CHAPTER I. STEEL MAKING II. COMPOSITION AND PROPERTIES OF STEELS III. ALLOYS AND THEIR EFFECT UPON STEEL IV. APPLICATION OF LIBERTY ENGINE MATERIALS TO THE AUTOMOTIVE INDUSTRY V. THE FORGING OF STEEL VI. ANNEALING VII. CASE-HARDENING OR SURFACE-CARBURIZING VIII. HEAT TREATMENT OF STEEL IX. HARDENING CARBON STEEL FOR TOOLS X. HIGH SPEED STEEL XI. FURNACES XII. PYROMETRY AND PYROMETERS APPENDIX INDEX INTRODUCTION THE ABC OF IRON AND STEEL In spite of all that has been written about iron and steel there are many hazy notions in the minds of many mechanics regarding them. It is not always clear as to just what makes the difference between iron and steel. We know that high-carbon steel makes a better cutting tool than low-carbon steel. And yet carbon alone does not make all the difference because we know that cast iron has more carbon than tool steel and yet it does not make a good cutting tool. Pig iron or cast iron has from 3 to 5 per cent carbon, while good tool steel rarely has more than 1-1/4 per cent of carbon, yet one is soft and has a coarse grain, while the other has a fine grain and can be hardened by heating and dipping in water. Most of the carbon in cast iron is in a form like graphite, which is almost pure carbon, and is therefore called graphitic carbon. The resemblance can be seen by noting how cast-iron borings blacken the hands just as does graphite, while steel turnings do not have the same effect. The difference is due to the fact that the carbon in steel is not in a graphitic form as well as because it is present in smaller quantities.