75
RIFLE-BARREL STEEL, .30 CALIBER.
No. 7396.
Marks, M 3 B.
Sectional area, .25 square inch. Gauged length, 1".
From butt of finished barrel.
!tolled, and annealed at residual heat.
Remarks.
Initial Joad.
Elastic limit.
Tensile strength.
Permanent set.	Successive permanent set.
Inch. 0.	Inch. 0.
	
	
	
	
	
0.	0.
	
	
	
	
	
	
	
	
	
	
	
Successive elongation per inch.
Elongation per inch.
Inch.
0.
.0002 .0002 . 0002 .0003 .0004 .0004 .0003 .0004 .0005 .0001 . 0025 . 0035 .0045 .0045 .016 .02 .03
Inch.
0.
.0002 .0004 .0006 .0009 .0013 .0017 .0020 .0024 . 0029 .0090 .0115 .0150 .0195 .0240 .04 .06 .09
Applied loads per square inch.
Pounds.
1,000
5,000
10,000
20,000
30.000
40.000 50, 000 60, 000
70.000
80.000
81,000
82,000 84, 000
88,000
92, 000
100,000
108, 000
116,000 117,680
General summary.
Tensile strength, per square inch of original section............................pounds.. 117 680
Elastic limit, per square inch of original section.................................do... 80000׳
Elongation per inch after rupture................................................inch..	’. 15
Elongation per inch under strain at elastic limit................................’.do.!!	.0029
Character of broken surface........................................................tine granular