374 STKKNCTll ()K STKEL. 



195. The Compressive Strength of low carbon steel is 

 effected in the same way as is the tensile, an increase of 

 nickel meaning an increase of compressive strength, the 

 maximum being reached at about 16 per cent., beyond 

 which point the strength diminishes. Mr. Hadfield gives 

 the compressive elastic limit for a steel having 11-39 per 

 cent, nickel as 100 tons per square inch. 



196. In Shear also the same result is found to take 

 place, the maximum strength being reached with about 

 16 per cent, nickel, the shearing strength at this point 

 being about 43 tons per square inch. 



JMr. Browne gives the result of a test of a nickel steel 

 tyre, the steel being made at the Parkhead Forge in 

 Glasgow. The steel contained 0-18 per cent, carbon and 

 3 per cent, nickel, and yielded results of 24-50 tons per 

 square inch elastic limit in tension ; 38-80 tons per square 

 inch ultimate strength ; 28-7 per cent, elongation ; and 

 46 per cent reduction in area. 



Nickel steel appears to possess excellent qualities for 

 the purposes for which tool steels are used. In this case 

 the percentage of carbon is raised also. It hardens and 

 tempers well, and retains more of its ductile properties 

 under the hardening treatment than do ordinary steels, 

 and attains a remarkably high tensile strength when 

 hardened. 



Another valuable property of nickel steel is its 

 incorrodibility. Tests would appear to show that this 

 alloy resists the attacks of damp atmosphere and cor- 

 rosive fumes to a remarkable degree. 



197. Elastic Moduli for Steel The modulus of elas- 

 ticity for steel in tension and compression varies from 

 26,000,0001bs. to about 31,000,0001bs. per square inch, 

 the more usual values being between 28,000,000lbs. and 

 30,000,0001bs. per square inch. For the same material 

 the modulus in tension is, as a rule, slightly higher than 

 that in compression. That the modulus of elasticity does 



J From Browne, American Institute of Mining Engineers, California 

 Meeting, 1900. 



