TRANSCRIBER’S NOTE Some minor misspellings in the text are silently corrected. Enclosed small caps in ≈double tilde≈, enclosed italics font in _underscores_, bold text in =equal sign=. The numbering of the drawings does not correspond to their marked number. However, they have been left as they are, as the author has entered them by hand in the drawings. In the table on the color of the oxide layer of tempered steel in the tempering section, the first column has been set without trailing commas, as the author has handled this inconsistently. The new original cover art included with this eBook is granted to the public domain. A FEW SECRETS OF THE METALLURGIST SIMPLY TOLD ATLAS CRUCIBLE STEEL CO. PUBLISHERS DUNKIRK, N. Y. A FEW SECRETS OF THE METALLURGIST SIMPLY TOLD BY GERALD W. HINKLEY, M. E. CORNELL UNIVERSITY ORDNANCE ENGINEER AND ASSISTANT TO PRESIDENT ATLAS CRUCIBLE STEEL CO. DUNKIRK, N. Y. FIRST EDITION COPYRIGHTED 1918 BY PRESS OF DUNKIRK PRINTING COMPANY PREFACE. This is not and is not intended to be a thoroughly complete explanation or discussion of the allotropic theory of iron and steel, but rather a brief outline of a few of the great principles of metallurgy written primarily for the layman. If without leading him astray from the real scientific understanding of the subject we have succeeded in briefly but satisfactorily answering the old familiar question, “Why do steels harden?”, we will in a large measure, have accomplished our purpose. Besides the personal observations which the writer has made from time to time in the metallurgical laboratory, he has availed himself freely of the works of many and eminent authors dealing with this subject and where disputable conditions have arisen in regard to certain theories, uses, etc., has attempted to adopt the most logical consensus of opinion. G. W. H. CONTENTS. A FEW SECRETS OF THE METALLURGIST SIMPLY TOLD. Page INTRODUCTION 17 CHAPTER I. ≈A Slight Test of the Imagination≈ 19 CHAPTER II. ≈Comparison Between Conditions Which Exist in the Iron and Steel Family to Those Which Exist with More Familiar Elements≈ 22 CHAPTER III. ≈An Experiment Performed with a Piece of Pearlitic Steel≈ 29 CHAPTER IV. ≈High Speed Steel≈ 51 CHAPTER V. ≈The General Effect of the More Important Elements in Tool Steels≈ 61 ≈Carbon Steels≈ 61 ≈Alloy Steels≈ 63 ≈High Speed Steels≈ 64 ≈Elements Which Occur in all Steels≈ 66 ≈Iron≈ 66 ≈Carbon≈ 67 ≈Manganese≈ 67 ≈Silicon≈ 68