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Micro-examination, analytical, and mechanical test report on the case-hardening of steel by the nitrogen process.


Identifier  ExFiles\Box 154a\1\  scan0101
Date  10th November 1928
  
X4469
Micro-Examination, Analytical and Mechanical Test Report M626.

By. {R.W. Bailey - Chief Engineer}
c to Mr. [crossed out]
c to Mr. [crossed out]
c to Mr. [crossed out]
c to Hs. {Lord Ernest Hives - Chair}

H11/EA10.11.28. Laboratory.

RE THE CASE-HARDENING OF STEEL BY THE NITROGEN PROCESS.

A supply of a special chromium-aluminium-molybdenum steel was submitted by Messrs. Firth-Derihon. This you had machined into the following mechanical test bars :-

Seven Tensile Test Bars.
Four Stanton Test Bars.
Four Upton-Lewis Test Bars.

The material had already been fully heat-treated by Messrs. Firth-Derihon, and the finished test bars were returned to them for the final case-hardening by the nitrogen process for, we understand, a period of fifty hours. The case-hardened bars were then submitted to us again for test.

We found the analysis of the special steel to be as follows :-

Carbon --------- 0.40 %
Manganese ------ 0.52 %
Aluminium ------ 0.97 %
Chromium ------- 1.80 %
Molybdenum ----- 0.24 %
Silicon -------- 0.28 %
Sulphur -------- 0.035%
Nickel --------- Nil.
Phosphorus ----- 0.022%

The results of the mechanical tests are given below:-

Tensile Tests.

The figures in Table I were obtained on a bar tested as received from Messrs. Firth-Derihon in the first instance, that is, fully heat-treated but not case-hardened.

Table I.
Test Bar No. Ult. Stress. Yield Point. Elong. % on 2" R.A.% Brinell Hardness.
FD {Frank Dodd - Bodies} 12 60.8 51.8 22.5 58.9 285

The test figures in Table II were obtained on bars fully heat-treated and case-hardened by the nitrogen process.
Table II
  
  
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).


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