SHEET NON-FERROUS METALS 



803 



Note. — By thin sheet material is meant material 0.05 in. or less, in thickness. 

 This thickness lies in the range where it becomes necessary to abandon the use of 

 the ordinary micrometer and to use the barrel type micrometer or a still more sensi- 

 tive device in order to keep the probable error of measurement as low as possible. 



(b) In case of any difference in the provisions of this and the individual specifi- 

 cation, the provisions of the individual specification shall govern. 



Specimens for Tension Tests 



2. Selection of Specimen. — The test specimens shall be chosen in such numbers 

 and from such locations in each lot of material as to be representative of the quality 

 of this material. The method of selecting specimens will be specified in the individual 

 specifications when found necessary. 



3. Dimensions of Specimens for Tension Test. — ■ 



(a) Materials \ in. or Less in Width. — -For strip or flat materials less than \ in. 

 wide, the specimen shall consist of the appropriate length cut from the material 

 as furnished. For gage lengths of 2 and 8 in., the length of the test specimen shall 

 be not less than 8 and 14 in., respectively. 



{b) Materials More Than \ in. in Width. — -For materials over h in. wide, two 

 alternative specimens are allowed. 



(i) Standard Specimen: 



The specimen which shall be regarded as standard shall have dimensions and 

 be machined as shown in Fig. 27. 



MUST BE MILLED OR 

 ^GROUND SMOOTH AND_, 

 NOT FILED. NO LAYOUT 

 MARKING ON SURFACE. 



TAPER TO 8:88l''- 



UNDERSIZE AT 

 MIDDLE WITH FINE 

 CARBORUNDUM STONE. 



: i . 



CJiO 



do 



MUST BE MILLED OR GROUND SMOOTH AND NOT FILED. 

 NO LAYOUT MARKING ON SURFACE. 



TAPER TO o^Ss'-'uNDERSIZE AT MIDDLE 



WITH FINE CARBORUNDUM STONE. V'raC 



TT 



14"- 



16-16 



Fig. 27 — Tension Test Specimens for Sheet Material Over I in. in Width. 



(a) Specimen for Use in Determining Tensile Strength and Elongation in 2 in. 



{b) Specimen for Use in Determining Proportional Limit and Modulus of Elas- 

 ticity. 



(2) Alternative Specimen: 



This specimen shall be in the form of a strip up to IJ in. in width, having parallel 

 sides and having about 0.001 to 0.002 in. of the material removed from the edges 

 of the specimen near the center by grinding with a fine-grained stone. This specimen 

 shall have the lengths given above for materials less than ^ in. wide. It may only 

 bemused so long as good breaks (which occur at the point of reduced section and 

 without tearing) are obtained and where the strength of the material does not 



