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HANDBOOK OF MECHANICAL DESIGN 



CARBON-STEEL SPRING WIRE SPECIFICATIONS 



Generally used for springs of wire diameter greater than 0.262 in. and also for 

 square or rectangular wire ranging from M2 X }i2 in. up to H X H in., advancing 

 by M2 in., and for sizes larger than H X /4 in., advancing by He in. 



1. Steel Manufacture 



This steel is to be made according to approved practice by the electric-furnace or 

 open-hearth process. 



2. Chemical Composition 



Carbon 0.60-0.70 Sulphur 0.025 max. 



Manganese 0.45-0.65 Phosphorus 0.025 max. 



3. Physical Properties 



Range of wire diameter, in. 



0.1055 and under. 

 0.1205-0.1350.... 

 0.1483-0.1920.... 

 0.2070-0.2625..,. 

 0.2813-0.3438.... 

 0.3625-0.4375. . . . 

 0.4615-0.5625.... 



Minimum tensile 

 strength, lb. per sq. in. 



Ultimate 



202,000 

 191,000 

 178,000 

 165,000 

 156,000 

 147,000 

 139,000 



Elastic limit 



132,000 

 125,000 

 117,000 

 108,000 

 102,000 

 97,000 

 91,000 



Minimum torsional 

 strength, lb. per sq. in. 



Ultimate 



165,000 

 157,000 

 145,000 

 136,000 

 127,000 

 121,000 

 114,000 



Reduction of area 48 per cent minimum. Elongation in 10 in., 5 per cent 



Elastic limit 



108,000 

 103,000 

 95,000 

 89,000 

 84,000 

 79,000 

 74,000 



minimum. 



4. Surface Conditions 



Upon etching with a hot solution of hydrochloric acid sufficiently to disclose sur- 

 face defects, no seams, hairline or otherwise, pits, gouges, die marks, or other imper- 

 fections shall be revealed. Decarburization must be held to a minimum. 



5. Limits of Variation in Diameter 



Wire diameter 0.1762 in. and less — plus or minus 0.0015 in. 

 Wire diameter 0.177 in. and over — plus or minus 0.002 in. 



6. Inspection, Rejections, and Replacements 



All springs will be rigidly inspected at the plants as received. If more than a 

 total of 10 per cent of the springs on any one purchase order are made of steel that 

 fails to comply with the above specifications, or with the specifications on the detail 

 drawing, the entire lot will be rejected. All springs rejected at the plants wUl be held 

 at the seller's risk for a reasonable length of time, subject to his instructions, and shall 

 be replaced by the seller without further cost to the purchaser. 



