the plastic state of the metal. While earlier tests have shown that different parts of a forging may move about relatively, within limits, at high softening heats, and when subsequently cooled left practically free from internal strains, such measureable relative movements are not apparently essential to the relief of internal strains. In the present series, measurements of the intact slices before and after annealing showed very small changes in dimensions, generally less than ".0001, and since the residual strains in the annealed slices were largely reduced, as may be seen upon comparison of the strains developed by the rings not annealed with those which were, it is inferred that the relief of internal strains may be accomplished with slight or perhaps no measureable change in the general dimensions of the forging.